WTB Taller Final Drive Differential

[Mikewaitwhat]

BIMMERPOST / Classifieds

Asking Price:

None

Item Interest

Hey guys I'm looking for a taller final drive for my 08 6MT. I think stock is 3.85:1 and I"m looking for <3.85:1. I've seen Turner has 2.81, 2.93, 3.15, 3.23 etc. I just picked up this M3 about 5 months ago and I commute long distances everyday so I want to make this thing slightly more economical on the highway at 80mph. Anybody have any used diffs that aren't too beat up?

Thanks!

[Redd]

3.15 is the stock DCT final drive and should be cheap as shit.

But why did you buy a 4L V8 that revs to 8400rpm if you wanted an economical drive?

[pbonsalb]

Originally Posted by Redd

3.15 is the stock DCT final drive and should be cheap as shit.

But why did you buy a 4L V8 that revs to 8400rpm if you wanted an economical drive?

I agree. The OP will lose significant performance. These small displacement motors that make good horsepower at very high rpm use short gearing to multiply their relatively low torque.

I think the OP bought the wrong car for his use. A car with a serious overdrive gear would have been a better choice. He could have great performance and relaxed low rpm more efficient cruising. Some domestic V8 have overdrive in the 50% range versus 88% for a 6 speed manual M3.

[Mikewaitwhat]

cuz I can do whatever the fuck I want with my money

[pbonsalb]

Originally Posted by Mikewaitwhat

cuz I can do whatever the fuck I want with my money

Yes, there are people with money who make bad choices every day. Please note that while we are noting the issues, we are also helping. Since you don’t know much and can’t seem to figure much out on your own, you should at least be appreciative of that. With your attitude you might soon be all alone with your bad choices and your money and your lack of knowledge.

[warddrew]

Originally Posted by Mikewaitwhat

cuz I can do whatever the fuck I want with my money

You're an idiot

[Scharbag]

Another option is to run 295/35/19 in the rear...

Diffs are expensive. At my current fuel economy, 10% savings would save me $8 every 300km. Or $80 every 3000km. So it will take you over a year, plus parts, fluid and labor to break even if you put on 30,000km a year.

Plus your car will be slow.

But man I wish BMW would have put a big assed OD gear in 6th.

Happy hunting.

[Mikewaitwhat]

Originally Posted by Scharbag

Another option is to run 295/35/19 in the rear...

Diffs are expensive. At my current fuel economy, 10% savings would save me $8 every 300km. Or $80 every 3000km. So it will take you over a year, plus parts, fluid and labor to break even if you put on 30,000km a year.

Plus your car will be slow.

But man I wish BMW would have put a big assed OD gear in 6th.

Happy hunting.

Cool thanks for the input. Sure there's not going to be as much torque, but shifting gears eats up time too. It'd be interesting to see the difference in a quarter mile, say only having to shift twice instead of three times.

[Kelse92]

If you wanted a car that goes 90mph in 2nd gear you should've gotten a Z06...

[pbonsalb]

Originally Posted by Mikewaitwhat

Sure there's not going to be as much torque, but shifting gears eats up time too. It'd be interesting to see the difference in a quarter mile, say only having to shift twice instead of three times.

One less shift over 12-13 seconds won’t offset roughly 20% less torque multiplication that comes from lengthening 3.85 diff to 3.15.

[Markymark's M3]

This is what you need!
https://www.ebay.com/itm/2008-Toyota...oAAOSw31pfdFdX

[Redd]

Originally Posted by pbonsalb

One less shift over 12-13 seconds won’t offset roughly 20% less torque multiplication that comes from lengthening 3.85 diff to 3.15.

With our S65 low engine torque with taller FD, your fuel consumption may actually increase due to using more throttle to get the heavier car moving.

[SAMM3Y]

Supercharge it.. that'll improve fuel efficiency

[Johnr3524]

Originally Posted by Mikewaitwhat

cuz I can do whatever the fuck I want with my money

Well said.