I have been asking alot to find out about the performance gains on upgrading to a performance diff (my 3.64 arrived yesterday, still in the box awaiting install).

I have read on this site that the standard diff from the factory on 95 540 is a 2.81. So, I figure my upgrade will be aggressive, but it is what Dinan recommends as well as others like Dan @ diffsonline.

So I am reading the Dinan site, and they I find their products with a description of their diff you can buy for $3600K...cough cough, but then I see this for the 540ia:

"For even faster acceleration, as well as improved handling, a 3.64 Limited Slip Differential is available for automatic 540 models (3.15 stock ratio). The 3.64 gearing provides an almost 18% increase in torque delivered to the ground for faster and more immediate acceleration, along with improved traction for faster cornering."

and then this for the 540i/6

"The 3.15 gearing for manual equipped 540s is also available in a limited slip version for improved cornering and acceleration. The shorter gearing (2.81 stock ratio) provides a 12% increase in torque delivered to the ground. "

http://dinancars.com/Series.asp?Series=15&Chassis=14&Model=62&Class=Driveline%20Tuning#1478

So is this true? How do I find out for sure? Is there a code in my VIN or is the part number off the old diff that I can match to confirm?

i believe it is stamped on the orig casing... just crawl p underneath the car and look

There is no number on my casing :( .This is true the 2.81 came stock on the 6 speed.I bought my car with a Dinan 3.15.

there should be a very small metal tag.

either way, =< 94 is 2.93 and 95's are 2.81... if i recall....

it is a 2.81 the dinan site is wrong. The only 540 that gets a 3.15 is 98 or 99 and newer sport auto 540's.

The Dinan site is right no?

it is a 2.81 the dinan site is wrong. The only 540 that gets a 3.15 is 98 or 99 and newer sport auto 540's.
sorry man, thats wrong ;)

sorry man, thats wrong ;)

no it's right.

95-2003 540 automatic non-sports are 2.81, 98 and up 540 sports (auto's) are 3.15, 6spds are 2.81.

When you're ready to admit i'm right, just let me know.

Thanks,

;)

edit: e34 540i6 are 2.93, not 2.81, however, that was not being argued, just thought i would throw that in :D

sorry man, thats wrong ;)

i just realized you and I are saying the same thing :dunno

His car has a 2.81, it's a 95 540.

I'm more confused then poop in a jar.

read my orig post in response to your post and keep in mind that i was talking about the e34's... i think we are agreeing.

There is no number on my casing :( .This is true the 2.81 came stock on the 6 speed.I bought my car with a Dinan 3.15.That sounds like my car, too.

read my orig post in response to your post and keep in mind that i was talking about the e34's... i think we are agreeing.

you said i was wrong? :dunno

it is a 2.81 the dinan site is wrong. The only 540 that gets a 3.15 is 98 or 99 and newer sport auto 540's.

the 2.81 on the dinan site is not wrong when talking about e34's. and the e34's get 3.15's as well. that is what i meant.

the 2.81 on the dinan site is not wrong when talking about e34's. and the e34's get 3.15's as well. that is what i meant.

I concur. :cool

I have been asking alot to find out about the performance gains on upgrading to a performance diff (my 3.64 arrived yesterday, still in the box awaiting install).

I have read on this site that the standard diff from the factory on 95 540 is a 2.81. So, I figure my upgrade will be aggressive, but it is what Dinan recommends as well as others like Dan @ diffsonline.

So I am reading the Dinan site, and they I find their products with a description of their diff you can buy for $3600K...cough cough, but then I see this for the 540ia:

"For even faster acceleration, as well as improved handling, a 3.64 Limited Slip Differential is available for automatic 540 models (3.15 stock ratio). The 3.64 gearing provides an almost 18% increase in torque delivered to the ground for faster and more immediate acceleration, along with improved traction for faster cornering."

and then this for the 540i/6

"The 3.15 gearing for manual equipped 540s is also available in a limited slip version for improved cornering and acceleration. The shorter gearing (2.81 stock ratio) provides a 12% increase in torque delivered to the ground. "

http://dinancars.com/Series.asp?Series=15&Chassis=14&Model=62&Class=Driveline%20Tuning#1478

So is this true? How do I find out for sure? Is there a code in my VIN or is the part number off the old diff that I can match to confirm?


Read in bold. This is what i was responding to. Supposedly that is from the dinan site. It says 3.15 stock ratio, that is wrong.

Read in bold. This is what i was responding to. Supposedly that is from the dinan site. It says 3.15 stock ratio, that is wrong.


That is what my thought is, is that Dinan was wrong. But I will find out soon enough....Getting installed next week.

BTW I just spoke with Dan/Diffsonline a moment ago about just this because I'm looking to upgrade my stock open diff to a LS-according to Dan the optimum street set up for an E34 540/6 spd is a 3.15LS with 40% lock up. The M60 delivers a whole lotta torque so even though a 3.25LS, 3.46LS or 3.64LS would all make the ultimate urine machine, the 3.15LS will definitely get all the power to the ground. Dan's words, so it must be so.........

Extremely old post but yes... 3.15lsd is the way to go. I ran a 3.64 open diff for about a year on my 540/6... way too short and with it being open obviously no traction in 1st or 1/2 of 2nd. Kind of interesting exiting a corner in 3rd and having to feather...

Where woud be a good place to buy a LSD for a 540.. Besides DINAN?? I just can't see paying that much for one. And what could I expect to pay for it? Love to have the 3.64.

Junkyard... diffsonline... diff out of an e32 750 is what you're looking for. My 3.64 as out of an e31. 3.64 is the ratio to get for an e34 540 auto. Obviously Whitney did this and liked it quite a bit...

ps... who else misses whitney. he needs to browse the e34 board a bit more.