30S And Taller Rwd Diffs ?

[WHITER33GTS-T]

there must be a 3.5 diff that comes out in a r32 or something similar... the diff in my r32 that i purchased here.. the diff was crazy... 4th gear will spin the rear wheels to 260km/h.

when i removed the diff it looked like a GTS-T diff of some sort, because it did not have the GTR type tail shaft setup that the gtr's do and it was a viscous because i shimmed the diff.

it was with my 380kw rb30det setup, and the car really did suck to drive, i hated it. off boost it was just boring for me, you couldnt get the wheels to spin or have any fun off boost you had to always load up the engine before anything interesting happen. when on boost the gears went forever and it was just boring.

when driving the car before i realised the diff gears were out the car was just dangerous, at that kind of speeds in 4th gear i slowed down and wondered why the car felt soo unsafe, i only worked it out when on the dyno and i saw the wheel speed at the top of a dyno pull when i started to wonder wtf is wrong.

and drifting that car SUCKED, had to drift in first gear because dropping the clutch in second gear was impossible, the car would go sideways but because the wheels are spinning sooo fast 140km/h + you just put out soo much smoke and then lose it because of the high wheel spin speed at such slow speeds.

i took the diff out and installed a r32 gtr diff, and welded it. all is good now the car is awesome to drive.

my 350z with a rb30dett with rb25det box also has a 3.5 ratio, this one i don't mind so much because its a daily driver, but same goes with r32.. i dont ever bother trying to do any kind of drifting or burnouts as it just puts too much strain on the drive train and its just plain old stupid... i already broke the diff in the 350z and i am looking at changing it back to a 4.11:1 to match the 25 box as these things had a 6 speed standard.

however the good thing is because i do alot of highway driving, i can cruise in 5th gear doing 155km/h for hours on end without any overheating issues or any problems at all, get great fuel economy also... i drive to work which is a 150km trip, 70% of that i am sitting on 155km/h and im reving at 3500 or so rpm, in the skyline it would be at 4.2k + (diff is a normal 32gtr one now) ??

if anyone can help me to get a 4.11:1 or even 3.9 into my 350z that would be nice.

I would seriously not change the diff gears unless you want better fuel economy and dont care about enjoying your car the way it should be enjoyed...

maybe if you can change the 5th gear cog only to drop the rpm down would be a better option too.

don't change it.. if your adding extra torque then.... ...... .. "enjoy it, don't destroy it!" IMHO

My problem is I only have 3 gears so thats why im looking to change diff ratios. The 4.1 in it is ok but i think a 3.5 would make it better to drive and faster down the track. Currently cruising down the highway if you pull out to pass anyone anymore that half throttle turns into wheelspin.

[Guilt-Toy]

the 6 speed can be adapted with a adapter plate.. but they are weak and people break them with NA 3.5's... in my car it would die for sure.

[WMDC35]

the 3.5 only seems to come with the re5 auto cars?

[KiwiRS4T]

the 6 speed can be adapted with a adapter plate.. but they are weak and people break them with NA 3.5's... in my car it would die for sure.

What about the R34 Getrag?

[Guilt-Toy]

not keen for a 34 getrag... its just a street cruiser.. not that into this car... good idea though.

[luke gtr]

ok, i have a 32 gtr that i have nearly finished the conversion in.

thinking about going to the tomi=ei 34 gtr "short"diff gear set.

3.8?? ratio.

my thoughts are, bring cruise rpm on freeway down, without sacraficing too much of the pick up.

extra capacity should outway that anyway.

inputwould be appreciated.

[KiwiRS4T]

Good idea - I am going 3.545 in my heavy Stagea... with your R32 and RB30 3.8 should be a breeze.

[AngryRB]

I partially agree only with an RB30 I think a slightly taller diff ratio and a shorter 5th ratio would make it nice .

I always thought the 0.76 5th was a big jump over a direct 4th and it may need to be this way if you wanted to drop back to 4th and boot it - as in get enough revs up to haul . Thats with a std capacity RB25 or 26 BTW .

I still think the revs needed at 110 km/h are too high with the standard gearing but without a closer spaced 6spd gearbox its always going to be a compromise . They obviously knew this and fixed it on the later Z cars .

I don't suppose the 6 cog can be grafted on an RB block ?

A .

reading your threads, you seem to be wanting an rb25 to have the torque that a big engine would have, as in low down streetable torque, to me an rb25 will never have that unless it has a smallish turbo that chokes on the top end so little top end.. you cant make a small engine a big engine even with E85 and whatever..

I agree that a streetable car needs low end torque at partial throttle, and the stock VL turbo has always had that, a stock vl turbo with the usual intercooler, boost, exhaust would have all the low down torque your after and with longer gears, eg 2500rpm in fifth is 110-115km/hr,

In my opinion its hard to beat the RB30et for street duties, the rb25 is just a different beast and needs 4000rpm onwards and will never be great on the bottem end.. if it is then its all wrong cause it was never meant for that and it will be sacrificed in the mid to top end, Im not sure what a rb2530 does down low, but im guessing it would need revs being multi-valve.. the rb30et's manual gear box is totally up to the task as far as ratio's, and its diff seemed very adequate to me, that was with 200kw's.. went like a cut snake..

[KiwiRS4T]

reading your threads, you seem to be wanting an rb25 to have the torque that a big engine would have, as in low down streetable torque, to me an rb25 will never have that unless it has a smallish turbo that chokes on the top end so little top end.. you cant make a small engine a big engine even with E85 and whatever..

I agree that a streetable car needs low end torque at partial throttle, and the stock VL turbo has always had that, a stock vl turbo with the usual intercooler, boost, exhaust would have all the low down torque your after and with longer gears, eg 2500rpm in fifth is 110-115km/hr,

In my opinion its hard to beat the RB30et for street duties, the rb25 is just a different beast and needs 4000rpm onwards and will never be great on the bottem end.. if it is then its all wrong cause it was never meant for that and it will be sacrificed in the mid to top end, Im not sure what a rb2530 does down low, but im guessing it would need revs being multi-valve.. the rb30et's manual gear box is totally up to the task as far as ratio's, and its diff seemed very adequate to me, that was with 200kw's.. went like a cut snake..

I have an RB30/25 in a heavy Stagea (280awkw atm) but it pulls fine from 1000 rpm - as my exhaust is quite noisy I drive around town changing up at just under 2000rpm. When I say it pulls fine it keeps up with the traffic but if I want to outdrag the Holden or Evo next to me at the lights I have to give it a bootfull of revs to launch it so I tend not to!

[luke gtr]

Good idea - I am going 3.545 in my heavy Stagea... with your R32 and RB30 3.8 should be a breeze.

this is what i was thinking.

i think even with the extra capacity, the 3.5s would just be too tall with standard gearbox ratios.

the 4.11s too short.

the tomeis seem to be a happy middle ground, that is available off the shelf.