[Bob H]

Sorry all,

I have been swamped with stuff, and missed the some great discussion. I am refering to norm asking Chris why he shifted so early. Then, phantom talked about someone on the other forum saying they had a stroker and could run 7k. That is me. I don't visit the other fourm anymore, got too out of hand. Anyways, maybe I can provide some background on why you can and cannot run 7k with the stroker.
First, by increasing the stroke, you have also increased the rod angle,(the ultimate angle the rod forms with the vertical). The larger this value, the harder the piston pushes against the side of the cylinder, and not towards the bottom. To aleviate this, the longer 240 rods are used to lower the ultimate angle. Consequently, you need a different piston combo for the longer rod to keep the piston in the motor, and not hitting the cylinder head. Which is where the 88/89/90mm pistons come into play - they have a higher pin height, which lowers their position in the cylinder in relation to the rod. The larger bore also helps with some of the side-loading as well as restore a reasonable bore/stroke/rod length combo. Some of us here know of the ill fated 400 small block chevy. It was a poor motor that never acheived any fame. It had a poor stroke/bore/rod combo. You can now buy 400 small block kits that replace the rods with 6in long rods to help some of its initial probs. There is a whole lot more than just these factors involved, but I don't want to write a book just yet.

Yes, I did have my motor balanced to the Nth degree, but it didn't cost an arm and a leg, I just had a very competent shop do the job. They raced the L6 motor succesfully for a while, and were familiar with how to balance it for 7-8k rpms. Now, while mine revs to 7k, that is not where I drive it all the time,(except when I am racing, but I usually shift about 65-6700).
First, there are several reasons why the stroker kits do an do not work well in the higher rpms. The biggest reason tends to do with balancing. When you mix and match that many different parts that were designed for compeltely different applications, and don't do a near perfect job balancing, you are asking for probs, from power producing, to motor longevity. With a poor balance job, the internal harmonics of the motor begin to take over at the higher rpms and destroy the power, hence why many strokers are only good for about 5-5500 rpm. The only thing really limiting me right now is my stock balancer. It was slightly ripped to begin with,(the rubber), so it is slowly self destructing. I plan on replacing it with a Doug Fisher balancer. The only down side is they are ~$400. But they are extremely lightweight and work better than anything out there, even fluid dampeners,(which are often just heavy duty diesel units). I don't want to go into flywheels vs balancers, etc.. for the stroker, that would be a whole different post. But my motor was built for the same type of driving as Chris. I drive mine on a daily basis, as a matter of fact, I will be going home for christmas, driving 900 some odd miles in it. BTW, with my triple SK's, I get from 17-20mpg on the road. In town, it depends on how heavy my foot is, real heavy drops it below 9, but normal is 13-15.
So where does my car produce power? The peak torque is about 3100 right now, which is too low - even lower than a stock motor, I think when we were working on the chasis dyno, something was wrong, for on the engine dyno, it was peakng torque about 4400. BUt it is putting over 200 ft-lbs to the wheels. Hp is a different story. The engine dyno was about 215. But more important that that was how flat the curve was. We tried some different cams and ended up with a fairly mild one,(the Motorsport Auto 2003 cam). The went above 200 hp at about 4600 and then didn't fall below until about 6900. With the peak at only 215 or I think 218. So you can see it was incredibly flat. Like nothing my builder had seen before,(it was his first L6 stroker motor). We had some problems on the chasis dyno, and the peak hp was only 4800rpm, and didn't match the curve from the engine dyno,(I can understand a lower power, even by a lot, but the curves should be similar, and they were nowhere near the same). My carbs weren't sync'd for the chasis dyno run, and we had some probs with the timing. So I still have some potential left. With street tires, smallish 205's, some cheap brand,(I am putting a better tire/wheel combo later), only one run under my belt, and running a 2.35 60ft time, I ran 14.4 at 97mph, using only the 1st three gears. I have only made those two runs. I still have the stock 3.54 non-lsd rear end. So I spun the tires all through first, and part through second. By then I was really moving. I top out in third at about 110mph. 1-40mph 2- 70, 3 110. 4-dont know yet, don't have speed rated tires). My power band comes on about the same time as Chris stated his does,(about 3k), and really moves from there.
Above all, when I was discussing with my engine builder what I wanted, I told him these things, one, I was going to drive it all the time, and at times, my mom might even drive it, so it had to be tractable. two- I wanted it to last at least 100k miles, so no race clearances, etcc... build it to last, and lastly, be the fastest non-turbo L28 out there, besides the dedicated racers. If I can get the traction, gearing, etc.. worked out, I think it is right where I want it.
I just looked at the time. I would write more, but I need some sleep. Feel free to ask whatever you want. I don't guarentee I can answer it, that my grammer or spelling will be good, but I will try.
-Bob Hanvey
73 240 3.1
PS-here is my web site. I have been working on it off and on for about 6 months now. I still have a lot to add, but it does have good links to the other two sites that have stroker info.

 

[Phantom]

Excellent Post Bob

Thanks for filling in the gaps in my memory.
Are you running a 4-spd? If so you need to get a 5-spd and the 3.90 gears. I'm running that combination now and turn about 115 in 4th at around 6,000 RPM. No way will 3rd get me over 100. The actual off-the-line-in-first combination ratio of tranny & rear end is close to what you are running now but the gearing is closer together, 3rd & 4th in the tranny are the same as you have now so the 3.90 gives you a lower combination for more accelleration and the OD will help the mpg when cruising. I can really feel the difference even with my totally stock L28.
Phantom

 

[Bob H]

Re: Excellent Post Bob

> Thanks for filling in the gaps in my memory.
> Are you running a 4-spd? If so you need to
> get a 5-spd and the 3.90 gears. I'm running
> that combination now and turn about 115 in
> 4th at around 6,000 RPM. No way will 3rd get
> me over 100. The actual
> off-the-line-in-first combination ratio of
> tranny & rear end is close to what you
> are running now but the gearing is closer
> together, 3rd & 4th in the tranny are
> the same as you have now so the 3.90 gives
> you a lower combination for more
> accelleration and the OD will help the mpg
> when cruising. I can really feel the
> difference even with my totally stock L28.
> Phantom

No, I am not running the 4 speed. I have an 83 ZX 5 speed. The one with the .74 overdrive. I am still searching for the 3.9 or 4.11. If I could find one that had the same speed ratios you have, ie ~115 max in 4th, I would likely get to low 13's in the 1/4. But that depends on so many things. I imagine that traction would continue to be a problem. Maybe in the next few weeks I can locate the 3.9. I have wanted to try out a R-160 LSD from a subaru. I want to run it till it breaks.
-Bob Hanvey

 

[Phantom]

Re: Excellent Post Bob

Bob,
If you have trouble in your area - call Jerry at All Z Car Specialist in Fort Worth, TX. (817) 483-0383.
I know I sound like a broken record but he can take care of your needs - and he'll make sure it's a good unit - not just any old high mileage differential laying around in his yard. I've done business with him for years and he is always my first call.
Phantom.

 

[240Dave]

Yes, my point exactly, very good post!!

> Sorry all,

> I have been swamped with stuff, and missed
> the some great discussion. I am refering to
> norm asking Chris why he shifted so early.
> Then, phantom talked about someone on the
> other forum saying they had a
> stroker and could run 7k. That is me. I
> don't visit the other fourm anymore, got too
> out of hand. Anyways, maybe I can provide
> some background on why you can and cannot
> run 7k with the stroker.
> First, by increasing the stroke, you have
> also increased the rod angle,(the ultimate
> angle the rod forms with the vertical). The
> larger this value, the harder the piston
> pushes against the side of the cylinder, and
> not towards the bottom. To aleviate this,
> the longer 240 rods are used to lower the
> ultimate angle. Consequently, you need a
> different piston combo for the longer rod to
> keep the piston in the motor, and not
> hitting the cylinder head. Which is where
> the 88/89/90mm pistons come into play - they
> have a higher pin height, which lowers their
> position in the cylinder in relation to the
> rod. The larger bore also helps with some of
> the side-loading as well as restore a
> reasonable bore/stroke/rod length combo.
> Some of us here know of the ill fated 400
> small block chevy. It was a poor motor that
> never acheived any fame. It had a poor
> stroke/bore/rod combo. You can now buy 400
> small block kits that replace the rods with
> 6in long rods to help some of its initial
> probs. There is a whole lot more than just
> these factors involved, but I don't want to
> write a book just yet.

> Yes, I did have my motor balanced to the Nth
> degree, but it didn't cost an arm and a leg,
> I just had a very competent shop do the job.
> They raced the L6 motor succesfully for a
> while, and were familiar with how to balance
> it for 7-8k rpms. Now, while mine revs to
> 7k, that is not where I drive it all the
> time,(except when I am racing, but I usually
> shift about 65-6700).
> First, there are several reasons why the
> stroker kits do an do not work well in the
> higher rpms. The biggest reason tends to do
> with balancing. When you mix and match that
> many different parts that were designed for
> compeltely different applications, and don't
> do a near perfect job balancing, you are
> asking for probs, from power producing, to
> motor longevity. With a poor balance job,
> the internal harmonics of the motor begin to
> take over at the higher rpms and destroy the
> power, hence why many strokers are only good
> for about 5-5500 rpm. The only thing really
> limiting me right now is my stock balancer.
> It was slightly ripped to begin with,(the
> rubber), so it is slowly self destructing. I
> plan on replacing it with a Doug Fisher
> balancer. The only down side is they are
> ~$400. But they are extremely lightweight
> and work better than anything out there,
> even fluid dampeners,(which are often just
> heavy duty diesel units). I don't want to go
> into flywheels vs balancers, etc.. for the
> stroker, that would be a whole different
> post. But my motor was built for the same
> type of driving as Chris. I drive mine on a
> daily basis, as a matter of fact, I will be
> going home for christmas, driving 900 some
> odd miles in it. BTW, with my triple SK's, I
> get from 17-20mpg on the road. In town, it
> depends on how heavy my foot is, real heavy
> drops it below 9, but normal is 13-15.
> So where does my car produce power? The peak
> torque is about 3100 right now, which is too
> low - even lower than a stock motor, I think
> when we were working on the chasis dyno,
> something was wrong, for on the engine dyno,
> it was peakng torque about 4400. BUt it is
> putting over 200 ft-lbs to the wheels. Hp is
> a different story. The engine dyno was about
> 215. But more important that that was how
> flat the curve was. We tried some different
> cams and ended up with a fairly mild
> one,(the Motorsport Auto 2003 cam). The went
> above 200 hp at about 4600 and then didn't
> fall below until about 6900. With the peak
> at only 215 or I think 218. So you can see
> it was incredibly flat. Like nothing my
> builder had seen before,(it was his first L6
> stroker motor). We had some problems on the
> chasis dyno, and the peak hp was only
> 4800rpm, and didn't match the curve from the
> engine dyno,(I can understand a lower power,
> even by a lot, but the curves should be
> similar, and they were nowhere near the
> same). My carbs weren't sync'd for the
> chasis dyno run, and we had some probs with
> the timing. So I still have some potential
> left. With street tires, smallish 205's,
> some cheap brand,(I am putting a better
> tire/wheel combo later), only one run under
> my belt, and running a 2.35 60ft time, I ran
> 14.4 at 97mph, using only the 1st three
> gears. I have only made those two runs. I
> still have the stock 3.54 non-lsd rear end.
> So I spun the tires all through first, and
> part through second. By then I was really
> moving. I top out in third at about 110mph.
> 1-40mph 2- 70, 3 110. 4-dont know yet, don't
> have speed rated tires). My power band comes
> on about the same time as Chris stated his
> does,(about 3k), and really moves from
> there.
> Above all, when I was discussing with my
> engine builder what I wanted, I told him
> these things, one, I was going to drive it
> all the time, and at times, my mom might
> even drive it, so it had to be tractable.
> two- I wanted it to last at least 100k
> miles, so no race clearances, etcc... build
> it to last, and lastly, be the fastest
> non-turbo L28 out there, besides the
> dedicated racers. If I can get the traction,
> gearing, etc.. worked out, I think it is
> right where I want it.
> I just looked at the time. I would write
> more, but I need some sleep. Feel free to
> ask whatever you want. I don't guarentee I
> can answer it, that my grammer or spelling
> will be good, but I will try.
> -Bob Hanvey
> 73 240 3.1
> PS-here is my web site. I have been working
> on it off and on for about 6 months now. I
> still have a lot to add, but it does have
> good links to the other two sites that have
> stroker info.

This is why I questioned Chris stating that he had more power available up top. These strokers tend to have a strong, but flat torque curve. A modified L28, will tend to peak a little later than the 3.1L, which makes 6500-7000 a more reasonable shift point, compared to a 'typical' stroker at 5500-6000. But, like Bob said, the stroker doesn't need to go that high, and it is almost pointless to do so, unless you get a serious cam. Remember a 3.1L stroker is injesting quite a bit of fuel/air at 7000 rpm!
Excellent post Bob, couldn't have said it better myslef.

 

[Chris Behney]

Balancing

> Sorry all,

> I have been swamped with stuff, and missed
> the some great discussion. I am refering to
> norm asking Chris why he shifted so early.
> Then, phantom talked about someone on the
> other forum saying they had a
> stroker and could run 7k. That is me. I
> don't visit the other fourm anymore, got too
> out of hand. Anyways, maybe I can provide
> some background on why you can and cannot
> run 7k with the stroker.
> First, by increasing the stroke, you have
> also increased the rod angle,(the ultimate
> angle the rod forms with the vertical). The
> larger this value, the harder the piston
> pushes against the side of the cylinder, and
> not towards the bottom. To aleviate this,
> the longer 240 rods are used to lower the
> ultimate angle. Consequently, you need a
> different piston combo for the longer rod to
> keep the piston in the motor, and not
> hitting the cylinder head. Which is where
> the 88/89/90mm pistons come into play - they
> have a higher pin height, which lowers their
> position in the cylinder in relation to the
> rod. The larger bore also helps with some of
> the side-loading as well as restore a
> reasonable bore/stroke/rod length combo.
> Some of us here know of the ill fated 400
> small block chevy. It was a poor motor that
> never acheived any fame. It had a poor
> stroke/bore/rod combo. You can now buy 400
> small block kits that replace the rods with
> 6in long rods to help some of its initial
> probs. There is a whole lot more than just
> these factors involved, but I don't want to
> write a book just yet.

> Yes, I did have my motor balanced to the Nth
> degree, but it didn't cost an arm and a leg,
> I just had a very competent shop do the job.
> They raced the L6 motor succesfully for a
> while, and were familiar with how to balance
> it for 7-8k rpms. Now, while mine revs to
> 7k, that is not where I drive it all the
> time,(except when I am racing, but I usually
> shift about 65-6700).
> First, there are several reasons why the
> stroker kits do an do not work well in the
> higher rpms. The biggest reason tends to do
> with balancing. When you mix and match that
> many different parts that were designed for
> compeltely different applications, and don't
> do a near perfect job balancing, you are
> asking for probs, from power producing, to
> motor longevity. With a poor balance job,
> the internal harmonics of the motor begin to
> take over at the higher rpms and destroy the
> power, hence why many strokers are only good
> for about 5-5500 rpm. The only thing really
> limiting me right now is my stock balancer.
> It was slightly ripped to begin with,(the
> rubber), so it is slowly self destructing. I
> plan on replacing it with a Doug Fisher
> balancer. The only down side is they are
> ~$400. But they are extremely lightweight
> and work better than anything out there,
> even fluid dampeners,(which are often just
> heavy duty diesel units). I don't want to go
> into flywheels vs balancers, etc.. for the
> stroker, that would be a whole different
> post. But my motor was built for the same
> type of driving as Chris. I drive mine on a
> daily basis, as a matter of fact, I will be
> going home for christmas, driving 900 some
> odd miles in it. BTW, with my triple SK's, I
> get from 17-20mpg on the road. In town, it
> depends on how heavy my foot is, real heavy
> drops it below 9, but normal is 13-15.
> So where does my car produce power? The peak
> torque is about 3100 right now, which is too
> low - even lower than a stock motor, I think
> when we were working on the chasis dyno,
> something was wrong, for on the engine dyno,
> it was peakng torque about 4400. BUt it is
> putting over 200 ft-lbs to the wheels. Hp is
> a different story. The engine dyno was about
> 215. But more important that that was how
> flat the curve was. We tried some different
> cams and ended up with a fairly mild
> one,(the Motorsport Auto 2003 cam). The went
> above 200 hp at about 4600 and then didn't
> fall below until about 6900. With the peak
> at only 215 or I think 218. So you can see
> it was incredibly flat. Like nothing my
> builder had seen before,(it was his first L6
> stroker motor). We had some problems on the
> chasis dyno, and the peak hp was only
> 4800rpm, and didn't match the curve from the
> engine dyno,(I can understand a lower power,
> even by a lot, but the curves should be
> similar, and they were nowhere near the
> same). My carbs weren't sync'd for the
> chasis dyno run, and we had some probs with
> the timing. So I still have some potential
> left. With street tires, smallish 205's,
> some cheap brand,(I am putting a better
> tire/wheel combo later), only one run under
> my belt, and running a 2.35 60ft time, I ran
> 14.4 at 97mph, using only the 1st three
> gears. I have only made those two runs. I
> still have the stock 3.54 non-lsd rear end.
> So I spun the tires all through first, and
> part through second. By then I was really
> moving. I top out in third at about 110mph.
> 1-40mph 2- 70, 3 110. 4-dont know yet, don't
> have speed rated tires). My power band comes
> on about the same time as Chris stated his
> does,(about 3k), and really moves from
> there.
> Above all, when I was discussing with my
> engine builder what I wanted, I told him
> these things, one, I was going to drive it
> all the time, and at times, my mom might
> even drive it, so it had to be tractable.
> two- I wanted it to last at least 100k
> miles, so no race clearances, etcc... build
> it to last, and lastly, be the fastest
> non-turbo L28 out there, besides the
> dedicated racers. If I can get the traction,
> gearing, etc.. worked out, I think it is
> right where I want it.
> I just looked at the time. I would write
> more, but I need some sleep. Feel free to
> ask whatever you want. I don't guarentee I
> can answer it, that my grammer or spelling
> will be good, but I will try.
> -Bob Hanvey
> 73 240 3.1
> PS-here is my web site. I have been working
> on it off and on for about 6 months now. I
> still have a lot to add, but it does have
> good links to the other two sites that have
> stroker info.

Apparently, balancing makes a lot of diffrence in the rpm range of the engines. That may be the biggest diffremece between our engines. I have a few questions though.

What was the benifet of building your engine capable of 7000rpm, if the torque curve falls so early. Is it just that your still working on it? Will the torque curve be difffrent, when you tune the engine? I just don't understand the benifet of making 2000 more rpm available to you if you can't climb through them faster than you can climb through the lower rpm, in the next gear. From my experience, as a serious driver,(over 200 1/4 mile passes made in varioius cars), it seems a waste to build the engine so that you have to up-shift to get back into the powerband.

Like you have probally read, I'm not a number cruncher, but I am a driver. The technical numbers, just don't tell me a lot about a car. Seeing it move, and actually driving are what i go by. So, from a drivers stand point, what is the benifet of a having 2000 more rpm, if they don't pull the car down the track fast enough to benifit you?

What are your shift points, when you run a quarter?

I'll tell you somwthig you probally already know. . .The limited slip diff, will make you a very happy camper! My times and traction are so much better than the cars that are built similiar to mine, that the owners don't have it. I had the rear end replaced in mine, and I have convinced several other Z owners in the area to do the same, after they raced me.

Did you say that your engine is carbed? I think this may have a little to do with the diffrence in our powerbands also. I have a fuel injected car, with large injectors and HUGE fuel rails. From what's been told to me, I understand that the carbed engines like the higher rpm more than the FI engines. Is this correct, or not?

I'm trying to get the hang of this technical stuff, but like i said, I'm a driver not a mechanic.

Thanks for your help.

Chris Behney
Redline Autosports

 

[240Dave]

Shift points explained.. I hope!

Balancing a straight six is the key to high rpm and longevity. 7 main bearings are great, but that is one long crankshaft to be spinning at 7K. I had mine done with flywheel and pulley for @$100 (dynamic balancing). Static balancing of all the rods and pistons was also included in the $100. Very smooth revving engine.

> What was the benifet of building your engine
> capable of 7000rpm, if the torque curve
> falls so early. Is it just that your still
> working on it? Will the torque curve be
> difffrent, when you tune the engine? I just
> don't understand the benifet of making 2000
> more rpm available to you if you can't climb
> through them faster than you can climb
> through the lower rpm, in the next gear.
> From my experience, as a serious
> driver,(over 200 1/4 mile passes made in
> varioius cars), it seems a waste to build
> the engine so that you have to up-shift to
> get back into the powerband.

What we are talking about is a torque curve. As everybody knows, when you shift, your rpm drops. What you want is to shift at a high enough point so that your rpm in the next gear doesn't drop below the torque peak. Essentially, you want to shift at the right point to stay in the powerband through all the gears. So, if the powerband peak is from 4000-6000, then maybe shifting a little above 6000 may drop the rpm to a little above 4000, which is just right. However, shifting at 5500 may drop you BELOW the desired torque curve, and your acceleration will suffer. There is more to performance, than just bolting on different parts. There is a formula to determine shift points, and will help you determine the best ratio rear end/tranny/shift point etc....These are some of the reasons I'm a 'number cruncher'.
The shift point formula:
(You need to know your torque curve from a dyno to do this.)
Say you're torque curve is farily flat from 4000-5500 @210ft/lbs and falls to 200ft/lbs @6000. Therefore you don't want to drop below 4000 rpm, because you'll be below the peak torque.

Gear torque = gear ratio x torque(at desired max rpm)
Next gear rpm = rpm1 (gear2/gear1)

1st gear = 3.321 x 200 = 664.2ft/lbs
2nd gear rpm = 6000 (2.077/3.321) = 3752rpm

So for shifting at 6000 we get 664.2ft/lbs in 1st gear, and drops us to 3752 rpm in second. This puts us BELOW our desired torque curve, therefore we need to shift higher. Even though torque drops off after 5500, we still need more rpms to stay in the torque curve. So, lets try with 6500rpm.

2nd gear rpm2 = 6500 (2.077/3.321) = 4065
This puts us right in the beginning of our torque curve, very nice. Just for the sake of argument, let's try 7000rpm.

2nd gear rpm3 = 7000 (2.077/3.321) = 4378rpm
A little high, we missed some early useable torque.

So, with the math, we can see the benefit of a higher rpm, even though there is no more power available. This is why NISMO offers close ratio trannys, so you don't have to shift so high. I wonder how a close-ratio tranny with the 3.1L would accelerate. I'm sure it would be faster than what it is now, and would eliminate need for above 6500rpm shifting.

> Like you have probally read, I'm not a
> number cruncher, but I am a driver. The
> technical numbers, just don't tell me a lot
> about a car. Seeing it move, and actually
> driving are what i go by. So, from a drivers
> stand point, what is the benifet of a having
> 2000 more rpm, if they don't pull the car
> down the track fast enough to benifit you?

Driving is one thing, technical numbers offer a definitive answer, rather than a 'seat of your pants' observation. What if people raced without posting mph and time?? I could say my car was faster than yours, but by how much?? We need numbers to provide quantatative answers. Hopefully this post offers a explanation to you as to why higher rpm's may be necessary.

> What are your shift points, when you run a
> quarter?

I'm curious as well now.

> I'll tell you somwthig you probally already
> know. . .The limited slip diff, will make
> you a very happy camper! My times and
> traction are so much better than the cars
> that are built similiar to mine, that the
> owners don't have it. I had the rear end
> replaced in mine, and I have convinced
> several other Z owners in the area to do the
> same, after they raced me.

I'm looking for one. They definetely help put more power to the ground, especially with all the torque these 3.1L can produce.

> Did you say that your engine is carbed? I
> think this may have a little to do with the
> diffrence in our powerbands also. I have a
> fuel injected car, with large injectors and
> HUGE fuel rails. From what's been told to
> me, I understand that the carbed engines
> like the higher rpm more than the FI
> engines. Is this correct, or not?

Yes and no. The reason is that they are individual runners and have seperate butterflies for each cylinder. This enables more air and less restriction. Each cylinder is dependent on it's own carb, not the entire intake. i.e. There is no restriction as with a single TB. This is why some people can 'overcarb' their engine. It is just too much air, and not enough velocity to draw the fuel out of the carb. A fuel injection system with seperate runners and butterfly valves can provide just as much air as individual carbs.

> I'm trying to get the hang of this
> technical stuff, but like i
> said, I'm a driver not a mechanic.

Hope this provides some answers to your questions.

240Dave

 

[Phantom]

Re: Shift points explained.. I hope!

> What we are talking about is a torque curve.
> As everybody knows, when you shift, your rpm
> drops. What you want is to shift at a high
> enough point so that your rpm in the next
> gear doesn't drop below the torque peak.
> Essentially, you want to shift at the right
> point to stay in the powerband through all
> the gears. So, if the powerband peak is from
> 4000-6000, then maybe shifting a little
> above 6000 may drop the rpm to a little
> above 4000, which is just right. However,
> shifting at 5500 may drop you BELOW the
> desired torque curve, and your acceleration
> will suffer. There is more to performance,
> than just bolting on different parts. There
> is a formula to determine shift points, and
> will help you determine the best ratio rear
> end/tranny/shift point etc....These are some
> of the reasons I'm a 'number cruncher'.
> The shift point formula:
> (You need to know your torque curve from a
> dyno to do this.)
> Say you're torque curve is farily flat from
> 4000-5500 @210ft/lbs and falls to 200ft/lbs
> @6000. Therefore you don't want to drop
> below 4000 rpm, because you'll be below the
> peak torque.

> Gear torque = gear ratio x torque(at desired
> max rpm)
> Next gear rpm = rpm1 (gear2/gear1)

> 1st gear = 3.321 x 200 = 664.2ft/lbs
> 2nd gear rpm = 6000 (2.077/3.321) = 3752rpm

> 240Dave

I understand Dave. You did a good job with the numbers as examples. Most people don't understand that torque = accelleration and HP = top speed.
I know the HP drops off on my stock L28 around 5,500 RPM so have never pushed it past that until last week. No additional boost between 5,500 & 6,000 but boy did the next gear come on strong when I shifted!!
Phantom

 

[Ken Hawkins]

> Sorry all,

> I have been swamped with stuff, and missed
> the some great discussion. I am refering to
> norm asking Chris why he shifted so early.
> Then, phantom talked about someone on the
> other forum saying they had a
> stroker and could run 7k. That is me. I
> don't visit the other fourm anymore, got too
> out of hand. Anyways, maybe I can provide
> some background on why you can and cannot
> run 7k with the stroker.
> First, by increasing the stroke, you have
> also increased the rod angle,(the ultimate
> angle the rod forms with the vertical). The
> larger this value, the harder the piston
> pushes against the side of the cylinder, and
> not towards the bottom. To aleviate this,
> the longer 240 rods are used to lower the
> ultimate angle. Consequently, you need a
> different piston combo for the longer rod to
> keep the piston in the motor, and not
> hitting the cylinder head. Which is where
> the 88/89/90mm pistons come into play - they
> have a higher pin height, which lowers their
> position in the cylinder in relation to the
> rod. The larger bore also helps with some of
> the side-loading as well as restore a
> reasonable bore/stroke/rod length combo.
> Some of us here know of the ill fated 400
> small block chevy. It was a poor motor that
> never acheived any fame. It had a poor
> stroke/bore/rod combo. You can now buy 400
> small block kits that replace the rods with
> 6in long rods to help some of its initial
> probs. There is a whole lot more than just
> these factors involved, but I don't want to
> write a book just yet.

> Yes, I did have my motor balanced to the Nth
> degree, but it didn't cost an arm and a leg,
> I just had a very competent shop do the job.
> They raced the L6 motor succesfully for a
> while, and were familiar with how to balance
> it for 7-8k rpms. Now, while mine revs to
> 7k, that is not where I drive it all the
> time,(except when I am racing, but I usually
> shift about 65-6700).
> First, there are several reasons why the
> stroker kits do an do not work well in the
> higher rpms. The biggest reason tends to do
> with balancing. When you mix and match that
> many different parts that were designed for
> compeltely different applications, and don't
> do a near perfect job balancing, you are
> asking for probs, from power producing, to
> motor longevity. With a poor balance job,
> the internal harmonics of the motor begin to
> take over at the higher rpms and destroy the
> power, hence why many strokers are only good
> for about 5-5500 rpm. The only thing really
> limiting me right now is my stock balancer.
> It was slightly ripped to begin with,(the
> rubber), so it is slowly self destructing. I
> plan on replacing it with a Doug Fisher
> balancer. The only down side is they are
> ~$400. But they are extremely lightweight
> and work better than anything out there,
> even fluid dampeners,(which are often just
> heavy duty diesel units). I don't want to go
> into flywheels vs balancers, etc.. for the
> stroker, that would be a whole different
> post. But my motor was built for the same
> type of driving as Chris. I drive mine on a
> daily basis, as a matter of fact, I will be
> going home for christmas, driving 900 some
> odd miles in it. BTW, with my triple SK's, I
> get from 17-20mpg on the road. In town, it
> depends on how heavy my foot is, real heavy
> drops it below 9, but normal is 13-15.
> So where does my car produce power? The peak
> torque is about 3100 right now, which is too
> low - even lower than a stock motor, I think
> when we were working on the chasis dyno,
> something was wrong, for on the engine dyno,
> it was peakng torque about 4400. BUt it is
> putting over 200 ft-lbs to the wheels. Hp is
> a different story. The engine dyno was about
> 215. But more important that that was how
> flat the curve was. We tried some different
> cams and ended up with a fairly mild
> one,(the Motorsport Auto 2003 cam). The went
> above 200 hp at about 4600 and then didn't
> fall below until about 6900. With the peak
> at only 215 or I think 218. So you can see
> it was incredibly flat. Like nothing my
> builder had seen before,(it was his first L6
> stroker motor). We had some problems on the
> chasis dyno, and the peak hp was only
> 4800rpm, and didn't match the curve from the
> engine dyno,(I can understand a lower power,
> even by a lot, but the curves should be
> similar, and they were nowhere near the
> same). My carbs weren't sync'd for the
> chasis dyno run, and we had some probs with
> the timing. So I still have some potential
> left. With street tires, smallish 205's,
> some cheap brand,(I am putting a better
> tire/wheel combo later), only one run under
> my belt, and running a 2.35 60ft time, I ran
> 14.4 at 97mph, using only the 1st three
> gears. I have only made those two runs. I
> still have the stock 3.54 non-lsd rear end.
> So I spun the tires all through first, and
> part through second. By then I was really
> moving. I top out in third at about 110mph.
> 1-40mph 2- 70, 3 110. 4-dont know yet, don't
> have speed rated tires). My power band comes
> on about the same time as Chris stated his
> does,(about 3k), and really moves from
> there.
> Above all, when I was discussing with my
> engine builder what I wanted, I told him
> these things, one, I was going to drive it
> all the time, and at times, my mom might
> even drive it, so it had to be tractable.
> two- I wanted it to last at least 100k
> miles, so no race clearances, etcc... build
> it to last, and lastly, be the fastest
> non-turbo L28 out there, besides the
> dedicated racers. If I can get the traction,
> gearing, etc.. worked out, I think it is
> right where I want it.
> I just looked at the time. I would write
> more, but I need some sleep. Feel free to
> ask whatever you want. I don't guarentee I
> can answer it, that my grammer or spelling
> will be good, but I will try.
> -Bob Hanvey
> 73 240 3.1
> PS-here is my web site. I have been working
> on it off and on for about 6 months now. I
> still have a lot to add, but it does have
> good links to the other two sites that have
> stroker info.

Very good post...but I must add some personal experience as it relates to the 400 Small block.

Ill fated....not accurate. There are good parts to be had...listen up you guys that like to put V-8s in your Z's

I have personally built a small block with the short 400 rods (5.565 vs 5.7) and the 3.48 (350 crank) with the taller pistons from the 327. A miricle it is not that compression height works out perfect, and the piston comes to the top just like it should.

This combination lowers the number referred to as rod ratio, which will decrease the engines ability to breathe at very high RPMs. Flip side is...what ever you take from the top you put on the bottom (suppose to be anyway if you do it right) That's right all you torque hungry folks, this sucker will pull like a big block. My version would spin (chevy here now) 7500 to 8000 no prob. I have seen it up to 8200 and it was still pulling!!!!! Although the pucker in the seat was pronounced seeing the revs this high, it stayed together.

In a nut shell longer rods are not the end all be all. Take into account what you want, and build an engine to do that. Each combo does something well, exploit that and you have a winner. Anyone want more specifics on this stump pullin small block I will tell [email protected]

Ken

 

[norm]

Re:what about a junkyard dog 3.1?

> Very good post...but I must add some
> personal experience as it relates to the 400
> Small block.

> Ill fated....not accurate. There are good
> parts to be had...listen up you guys that
> like to put V-8s in your Z's

> I have personally built a small block with
> the short 400 rods (5.565 vs 5.7) and the
> 3.48 (350 crank) with the taller pistons
> from the 327. A miricle it is not that
> compression height works out perfect, and
> the piston comes to the top just like it
> should.

> This combination lowers the number referred
> to as rod ratio, which will decrease the
> engines ability to breathe at very high
> RPMs. Flip side is...what ever you take from
> the top you put on the bottom (suppose to be
> anyway if you do it right) That's right all
> you torque hungry folks, this sucker will
> pull like a big block. My version would spin
> (chevy here now) 7500 to 8000 no prob. I
> have seen it up to 8200 and it was still
> pulling!!!!! Although the pucker in the seat
> was pronounced seeing the revs this high, it
> stayed together.

> In a nut shell longer rods are not the end
> all be all. Take into account what you want,
> and build an engine to do that. Each combo
> does something well, exploit that and you
> have a winner. Anyone want more specifics on
> this stump pullin small block I will tell
> [email protected]

> Ken

I emailed Bob today about my plans to do a junkyard dog 3.1.This is the deal ,when I broke my crank on my 2.8 i got some main bearing cap walk which left #5 main bearing cap fitting looser than the other 6 caps.However the rings rods and pistons are in great shape and motor used no oil at time of crank breakage.However I really dont want to reuse block due to loose fit of cap.Now the second part is this, the maxima diesel that i got two weeks ago turned out to have a broken rod caused by idiot not changing oil resulting in rod journal to big end seizure.So this crank has a pretty bad lookin journal( I think I can sand it smooth enough to work with bearing again but it will probably be a little loose) and could possibly be cracked internally.The car ran but vibrated badly ,I was hoping diesel injectors were really screwed up but i wasnt so lucky! SO now I have two junk parts that look like they will end up together .I am hoping to shave pistons .040 on top to avoid hitting valves or head if this isnt enough i will put a 2 mm gasket which will lower compression to maybe arond 10.4:1 I figure about 11.5:1 with 1.2 mm gasket. Math may be off i havent figured exact compression yet.Anyway the biggest hurdle will be sanding down wear lip at top of block to be even with rest of bore so that rings wont flutter wildly.also the piston ring lands may break first time I run engine that would really suck if they did and damaged my modified head.The last post has encouraged me that the 1.5 rod to stroke ratio will work.I figure I can do this for less than $100 and if it blows up at first run then we will all know what to never try again.If anyone has already tried this and failed, please tell me so i wont waste 2 days changing engine over..After seeing bob's([email protected]) 1/4 mile time vs my 2.8 block([email protected]) I dont know if i want to spend 3-4 thousand $$$ on a 3.1 and end up being slower than a a stock $150 2.8 block?( no offense intended bob)You dudes respond and tell me either if you like this idea or think its the stupidest thing you have ever heard someone suggest???? Thanks norm

 

[norm]

Please take 3.1 junkyard dog survey at index top

> I emailed Bob today about my plans to do a
> junkyard dog 3.1.This is the deal ,when I
> broke my crank on my 2.8 i got some main
> bearing cap walk which left #5 main bearing
> cap fitting looser than the other 6
> caps.However the rings rods and pistons are
> in great shape and motor used no oil at time
> of crank breakage.However I really dont want
> to reuse block due to loose fit of cap.Now
> the second part is this, the maxima diesel
> that i got two weeks ago turned out to have
> a broken rod caused by idiot not changing
> oil resulting in rod journal to big end
> seizure.So this crank has a pretty bad
> lookin journal( I think I can sand it smooth
> enough to work with bearing again but it
> will probably be a little loose) and could
> possibly be cracked internally.The car ran
> but vibrated badly ,I was hoping diesel
> injectors were really screwed up but i wasnt
> so lucky! SO now I have two junk parts that
> look like they will end up together .I am
> hoping to shave pistons .040 on top to avoid
> hitting valves or head if this isnt enough i
> will put a 2 mm gasket which will lower
> compression to maybe arond 10.4:1 I figure
> about 11.5:1 with 1.2 mm gasket. Math may be
> off i havent figured exact compression
> yet.Anyway the biggest hurdle will be
> sanding down wear lip at top of block to be
> even with rest of bore so that rings wont
> flutter wildly.also the piston ring lands
> may break first time I run engine that would
> really suck if they did and damaged my
> modified head.The last post has encouraged
> me that the 1.5 rod to stroke ratio will
> work.I figure I can do this for less than
> $100 and if it blows up at first run then we
> will all know what to never try again.If
> anyone has already tried this and failed,
> please tell me so i wont waste 2 days
> changing engine over..After seeing
> bob's([email protected]) 1/4 mile time vs my 2.8
> block([email protected]) I dont know if i want to
> spend 3-4 thousand $$$ on a 3.1 and end up
> being slower than a a stock $150 2.8 block?(
> no offense intended bob)You dudes respond
> and tell me either if you like this idea or
> think its the stupidest thing you have ever
> heard someone suggest???? Thanks norm

 

[norm]

OOPS I mean 2.9 junkyard dog

> Very good post...but I must add some
> personal experience as it relates to the 400
> Small block.

> Ill fated....not accurate. There are good
> parts to be had...listen up you guys that
> like to put V-8s in your Z's

> I have personally built a small block with
> the short 400 rods (5.565 vs 5.7) and the
> 3.48 (350 crank) with the taller pistons
> from the 327. A miricle it is not that
> compression height works out perfect, and
> the piston comes to the top just like it
> should.

> This combination lowers the number referred
> to as rod ratio, which will decrease the
> engines ability to breathe at very high
> RPMs. Flip side is...what ever you take from
> the top you put on the bottom (suppose to be
> anyway if you do it right) That's right all
> you torque hungry folks, this sucker will
> pull like a big block. My version would spin
> (chevy here now) 7500 to 8000 no prob. I
> have seen it up to 8200 and it was still
> pulling!!!!! Although the pucker in the seat
> was pronounced seeing the revs this high, it
> stayed together.

> In a nut shell longer rods are not the end
> all be all. Take into account what you want,
> and build an engine to do that. Each combo
> does something well, exploit that and you
> have a winner. Anyone want more specifics on
> this stump pullin small block I will tell
> [email protected]

> Ken

 

[Bob H]

> Ill fated....not accurate. There are good
> parts to be had...listen up you guys that
> like to put V-8s in your Z's

Ken,
I couldn't agree more. You can make the 400 a great engine, but it usually involves changing some of the internals to different dimensions.

Now, on to the other questions. First, norm, my 14.4 at 97 was only my second ever 1/4 run. That car has a whole lot more potential in it. If I ran slicks,(or at least stickier tires), a LSD, w/ at least a 3.9, vice the3.54 I have now, and power shifted it,(which I have no intention of doing, it puts too much stress on not only the transmission, but thrusts the crank forward each time, causing lots of for/aft stress on the bearings,(hence your broken crank). I would imagine I could run at least the same as you, if not faster, for our trap speeds are very close, so that means you are launching much harder. What are your 60 ft times? i would guess 1.7-1.9. One day, I may do a powershift run, just to see how it does, but only after I seem to have maxed the 1/4 time. Again, my car was built for daily driving and autocross, not drags. But I digress.
So back to your questions Chris. First, our power bands are not 2000 rpm off, but mine may spread 1000 rpm higher. Remember, both my torque and hp curves were extremely flat. It was when I took the engine apart,(rather, the intake, exhaust, to take it off the dyno, and put it in the car), The linkages for the carbs were changed, and they are no longer syncronized. That coupled with some minor details, the power had some funny characteristics on the chasis dyno. Interestingly enough, the reverse hp check showed an extremely low drivetrain loss of 11hp. We checked it a few times, and it was right. That was all new synthetic fluids front to rear. It was close, but lower than other Z's he had checked. One problem I was encountering that is mostly fixed now, is my front differential mount was broken,(too much torque). So under power, the nose of the diff would lift up, against the retaining strap. that caused some odd angles in the drivetrain, and that was accounting for some loss under power,(for when coasting, ie the reverse hp check, or drivetrain loss), the nose of the diff would come back down, and the driveshaft would be aligned. I have recently put the solid diff mount in, and it made a very noticable difference. now, with any quick shift, the tires chirp. With a really fast full power shift, they break loose big time, where before, the diff would wind up and take most of that power. So I expect to be in the 13's from just that. So until I can get the strange losses of power and the differences in power curves from the engine dyno, we can't really evaluate what my engine can do and compare it to others.
So what are my shift points? I don't honestly know, for I haven't had a tach hooked up since I got it running. I have a Crane Hi-6 igntion unit,and it is not compatible with the 240 tach, and I just haven't bought the adapter, or got a 280 tach to work. no time. I think it is about 68-6900. Right about where the really strong pulling stops. I have the built in rev limiter set at 7200. I have run into it a few times, and I know the rpms fairly well. Like I said, I have only made a few 1/4 mi runs, so I can't tell you about that until I get some things sorted out with the car.
I do have a comparison, though. Bryan Little, who has the web page The Datsun Garage,(which is an excellent page btw), has a fairly consistent check to see what performance gains the things he has done are doing. He puts it in third, and hammers it, then times from 70-90mph. It is much eaiser to repeat and be consistent than 0-60. Anyways, he was getting 4.5 and higher before he did this head mod that brought his compression up above 9.5:1. And he has a good motor. But after, he was getting consistent 3.9's to 4.1. And I think he ran about 14.5/[email protected]/6 mph. So it is near what I have now. The same 70-90 test in mine is almost a second faster, about 3.1-3.2sec. That should give some idea of what is there with the stroker, for that is mostly the difference in my stroke/displacement, for he has many things like mine,(except he has well tuned dual SU's).
So what is the advantage of having all the hp up top, but the torque down low? again, you are mixing up the dyno run with the chasis dyno run. But lets say they were that way. While torque = acceleration, it is not the end all be all. Think of formula 1 cars. They have very little torque where they are running,(10000 rpm), but with the hp, and the high rpms, they can take advantage of gearing. There was an excellent post either to one of my mailing lists, or on a web page, but it very sucinctly explained the concept. You could build a motor all about torque, and get beat by a high hp motor. It is the balance, and how the two interact,(for they are directly related). So while I may have tons of torque down low, I can take advantage of some of my gearing by running the rpms higher, which is part of the reason I shift near 7k, for that is where my overall power curve starts to fall off. Now, with a different rear-end, that may not be the case. And I don't know what difference it would make. But optimum shift points,(rpms wise), go down as speed increases. So you may get your best acceleration shifting at 7k in first, 6900 in second, and 6700 in third. It is a function of how long you will be in that gear, the ratio, etc... Look at any popular program to figure out best launch rpms, shift points, etc... They will all have the shift points higher for the lower gears.
This is really long, and I think I have missed a few questions, so time to end this post, ask if I missed any.
Oh, why the difference btw FI and carbs. As Dave said, i am running short runners with individual throttle bodies,(excuse me, butterflies), for each cylinder. Short intake runners are generally for higher rpms, and longer runners are for lower rpms and torque,(look at some modern cars, and the intake designs, long individual runners). As a matter of fact, I have the shortest runners you can get, the TWM manifold. The popular cannon manifold is longer, which is better for lower speeds/rpms. Your power curve is mostly a function of the design of the Datsun intake. You are sucking air through that single throttle body,(I believe you said it was the larger one). And the manifold distributes it to the individual cylinders. I have much better throttle response, for the time delay is minimal. That is why Turbo motors often don't feel peppy, for they have intake plumbing that runs all over the car,(of course, the throttle body is still on the intake manifold, but all the plumbing ahead of it can take some time to react).
You can get more power than I can with your FI because you have more tunability. I have the capability to get the utmost power, but change one environmental condtion, and my jetting is no longer optimal, etc.. So tuned perfectly, i can outdo a FI system,(except the TWM individual throttle bodies, BIG BUCKS, basicly Fuel Injected sidedrafts), but 95% of the time, the FI can do better than me, that is assuming to equal systems. My sidedraft setup is better than the stock Nissan FI, but in the end they all have their pros/cons and limitations.
Ok, enough rambling.
-Bob Hanvey

 

[norm]

Re:Bob, I wont be speedshifting anymore either

Beleve me, I dont blame you for not wanting to shift without lifting off the gas it breaks cranks,clutches,ujoints,tranny countershaft bearings ,and surely doesnt help any other part of the car either .I will no longer be doin' it in my Z 2.4 2.8 or 2.9 junkyard dog(If I build it I will have to keep revs at max 6500 even if it manages to run_) You are right about 60 ft times i have had best of 1.84 with nittos and they still spun hard off the line.The night I ran 13.4 it was on strictly regular strret tires and 60ft was 1.942.Get some good slicks and you ought to have 1.7 60 ft times . norm

 

[Chris Behney]

Great job, thanks.

> Balancing a straight six is the key to high
> rpm and longevity. 7 main bearings are
> great, but that is one long crankshaft to be
> spinning at 7K. I had mine done with
> flywheel and pulley for @$100 (dynamic
> balancing). Static balancing of all the rods
> and pistons was also included in the $100.
> Very smooth revving engine.

> What we are talking about is a torque curve.
> As everybody knows, when you shift, your rpm
> drops. What you want is to shift at a high
> enough point so that your rpm in the next
> gear doesn't drop below the torque peak.
> Essentially, you want to shift at the right
> point to stay in the powerband through all
> the gears. So, if the powerband peak is from
> 4000-6000, then maybe shifting a little
> above 6000 may drop the rpm to a little
> above 4000, which is just right. However,
> shifting at 5500 may drop you BELOW the
> desired torque curve, and your acceleration
> will suffer. There is more to performance,
> than just bolting on different parts. There
> is a formula to determine shift points, and
> will help you determine the best ratio rear
> end/tranny/shift point etc....These are some
> of the reasons I'm a 'number cruncher'.
> The shift point formula:
> (You need to know your torque curve from a
> dyno to do this.)
> Say you're torque curve is farily flat from
> 4000-5500 @210ft/lbs and falls to 200ft/lbs
> @6000. Therefore you don't want to drop
> below 4000 rpm, because you'll be below the
> peak torque.

> Gear torque = gear ratio x torque(at desired
> max rpm)
> Next gear rpm = rpm1 (gear2/gear1)

> 1st gear = 3.321 x 200 = 664.2ft/lbs
> 2nd gear rpm = 6000 (2.077/3.321) = 3752rpm

> So for shifting at 6000 we get 664.2ft/lbs
> in 1st gear, and drops us to 3752 rpm in
> second. This puts us BELOW our desired
> torque curve, therefore we need to shift
> higher. Even though torque drops off after
> 5500, we still need more rpms to stay in the
> torque curve. So, lets try with 6500rpm.

> 2nd gear rpm2 = 6500 (2.077/3.321) = 4065
> This puts us right in the beginning of our
> torque curve, very nice. Just for the sake
> of argument, let's try 7000rpm.

> 2nd gear rpm3 = 7000 (2.077/3.321) = 4378rpm
> A little high, we missed some early useable
> torque.

> So, with the math, we can see the benefit of
> a higher rpm, even though there is no more
> power available. This is why NISMO offers
> close ratio trannys, so you don't have to
> shift so high. I wonder how a close-ratio
> tranny with the 3.1L would accelerate. I'm
> sure it would be faster than what it is now,
> and would eliminate need for above 6500rpm
> shifting.

> Driving is one thing, technical numbers
> offer a definitive answer, rather than a
> 'seat of your pants' observation. What if
> people raced without posting mph and time??
> I could say my car was faster than yours,
> but by how much?? We need numbers to provide
> quantatative answers. Hopefully this post
> offers a explanation to you as to why higher
> rpm's may be necessary.

> I'm curious as well now.

> I'm looking for one. They definetely help
> put more power to the ground, especially
> with all the torque these 3.1L can produce.

> Yes and no. The reason is that they are
> individual runners and have seperate
> butterflies for each cylinder. This enables
> more air and less restriction. Each cylinder
> is dependent on it's own carb, not the
> entire intake. i.e. There is no restriction
> as with a single TB. This is why some people
> can 'overcarb' their engine. It is just too
> much air, and not enough velocity to draw
> the fuel out of the carb. A fuel injection
> system with seperate runners and butterfly
> valves can provide just as much air as
> individual carbs.

> Hope this provides some answers to your
> questions.

> 240Dave

Great job explaining, but now i have more questions.(I know, they just keep coming.)

So, judging by the formula, and your shift points, your powerband starts a little higher than mine, right? Mine comes on very strong, right at 3000rpm, and pulls hard untill about 5400. Does yours start at about 4000rpm, or somewhere in there? I was assuming your powerband started at around 3000rpm, like mine, and that's why I couldn't figure out the need for higher shift points, with a relitivly flat torque curve in the high rpm. Apparently, our cams are a world apart. What kind of idle has your car got? Does it idle around 1500rpm, or a little higher?

If I shift at 5200, and jump into the next gear, it will never fall below 3000rpm, so I'm driving the car right where it needs to be. Not to sound cocky, but I didn't need a formula to tell me that, the seat of my pants lets me know when the car is accelerating too slowly.

I understand that a lot of people do need the quantitive numbers to let them know how fast thier car is, but remember MANY of the races I run, don't have a screen posting elpsed time, and trap speed. Most farmers just don't put these things up out in the country. So, whoever crosses the line first, wins. Regardless of shiftpoints, horsepower, topspeed, traction, rearend gears, induction ratios, or whatever # someone can give me, if I make it through the traps at the other end first, I go home with the money.

Thanks for taking the time to explain, it helped.

Do you have a carbed engine, or are you running fuel injection? Intake port and polished? What about exhaust, manifold or headers?

Take it easy,
Chris Behney

 

[Chris Behney]

> Very good post...but I must add some
> personal experience as it relates to the 400
> Small block.

> Ill fated....not accurate. There are good
> parts to be had...listen up you guys that
> like to put V-8s in your Z's

> I have personally built a small block with
> the short 400 rods (5.565 vs 5.7) and the
> 3.48 (350 crank) with the taller pistons
> from the 327. A miricle it is not that
> compression height works out perfect, and
> the piston comes to the top just like it
> should.

> This combination lowers the number referred
> to as rod ratio, which will decrease the
> engines ability to breathe at very high
> RPMs. Flip side is...what ever you take from
> the top you put on the bottom (suppose to be
> anyway if you do it right) That's right all
> you torque hungry folks, this sucker will
> pull like a big block. My version would spin
> (chevy here now) 7500 to 8000 no prob. I
> have seen it up to 8200 and it was still
> pulling!!!!! Although the pucker in the seat
> was pronounced seeing the revs this high, it
> stayed together.

> In a nut shell longer rods are not the end
> all be all. Take into account what you want,
> and build an engine to do that. Each combo
> does something well, exploit that and you
> have a winner. Anyone want more specifics on
> this stump pullin small block I will tell
> [email protected]

> Ken

Wonderful explination.
All along, I've been telling people that theses Z engines can built many diffrent ways, to gainpower in a variety of power bands, much like the V-8's. I have a **** of a lot more torque in the low end than many of the Z's out there, but I have seen a few Z's take it from me, above 100mph. So they obviously had it in the top end, where I had it in the bottom.

Hey man, to each his own.

Chris Behney

 

[Bob H]

Re: Great job, thanks.

> So, judging by the formula, and your shift
> points, your powerband starts a little
> higher than mine, right? Mine comes on very
> strong, right at 3000rpm, and pulls hard
> untill about 5400. Does yours start at about
> 4000rpm, or somewhere in there?

No, mine starts about 3k, with it really pulling strong by 3500. I would say it is full bore by about 3500. We were having problems on the dyno, because we couldn't adjust the brake,(that what resists the engine, so we could tell what power it was producing, it needs a tenth of a second or so at each 100 rpm), what would happen, was the cam and the main venturi's of the carbs came on about the same time, ~3300 rpm, and it would rev up to fast, and Chuck,(the guy who did my engine), couldn't adjust the brake quick enough, for you are constantly adjusting it as it goes through the powerband. Anyways, it is almost like a minor turbo feel if you punch it from ~1500 in second as it hits about 30 mph, which is really close to 3000, for it tops out at 70 in second, and I have the rev limiter set to 7200. But mine pull fairly consistently till about 6500. In the lower gears, I gain some benifit from running a little higher, as I said before about shift points. When I shift, it puts it back about 4k or a little below. Again, remember, I have a really odd gearing right now, so a higher rear end, which keeps the engine from falling so low after each shift, I might not shift so high.
As for camshafts, I have a very mild one, and my car idles great, beyond the fact that I need to syncronize my carbs. I am running the Motorsport Auto 2003 cam, ie 460 lift, 270/280 split duration. It is supposed to make power from 2-6500 and it does. The limiting factor on the lower rpms is that my carbs have not really come on line yet, and are still running off the idle curcits and such. Once the main jets are dumping fuel, things are going strong. Just as a side note, they come on line so late because I am running the triples. It is at ~3300 that the airflow through each runner is enough to start sucking fuel from the main jets, and not just the idle and off idle circuits.

> Do you have a carbed engine, or are you
> running fuel injection? Intake port and
> polished? What about exhaust, manifold or
> headers?

I assume that was for Dave, since you already asked me about my carbs. As for others, I will throw it out. Yes, it is port matched, and mildly polished. I am running the Nissan Motorsports 6-2 large diameter header, into a 3 in exhaust.
I see you said you have run many times in the country. Have you taken it to a drag strip and run there? If so, what did your time slip say? (sorry if you already said, i have been acused of not being the most observant at times).
-Bob Hanvey

 

[Chris Behney]

Re: Great job, thanks.

> No, mine starts about 3k, with it really
> pulling strong by 3500. I would say it is
> full bore by about 3500. We were having
> problems on the dyno, because we couldn't
> adjust the brake,(that what resists the
> engine, so we could tell what power it was
> producing, it needs a tenth of a second or
> so at each 100 rpm), what would happen, was
> the cam and the main venturi's of the carbs
> came on about the same time, ~3300 rpm, and
> it would rev up to fast, and Chuck,(the guy
> who did my engine), couldn't adjust the
> brake quick enough, for you are constantly
> adjusting it as it goes through the
> powerband. Anyways, it is almost like a
> minor turbo feel if you punch it from ~1500
> in second as it hits about 30 mph, which is
> really close to 3000, for it tops out at 70
> in second, and I have the rev limiter set to
> 7200. But mine pull fairly consistently till
> about 6500. In the lower gears, I gain some
> benifit from running a little higher, as I
> said before about shift points. When I
> shift, it puts it back about 4k or a little
> below. Again, remember, I have a really odd
> gearing right now, so a higher rear end,
> which keeps the engine from falling so low
> after each shift, I might not shift so high.
> As for camshafts, I have a very mild one,
> and my car idles great, beyond the fact that
> I need to syncronize my carbs. I am running
> the Motorsport Auto 2003 cam, ie 460 lift,
> 270/280 split duration. It is supposed to
> make power from 2-6500 and it does. The
> limiting factor on the lower rpms is that my
> carbs have not really come on line yet, and
> are still running off the idle curcits and
> such. Once the main jets are dumping fuel,
> things are going strong. Just as a side
> note, they come on line so late because I am
> running the triples. It is at ~3300 that the
> airflow through each runner is enough to
> start sucking fuel from the main jets, and
> not just the idle and off idle circuits.

> I assume that was for Dave, since you
> already asked me about my carbs. As for
> others, I will throw it out. Yes, it is port
> matched, and mildly polished. I am running
> the Nissan Motorsports 6-2 large diameter
> header, into a 3 in exhaust.
> I see you said you have run many times in
> the country. Have you taken it to a drag
> strip and run there? If so, what did your
> time slip say? (sorry if you already said, i
> have been acused of not being the most
> observant at times).
> -Bob Hanvey

I've run a few times at the track, not long after the engine was put in. I don't mind repeating, I'm quite proud of the few passes I've made.

September 20-30 1997
Several runs were taken on some street tires.
a few low 14's at around 95 miles an hour. I couldn't get traction for anything. I was running a set of Yokohama 352's at the time, and they were great for the streets, but not at the track. Every time going into 2nd and 3rd gear, I broke the tires loose, and had to feather the throttle to keep everything going straight. A few rustangs made me look bad on this night. I beat a 3000GT SE, nothing to be proud of.

November 1997
The next time out, I found a friend of mine, and borrowed a set of 15 inch wheels from him, that had a set of 245 BFG comp T/A Drag radials. Great improvement. 13.9 at 101 was the best of the night. Still though, I had traction problems. 1.9 60 foot time wasn't helping much. Lots of smoke through 1st and 2nd gear, and it was fish-tailing on me BAD! I did beat a 80 camaro, that lost it so bad, he almost put it into the wall. A '69 Chevelle made an idiot out of me, and took $50 bucks from me. He unleashed the NOS on me at the 1/8 mile marker and walked off on me. A 250 shot of NOS does wonders for big cars.

March 1998
The next time out, I borrowed a set of chrome pony 5 stars off a guy's mustang LX, that had M/H street strip tires. A great set of tires, mid 60 degree weather and about 25% humidity, all totaled up to what was about to be a great night of racing. Several high 13's at about 100. Then, on the 4th run of the night, all **** broke loose! 13.5 at 105. Something still wasn't quite right though. Then on the following run, with a huge burnout, the thumbs up from the staging crew, and the pole lit, I pulled up for the best run yet. A 13.2 at 110mph. Tires spun just a little. I jerked the tires loose going into 2nd, but not enough to blow the run. All shift points were between 5200 and 5600 on this run. I wasted a guy in a new T/A, that thought he was nothing short of heaven sent. Then a man(50 years old or so) in a '97 camaro layed down a 10.8 to my 13.2. Turns out that he had an ATI procharger. Went through the traps at 131mph. He made me look bad, but I had my best run ever in my Z.

After this run, I packed up my gear and called it a night. This was the last run that I've seen on the track, and was quite proud of the show that I put on. I raced a couple of 300ZXTT that night, and a 3000GT VR-4, and was impressed with the way I smoked 'em.

Sorry for the long story, but I'll sum it up.

Best run with new engine is a 13.2 at 110mph. This was made with a set of 15x8 Pony rims, with 26 inch tall M/H street strip series tires. Before every run, I layed down a vicious burnout. (Somewhat of a signature move for me.) No muffler was on the car that night, and the exhaust was dumped off about 3 feet after the downpipe. (This set up has since been changed to a pretty much stock set up.)

I'll take a few more passes next march, after the last of the work is done to my car in Dec. Then, my track days are over with this car. I can't really risk blowing something at the track, while I have other cars to fix.(I have a '64 Impala, I'm looking for late 80's Monte Carlo.)

Keep on Z-ing,

Chris Behney