[turugara]

Pros:

• Cools the LSD gear fluid much better than stock
• Adds port to monitor differential temperature
• Adds drain/fill plug for easy fluid change
• Shiny

Cons:

• $800
• Can be low to the ground (no issues surprisingly even in horrible Philly roads)

This is merely my opinion. Link to VAC's thread for more information:
http://www.e90post.com/forums/showthread.php?t=719991

Why bother with this?
This is one of those items that seem like a true enthusiast product for the "hardcore track junkie."
I thought the same until I discovered that I might be in serious need of such a product.

Many of you have LSD's in your OEM diff unit with BMW's "lifetime" gear oil.
Unfortunately, I recently discovered that this gear oil doesn't last anywhere near the "lifetime" of the vehicle, especially when coupled with a Quaife LSD and a few (15+ ) very hot track days.

My old unit had begun to spurt gear oil after track events.
After track events I would go under my car and find the pumpkin to be covered with gear oil. I would then clean it off and begin to worry. At first I thought it was the seals so we replaced those. Then after replacing the seals, the diff was still getting fluids all over itself after track events.

After some researching, I suspected it was because the diff oil was boiling and coming out of the top vent. After opening my diff up and seeing that the gear oil had gone to an extremely nasty shade of black, it was confirmed that I had cooked my gear oil and cooked it pretty bad.

Old Differential Cover: no Cooling options, fins, or drain plug




Which begs the question...
If I, an intermediate level driver at best, is cooking diff fluid in the New Jersey weather, how the hell is your diff fluid holding up if you live in a warmer climate, producing more power (all tuned n54...), or have more experience tracking?????

New Differential Cover




Driving Impressions:

This was the most surprising part. My Quaife unit felt like it was slightly more progressive, almost smoother with the new fluid and not boiling the fluid at the track. I hadn't expected a change at all but it was noticeable today at the track in 100+ degree weather when compared to just two weeks ago. This could also be attributed to the fact that my previous fluid had been boiled multiple times and was probably in horrible condition. Nevertheless, it's looking like this new differential cover will prevent that from occurring again.

On the street I've had zero clearance issues. I don't baby this car around the mean streets of Philly and South Jersey. Our potholes and bumps are legendary. I've seen a Ford F150 get stuck in a huge pothole in West Philly before. So far my lowered 335i has confirmed the VAC note that the race length (long finned) differential on a lowered vehicle generally has no clearance issues. Obviously if you ran through a curb that would take off your front bumper and various other underbody parts, you would probably scratch this differential cover. Best part is that even if you do hit it, it's made out of one piece forged billet aluminum so it's strong as hell.

Because Racecar



A properly oiled LSD with proper cooling means you go faster and kill your tires more to the point where street tires give out suddenly. XD

[GreekboyD]

Nice write-up man. Keep us posted. I'm getting a Quaife LSD this month.

[CJ421]

Superb write up. VAC machines these things in house so it's pretty cool you got it installed less than 100ft from where it was created (cheap shipping right? )!

Note to self: I think I'm gonna put turugara on my ignore list so I don't read about his racecar upgrades anymore; at first I'll deny wanting the upgrade but that is just delaying the inevitable.

[cvc 22349a]

Looking forward to getting a short fin cover from VAC soon...

[turugara]

Originally Posted by cvc 22349a

Looking forward to getting a short fin cover from VAC soon...

That's awesome. I'm actually moving out to the Bay area this fall. Should see you around at some of the local track events.

[cleex024]

Just got fine installed a couple weeks ago with my os giken lsd...the thing is just good looking you can't stop looking at it...I used to back into spots but now I go in forward now to see my diff

[tres]

VAC is a top notch shop I plan on getting one soon

[TurboBimmer]

Great review! Will have to add this to my to-do-list

[DallasBoosted]

I get that you're saying you haven't had clearance issues but that LOOKS like it is just waiting to be torn off.

[Brian_VACsales]

Originally Posted by DallasBoosted

I get that you're saying you haven't had clearance issues but that LOOKS like it is just waiting to be torn off.

We have run our race cover on our slammed shop 135i on the mean streets of Philly with no concern

[CALWATERBOY]

Originally Posted by turugara

I've seen a Ford F150 get stuck in a huge pothole in West Philly before.

I won't forget seeing a crew cab some cars ahead go straight up; down on its side in San Rafael.

Pothole. Beyond belief. Made front page, Independent Journal. Perfectly good weather too.

[turugara]

If you look under the car from a different angle, it's not THAT low to the ground. If you worry, might as well get the shorter one.

[nitehawk]

OP, I mentioned this on the other forum but maybe you didn't see it yet. Why did you not switch to a high temp oil such as the Motul Gear Competition 75W140? It may have been sufficient in preventing your overheating woes...without the diff cover

[Alpina_B3_Lux]

Originally Posted by Mike@VAC

We have run our race cover on our slammed shop 135i on the mean streets of Philly with no concern

I have the short version and I already had clearance issues, for example on slanted driveways. And my car isn't that low since I installed the Öhlins coilover.

Not saying it's not worth it, I'm very happy with it. But you have to be conscious that it is where it is in the middle of the undercarriage, and have to be more careful in some instances.

Alpina_B3_Lux

[Brian_VACsales]

Originally Posted by Alpina_B3_Lux

Not saying it's not worth it, I'm very happy with it. But you have to be conscious that it is where it is in the middle of the undercarriage, and have to be more careful in some instances

Sure, that should be a given IMO. I think I address that in the official sale thread too. Tony hit our cover once, but he had no business driving in a road divot that deep.

[cvc 22349a]

Originally Posted by Alpina_B3_Lux

I have the short version and I already had clearance issues, for example on slanted driveways. And my car isn't that low since I installed the Öhlins coilover.

Not saying it's not worth it, I'm very happy with it. But you have to be conscious that it is where it is in the middle of the undercarriage, and have to be more careful in some instances.

Alpina_B3_Lux

I thought so. I remember scraping my undercarriage a bit going up and over a driveway at an angle and certainly would have scraped a dropped diff cover. Did it damage the cover, bolts or housing, or just scratch the bottom of the cover?

OT I know: where's that Ohlins review?

[nitehawk]

Originally Posted by cvc 22349a

OT I know: where's that Ohlins review?

LOL, I bugged him about that earlier as well

http://www.e90post.com/forums/showpo...&postcount=147

[Alpina_B3_Lux]

Originally Posted by cvc 22349a

I thought so. I remember scraping my undercarriage a bit going up and over a driveway at an angle and certainly would have scraped a dropped diff cover. Did it damage the cover, bolts or housing, or just scratch the bottom of the cover?

OT I know: where's that Ohlins review?

No damage to the cover at all. It was of course also at very low speeds, and the cover is very sturdy.

Originally Posted by nitehawk

LOL, I bugged him about that earlier as well

http://www.e90post.com/forums/showpo...&postcount=147

Yeah I know, I'll do it probably at the end of the month, depending on when I find time.

I'm also indirectly using your pro tuning results by the way, Dzenno sent me a few maps with the 1M throttle mapping. Haven't tried them out yet though, but the protuning is one of the things that keeps on eating away my time. And now I have to wait (again) until my clutch is properly broken in...!

Alpina_B3_Lux