I am close to purchasing drivetrain parts for my 82 280 :hpydance: , and need to know what tranny and what diff. will give me the lowest RPM in fifth gear? It is a coupe if that makes a difference.

 

The 1979 2+2 4-speed came with the differential you want: 3.364 R200

The 1981 to 1983 5-Speed (Non-Turbo) has the tallest 5th gear: 0.745:1

These two will give you the lowest rpm in 5th gear but you're going to have trouble finding a 4 speed 79 2+2. Most people opted for the 5-speed which had a 3.7:1 R200.

If you go to an R180, you'll have better luck but you'll also have to modify your mount points and change your axels since the R200 is offset to one side where the R180 is centered.

What transmission did you have previously?

 

Or go for the 3.54 rear end R200. Those are easy to find. then use the transmission suggested above. That will still be a very low rpm on the freeway.

I have never in my life seen a 4-speed 280ZX.

 

This is fun too: http://www.geocities.com/z_design_studio/

 

Yup, gotta bookmark that one and the tire size calculator. Invaluable information. Too bad I can't have programs like that saved locally... (?)

Seems to me 3.36 is too low, but maybe you drive 85mph all the time!

 

Thanks that helps alot

 

where are those Borg Warner T56 transmissions??? sounds like i could use one of those babys...

 

Naw, you don't need a 6-speed. Besides, they don't bolt up to the L-seres engine. I think they are on the website because some V8 swap Z's use those. The T56 was found in late model Firebirds, and maybe Vettes? They bolt up to a V8.

 

My 82 zx is a four speed, well it has five gears, but no change in RPM... :chug:

 

:headspin: That does not seem possible to grab two 1:1 gear ratios. You might have the early 280Z 5-speed with an overdrive gear that is not much differance than 4th gear.... or a really screwed up transmission. In either case, its not a true 4-speed transmission. If your car had a transmission swap, then you could have had the differential swapped to. There could be any gear ratio in there, but most likely an R200 was used because it requires no modifications to isntall. :chug: :chug:

 

what would be the advantage of a 6-speed over a 5-speed??? a 6-speed would lower the ratios and plus always good to have an extra gear..

or am i wrong?

 

Yeah like I said in my previous forum, my tranny was rebuilt 4 times and I believe has a different bellhousing on it so that is why it leaks..But 5th gear is the same as 4th there may be a 100 rpm change. Maybe

 

Here's a comparison of T5's and T56's used in various Chevy's:

Type First Second Third Fourth Fifth Sixth
T5 2.95 1.94 1.34 1.00 0.63(TBI) -
T5 3.07 1.92 1.31 1.00 0.63(TPI) -
T56 2.97 1.94 1.35 1.00 0.84 0.62
T56 3.36 2.07 1.35 1.00 0.84 0.62

You'll notice the T5's have 0.63 5th gears and the T56's have 0.62 6th gears.

I have seen a 0.50 5th gear T56 but it came with a 2.66:1 first gear. Not a hard launcher without a crazy diff ratio to compensate for it and then you're loosing the advantage gained from the 0.50 6th gear anyway.

Gearing is generally a balance struck between multi-purpose vehicles. Do you want to go fast in the 1/4 mile or do you want a boulevard cruiser? Generally, we all want something in between. We want to go fast when we want to go fast and we want good mileage when we're not.

Special or single purpose vehicles can afford to avoid the compromise. We see these every day on TV and at the track. I wouldn't sweat it too much.

Here's a list of all the T5's and their applications over the years:

http://www.kamikazeracing.org/dl/borgwarner-t5.txt

And yes s/cL3.0 has a bad tranny...