What is your ideal differential ratio for the e30

[Bearmw]

My ideal ratio right now is a 3.46 with a robust B35 swap. As others have said there is no perfect ratio as all are application specific and subjective at that, just like having an ideal exhaust or suspension setup. Everything is a trade off. At times I consider a 3.64 in my car but that would be as far as I would go due to how short each gear would be. It would be quick though.

[LowR3V'in]

i vote 2.93

Cruising at 2k on the freeway is nice.
not having to row through the gears all the time is great.

if you feel it's slow your car is too slow. a 3.73 isn't going to make it much faster.
just more shifting. more pushing in the clutch and rowing through thoses gears. you like being in 4th gear by 30mph? Great.

right now i'm using a 3.15 from an mroadster. it's ok. But cruising on the freeway isn't as nice.
it's sorta the 'performance' upgrade but i'll end up putting the 2.93 back in soon.

[digger]

i use 391 with the CR G260 3.35/2.03/1.36/1.00/0.81

with a regular g260 a 3.46/3.64 would be closer to the money and be a better cruiser

[The Dark Side of Will]

i use 391 with the CR G260 3.35/2.03/1.36/1.00/0.81

with a regular g260 a 3.46/3.64 would be closer to the money and be a better cruiser

Close ratio 260? Wasn't aware of such a thing.
The ratios you mention sound like an M3 G265.

[digger]

was available in "euro" 325i "sport" models, also in oz BMW Australia spec'd a few hundred 325is with some goodies one of which was the box, SA 325is with 2.7L alpina spec engines got them to

http://www.e30zone.net/e30zonewiki/index.php/Drivetrain

[The Dark Side of Will]

was available in "euro" 325i "sport" models, also in oz BMW Australia spec'd a few hundred 325is with some goodies one of which was the box, SA 325is with 2.7L alpina spec engines got them to

http://www.e30zone.net/e30zonewiki/index.php/Drivetrain

GDMF. Now I have another Euro part to lust after. And I thought the Caddy gearbox was a good find.

Per E30zone the TNN code is the close ratio box.
RealOEM link:
http://www.realoem.com/bmw/enUS/part...&q=23001221138

PN's: 23001221572, 23001221138

[ak-]

3.46

I do everything but "cruise" when I take the car out so low ratios are ass in my opinion - you're so slow out of the hole.
The 3.46 has been the best happy-medium between street, highway, canyons, and tracks.
I've tried the LSD 2.93, 3.25, 3.73, and 4.10.
The 2.93 in the S52/260 and Turbo S50/260 were dogs, except for the highway in the turbo S50.

[zaq123]

was just trying to remember what diff I have....gonna put it here before I forget again as the tag long gone - 3.64 LSD from Z3

[Panici]

3.73 with the G260 felt pretty good behind the M20.

Went with a 2.93 with a ZF320 on the Turbo M52. (No overdrive)
Although it makes plenty of power to make up for it, I do miss the shorter gearing just for the occasion of shifting more often.

[Northern]

3.73 with an M20/G260 was fine and I never wanted anything else.

I ran my M52/ZF320 with the 3.73 and it was terrible. Finally swapped to a 2.93 and it feels "right" for a street car even with +5% oversized tires. (after all it works out the same as a G260+3.73)

I could imagine +/- 1 ratio from that would be fine - a 2.79 for a big turbo or highway cruising car, or a 3.08/3.15 could be fine for something a little shorter, but I don't think the 2.93 needs it.

[AWDBOB]

3.73 is great with m20/g260.

I have a 3.46 in my car now with a stroker m20 and it's good. I think a 3.64 would be perfect, though.

[digger]

i have the G260 with close ratio where 4th and 5th same but 1st to 3rd about 5-10% longer

G260 3.83/2.20/1.40/1.00/0.81
G260 CR 3.35/2.03/1.36/1.00/0.81

i find the 391 works well with the CR for around town and not too much cruising, the 373 cruises better but around town it is a bit long and this would be similar to a 3.46 with standard g260.