View Single Post
      04-22-2008, 11:17 PM   #9
Adam@Riss Racing
Banned
United_States
79
Rep
1,310
Posts

Drives: 2006 Interlagos Blue BMW M5
Join Date: Jul 2007
Location: Irvine, CA

iTrader: (1)

Garage List
Quote:
Originally Posted by JohnnyTT View Post
Thanks for the info. 20+ is a lot. Is that with a tune??

Also, my question still stands though. Is having 3" -> 2.75" -> 2.5" still a waste? Because 2.5" will bottleneck the rest??? Isn't that the same as 2.5" all the way through?

I'm not doubting the performance gains, I'm just curious about the tech behind them.
The flow characteristics with 3" flow will be much more different than 2.5" throughout. I've heard of some turbo Volvo race cars that had 4" downpipes which continually taper down to 2.5" making about 30% more power than 3" throughout. Gains on a stock car were around 30whp. Tuned, you'll see around 60whp bump with a downpipe map.
Appreciate 0