He said he heard about that on one of his forums. 
Cutout Backpressure question
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Cutout Backpressure question Are there any problems with running a cutout wide open? I heard from a buddy of mine that if you have a cutout open for a long period of time, it can cause problems. he said that an open cutout is the same as open headers. He also said that the lack of backpressure from the open cutout, can cause your valves and seals to burn up quicker. does anyone have any evidence of this? or is he full of it. Thanks for any input.
i've never had any problems and my car drives faster and smoother with them open. open headers are a little different because the O2's are so clese to the outside air (only a few inches). i've ran both. my car would hardley idle with open headers, but once i but my Y-pipe back on with dual cut out's the car idled fine. the cutouts are on'y abpbut 12 inches from the headers but it makes a difference
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From: England
Originally Posted by 99_hugger_Z
Are there any problems with running a cutout wide open? I heard from a buddy of mine that if you have a cutout open for a long period of time, it can cause problems. he said that an open cutout is the same as open headers. He also said that the lack of backpressure from the open cutout, can cause your valves and seals to burn up quicker. does anyone have any evidence of this? or is he full of it. Thanks for any input.
Have a read of the sticky in this forum (exhaust/induction) and learn what back pressure is and what it does and doesn't do.
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From: Yorktown, VA
If backpressure creates power, then stick a banana in your exhaust and go pull some tree stumps. Proper Sonic tuning is what scavenges the exhaust gases from the cylinder and creates power. As far as burning up valves, I've personally never seen anyone have a problem with that (doesn't say a whole lot). I've seen videos of engines running without any exhaust manifold(s) at all. A Cutout probably won't net you better gains than a properly tuned exhaust, but from what I can tell anything seems to be better than the stock configuration.
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Teching In
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From: Saginaw, MI
Originally Posted by 99_hugger_Z
He also said that the lack of backpressure from the open cutout, can cause your valves and seals to burn up quicker.
Its a fact from back in the day when valve seats were not hardened. In the 60's you needed back pressure, and High octane fuel or the valves were not happy. Alot of people think the same is true about todays engines.
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From: England
Originally Posted by carado1984
maybe it has something to do with his being a 4.6 and ours a 5.7.. is there a certain cu. where a cutout loses power? has to be
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From: England
Originally Posted by OBO
Its a fact from back in the day when valve seats were not hardened. In the 60's you needed back pressure, and High octane fuel or the valves were not happy. Alot of people think the same is true about todays engines.
The valve seats are fine, aircraft engines don't run an exhaust except of some angled tubing - this has always been this way yet they don't have issues with the valve seats.
The only time backpressure is an issue is for proper tuning. If you remove the restriction and reduce back pressure and FAIL to retune for the new a/f mixture then problems can occur, however this is NOT a result of backpressure but the lack of ability to set the engine up.
