an exhaust is sprung weight, rims are unsprung weight...still curious to know. anyone know exactly what the stock si cat back weighs? a lightweight exhaust combined with some nice light weight wheels is a decent amount of unsprung weight reduction
I have an em2 also with 15" rota slipstreams and kumho ecstas the rims are 11 pounds a piece...I put them on after having 17's and the difference is tremendous...if you want lightweight rims, look into spoon sw388(I believe) or desmond regamasters the 16" weigh around 11 pounds...it helps every aspect brakes, suspension, acceleration.how light do the rims have to be before you notice a performance gain?
Yes you are absolutely correct...the difference is nominal especially when you don't do everything at once...but it is proven that weight reduction improves, lap times, 1/4 mile times.I have a dc header, greddy cat back, motegi track light rims (15 lbs), aluminum skunk 2 rear adjustable arms, aftermarket coilovers (weighs less) and I notice (drum roll) 0% diffrence in daily driving. I figure I have shaved about 50-60 lbs and maybe 1/2 of that is unsprung weight. These kinds of small savings can only be noticed on timed laps and in my opinion changes in ambient air temp would have more of an effect than 50 lbs.