ZCar Forum banner
Status
Not open for further replies.
1 - 19 of 19 Posts

·
Registered
Joined
·
90 Posts
Discussion Starter · #1 ·
I hear alot about 5-spds put into 240-z's.

Should I put one in?

SHould I use 3.54/3.90 or something else?

R 200 or R 180?

Is this something I would regret doing because the car wasn't designed for a 5 spd?

If I put one in what year zx tranny should I use?

Thanks for your time.
 

·
Registered
Joined
·
107,695 Posts
> I hear alot about 5-spds put into 240-z's.

> Should I put one in?

> SHould I use 3.54/3.90 or something else?

> R 200 or R 180?

> Is this something I would regret doing
> because the car wasn't designed for a 5 spd?

> If I put one in what year zx tranny should I
> use?

> Thanks for your time.

NO
 

·
Registered
Joined
·
1,610 Posts
Your Decision

Mike,
It's your decison guy. The early 240's are starting to have some collectable value. You do anything to change it from stock and it becomes just another Z You have to decide if you want to restore the car to a mint original condition or just have fun driving it and not worry about its originality.
If you want to improve its driveability and strength go for the transmission and differential out of an '81-83ZX. That will require an upgrade to the R-200 and several other modifications. A partway move would be the 5-spd out of the 77Z-79ZX. It wouldn't require a differential change and should pretty much bolt in.
Again - your decisions and your wallet.
Phantom
 

·
Registered
Joined
·
107,695 Posts
> I hear alot about 5-spds put into 240-z's.

> Should I put one in?

> SHould I use 3.54/3.90 or something else?

> R 200 or R 180?

> Is this something I would regret doing
> because the car wasn't designed for a 5 spd?

> If I put one in what year zx tranny should I
> use?

> Thanks for your time.
Mike, what year is your car? 70's and early 71's
may need some tunnel modification, or shift linkage modification.
If your car has the two piece 4 spd, late 71 or newer, it's no big deal to put in a 5spd out of a
280z, or 280zx. You can use the 77/78 shifter in the later 5 spd, and or bend one in a vise to make it fit perfect. Also, the differential R200
will bolt right in, with a 280z mustache bar.
I would put the 5 spd, and 3:90 diff in, and save all of your old parts if you are worried about collectable value.
We stock rebuilt transmissions, and have the 3:90
diff available. We also have been putting together
some 4:11 ratio diffs, if you want to relly gear down. Joe 1-800-533-5659
 

·
Registered
Joined
·
399 Posts
Yes, If you don't like 4000 r.p.m. cruisin' highwy

> I hear alot about 5-spds put into 240-z's.

> Should I put one in?

> SHould I use 3.54/3.90 or something else?

> R 200 or R 180?

> Is this something I would regret doing
> because the car wasn't designed for a 5 spd?

> If I put one in what year zx tranny should I
> use?

> Thanks for your time.
I am trying to make the same decision for my ealrly 260Z. At my normal highway cruising speed, I'm running at 4000 r.p.m. with the 4sp. This sucks. I say do it, and save the4 sp tranny to preserve the collectability of your car.
 

·
Registered
Joined
·
1,610 Posts
How 'bout 3,200??

Coop,
Know what you mean. Had the same problem with the 4-spd in my '77. With a 3.545 differential and 215/60-14 tires it was turning 4,000 at 80 mph. Went to 225/60-16's, the .745:1 OD 5-spd and 3.90:1 differential out of an '83ZX , and now it turns about 3,200 at 80. (2,500 at 65 for those who never exceed the speed limit). Car is much quieter and, because of the different gearing, the car is about the same off the line in 1st & 2nd but stronger in 3rd & 4th. Car is quicker and quieter at cruise speeds. Wish I had done it 5 years ago.
Cost me $550 parts & labor.
Phantom
 

·
Registered
Joined
·
399 Posts
4spd=3.90:1=4000 rpm @ 65 mph, which SUCCKKK!!!!

> Coop,
> Know what you mean. Had the same problem
> with the 4-spd in my '77. With a 3.545
> differential and 215/60-14 tires it was
> turning 4,000 at 80 mph. Went to
> 225/60-16's, the .745:1 OD 5-spd and 3.90:1
> differential out of an '83ZX , and now it
> turns about 3,200 at 80. (2,500 at 65 for
> those who never exceed the speed limit). Car
> is much quieter and, because of the
> different gearing, the car is about the same
> off the line in 1st & 2nd but stronger
> in 3rd & 4th. Car is quicker and quieter
> at cruise speeds. Wish I had done it 5 years
> ago.
> Cost me $550 parts & labor.
> Phantom
I guess I have a 3.90, because at about 65, mph, which is what I cruise at on the highway I take to work (55 speed limit), I am running right at 4000 r.p.m. That is RIDICULOUS!!! I had Mustang 5.0 that ran at 1,300 rpm at 55mph in 5th. I bought a 5spd from a 79ZX from a U-Pull it yard for $50, which is sitting in my garage waiting until my wife leaves town so that I have time to bolt it in.
 

·
Registered
Joined
·
399 Posts
4sp+3.90:[email protected]=4000 rpm in 4th-SUUUCKKSS!!!!

> Coop,
> Know what you mean. Had the same problem
> with the 4-spd in my '77. With a 3.545
> differential and 215/60-14 tires it was
> turning 4,000 at 80 mph. Went to
> 225/60-16's, the .745:1 OD 5-spd and 3.90:1
> differential out of an '83ZX , and now it
> turns about 3,200 at 80. (2,500 at 65 for
> those who never exceed the speed limit). Car
> is much quieter and, because of the
> different gearing, the car is about the same
> off the line in 1st & 2nd but stronger
> in 3rd & 4th. Car is quicker and quieter
> at cruise speeds. Wish I had done it 5 years
> ago.
> Cost me $550 parts & labor.
> Phantom
Correction to my previous title
 

·
Registered
Joined
·
1,610 Posts
Re: 4sp+3.90:[email protected]=4000 rpm in 4th-SUUUCKKSS!!!!

Coop,
Don't know how to break this to you except just straight out. The '79ZX had the same 5-spd as the '77 & 78Z which means it's overdrive is a .864:1 and is designed for use with a 3.545:1 differential. The '80ZX has a .777:1 5-spd and the '81-'83ZX's had the .745:1 5-spd's that match up well with the 3.90:1 rear ends.
The '79ZX 5-spd will drop your rpm at 65 to about 3,450. That is still pretty busy. It's still better than 4,000, puts you in the middle of your torque band so you should have great response in 5th gear (I have to downshift ot 4th) at 65, and you should come off the line with all the gusto you've become accustomed to since 1st-4th are the sameas your current 4-spd.
Just don't expect 2,500.
What are you running for tires? Maybe a 60 series 14?
Phantom.
 

·
Registered
Joined
·
107,695 Posts
Re: How 'bout 3,200??

> Went to
> 225/60-16's, the .745:1 OD 5-spd and 3.90:1
> differential out of an '83ZX , and now it
> turns about 3,200 at 80. (2,500 at 65 for
> those who never exceed the speed limit). Car
> is much quieter and, because of the
> different gearing, the car is about the same
> off the line in 1st & 2nd but stronger
> in 3rd & 4th. Car is quicker and quieter
> at cruise speeds. Wish I had done it 5 years
> ago.
> Cost me $550 parts & labor.
> Phantom

Phantom did is the rearend limited slip
and did you change the gears or the whole
the including the half shafts. I don't want
to spend $700 for a rearend from Motorsports.

I have a '76 280Z 2+2 stock for now.
 

·
Registered
Joined
·
107,695 Posts
Re: Yes, If you don't like 4000 r.p.m. cruisin' hi

In me 80' 280zx with the factory 5 speed, factory gearing, and 225/50/15 tires I run 70MPH @ 2600 RPMs.
 

·
Registered
Joined
·
107,695 Posts
> Mike, what year is your car? 70's and early
> 71's
> may need some tunnel modification, or shift
> linkage modification.
> If your car has the two piece 4 spd, late 71
> or newer, it's no big deal to put in a 5spd
> out of a
> 280z, or 280zx. You can use the 77/78
> shifter in the later 5 spd, and or bend one
> in a vise to make it fit perfect. Also, the
> differential R200
> will bolt right in, with a 280z mustache
> bar.
> I would put the 5 spd, and 3:90 diff in, and
> save all of your old parts if you are
> worried about collectable value.
> We stock rebuilt transmissions, and have the
> 3:90
> diff available. We also have been putting
> together
> some 4:11 ratio diffs, if you want to relly
> gear down. Joe 1-800-533-5659
While your on that subject, I've been getting quotes to have a five speed setup from an 82 2+2 transplanted into a 81 turbo automatic. The few shops that would do the work are quoting me 15 to 25 hours labor or about $850 to $1500 labor. This seems rather excessive. If you were to take on ajob like this, how many hours would we be talking about. Btw, thanks for the info on current pricing that you e-mailed me.
 

·
Registered
Joined
·
486 Posts
Once up on car ramps and jacked up in the back, it took me about 2.5 hours to completely swap trannies in my 83. It took me about 2 hours to pull the engine out of my 70 with the tranny, swap manifolds, tranny, flywheel, clutch, and fan and reinstall into car, less wiring. Very easy, I have done it a couple of times, but not professionally, without a floor jack. They are really easy, I think that quote is very high.
Joshua L.
 

·
Registered
Joined
·
399 Posts
I'm confused. HEELLPP on ratios

> Coop,
> Don't know how to break this to you except
> just straight out. The '79ZX had the same
> 5-spd as the '77 & 78Z which means it's
> overdrive is a .864:1 and is designed for
> use with a 3.545:1 differential. The '80ZX
> has a .777:1 5-spd and the '81-'83ZX's had
> the .745:1 5-spd's that match up well with
> the 3.90:1 rear ends.
> The '79ZX 5-spd will drop your rpm at 65 to
> about 3,450. That is still pretty busy. It's
> still better than 4,000, puts you in the
> middle of your torque band so you should
> have great response in 5th gear (I have to
> downshift ot 4th) at 65, and you should come
> off the line with all the gusto you've
> become accustomed to since 1st-4th are the
> sameas your current 4-spd.
> Just don't expect 2,500.
> What are you running for tires? Maybe a 60
> series 14?
> Phantom.
Phantom, I need your help to sort out my confusion. First, the 260 is supposed to come with a 3.364:1 rear end (the lowest of any Z, but the tranny has the highest 1st gear). BUT, as I said with my 4sp (4th gear is 1:1), I am running at very high rpms on higway. I checked again last night. Actually around 3900 rpm at 70 mph, still VERRYYY high for highway crusing. My tires are close to stock (1857014). Is this rpm what it is supposed to be at 70 mph with a stock rearend? Or, did somebody change rear ends on me. Is there a way to tell which differential I have without taking it apart?

After I have confirmed which rear end I have, I should know which tranny is best, but you are right. The 280ZXb (81-83) tranny has the lowest 5th (but it would not run well with a stock 260 rear end).
 

·
Registered
Joined
·
96 Posts
Re: tire size vs MPH

> In me 80' 280zx with the factory 5 speed,
> factory gearing, and 225/50/15 tires I run
> 70MPH @ 2600 RPMs.

Just so that everybody is clear out there:
Your tire size or rear end gears will not change the ratio between the rpm and mph gauge readings one bit unless you change the speedo gear in the tranny. Meaning, you certainly will be going faster or slower with different tire sizes/rear end gears, but the speedometer is a constant reading from your transmsision not the road. That's why there's a different speedo gear depending on the rear end that the car came with.

So in the case of the 225/50/15 tires, you may be going a tad slower than 70mph because the car is spec'd for 205/60/15 which have a slighty taller aspect ratio than the others. The same goes for the 185/70/14s.

I think I'm right on this, but after writing it the whole idea makes my head spin. Correct me if I'm wrong.

Matt
 

·
Registered
Joined
·
1,610 Posts
HELP on ratios

> Phantom, I need your help to sort out my
> confusion. First, the 260 is supposed to
> come with a 3.364:1 rear end (the lowest of
> any Z, but the tranny has the highest 1st
> gear). BUT, as I said with my 4sp (4th gear
> is 1:1), I am running at very high rpms on
> higway. I checked again last night. Actually
> around 3900 rpm at 70 mph, still VERRYYY
> high for highway crusing. My tires are close
> to stock (1857014). Is this rpm what it is
> supposed to be at 70 mph with a stock
> rearend? Or, did somebody change rear ends
> on me. Is there a way to tell which
> differential I have without taking it apart?

Coop,
Let's see what I can dig up here at home.
You're correct - the 260Z Coupe with a 4 or 5-spd is supposed to have a 3.364:1 differential. A 2+2 has a 3.70:1 and the automatic has a 3.545:1.
The stock tire size for the 260 is a 195/70-14. The difference betwenn in and the 185's you are running would only make about a 5% difference in engine RPM. I once did all the math on this and came up with a formula that, if you knew your transmission ratios, differential ratios and tire diameters you could calculate engine rpm at any speed & vice versa.
Bottom line, in fourth gear with your tires you should be turning about 3,500 rpm at 70 with a 3.545:1 Differential. With the 3.90:1 you would be running 3,850. My bet is that a previous owner installed the 3.90's to get off the line a bit quicker. If you put an '81-83ZX transmission in you'll drop that speed to about 2,870 in 5th. That would be a very pleasant rpm. The 79ZX tranny 5th gear will drop you to just over 3,300.
Hope this helps a bit.
Phantom

> After I have confirmed which rear end I
> have, I should know which tranny is best,
> but you are right. The 280ZXb (81-83) tranny
> has the lowest 5th (but it would not run
> well with a stock 260 rear end).
 

·
Registered
Joined
·
1,610 Posts
Re: tire size vs MPH

> Just so that everybody is clear out there:
> Your tire size or rear end gears will not
> change the ratio between the rpm and mph
> gauge readings one bit unless
> you change the speedo gear in the tranny.
> Meaning, you certainly will be going faster
> or slower with different tire sizes/rear end
> gears, but the speedometer is a constant
> reading from your transmsision not the road.
> That's why there's a different speedo gear
> depending on the rear end that the car came
> with.

> So in the case of the 225/50/15 tires, you
> may be going a tad slower than 70mph because
> the car is spec'd for 205/60/15 which have a
> slighty taller aspect ratio than the others.
> The same goes for the 185/70/14s.

> I think I'm right on this, but after writing
> it the whole idea makes my head spin.
> Correct me if I'm wrong.

> Matt

You're correct Matt. Example: My '77 was designed to run 195/70-14's but it had 215/60-14's on it. The speedometer said that the car was going 66 at 3,000 rpm in 4th gear but, in reality the smaller tire was allowing it to only go 60. A 10% error. The dangerous part is when you go the other way with a +10% error and yu're going 66 instead of 60 because you're running 195/70-15's instead of 14's. The speeding tickets accummulate at a horrendous rate.
There is a very complex relationship between transmission gearing, differential gearing, and tire sizes. Each transmission has a color keyed gear for running each differential ratio. They both assume, however, that the tires are of a stock diameter. That is why tire manufacturers came up with the +1 and +2 sizing scheme. 195/70-14 = 205/60-15 = 215/50-16 = 225/40-17 = 235/30-18
Stick with those sizes and the stock differential gearing and you won't have to do mental gynastics trying to figure out how fast you are really going.
Phantom
 

·
Registered
Joined
·
107,695 Posts
Re: Should I put in a 5-SPD? - YES

Mike,

I have a 260Z 2+2 and replaced the automatic transmission with a 81-83ZX 5 spd gearbox & R200 3.7:1 diff. (I do a lot of highway driving) and at 65 mph the tacho reads 2300 revs.

This is a lot better than cruising at 3120 revs with the auto.

Colin 260z
 

·
Registered
Joined
·
1,511 Posts
Re: Yes, If you don't like 4000 r.p.m. cruisin' hi

I was thinking about doing that to my 81Turbo
but 1st gear goes up to 50 thats when I let off
because the cars not on the street yet and I was on my little road but that was in D and not 1 it did not shife until I let off the gas

what RPMs will I see going down the highway?
81ZXT is a three speed right?

Jeff280ZXT
 
1 - 19 of 19 Posts
Status
Not open for further replies.
Top