Final Drive

[yky]

Has anyone tried installing a lower final drive into their cars? Heard that it can do wonders for acceleration by torque multiplication.
What is the experience like? Problems? Cost ?

 

[Racebred]

what is your car now and what's your current final drive ratio?

 

[yky]

E65 730i. Don't know the final drive ratio. Not stated in the specs in the car's manual.

 

[Tanzy]

yky,

Usually car manufacturers will tune the final drive to allow the second gear to redline at 100km/h. It's all about marketing and numbers. If you do shorten the final drive, the acceleration will improve but 0-100 time might increase because the car will need to go into third gear to reach 100km/h.

 

[rex7_vtec]

Tanzy,

Maybe he wants to play 0-200? Anyway a shorter final drive is'nt really a bad thing, feels damn good to do city driving

 

[Racebred]

for 7 series, there may not be shorter ratios available which can fit your driveshafts. need to check etk, or go aftermarket

 

[rex7_vtec]

Would the diff be same as an E46 330?

 

[TripleM]

yky,
Think the factory's FD set up for 6potter is great for driving on Singapore roads. It's expensive to change FD, dont waste your money.

People would normally play ard with FD ratios when they are more into tracking or a rather hardcore one..

 

[Racebred]

i havent checked, but i'm almost certain the e65 drive and prop shafts are thicker than the e46. to change to a new rear diff, will cost probably 3-4k.

 

[yky]

I was asking about the FD because in Singapore, how fast can u go? Torque ( acceleration ) is more useful then BHP.
Most current mods that improve both the torque and bhp substentially are expensive and non discrete eg. SCs. Electronic tuning and other things like CAI, ecoteks, etc can improve the butt feel of the Gs from the traffic lights by only so much.
I was thinking that if a lower FD ( cheaper then a SC right? ) may improve torque delivery even without bhp increase and is also more discrete, why not?

However,as is discussed, the FD for the IL6 is probably optimised already and it is also not that cheap ( though not as ex as the SC ).

Thanks all for the inputs.

 

[Racebred]

even for a very very short ratio of 3.91, you can still hit 250kmh. good enough liao