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Diff Ratio's

Nee-san

By Nee-san,
in Motorsport Discussion & Builds

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Beer Baron Grand Master

Beer Baron

Posted
Posted

yeah I think $900 to do a front and rear diff change is probably about right. good going. like brad said there is no need to take the sump off to get the diff out, it was more that in the past most diff places didn't want the car, just the diff and it's housing (in this case sump) so you had to. but if award offer drive in drive out for $900 I'd be doing that.

Super_Dude Enthusiast

Super_Dude

Posted
Posted

I'm running 4.375's with an OS giken 1-5 tranny. I'm running a GT4088r so I switched to 4.375 to gain back response. I like it but it's a little annoying on the highway.

I'm planning on building a stroker or an RB30 this winter and switching the 4088r to a new borg warner EFR 8374. I will probably switch back to 4.11 or maybe even go 3.9. I believe 3.9 is stagea 4wd ratio and will bolt in. Am I correct?

Nee-san Grand Master

Nee-san

Posted
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Posted
yeah it's not for everyone. if you do a lot of freeway driving at 110-120 it's going to get annoying buzzing along at 3500rpm+ in 5th all the time. :)

Don't know what you mean baron, GT-R's are quiet as a mouse :P

Beer Baron Grand Master

Beer Baron

Posted
Posted

hehe. :P well it's more just the feeling that you're revving the nuts off the thing just to do a quickish cruising speed. and I've had pretty quiet GTRs. even had one with a stock exhaust. current grey 32 has no mufflers at all. that's right. nothing between turbine wheel and complete open tip. its fairly loud but not as loud as many would think due to fairly well designed exhaust and of course two little turbos keep it quiet-ish.

  • 3 months later...
Deano 1 Mentor

Deano 1

Posted
Posted

people that have done this and still use your car as a street car, what did you do about your speedo? is there away to make it read right still? how far will it be out?? any idea what the top speed of that ratio would be in a r32 gtr, i geting 240klms down the eastern creek now, with only 300kw. i was thinking of changing my raitios when my motor is out, but i dont want to run out of legs on the track with 400kw

Beer Baron Grand Master

Beer Baron

Posted
Posted

hmmmmmmmmmmm id like to do this

i think i saw some n.z 32 gtr have this done and he was really quick off the line and maxed out around 200 k's or so?

lol. umm maybe 200km in 4th gear. stock GTR gearing with stock diffs will get you 300+ (providing you have the power and the length of track to get there). with GTS4 diffs top speed drops to around 260-270ish. but you actually have a chance of getting there. acceleration is pretty lazy in 5th with stock diffs and not too much power. which is why people go to 4.375:1 for better acceleration.

Beer Baron Grand Master

Beer Baron

Posted
Posted

people that have done this and still use your car as a street car, what did you do about your speedo? is there away to make it read right still? how far will it be out?? any idea what the top speed of that ratio would be in a r32 gtr, i geting 240klms down the eastern creek now, with only 300kw. i was thinking of changing my raitios when my motor is out, but i dont want to run out of legs on the track with 400kw

you won't run out of legs at most tracks in aus even with 400kw with stock 5th gear and 4.375:1 diffs, well except bathurst and maybe P1 as you enter the straight there around 160-180km/h. You would hit the limiter down conrod for sure.

let me ask any GTR owner even with 400kw or 450kw how many can put there hands up and say they have ever hit the limiter in 5th gear with either 4.1 or 4.375 diffs?

as far as the speedo goes you can get it recalibrated, or it may be possible to use a GTS4 sender (never tried that option).

240k at eastern creek is pretty fast for 300kw. but even still with 400kw you're like to get to 260 or so.

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