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Discussion Starter · #1 ·
Hey ya'll... I am looking at getting either a 3.90 or a 4.11 gear, I haven't decided yet. First, let me preface this by saying "I don't CARE about highway RPMS. This is not a daily car, it is STRICTLY a toy car".

I run a 81' ZX 5speed tranny in my '77, currently I have a 3.54 rearend in it. My question is this, with a 81zx 5speed, and a 4.11 gear, what would my top speed be limited to by GEAR... In otherwords, what would redlining be in 5th gear for me? Currently I run 120mph - 130mph before hitting 5th gear, and wanted to make sure I can still run those speeds without being limited by the gear...

I used to hate it when i had a fourspeed, i'd get to 130 and it was all the faster I could go because I was at 6000 rpms.... ugh

Brett
 

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RE: RearEnd/Transmission combo question (yet anoth

My 3.70 would turn 200KPH (125...) in 4th at 6350rpm.
The stock 3.36 with the trans you spec would be geared for 162mph in 5th at 6500 (if I remember correctly).
I used to have it printed out somewhere, but if you know your current speed, rpm, and gear ratio, you can figure out the new speed by setting it up mathematically and substituting the new ratio, and solving the equation for the variable "speed".
I don't believe I just wrote that....
SOMEONE WITH A 4.11 TELL HIM HOW FAST HE CAN GO!
 

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RE: RearEnd/Transmission combo question (yet anoth

Hey Brett - how's your holeshot? Is first and second low enough for decent performance with the 3:54? I believe a 3:90 is what that transmission was originally mated to. I'm about to put a similar 5speed in my car with a 3:54 and am curious about the low end performance - I do have a 3:90 standing by if needed.
 

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Discussion Starter · #5 ·
RE: RearEnd/Transmission combo question (yet anoth

Out of the hole, its still pretty respectable I would say. I noticed only a very SMALL difference when I switched over to the 5speed tranny. However, I did a few other mods while I was at it that probably made of the that malady. Really, unless you are worried about your topend speed, I would run the 3.90 if you have one..

On the side, it always screws me up when I drive my '98 Talon, I always drive too slow because my speedo on the Z is now 5 miles slow. hehe

Brett
 

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Discussion Starter · #6 ·
<b>Don't Forget Tire Size!</b>

Tire size will affect your ratios as well.
With 245/45/16 rear wheel, 77 5spd, 3.54 rear end I could do 144 mph at I believe 5200-5400 rpm (can't remember right now)
If you are running a low profile 15"wheel then that could make a big difference ie 205/50/15 is smaller in dia than what I have.
I would recomend the 3.9
My friend has a 240 with 215/60/15's with an 81 5spd and 4.11 rearend and he can barely hit 140mph at somthing close to 7000rpm and he has about 275 hp so I would think you would need some serious hp and balancing to turn some fairly high rpms.

I recall making some calculations a few years back that with my current set up *IF* I could turn 7500 rpm in 5th I would be somewhere over 200mph!
ZR8ED.
 

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Discussion Starter · #7 ·
RE: My 83 turbo goes 85 MPH!!

I don't know why everybody else on the way to work is going so slow though. Seems they are going about 40 mph compared???!!!
 

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RE: My 83 turbo goes 85 MPH!!

crap some thing wrong with you Z Mine going about 110 mph
and It seem slow hehehehehehe .
 
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