which box and diff ratios

[baurboy325]

Hi all ,have just finished a very costly 2.7 stroker build to my 325i baur cab 1989.Cheers Ant for the Chip by the way ,my problem is which gear box and which diff ratio should i use to make the most of all that lovely power ? i found one site that suggests Alpina used the standand gear box with a 3.64 LSD what is a little worrying i just bought a late Sport gear box ,please someone help ,cheers ,James.

[Brianmoooore]

It's only the lower gears that are different on the 'sport' box - fourth and fifth are the same.
3.64 sounds about right.

[baurboy325]

It's only the lower gears that are different on the 'sport' box - fourth and fifth are the same.
3.64 sounds about right.

Cheers ,was wondering if the lower gears would be to short as well ? should i still with my standard box ,or swap to the Sport?

[Brianmoooore]

The more torque you have, the less you need a close ratio box.

[baurboy325]

Cheers ,wiil stay as i am then .

[daimlerman]

I am using a standard 320(Getrang 240)'box with my 2.7,and a 3.64 diff.

[baurboy325]

So is it worth me fitting the sport box in your oppinion then mate ?

[daimlerman]

So is it worth me fitting the sport box in your oppinion then mate ?

Frankly,no!

The 'box I am using has almost the same ratios,but the 325i 'box is bigger,has bigger bearings and holds a little more oil,the 'sport' 'box gains the closer lower three ratios and the bigger bearings and oil capacity.

BMW engineering in the '80's used both belt and braces....

[baurboy325]

Thanks for your help,its much appreciatred will stick with what i have and put the sport box in my auto touring lol ho hum yet another project