[DialedIn]

Hello,

After installing polyurethane bushings in the rear (differential, subframe, control arms, the lot), I noticed a nasty noise coming from my differential when letting off the gas at highway speeds. The noise in directly correlated to engine rpm and dies down as they drop. - So I need new bearings for my differential!

But, should I install a Quaife Torsen differential at the same time?

Are the 325i's drive axles (my drive axles are 38mm in diameter) strong enough to handle the beatings that come with owning an LSD differential and doing burnouts?

[Biginboca]

Wheel hop during a burnout is the most likely thing to break your axle.

I think you are on the right track, the driveline in the n52 cars is pretty weak except for the 330i which shares some driveline parts with the 335. I would not consider the 325 to be a good hoonigan car but unless you are getting wheel hop I doubt you would have an issue. There’s quite a few of us with lsd and I’ve not heard any issues with broken axles.

Btw I would bet that not a single person in the N52 forum installed a LSD with the goal of doing burnouts. The car will do burnouts without the lsd. The LSD has benefits for tracking and autocrossing which is why people on this forum put them in.

These tire marks were made in a single pass by my car before LSD install. You can see both rear tires spun through first and then when I shifted to second continued to both spin until I let off...

[DialedIn]

Originally Posted by Biginboca

I would not consider the 325 to be a good hoonigan car but unless you are getting wheel hop I doubt you would have an issue.

I like less powerful cars to be honest. I think the 325i with the 2,5 liter N52 engine is the most fun car to drive. I have already done all the handling upgrades possible except for the LSD.

Originally Posted by Biginboca

Btw I would bet that not a single person in the N52 forum installed a LSD with the goal of doing burnouts. The car will do burnouts without the lsd. The LSD has benefits for tracking and autocrossing which is why people on this forum put them in.

I have a few sets of old and dry all season tyres that I can destroy, so I want to have the possibility to do burnouts. The main thing would be to get better wet and snow traction.

I might be able to use this car in the winter on icy roads with studded tyres and a disconnected rear sway bar, I think.

[Efthreeoh]

Any chance you've considered that changing the durometer of the rubber in the bushings has created the noise?

[DialedIn]

Originally Posted by Efthreeoh

Any chance you've considered that changing the durometer of the rubber in the bushings has created the noise?

Yes, but a friend has the same set-up and does not have the noise.

Probably changing the hardness of the bushing amplified the noise and made me discover the problem at a very early stage. - It is not a noise as much as a vibration so it definitely travels through the body of the car.

[Efthreeoh]

I'd consider the driveshaft first.

[DialedIn]

Originally Posted by Efthreeoh

I'd consider the driveshaft first.

What makes you suggest the drive shaft as the culprit?

[Efthreeoh]

Originally Posted by DialedIn

What makes you suggest the drive shaft as the culprit?

Well, it sounds like you abuse the hell out of your fine european car (look to Ford or GM for burnout machines - just sayin'), and the driveshaft has very tight tolerances. I suspected my rear bearings, then diff, and finally it turned out to be the driveshaft. It probably was just the center bearing (which I had already replaced once prior - like 150,000 miles prior), but for about double the price of the center bearing (part) a rebuilt driveshaft can be had and it's an easy install.

[DialedIn]

Originally Posted by Efthreeoh

Well, it sounds like you abuse the hell out of your fine european car.

I have no clue how previous owners have treated the car. But the driveline noise is most likely due to abuse as you say.

I'm interested in an LSD for performance and enjoyment. But I don't want to abuse my car.

I know you should not do burnouts in a car with an open diff. :/

[DialedIn]

I switched in another differential and the sound is completely gone now.

I'm fairly sure the old bearings were bad due to abuse. :/

[DialedIn]

I ordered some new Meyle drive axles to go with my new Quaife Torsen differential. My drive axle rubber boots near the wheel are a little torn and require new boots.

The Meyle drive axles were almost as cheap as buying new boots so I just went with the complete drive axles to save some labour time. But the new axles are only 29,5mm in diameter, while the ones on the car are 38mm diameter ones.

is 29,5mm diameter strong enough to handle the abuse of doing burnouts and donuts?

[Biginboca]

Originally Posted by DialedIn

I ordered some new Meyle drive axles to go with my new Quaife Torsen differential. My drive axle rubber boots near the wheel are a little torn and require new boots.

The Meyle drive axles were almost as cheap as buying new boots so I just went with the complete drive axles to save some labour time. But the new axles are only 29,5mm in diameter, while the ones on the car are 38mm diameter ones.

is 29,5mm diameter strong enough to handle the abuse of doing burnouts and donuts?

If you plan on hooning your car I would not run those axles. That’s a significant downgrade in strength that I would not be comfortable with. I would send them back and replace the boots on the original ones.