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      06-22-2009, 10:10 AM   #37
E92Fan
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Quote:
Originally Posted by Ant Man View Post
E92Fan
10kg for the wheel! Was that the front or rear? Either way, that's incredibly light. BMW state 12kg for the Performance 225 rear wheel in 19" and 25kg including RFT. 10kg for a 19" is getting near forged rim territory.

What rear camber settings are you running now, closer to M3 per chance?

Did you get each corner weighted too?

One question I've been wanting to ask you is about the auto gearbox. Given you're a real driving and car enthusiast. How do you get on with the auto and how well does it work in manual / paddle mode around a track and spirited road driving?

Sorry for the delay in replying...!

10kg is for the front wheel, the rear is .75kg heavier or so. Yes, they're light wheels, but not when you compare them to really really lightweight wheels like OZ Superleggera, which I believe weigh around the 8.5kg mark in 19" fitment! The tyres are the killer, although Bridgestone runflats aren't as heavy as I thought. They're only a kilo or so more than the Michelin PS2s. Goodyear Eagle F1s non-RFTs are heavier than the Bridgestone runflats in fact!

You also have to ignore the BMW wheel weights they specify in the ETK - you'll notice that ALL the wheels say 12kg...!! They're not, incidentally..!

I'm running about a degree and a quarter of negative camber, slightly less on the rears to prevent inside-edge wear. Nothing too aggressive by any stretch, and yes it's pretty similar to the M3 setup. Front end response is very good, very direct and linear, and yet without being too twitchy on a motorway run. I just changed the rear tyres three weeks ago. Had 1.8mm tread on the centre, 2mm tread on both edges, so a completely even wear pattern. The rears lasted almost 19,000 miles including all the visits to the 'Ring and suchlike. Pretty impressive!!

I didn't get the suspension corner-weighted totally - instead the car is just balanced four-square to a plane. The reason I didn't go for the corner-weighting is because I generally take passengers when I'm going round the 'Ring, and so it would be pointless balancing the car for just a driver (me).

The auto box works very well under spirited driving. The remap has enlarged and smoothed the torque curve with the net result being the auto box changes gears much more smoothly and precisely as the shift points have a better match to the available torque. It does help that I'm using the Alpina gearbox software too

A lot of people will say that the manual gearbox is the way to go for a true driving enthusiast, and I agree with this point of view entirely. However there is an issue with the amount of torque the 335i manual gearbox can take (ie. not very much) and putting the 635Nm of torque that my car produces through a clutch/flywheel/gearbox combination that was only designed for 400Nm is not ideal! The way around that is obviously to upgrade the clutch - however a really good race clutch that's also suitable for everyday driving just isn't available for this car. A clutch would have to be custom built, and flywheel machined etc etc...

The alternative is to go for a replacement Quaife sequential manual gearbox and clutch combination, which would be great, but it's mega money!!

For my car and what I use it for, the automatic is the only option. It can take the torque, the paddles give me enough control, the gear changes are quick and smooth, it downshifts when I want it to without throwing the car off balance, and overall the whole car gels together very well.