Jump to content
SAU Community

Recommended Posts

Anyone know where I can get some taller diff ratios for a GTR

S15 manual uses 3.7 CWP from memory and is same R200 (more-or-less), so should fit, but I haven't tried this one. But what do you do with the front diff ??....might be some aftermarket CWP's for the front diff, but probably not common and whether you could get the same ratio is another matter. Of course you could just always run in RWD, but the taller ratio will kill acceleration.

Thanks for the responses:

ookami; it's an R32 GTR.

SteveL; yes the front diff is a problem. using RB26/30 with a 7250 redline so would like to try using extra torque and taller ratios to give it longer legs. In 2wd I couldnt afford the tyres :)

TO4GTR; the 34 GTR ratios look good. It's got to be a signficant difference otherwise it's not worth the effort so the Stagea is probably out. Now to find some 34 GTR centres....

Cheers

Thanks for the responses:

ookami; it's an R32 GTR.

SteveL; yes the front diff is a problem. using RB26/30 with a 7250 redline so would like to try using extra torque and taller ratios to give it longer legs. In 2wd I couldnt afford the tyres :yes:

TO4GTR; the 34 GTR ratios look good. It's got to be a signficant difference otherwise it's not worth the effort so the Stagea is probably out. Now to find some 34 GTR centres....

Cheers

it will be tall as f**k

there are heaps of choices...3.5, 3.7, 3.9 4.08, 4.11, 4.3 etc..

as long as they are all r200 meh :P

3.9 is my vote for rb30det ( i know the pain of short gears with the 3lt ;) )

Yer - but there aren't heaps of choices for the F160 front diff

I've gone the other way (put a 4.11 diff into my R34 GTR) and I can tell you it has made a massive difference. For my applications it's been awesome but I'd hate to imagine going back the other way. Still if thats what you are chasing it sure is an option.

Hi Snowman, I thought that putting a 4.11 into an R34 would make it really short as from memory the box ratios are shorter in the R34, just more of them. If the intended application you're referring to is track work, that makes sense. Looked into an R34 box with standard diffs once and decided against it as there wasn't much gain in legs overall compared to the standard R32 set up.

  • 2 months later...

still wanting to run either 3.7 or 3.5 ratios, rarity of 3.7 looks like it will have to be 3.5 which means 34 GTR.

i think the 34 and 32 housings are the same but not sure if the internals are the same, and i'm under the impresson that that all 34s have active diffs.

does anyone know if the crown and pinion from a 34 will bolt into an R32 GTR and work, particularly if my assumption about the 34 diffs all being active is correct?

still wanting to run either 3.7 or 3.5 ratios, rarity of 3.7 looks like it will have to be 3.5 which means 34 GTR.

i think the 34 and 32 housings are the same but not sure if the internals are the same, and i'm under the impresson that that all 34s have active diffs.

does anyone know if the crown and pinion from a 34 will bolt into an R32 GTR and work, particularly if my assumption about the 34 diffs all being active is correct?

I assume that you have actually done the numbers on this? Worked out the max speed in each gear and the top speed?

With 245/45/17 tyres and a 4.1 diff ratio you are currently looking at the following ~KPH in each gear at 7,500 rpm

1st = 66 kph

2nd = 115 kph

3rd = 168 kph

4th = 220 kph

5th = 289 kph

Do you really need a top speed more than 289 kph?

For cruising, 2,850 rpm = 110 kph (speed limit) in 5th gear. That's off boost for any turbo sized to allow max power at 7,000 rpm. So economy is good, but overtaking power is only a short squeeze on the throttle away, no down change required.

Keep in mind that R32GTST's have a 4.3 to 1 diff ratio and weigh 200 kgs less than your GTR. Similary comparing your GTR to a R33GTST with RB30 may lead to the wrong conclusion. So don't ignore the weight factor when you are working out optimal gearing or the extra transmission losses from the 4wd.

How often did you drive around 5th gear with the 2.6 litre? Not often (other than highway driving) I bet. With the 3 litre you just use a higher gear than you would with the 2.6 litre.

My suggestion, as it has been with 20 or so others that have had RB30DET's, drive it around first, then decide. So far not one of those guys has changed the diff ratio.

:pwned: cheers :O

Hi Gary:

it's not the top speed I'm wanting, it's the legs in lower gears. i know someone with a GTR and 26/30 and he suggests that it feels very short in the gears, from memory Cubes has remarked on the same thing.

i would like to take the drive it first then decide approach, i understood that getting the front diff out with the engine in place was almost impossible.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • The average previous owner for these cars were basically S-chassis owners in the US. Teenagers or teenager-adjacent. I often tell people that neglect is easier to fix than something that was actively "repaired" by previous owners.
    • Update 3: Hi all It's been a while. Quite a lot of things happened in the meantime, among other things the car is (almost) back together and ready to be started again. Things that I fixed or changed: Full turbo removal, fitting back the OEM turbo oil hardlines. Had to do quite a bit of research and parts shopping to get every last piece that I need and make it work with the GT2860 turbos, but it does work and is not hard to do. Proves that the previous owner(s) just did not want to. While I was there I set the preload for the wastegates to 0,9bar to hopefully make it easier for the tuner to hit the 370hp I need for the legal inspections that will follow later on. Boost can always go up if necessary. Fitted a AN10 line from the catch can to the intake hose to make the catchcan and hopefully the cam covers a slight vacuum to have less restrictive oil returns from the head and not have mud build up as harshly in the lines and catch can. Removed the entire front interior just shy of the dashboard itself to clean up some of the absolutely horrendous wiring, (hopefully) fix the bumpy tacho and put in LED bulbs while I was there. Also put in bulbs where there was none before, like the airbag one. I also used that chance to remove the LED rpm gauge on the steering column, which was also wired in absolute horror show fashion. Moved the 4in1 Prosport gauge from sitting in front of the OEM oil pressure gauge to the center console vents, I used a 3D printed vent piece to hold that gauge there. The HKB steering wheel boss was likely on incorrectly as I sometimes noticed the indicator reset being uneven for left vs. right. In the meantime also installed an airbag delete resistor, as one should. Installed Cube Speed premium short shifter. Feels pretty nice, hope it'll work great too when I actually get to drive. Also put on a fancy Dragon Ball shift knob, cause why not. My buddy was kind enough to weld the rust hole in the back, it was basically rusted through in the lowermost corner of the passenger side trunk area where the wheel arch, trunk panel and rear quarter all meet. Obviously there is still a lot of crustiness in various areas but as long as it's not rusted out I'll just treat and isolate the corrosion and pretend it's not there. Also had to put down a new ground wire for the rear subframe as the original one was BARELY there. Probably a bit controversial depending on who you ask about this... but I ended up just covering the crack in the side of the engine block, the one above the oil feed, with JB Weld. I used a generous amount and roughed up the whole area with a Dremel before, so I hope this will hold the coolant where it should be for the foreseeable future. Did a cam cover gasket job as the half moons were a bit leaky, and there too one could see the people who worked on this car before me were absolute tools. The same half moons were probably used like 3 times without even cleaning the old RTV off. Dremeled out the inside of the flange where the turbine housing mates onto the exhaust manifolds so the diameter matches, as the OEM exhaust manifolds are even narrower than the turbine housings as we all know. Even if this doesn't do much, I had them out anyways, so can't harm. Ideally one would port-match both the turbo and the manifold to the gasket size but I really didn't feel up to disassembling the turbine housings. Wrapped turbo outlet dumps in heat wrap band. Will do the frontpipe again as well as now the oil leak which promted me to tear apart half the engine in the first place is hopefully fixed. Fitted an ATI super damper to get rid of the worn old harmonic balancer. Surely one of the easiest and most worth to do mods. But torquing that ARP bolt to spec was a bitch without being able to lock the flywheel. Did some minor adjustments in the ECU tables to change some things I didn't like, like the launch control that was ALWAYS active. Treated rusty spots and surface corrosion on places I could get to and on many spots under the car, not pretty or ideal but good enough for now. Removed the N1 rear spats and the carbon surrounding for the tailpipe to put them back on with new adhesive as the old one was lifting in many spots, not pretty. Took out the passenger rear lamp housing... what do you know. Amateur work screwed me again here as they were glued in hard and removing it took a lot of force, so I broke one of the housing bolts off. And when removing the adhesive from the chassis the paint came right off too. Thankfully all the damaged area won't be visible later, but whoever did the very limited bodywork on this car needs to have their limbs chopped off piece by piece.   Quite a list if I do say so myself, but a lot of time was spent just discovering new shit that is wrong with the car and finding a solution or parts to fix it. My last problem that I now have the headache of dealing with is that the exhaust studs on the turbo outlets are M10x1.25 threaded, but the previous owner already put on regular M10 nuts so the threads are... weird. I only found this out the hard way. So now I will just try if I can in any way fit the front pipe regardless, if not I'll have to redo the studs with the turbos installed. Lesson learned for the future: Redo ALL studs you put your hands on, especially if they are old and the previous owners were inept maniacs. Thanks for reading if you did, will update when the engine runs again. Hope nothing breaks or leaks and I can do a test drive.
    • No those pads are DBA too  but they have colors too. I look at the and imo the green "street" are the best.
    • I’m not sure what happened I told them about sonic tunes free OTS tune and the next the I know .. I was booted..   To funny 
×
×
  • Create New...