Lessons Learned (I’m not too proud to admit I’ve made mistakes)
Brakes. I rushed in and ordered some brand new discs/rotors and callipers to replace the old rusted ones. These are standard 325x25mm 330Ci items. This restricts the options that I have to upgrade them. Standard practice is to get “just enough wheel to cover the callipers” to reduce unsprung mass and allow the suspension to function easier. In this case 17″ rims. I now have 2 sets of new rims, and new wet and dry tyres for 17″ wheels. However all of the proposed race series have ‘free’ brake mods. If I’d settled for 18″ rims I could have fitted the brakes from a 440i (twin pot) and the 345x28mm rotors from the E46 M3 CSL. These require a minimum of 18″ rims. The only option that I now have under the 17s is to fit the e46 standard M3 callipers and 325x28mm discs. They’re the same diameter as the 330Ci originals but the discs are slightly thicker at 28mm, so can absorb more energy and wear a little longer. I could upgrade in the future to the 440i/CSL combo but that would require new wheels and tyres. So don’t do what I did and do more research. I guess that’s why you’re here? 🙂
Wheels/Tyres. As a result of number 1 above I’m now committed to running the 17″ rims and tyres that I’ve already bought. Not necessarily an issue with the brake setup that I have but limits future upgrade options. The lightened overall weight though should see them perform better than the standard road car. It’s a sizeable investment (over £1500) and too much to correct. In fairness a well maintained standard system with decent Ferodo 1.11 pads and some air ducted cooling would be more than adequate.
Rear upper adjustable control arms. These true coilover upper control arms manufactured in Poland, whilst being adjustable, when weighed are slightly heavier than the originals. As a true coilover conversion they ‘do away’ with the wide spring pans of the originals. Now inside the coilover springs, the unsprung mass is unaffected BUT I was sorry to see that the attachment point for the xenon headlamp sensor (seen here as the little cutout in the middle) was missing. Fine for the standard headlamp cars but not ok for this application. The uniball bearing was welcome but the extra adjustability is unnecessary. Instead I’ve decided to refurbish the original arms and fit the Power Flex black series bushes to match the rest of the car, saving £150 in the process for little compromise.