Which diff ratio ?? - The Unofficial BMW M5 Messageboard (m5board.com)

madmax · 13th July 2003, 07:05

I am about to order a Quaife diff and was wondering about any opinions regarding the ratio.
Was thinking about 3.64 but also am tempted by the 3.71 ratio.
Any thoughts or personal experiences would be appreciated, muchly.
TIA

MIB · 13th July 2003, 07:14

Hey Max,

Those are pretty short, are you planning on a lot of Quarter Mile runs?

Whats your source for the Quaife?

Don't quote me but I think they only make diffs for the 840, I don't know if they do one for the M5. Of course I could be wrong.

I'll probably go with the Dinan 3.45.

Regards Mark.

01M5 · 13th July 2003, 07:28

Rallistas installed 3.73 gears. Check with him. Here's the thread: http://www.bmwm5.com/vbulletin/showt...highlight=3.73

Where are you getting yours from? Let us know how it turns out.

Najeeb

MIB · 13th July 2003, 07:31

Or this one Quaife Impressions.

stever · 13th July 2003, 07:41

i've got the Dinan 3.45 and think this about the optimum ratio (maximizes top speed if you care about that) and has reasonable revs for cruising in top gear, and noticeable in-gear improvement in 3,4,5,6 responsiveness

the 3.64 would be okay, but with the M5s torque and drivability tradeoffs, i don't think the 3.71 would be a benefit

with 6 gears and M5 torque there are lots gear options -- in hot weather on track, if i run max revs in 3rd for too long the oil temp overloads the cooling system -- revising shift points for more 4th gear has virtually no impact on lap times

madmax · 13th July 2003, 09:28

Getting it from Koalamotorsport.
Think the 3.64 would be a good comprimise
The 3.45 is only 9.5 % increase and with exchange costs etc am looking for MAX bang for my bucks!!!

MIB · 13th July 2003, 10:01

Hey Max,

3.45 = 9.8% change.

3.64-3.15= .49/3.15 x 100 = 15.5% change for a 3.64

Ralistas

3.73-3.15= .58/3.15 x 100 = 18.41 % Change for a 3.73.

Thats a lot of extra shifting.