Butterfly valve

integra08

New Member
Mar 25, 2009
145
0
0
Florida
Hi guys.Ok my friend had what he said was a butterfly valve on his subaru wrx. Whenever he opened the valve it was open headers and then closed was quiet as stock. He also told me when the valve was set on open he gained horspower.Is there any truth behind this and what is it called?
 

86_sports_1jz

slow 700hp build...
Aug 27, 2006
1,217
0
0
OK
integra08;1317708 said:
How would I have it done to my supra

you buy the cutout then have it welded on your exhaust system. the closer it is to the turbo the more power you will get out of it and the further way from the turbo the less power you get out of it. most people would use the cutout right after the downpipe, then after the cutout they have a very quiet exhaust system. you can get that driftmotion electronic cutout^^^ or you could get manual cutout sold by summit racing
 

tissimo

Stock is boring :(
Apr 5, 2005
4,238
0
0
40
Melbourne, FL
Just build a proper exhaust and don't worry about the 2-3 hp you'll lose.

Unless you want a stock exhaust, then by all means use the valve for the track,dyno,etc.
 

87M-GTE

Slow
Sep 12, 2007
1,705
0
0
Milwaukee WI
Has anyone every compared open 3'' DP vs. the same car with a full 3'' cat back on the dyno?

I know BIC documented a DDP vs. DP on the dyno..
 

SeanMcCabe

New Member
May 29, 2008
24
0
0
Arizona
^^^ I'd be curious to see that as well. Though it would still be pretty fun to run a cutout with a stock exhaust.. Talk about sleeper
 

Cya

New Member
Aug 12, 2005
628
0
0
42
Columbia, S.C>
87M-GTE;1318581 said:
Has anyone every compared open 3'' DP vs. the same car with a full 3'' cat back on the dyno?

I know BIC documented a DDP vs. DP on the dyno..

Do not do run open DP, my main reason being the exhaust fumes coming back into the cab.
 

87M-GTE

Slow
Sep 12, 2007
1,705
0
0
Milwaukee WI
Cya;1318628 said:
Do not do run open DP, my main reason being the exhaust fumes coming back into the cab.

Only if youre sitting at a stand still, driving wasnt noticable at all for me, drove it open DP for like 3months