Reply With Quote3.91 to 4.27? it's been suggested that you may gain a couple mph with the better mechanical advantage, i never topped out my 535ia but on the happy side of 135 it still had noticeable acceleration
Major Contributor
Diff.
How will my top end be effected if i swap out for a 4.27 LSD on my '89 535?
5-10 Grand Master
3.91 to 4.27? it's been suggested that you may gain a couple mph with the better mechanical advantage, i never topped out my 535ia but on the happy side of 135 it still had noticeable acceleration
all america wants is cold beer warm cat and a place to take a poop with a door on it
Major Contributor
Are there any negative sideffects from going to a 4.27?Originally Posted by winfred
5-10 Grand Master
it goes faster and if you drop the old one on your foot it could hurt
all america wants is cold beer warm cat and a place to take a poop with a door on it
Major Contributor
Assuming your 89 presently has a 3.91, the rpm's at 80 mph will increase from 3000 to 3300 with a 4.27. Adverse effects from running a 4.27 should be minimum. The factory made them std. on 91-93 535ia's. Back when mine was still an automatic, I would have put a 4.45 in it if they weren't so expensive.
gale
92 735i 5-spd, turbo project finally underway!
Major Contributor
Will my top speed be decreased?
Major Contributor
Yes. There is a great set of resources on the Koala MotorSports Website for calculating the differences between where you are now and where you want to go. I just bought the 40% LSD / 3.15 Diff from them to put on the 540/6 I have. It is a wonderful difference - especially since I am running 18" wheels. - JT
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