Originally Posted by 335dFan
Originally Posted by dbicker
I'm new to tuning and have taken a rather slow progression since my car came out of warranty two years ago. I have generally read various threads, researched prices and made small changes to my car. I came across the idea of installing the Quaife LSD on these forums and since I didn't really understand the difference it would make, went with other upgrades I have a better feel for in terms of cost/benefit. Boy was I wrong.
I went to VAC motorsports last Monday and had the Quaife installed on my day off. Although I had a welded diff, Mike had a pre-built one in stock and they were able to swap it out in about 5 hours. They took great care of me and I passed the time on their wifi/reading. Mike even gave me a tour and took me back a few times to see the progress on my car.
It's CRAZY how much more traction my car has. We got a snowstorm here in Maryland the day after the install and I usually struggle to get up the hill into my neighborhood in the city; it is now no problem. Instead of the DTC kicking in immediately, I can FEEL the rear end searching for traction. The rear end used to kick out to one side pretty consistently if I was driving in a straight line in the snow and I lost traction (before the DTC kicked in). Now it kicked a little to one side and then back to the other but pretty much stayed planted and moved forward. If the improvement at the track is anything like in the snow, it will have been worth all of the research and inner turmoil over the cost.
I will parrot some of the things said in earlier threads about just feeling more safe and planted and hope this translates into more confidence mid-corner on the few HPDE events I go to a year. After just a few days of driving with the Quaife, I can't understand from a safety standpoint how this isn't standard. I've read various things about BMW wanting to differentiate between the E90/91/92 and the M's, but this is a no-brainer. I'm not sure I would have taken a different upgrade path (I really liked what the COBB did to my car), but so far I'm very happy. Oh, and there is no difference in noise - no clunking.
I did notice a difference at the Summit Point HDPE events before LSD and after LSD. However, it's hard to pin down the exact cause-and-effect. Because, before I had a stock non-sport suspension except Bilstein B6 dampers and I was still on OEM 17" runflats. Afterwards I was on Michelin 18" PSS and a completely redone suspension as can be seen in my signature block or my profile. However, perhaps the best indication was when applying power coming out of a turn. As I have mentioned in other posts, I find it hard to control power output; I have a hard time not overdoing it, and with all the torque I have the rear end can get away from you. Having said that, the "after" corner exit experience was much more composed. The rear end had more control, for example not wanting to slide out to the left coming out of a high speed right-hander as in the "before" case. Of course some of that could be attributed to better tires and to slightly improved driving skills on my part.
Jack. Like you i started from stock. The 2d track day was a little wet so i think it tended to amplify the shortfalls of the car. I knew after day 1 i would need a brake upgrade (pads) and LSD. I could feel brake fade on successive laps and also could feel an inability to put all mu power down without DSC kicking in out of corners. Suspension mods are needed too but im surprised VAC didnt sell you on brakes first.