[748adam]

Hi guys,
I have an 07 335i and now I’m running considerably more power than stock I am finding the standard open diff a massive disappointment. I’ve looked into LSD from Quaife, Wacetrac etc and seen a few threads about putting the M3 diff in.
I know it requires a bit of work on the prop shaft to get it to fit (use 1/2 the 335 shaft and 1/2 the M3 shaft, 335 also need shortening).
Has anyone on here done it and know the length that the prop needs cutting to?
I have also seen a diff insert kit that claims to make the standard open diff as food as a LSD for €299. Anyone heard of Racing Diffs or even better used one?

Thanks
Adam

[Wareham]

I looked into this, did intend to go along with it also.

However, after thinking about it for awhile I decided against it due to the amount of work and effort as opposed to fitting a Quaife LSD. This way you do not change the ratios at all as the M3 is different. Probably would be much but I’d rather keep it geared how it is.

Birds do a very reasonably priced LSD instal by the looks of the website so I intend to do that instead.

Sorry if it’s not much help but I was in your shoes, then decided to take the easier option when the time comes. I’d suggest just have a good think and weigh up the difference in effort and cost...

[748adam]

Cost wise I imagine the m3 diff swap could be done for £1500 depending on the cost of the diff. Quaife and wavetrac come in at about £2300.
Racing diffs do a conversion for a standard diff for £300 but isn’t the way I’d like to do it as I’d prefer a proper LSD but the cost is is the biggest thing!

[Wareham]

Have you taken into consideration the cost of welding up the prop and balancing aswel?

Along with a oil change on the diff and anything else that may crop up during the install. There’s always something..

Personally I wouldn’t want a £300 conversion job, I’d go for a well known brand with visible reviews.

Birds Auto do a Quaife install on my model 335i fitted for £1392 ex VAT which works out around £1670 inc VAT. No hassle no bother. Proven performance from a brand new part.

https://birdsauto.com/quaife/search?...=47270&mi=335i

I’ve read the M3 LSD is abit of a smoother drive but no other benefits. I just think there is a reason why there isn’t loads of people doing it. Cost.. unless you’ve got the parts for near nothing.

[748adam]

I don’t know of a lot of people fitting lsd’s to be fair, the cost for a Quaife is £2014 according to Birds website.
I have spoken to a couple of guys (not at length) about the racing diffs conversion and they have said that as a daily driver it’s great, if you do a lot of track stuff then it would probably show it’s limitations.
The m3 conversion has pros and cons as the m3 axles are beefier, parts are easily obtainable if needed, but it’s more work to fit
The Quaife is a bolt in fit and forget kit, but is dear
The racing diffs would be the cheapest way to do it but appears to be a bit bodgey?

[nomiS330d]

Your car is a beauty Adam and I would think a long term keeper. If my very average car is worth it then yours certainly is. As I said on Saturday, quaife it and be done and as you said to me, you’ll get your money back come sale time.
One thing that did occur to me on my way home was can’t you get a diff off an older car with the bolt on ‘wheel’? That way the quaife would be cheaper and you could courier it so you don’t have to drive to slough. Also it took most of the day to do mine so would save you a ‘wasted’ day.

[748adam]

Hi Simon,
I know the diff will always sell for good money when the time comes, its just the initial outlay (especially with an upcoming wedding).
My build date is just after the change so as I belive I may have a bolted diff already, RealOEM says it can be 1 of 2 diffs even when I put in my chassis number.
I have tried to find early diffs just incase but so far have drawn a blank.
The 2 numbers that RealOEM give are
33107571187
33107566152

[748adam]

£1800 for a Quaife if i post them my diff and I would have no car for circa 10 days

[Wareham]

But then how long would it take for the M3 diff conversion..?

[BSSBMW]

The Quaife is not a true LSD, its an ATB (automatic torque biasing) differential and only behaves like a true LSD on acceleration.

A wavetrac is also an ATB but but has a feature built into it to make it behave more like a true LSD.

A drexler LSD is the best bet and its was Alpina use in the E92 GT3, the F3x B3 and D3 models as well as BMW motorsport in their race cars.

I got a price and its about £2k+vat+fitting and for the E9x it needs to be sent to Drexler due to the E9x welded crown wheel.

[Tambohamilton]

So what's the advantage of a drexler diff over quaife?

[RajB]

I’d definitely say it’s an easier process to go with a Quaiffe or Wavetrac etc. The M3 diff is a good upgrade but it’s certainly not just a simple diff replacement as there’s other mods required to get it all hooked up and running.