s14 rb25det diff to pick? what ratio?

[bobob729]

anybody got any suggestions on which diff i should pick i will also be converting everything to 5 lug at the same time if that makes a difference so any help would be helpful, i've did some research and i'm thinkin the q45 may be my best option but i'm not sure. so... yathanks

matt

[bobob729]

anybody

[meet07]

get the q45 diff. That will make your car super fast!!! so....ya

[crazyandevil05]

i got a 4.4 vlsd from some skyline, i think r33 rb25? works great. ~3000 at 70, depending on tire size. you shift alot, but it makes 2nd and 3rd wicked.

[stevespeed]

I thought about knocking to the Z rear gear which is what a 3.7 ~3.9 or something?

First and second in my car i sit in the powerband of my rb for like 2.2 seconds (where it really pulls hard) but 4th OMG with my stock rear gear is f***ING cRAZY!

[l0nestar]

I went with the stock R33-RB25DET 4.1 LSD & axles, I feel it works well. I retained the stock 4-lug hubs though.

[bobob729]

how bad will the low end power be in first second and third be with the 3.5xx ratio or would it be better to swap it to the 240sx (4.0xx) ratio

[Chaos the Xile]

I was using the R33 GTS-t diff and it was wonderful, great high mile per hour diff ratio, but I am thinking about running the Q45 3.9 diff in my new setup...

[240slidekat]

i guess it depends on how much power you want to make.

lots of power, id go with a taller gearnot so much power, shorter gear

no point of having alot of power if you cant put it down on the ground.

[Chaos the Xile]

i guess it depends on how much power you want to make.

lots of power, id go with a taller gearnot so much power, shorter gear

no point of having alot of power if you cant put it down on the ground.

Very well put, or you could just be a BALLER and buy the OS Giken Super Lock LSD and adjust your setting according to what you are looking for.

[bobob729]

smaller as in the 3.5 or 4.0

[WhatsADSM]

FWIW I have the standard 4.1s (came in my R33 diff) in my 26 and reving to 8k I think 1st goes to like 45, second to like 75, and third to 115 or so..

For most people that is more than sufficient and you wouldn't want the gears to be too much longer.. unless you have a lot of torque or are targetting a specific circuit track or something.

Here is a good calculator online where you can choose the RB25 trans, your tires, and a diff ratio.http://justskylines.com/skylin....aspx

[bobob729]

so what is better for the track 4.0 or 3.5

[SuperHatch]

so what is better for the track 4.0 or 3.5

Depends what track.

For anyone reading this thread, only one person that has replied actually has any clue what they're talking about. Everyone else should be ignored. Test your intelligence and try to figure out who it is.

[bobob729]

ok so still am i wanting longer or shorter gears is the question basically this car will be a street/strip car so....

[WhatsADSM]

ok so still am i wanting longer or shorter gears is the question basically this car will be a street/strip car so....

Honestly, no one can really spoon feed you the answer. Because it depends on your overall setup and what you plan to do with the car.

With that said the stock rear gear is probably the best bet for 90% of the RB owners out there in part because RBs rev so well. So my *guess* is the stock rear gear or something slightly longer like the 95+ J30s which IIRC are like 3.96 or something. The Q45 will likely be too low of a gear.

[bobob729]

thanks that's what i wanted to know

[rbs14kouki]

on my rb26 s14 ... i have a stock welded s14 diff 4.08 ...

i may change it to a 4.30 form a 180sx(ca18det) i want more torque and shorter gears

[flatrate]

are you talking about ring/pinion gears or the type of limited slip?

I love my Helical S15 Diff however im on stock S14 auto rear end gearing and id like to step it upto perhaps the 4.2-4.3 area