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Diff Ratio Question Regarding S15

Mr_G
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Mr_G Mentor

Mr_G

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Hey guys,

Im looking to change the diff ratio in the s15 as im looking for abit more acceleration (too laggy).

Im considering changing to the r33 diff, but not sure of the ratio??? Can anyone advise me what the ratio is?

Also to run this in the car, do I take out the internals of the diff housing in the s15, and simply swap over with another r200 gearset (Pinion and wheel) ?

Any help or info most appreciated, im sourcing a ratio of around 4.1 or 4.3

This ratio is to be used with the 6spd box

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https://www.sau.com.au/forums/topic/121099-diff-ratio-question-regarding-s15/
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Bl4cK32 Grand Master

Bl4cK32

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S15 runs a r200 shortnose diff with a helical centre.

Skylines (r32/33) runs the same diff, except with a vlsd centre.

The centres have to be taken out to swap over the cw & pinion(so u can keep your hlsd :laugh:)

R33 is 4.1 and r32 is 4.3.

What ratio are u running atm? I may want to swap my 4.3 for a 3.9 if u are interested...

Mr_G Mentor

Mr_G

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S15 runs a r200 shortnose diff with a helical centre.

Skylines (r32/33) runs the same diff, except with a vlsd centre.

The centres have to be taken out to swap over the cw & pinion(so u can keep your hlsd :D)

R33 is 4.1 and r32 is 4.3.

What ratio are u running atm? I may want to swap my 4.3 for a 3.9 if u are interested...

Hey buddy, yeah, i wouldnt mind swapping if you want to do that. Are you located in sydney??? Is it a hard job to do, cause i never really pulled the diff out before, hehe...

Im just running the std s15 ratio which is in manual, I believe its 3.7. I wouldnt mind trying a 4.3.... and testing that out for a while :rofl:

So basically its a straight swap, ie just take the diff out, take then open the casing up, swap the CW and pinion, put back together, and off you go?

Is it as simple as that?

From what I read, the s15 also has a sender from the diff for the speedo... how do i correct this so the speedo isnt out?

Thanks for your help though, much appreciated :rofl:

Bl4cK32 Grand Master

Bl4cK32

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Posted

Unfortunatly I live in Adelaide. It would have to be done by a diff place (ie 4x4 or a workshop capable) to setup clearances etc.

I heard manual ratio was 3.9 and the auto was 3.7? If yours was 3.9 it would be better for me...

Yes its just a swap of the cw& pinion.

You can get the speedo re-calibrated at some places.

PT Community Regular

PT

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diff ratio for S15 manual is definitely 3.7 and 3.9 for auto

unfortunatley the length of the halfshafts in the helical S15 are unique and are a different length to that of all other R200 diffs.....go speak to a diff shop/jap import shop first but I have been lead to believe that you can't just change crown/pinion on the helical.

as long as you use a diff with ABS sensor in it your speedo and odo will continie to work (I used an ABS diff from a CA but bolted the S15 sensor on as is much newer). I have chnaged to an RB25 box on my S15 and initially had 3.7 diff...gears very long, now have 4.3 ratio and certainly revs out/accelerates much quicker, on both occasions speedo reading changed for any given gear and RPM and at present I think the calibration is either spot on or 2-3% out

(unfortunately I never wrote down speed readings/RPM with 6spd box to compare 5th gear against 4th gear of new box ie 1:1 ratio)

The 6 speed is already short ratio box, if I were you I'd look at 3.9 or at most a 4.1 final ratio

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