Limited Slip Diff / 335i SCCA class questions

[clifton23]

So I found out I am lucky and my 335i's has a bolted ring gear. This makes swapping to a LSD much much easier. Most 335i's have a welded ring gears, which means you have to swap the whole carrier out. My build date was one of the few with a bolted ring gear.

I have a few questions about LSD's.. I have heard nothing but good things about Quaife Differentials.. What are your opinions on them? They have a diff for my car that is less then $2k.

I really really miss autocrossing. So if I wanted to get back into it with this car + LSD, what would that do to my class?

I don't even know where the 335i is classed stock.

[Fair!]

Re: Limited Slip Diff / 335i SCCA class questions

So I found out I am lucky and my 335i's has a bolted ring gear. This makes swapping to a LSD much much easier. Most 335i's have a welded ring gears, which means you have to swap the whole carrier out. My build date was one of the few with a bolted ring gear.

I have a few questions about LSD's.. I have heard nothing but good things about Quaife Differentials.. What are your opinions on them? They have a diff for my car that is less then $2k.

I really really miss autocrossing. So if I wanted to get back into it with this car + LSD, what would that do to my class?

I don't even know where the 335i is classed stock.

The 335 was just moved to D Stock (with the 135i) from F Stock in this month's FasTrack. But you cannot add or alter the factory differential in Stock category. Stock class is boned...

You are probably better off running it in STU anyways, where you can not only add the Limited Slip Diff you want and need, but you can fix the lack of camber and super soft spring rates as well. You can also add a "tune" and that means +100 hp in a 335.

As for the Quaife, Torsen or other gear differentials, these are usuaully shunned b BMW autocrossers. These diffs quit working if a tire ever comes off the ground - it goes completely open. The crazy gyrations and transitions in autox can make this happen. So, you are better off going with a clutch style or a hybrid diff. Check out my DSP thread for much more information on diffs

Good luck,

[clifton23]

Re: Limited Slip Diff / 335i SCCA class questions

Thanks for the info Terry.

my first mod was going to be the LSD and my second mod was going to be the JB3+ tune... +80hp +80tq on pump gas

I have read reviews about the Quaife and them going open when a wheel is lifted.. That pretty much defeats the purpose when that scenario presents itself.
Clutch diffs require maintenance though.

STU is a pretty competitive class, or at least it used to be when I autocrossed. Interesting, that would be a fun class!

[McCall]

Re: Limited Slip Diff / 335i SCCA class questions

Thanks for the info Terry.

my first mod was going to be the LSD and my second mod was going to be the JB3+ tune... +80hp +80tq on pump gas.....

.....STU is a pretty competitive class, or at least it used to be when I autocrossed. Interesting, that would be a fun class!

When talking about a tune on a turbo car, do remember to be 100% legal for STU (no snickering), any tune can NOT include changing the boost levels. You can only change the timing, air/fuel, and rev limiter.

If you change the boost, then you are bumped to Street Mod (SM), where the spending levels are just off the chart if you want to be competitive regionally/Nationally (fully built motors/crazy chassis lightening/big flares/biggest wheels/tires/full aero/etc). If being competitive is important, then you will have to sacrifice some hp in the tune and stay in STU.

[clifton23]

Re: Limited Slip Diff / 335i SCCA class questions

well that sucks.. almost every tune/chip for this car is mainly increased boost.

[Fair!]

Re: Limited Slip Diff / 335i SCCA class questions

But... in reality a lot of STU cars have boost.

The clutch diffs I'm referring to don't need much if any maintenance. The hybrids are even better. Look at the OS Giken - that's what I'm using in my DSP E46 build.

[clifton23]

Re: Limited Slip Diff / 335i SCCA class questions

But... in reality a lot of STU cars have boost.

The clutch diffs I'm referring to don't need much if any maintenance. The hybrids are even better. Look at the OS Giken - that's what I'm using in my DSP E46 build.

Turner sells a OS Giken for the 335i