electric cut outs on stock exhaust hp gain or loss??
Race Director
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From: Missouri City Texas
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St. Jude Donor '08
Burning Brakes
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Safety Car
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St. Jude Donor '07-'08-'09-'11-'12
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Pro
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No car will lose horsepower by reducing exhaust restriction. Ever been to a race track, ALMS, NASCAR, NHRA, IndyCar, etc. Not a lot of muffling going on.
There may be certain low rpm situations where the back pressure waves are required for optimal power, but I've never seen anyone post a peak hp loss from going to a less restrictive exhaust.
There may be certain low rpm situations where the back pressure waves are required for optimal power, but I've never seen anyone post a peak hp loss from going to a less restrictive exhaust.
Instructor
Joined: Jan 2008
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From: Denton Texas
St. Jude Donor '09-'10
When I had only the FAST intake and headers, I had the same findings as Joe. No HP/TQ change. But the sound was awesome (and less drone than my Z06 muffs with muff mod).
However, now that I am FI, the AFR does skew slightly when the cutouts are open. I did not try to tune for cutouts however - as this is my DD. Someday, I might tune for cutouts for track days only to see if it makes a difference (low priority at this time). Since I do my own tuning, it often takes a few days to get everything right how I like it. I don't anticipate making this kind of time investment any time soon.
So the real answer more like:
stock or close to stock = no
FI or big cam = probably/maybe, but # unknown and probably smaller than you would think (z06 muffs are pretty free flowing as is).
Tech Contributor
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From: St. Louis, MO
St. Jude Donor '08
When I had only the FAST intake and headers, I had the same findings as Joe. No HP/TQ change. But the sound was awesome (and less drone than my Z06 muffs with muff mod).
However, now that I am FI, the AFR does skew slightly when the cutouts are open. I did not try to tune for cutouts however - as this is my DD. Someday, I might tune for cutouts for track days only to see if it makes a difference (low priority at this time). Since I do my own tuning, it often takes a few days to get everything right how I like it. I don't anticipate making this kind of time investment any time soon.
So the real answer more like:
stock or close to stock = no
FI or big cam = probably/maybe, but # unknown and probably smaller than you would think (z06 muffs are pretty free flowing as is).
However, when you get over 500 rwhp the cutouts (or z06 muffler flaps) make a huge difference, like 30 rwhp. I've seen it several times on the dyno with my friend GtoDoug on his various super high HP c6's.
p.s. Craigster... Dougie hit the dyno today with his h/c package...keep your eyes peeled on the z06 section...
matter of fact here it is!
http://forums.corvetteforum.com/c6-z...heads-cam.html
Le Mans Master
Joined: Mar 2005
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From: Minnetonka MN
St. Jude Donor '06
on my c5r 427, i gained 21rwhp and 12rwtq open cutouts thru an auto that was NOT locked... i believe when it was locked, i gained 4x rwhp and 3xrwtq.
in the 1/4mi i gained a consistent .20 and 2mph.
They are def worth the money.
Aj
in the 1/4mi i gained a consistent .20 and 2mph.
They are def worth the money.
Aj
Melting Slicks
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From: On the east coast we drive until we die
Hmm...I was considering adding cutouts to my H/C LS2 but I already have Borla Stingers. Do you think it would make much of a difference at this point? I'm in the 480-500rwhp range.
Tech Contributor
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From: St. Louis, MO
St. Jude Donor '08
I had stingers. Cutouts would be a waste of money with these. They wouldn't add power and you are already breaking eardrums loud so you wouldn't hear the cutouts. Cutouts aren't as loud as stingers as they are redirected at the ground.
Melting Slicks
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From: On the east coast we drive until we die
Burning Brakes
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From: Redondo Beach California
I have some Badlanz HPE cutouts in the H-pipe before the mufflers connect.
I did 2 dyno runs with a cool down in between. The cutouts gave me 2 more lbs of TQ at about 4k. The HP was identical.
Vararam, LG LT's, A lil porting, MSD, and a 160 T stat
I did 2 dyno runs with a cool down in between. The cutouts gave me 2 more lbs of TQ at about 4k. The HP was identical.
Vararam, LG LT's, A lil porting, MSD, and a 160 T stat
