Can I change diff's with a steptronic?

[rana]

I know/think my car comes with 3.46 gears since its an auto. However, the car is just too slow and most of my driving is city driving anyways.

SO, I was thinking, what diffs could I upgrade to if it is even possible.

I was thinking maybe 3.64, or 3.93...

ur thoughts pls....

[jasyn]

I know/think my car comes with 3.46 gears since its an auto. However, the car is just too slow and most of my driving is city driving anyways.

SO, I was thinking, what diffs could I upgrade to if it is even possible.

I was thinking maybe 3.64, or 3.93...

ur thoughts pls....

this link should help you out - http://www.bokchoys.com/differential/

[rana]

this link should help you out - http://www.bokchoys.com/differential/

thnaks....great site!

this is what I have now:

33 10 1 428 171 --- 320i/ci/iT/cic M52 3.45

should I / can I upgrade to this:

33 10 7 504 315 --- 320i/ci/iT/cic M54 3.91

[samir@technik]

3.91 would be a good upgrade from 3.46.

[rana]

3.91 would be a good upgrade from 3.46.

YES! :woot:

I think this mod will really deliver the punch I am looking for without supercharging. I really dont want to dump $10 000 cdn into this car. Just want to make the most of whats there.

Kind of a long winded question, but my car does 0-60 in about 10 seconds. With the new diff, will I be able to break into low 9's or even high 8's?

I know 0-60 is not an indicator of anything, but I want to know because it will give a general idea of how my car will feel.

I just wish there was a Shark Injector available for my car so it would increase the redline to 7000 :(

[des744]

You would need a new prop shaft and rear axle to match the differential due to length mismatch.
3.91 is a smaller unit(entire casing and gearing teeth) hence much weaker. This unit will, and it already did break on many guys running with only stock 170 bhp 2.2 litre engine. Not a good idea.

Having said that, my friend had his 325 with a 3.91 diff installed. I believe he is rather gentle with it at the moment.


3.91 would be a good upgrade from 3.46.

[rana]

You would need a new prop shaft and rear axle to match the differential due to length mismatch.
3.91 is a smaller unit(entire casing and gearing teeth) hence much weaker. This unit will, and it already did break on many guys running with only stock 170 bhp 2.2 litre engine. Not a good idea.

Having said that, my friend had his 325 with a 3.91 diff installed. I believe he is rather gentle with it at the moment.

Oh really. Well that sucks :thumbdwn:

Let us know how it goes with ur friend though.

What other diffs could I go with then? 4.10? Didnt find any listed on that site.

[jasyn]

Oh really. Well that sucks :thumbdwn:

Let us know how it goes with ur friend though.

What other diffs could I go with then? 4.10? Didnt find any listed on that site.

3.64 :dunno:

[des744]

Oh really. Well that sucks :thumbdwn:

Let us know how it goes with ur friend though.

I forgot to mentioned that he is very happy with the responsiveness of his car now that it's on 3.91. I guess if you are gentle, perhaps like him, it shouldnt be a problem.

[rana]

I forgot to mentioned that he is very happy with the responsiveness of his car now that it's on 3.91. I guess if you are gentle, perhaps like him, it shouldnt be a problem.

im actually quite the opposite. The only time I am gentle with my car is when it is raining very hard or it is snowing. Most other times its pedal to the metal.

[rana]

3.64 :dunno:

oh yea, didnt even realize that. I can possibly do the following:

33 10 7 506 246 --- 316i/iT auto 3.73
33 10 7 510 425 --- 316ci 3.64

but will I need different prop shafts/rear axles for these diffs as well?

[des744]

Unable to confirm an answer on this as I have never seen or researched on a 316i/ci.... sorry



oh yea, didnt even realize that. I can possibly do the following:

33 10 7 506 246 --- 316i/iT auto 3.73
33 10 7 510 425 --- 316ci 3.64

but will I need different prop shafts/rear axles for these diffs as well?

[rana]

I went to diffsonline.com and it seems I can send them my stock diff and they will rebuild it for $525 + $200 for 3.64 gears or $700 for 3.91.

hmmm....so $725 total for 3.64.