cut outs
Tech Contributor
Joined: Jul 2002
Posts: 14,949
Likes: 263
From: St. Louis, MO
St. Jude Donor '08
I did on my manual, I would think there is plenty of room where I did it even on an automatic. Very happy with them.
Here's some pics and write up:
http://forums.corvetteforum.com/show....php?t=1628234
Here's some pics and write up:
http://forums.corvetteforum.com/show....php?t=1628234
Tech Contributor
Joined: Jul 2002
Posts: 14,949
Likes: 263
From: St. Louis, MO
St. Jude Donor '08
Thanks! I love it. When you open it up it sounds MEAN!!
I will make note and want to be perfectly clear - I have not seen any performance gain from them at the drag strip over 2 events and 10 runs. The benefit is for sound - quiet or loud, my choice. And for that they are worth every penny to me.
I will make note and want to be perfectly clear - I have not seen any performance gain from them at the drag strip over 2 events and 10 runs. The benefit is for sound - quiet or loud, my choice. And for that they are worth every penny to me.
Le Mans Master
Joined: Feb 2006
Posts: 5,762
Likes: 4
From: Chandler Arizona
You may want to do what a friend of mine did with his new Mustang. Just where the catback bends to go up and over the rear axles, weld in a 2.5" pipe with a flange on it. Cap off the flange with a plate and three wingnuts or bolts. This would be an old fashion mechanical cutout, but at least you could uncork them when you go to the strip. I doubt if you'll find the room to put in electric cutouts with the auto. However, the mechanical is fine with me because I had an electric one on my 01 Z28 and I hit the button way too often. I was just flat lucky I never got a ticket.
Tech Contributor
Joined: Jul 2002
Posts: 14,949
Likes: 263
From: St. Louis, MO
St. Jude Donor '08
You may want to do what a friend of mine did with his new Mustang. Just where the catback bends to go up and over the rear axles, weld in a 2.5" pipe with a flange on it. Cap off the flange with a plate and three wingnuts or bolts. This would be an old fashion mechanical cutout, but at least you could uncork them when you go to the strip. I doubt if you'll find the room to put in electric cutouts with the auto. However, the mechanical is fine with me because I had an electric one on my 01 Z28 and I hit the button way too often. I was just flat lucky I never got a ticket.
I truly wonder if these are allowing my exhaust to be too free flowing with my American Racing 1 7/8 headers and 3" catted cat back. My buddy (who's older than me and usually proves to be correct) tells me I need some backpressure to keep the cylinder pressures higher and my cutouts might cause performance loss.
I plan to add some more timing (ran out of time last time at the strip) to see if I can make up the difference, in cylinder pressure as I'm not getting any knock retard at all at about 21-22 degrees. I will do some more tuning this Friday at our test day and report back if anyone is interested.
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Le Mans Master
Joined: Feb 2006
Posts: 5,762
Likes: 4
From: Chandler Arizona
Well, if you're doing a manual cutout you'd be doing it for performance, and I'm afraid you'd be disappointed. I have found no performance benefit from the cutouts on the track so far. I would love for someone else to chime in and see if they got any performance gain. I adjusted my fueling with HP Tuners as it seemed to go a bit lean with the cutouts, but no avail. In fact, just now reviewing my 11 runs with cutouts, I lost about 2 mph. I added 1 degree of timing and picked up 1 mph on my final run.
I truly wonder if these are allowing my exhaust to be too free flowing with my American Racing 1 7/8 headers and 3" catted cat back. My buddy (who's older than me and usually proves to be correct) tells me I need some backpressure to keep the cylinder pressures higher and my cutouts might cause performance loss.
I plan to add some more timing (ran out of time last time at the strip) to see if I can make up the difference, in cylinder pressure as I'm not getting any knock retard at all at about 21-22 degrees. I will do some more tuning this Friday at our test day and report back if anyone is interested.
I truly wonder if these are allowing my exhaust to be too free flowing with my American Racing 1 7/8 headers and 3" catted cat back. My buddy (who's older than me and usually proves to be correct) tells me I need some backpressure to keep the cylinder pressures higher and my cutouts might cause performance loss.
I plan to add some more timing (ran out of time last time at the strip) to see if I can make up the difference, in cylinder pressure as I'm not getting any knock retard at all at about 21-22 degrees. I will do some more tuning this Friday at our test day and report back if anyone is interested.
Tech Contributor
Joined: Jul 2002
Posts: 14,949
Likes: 263
From: St. Louis, MO
St. Jude Donor '08
That's good to hear. I'll stick to the normal catback even though I do miss the sweet sound of an LS engine running through open pipes! We are lucky our catbacks are so good. I had a cam/headers LS1 Z28 that would run 12.72 at 113.75 mph. It made 381 rwhp with the open cutout (Stainlessworks headers, 2.5" Y pipe, high flow cats, then hooked up to the stock 2.75" I pipe. The cutout was right before the rear axle. When I closed the cutout and ran through the stock cross flow muffler, I made 355 rwhp (26 less). You talk about a potato in the tail pipe!
