E30 Zone

As above im looking to fit an lsd to my 325 touring which now has an rb25 engine. The car currently has the standard diff fitted which i believe a 3.91. Theres nothing wrong with the diff itself, i'd just like an lsd for better traction etc.

you just need a 3.91 lsd then from an e30 .

U need my 3.91 LSD!

Answer to this question depends a lot on the intended use for this car and the power output of this RB25 engine.
IMHO, BMW made a mistake with the original ratio for this car. One of the best mods. I ever did to my otherwise standard 25 touring was to change the 3.91 for a 3.76. Gave more relaxed motorway driving, better fuel consumption, made third gear more usable, with no noticeable adverse effects.
Assuming this engine produces a bit more than the standard BMW engine, then I'd advise against using any small case diff, which restricts your choice to a 188 LSD in a medium case diff. You just have to decide on the final drive ratio.

Just weld up the diff you already have, much better snd much cheaper

TommyM wrote:Just weld up the diff you already have, much better snd much cheaper

And will be impossible to legally insure for use on UK roads.

I drive one on my daily, i wouldnt have it any other way to be honest.

TommyM wrote:I drive one on my daily, i wouldnt have it any other way to be honest.

Then you are driving with invalid insurance!

Brianmoooore wrote:

TommyM wrote:I drive one on my daily, i wouldnt have it any other way to be honest.

Then you are driving with invalid insurance!

That is a myth! Just weld the bitch up and once this snow hits ul just keep on going ;)

TommyM wrote:

Brianmoooore wrote:

TommyM wrote:I drive one on my daily, i wouldnt have it any other way to be honest.

Then you are driving with invalid insurance!

That is a myth!

You reckon! Yours declared to your insurance company?

Brianmoooore wrote:

TommyM wrote:

Brianmoooore wrote: Then you are driving with invalid insurance!

That is a myth!

You reckon! Yours declared to your insurance company?

Yeah my insurance company loved it! U going to tell yours if u fit lsd? Id still highly recomend the welded option

I'm aware that a very few on here do claim to have declared welded diffs to their insurance companies and have had the mod. accepted, but I'm almost certain that if the worst did happen, and the car was inspected by a police/VOSA examiner, you'd find your insurance retrospectively voided, as it will be if one of your other threads on here is noticed by the appropriate authorities, where you openly admit to refitting cut springs on your car, after having a MOT certificate refused for the use of them, thus rendering your car unroadworthy.

Yeah if u go into enough detail alot of things could be meaning you have no insurance as far as going on a cd player etc, fitting a lsd is still a modification to standard if car came with open diff so insurance void again
Well this is it i have a love of cut springs like many others

If I fit a LSD to any of my cars, I notify it to my insurance company as a mod. AFAIK, it hasn't affected any quote so far.
In the real world, any E30 owner is unlikely to get themselves into trouble by fitting any optional extra to their E30 that could have been fitted from new, not least because after several changes of ownership, the current owner cannot be expected to know what has been fitted since new, or even be expected to investigate to find out what the original spec. was.
However, welded diffs and cut (= loose) springs were not fitted as standard. A new owner cannot be ignorant of the welded diff after the first low speed corner, and the cut springs should be picked up within thirteen months at most, at the first MOT test.

Its the future, lsds are still anyway away from awsome cut springs subject i think this guy just wants better traction

I love that this has just sparked of an argument