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Old Oct 16, 2008 | 02:41 PM
  #1  
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Default Cutout Exhaust

I have a 98 TA WS6 and i bought it with flowmasters and a cutout after the cats. it sounded sick and when i took it to my mechanic he told me that i should put the cover on the cutout because its only meant for racing and can cause the valves to burn over time because of a lack of back pressure i did research on it and herd it was a unproven myth im not saying my mechanic is lying but he is the one who would be passing it for inspection and i think for him an easy way to avoid akwardness when that came around was to tell me it would cause problems any words of wisdom or advice would be helpful.....thanks
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Old Oct 16, 2008 | 02:44 PM
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Your cutout will not cause any valves to burn, especially not after the cats.
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Old Oct 16, 2008 | 02:47 PM
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I dont know why but alot of "older" mechanics seem to think running a cutout will burn valves up, I've heard the same thing about running open headers... i dont think its true at all...
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Old Oct 16, 2008 | 03:53 PM
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A lot of guys including me run cutout open all the time with no problems that ive heard of
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Old Oct 16, 2008 | 04:02 PM
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Time to find a new mechanic
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Old Oct 16, 2008 | 06:18 PM
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Just for the record, has anyone here ever experienced burnt valves from running open headers/cutouts at the end of the headers?
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Old Oct 16, 2008 | 06:18 PM
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The myth comes from the old days, when running without manifolds/headers would cause cold air to rush in and hit the hot exhaust valves. This caused them to warp, and not seal properly.

This is not an issue with cutouts, as there's no way for cold air to get all the way up through the cats, manifolds and onto the valves. Even if it did, todays engines are made of better materials, and I doubt it would be an issue even if you ran it without headers/manifolds.

So, time has skewed this completely.
Without manifolds became "open headers"
And old engines got confused with newer engines.
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Old Oct 16, 2008 | 06:25 PM
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Originally Posted by TA-Swede
The myth comes from the old days, when running without manifolds/headers would cause cold air to rush in and hit the hot exhaust valves. This caused them to warp, and not seal properly.

This is not an issue with cutouts, as there's no way for cold air to get all the way up through the cats, manifolds and onto the valves. Even if it did, todays engines are made of better materials, and I doubt it would be an issue even if you ran it without headers/manifolds.

So, time has skewed this completely.
Without manifolds became "open headers"
And old engines got confused with newer engines.
well said sir...

dual cutouts open most of the time for two years now, no problems, but i did switch heads halfway through though
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