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.
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.