5-Series (E12,E28, E34, E39, E60)Chat relating to the BMW 5-Series of all generations. Specific models include: BMW 518, BMW 520, BMW 520i, BMW 530i, BMW 528i, BMW 530i, BMW 518i, BMW 524d, BMW 525i, BMW 525e, BMW 528e, BMW 540i, BMW 535i, BMW 520d, BMW 525td, BMW 525d, BMW 530d, BMW 525i/xi, BMW 530i/xi. (BMW 5-Series Forum)
I have a 97 540i automatic and was thinking of going from my stock 2.81 diff to a 3.15 non limited slip from a newer model 540 but I had a few questions.There is a top speed govenor of 155mph on a stock 540.Is that limited by engine/transmission speed or by actual vehicle speed gauged by the front tire/s?The reason I think the vehicle speed is gauged by the front tires is that when i break the rear tires loose with traction control off the tachometer raises while the speedometer still shows the actual vehicle speed.Dinan sells a 3.15 lsd diff for alot more than I can afford and they claim no effictive top speed loss but I dont know if thats because software comes with it to compensate or not.Also I was wondering if anybody knows how to get in contact with RevHigh about engine software.And my last couple questions,how dramatic would the differential upgrade be?Is there any other modifications needed to accomodate this upgrade?How much should a shop charge for installation?Has anybody else had experience/luck with this or a similar upgrade?How did you like or not like it?Thank you so much for your time and input.
the car is Electronically limited to 155mph meaning no changing the diff wont effect that much(donno how close to redline in 5th you are at with the current diff) Btw why does that matter? you cant really do 155 on the street or many tracks for that matter......
__________________ 1991 Ford Taurs SHO 5 Speed White on Tan
1996 Chevy Lumina LTZ Rep 3.4L
1992 318i Coupe parts car
1992 325i Ls1 swap with a T56 6 speed 12.2 quarter mile
1976 Mercedes Benz 300D with a Ford 5.0L Fuel Injected soon to be Modded I am Captain Obvious
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