I originally posted this in my regional forum, but I thought to share it with those who might be sitting on the fence about a differential swap. If anyone has any misgivings about a diff install, that is what BMW would have you believe...that way more M3s are sold.
However, installing a diff, any kind of diff, is as much a safety issue as it is a performance enhancer! I would highly recommend this mod before anything else for the 335i. Why? Performance bang for the buck.
Better tires, intake, exhaust, ecu upgrade.....NOTHING, if you can't transfer that power to the pavement efficiently, economically, and FORCEFULLY!!!
Hence, my testimonial,
QUAIFE: Power to the Pavement!
Any Diff Over the Open Diff Makes a Big Diff!
Quaife diff installed!--First Impressions!
The Quaife Diff Install
Well, I finally pulled the trigger on my Quaife differential installation. Back in November 2008, I researched diffs enough to purchase the Quaife w/3.08 gearing for my 6MT 2007 SG e90 335i from Harold at HPAutowerks for an unbelievably good price at the time, but couldn't get around to having it installed until now, due to the uncertainty of the quality of installers in the area and mixed reviews of install costs from some of the forum members.
After much hand wringing and good advice about local DC metro installers from some of the e90post Mid-Atlantic chapter forum guys, I took my ride to Ivan at IMA Motorsport in Chantilly, VA, a service and tuner shop for Porsches, BMWs, Mercedes, and Corvettes. Gearhead in Chief Ivan knows BMWCCA member, golf pro, and fellow gearhead Willie Lutz at South Riding Golf Course, and he was at our BMWCCA DC Chapter Spring Golf Outing, but it didn't occur to me to take the diff installation to him until I saw his ad in the South Riding Golf Course web site.
Check out IMA's web site: http://www.imamotorsport.net/index.html
IMA recently moved into its new digs in Chantilly (located equidistant from Pleasant Valley and South Riding Golf Courses) and was offering performance auto services while you played a round of golf. They have been custom-tuning vehicles, especially Porsches, for the track and the street, which is the main reason I brought my business to IMA.
New Chantilly location off of the Pleasant Valley Road intersection:
A view of the waiting room:
What first impressed me was the cleanliness of the spaces. Here is a shop that takes pride in its work by the orderliness and professionalism displayed in the work area. I was especially taken by the six lifts IMA sports:
Not to mention the race car projects underway:
Jimmy and Aaron put my ride on the lift and commenced to rip out the open diff casing (YES!!):
Closeup of Jimmy rummaging under the diff case (nice Hankooks):
View of the open diff case EMPTY!!! (Note the exhaust system still attached):
Open diff (left) next to Quaife diff (right) ready for swap out:
Quaife diff ready for install:
Quaife diff inside the diff case awaiting case cover and gear oil:
So, after all is said and done....is there a diff with the diff?
Why would anyone want to install an automatic torque biasing differential like a Quaife, Torsen, Wavetrac, or clutch type limited slip differential? There are a few other threads that thoroughly explain the advantages of an LSD over an open differential, so I won't regurgitate what has already been covered, but I will refer you to all of those links, if they're still available:
WOW!!! Wotta Difference!
I know, I know...everyone who has ever had a diff replacement has probably said the same thing.....so, I echo their sentiments!
My wife drives a Mercedes E350 4Matic Sport Sedan, which is the AWD equivalent of the BMW XiDrive and Audi, etc., etc., so I have had the pleasure of flailing my wife's E350 up and down the eastern seaboard with complete confidence in rain or shine....or snow. I wanted the same feeling in the e90, and now I have it!
After "gently" breaking in the e90 with the Quaife installed, I noticed that the car felt more "planted," more purposeful, and tighter in overall handling and performance. There seemed to be more get up and go, more (this is scientific seat-of-the-pants analysis, mind you) OOOMPH!! and tighter lines in the sweepers around RTE 28, the Dulles corridor, and all of those new ramps being built between RTE 66 and RTE 7 in Northern VA.
For the unaccustomed, be prepared to change your driving habits with a diff installation....and increase your tire pressure, baby, because you will have nothing but fun! Take it to an empty parking lot and feel the new dynamics of the BMW's enhanced handling and performance characteristics.
I do feel the difference in the rain at the toll booths heading onto the Greenway towards Leesburg, especially as I slow to a crawl through the gate in second gear and then PUNCH IT in the merge area, careful to avoid all of the ... ummmm ... "drivers" ... in the far left lane, as I wind it out to the "speed" limit cruising speed.....
I recently switched to Hankook Ventus V12 Evo non-runflats, which has also enhanced my driving experience because they are quieter, excellent in the rain, and very reasonably priced....so it is like night and day compared to the RFTs...
Why Quaife? Why Not?
I have been reading about the Quaife diff, its lifetime warranty, and the overall advantages of Old School "positraction" inherent with any limited slip differential.
First and foremost, there is the safety factor. I now have the ability to control my destiny (and my car) under nearly any road condition. I have enhanced my ability to negotiate wet traction issues by combining my Hankook non-RFTs with the Quaife diff. I now have the low-end torque transfer, thanks to the Quaife, to handle any emerging driving situation. I am now better equipped to handle most of the day-to-day driving that occurs in the lower end of the speed and RPM spectrum, handling daily commuting with aplomb....and yes, a little rancor...at some of the atrocious driving habits of some in the DC metro commuter community.
Yes, the Wavetrac has added features, but with either one (Quaife or Wavetrac), you can't go wrong. I don't plan to track my car in the near future, but I do want to maximize the power and strength that BMW has built into the TT6 with the minor addition of a much-needed mechanical limited slip differential. Yes, Wavetrac is initially less expensive, but the Quaife ATB differential has been around a long time and has a proven "track record" with a lifetime warranty against mechanical failures.
What about that Thump?
Oh, and that thump that everyone keeps talking about .... nada .... nichts .... zilch .... it is not inherent in the Quaife, Wavetrac, or any other brand diffs.... proof is in the pudding... a professional installation from knowledgeable gearheads is all the difference in whether or not you experience a thump, thunk, or bump....Thanks to Jimmy and Aaron at IMA....don't expect any backlash from them...hehe
2007 Sparkling Graphite e90 335i sedan, 6MT/Sport/Cold Weather/Premium
Drivetrain: Quaife ATB Differential, courtesy of Harold at HPAutowerks
Diff install: 5 hours, courtesy of Ivan at IMA Motorsports.
(Note: IMA has a $50 off Refer a Friend promo.) Tell them Jose sent you (LOL)... Check Ivan out on what they could do on welded diffs and pumpkin swaps (getting close to Halloween, I reckon) at 703-327-9858.
Tires: Hankook Ventus v12, courtesy of Tire Rack
I want to add a BMW aluminum rear guide rod kit to strengthen my ride for better traction and handling. See the following:
HKS exhaust system (no burnt tips) to lighten the load and let it breathe easier
For more info on Wavetrac: