Headers
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Race Director
Joined: Dec 2011
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Headers
Does a ZR1 come stock with headers? If not, why not? Here is my point--- there must be SOME cons (as opposed to all pros) when it comes to headers vs. exhaust manifold. Possibly to actually keep the engine operating at a higher temp (though, obviously, not too hot) and/or to keep the engine from cooling down too fast when turned off in cold ambient air conditions? There MUST be some good reason to not have headers isn't there?
Thread Starter
Race Director
Joined: Dec 2011
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I am thinking that it wouldn't be any more expensive for GM to put headers on ALL LS9s instead of an exhaust manifold. Don't see why that would cost any more if the ZR1 currently has an exhaust manifold setup unique to LS9.
Burning Brakes
Joined: Nov 2005
Posts: 815
Likes: 1
From: Georgetown TX
You have to have room and the bean-counters have to approve it.
If the ZR1 didn't need them to reach the hp #'s that the execs desired or deemed appropriate, why would they bother? There also may be additional, not-so-obvious NVH, heat, or emissions issues, as others have noted.
Interestingly, the new 650hp GT500 uses typical cast-iron manifolds, while the new 5.0 Mustangs have a shorty "header" stock.
If the ZR1 didn't need them to reach the hp #'s that the execs desired or deemed appropriate, why would they bother? There also may be additional, not-so-obvious NVH, heat, or emissions issues, as others have noted.
Interestingly, the new 650hp GT500 uses typical cast-iron manifolds, while the new 5.0 Mustangs have a shorty "header" stock.
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Safety Car
Joined: Jan 2004
Posts: 4,974
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From: Pinellas Park Fl
St. Jude Donor '08-'09 & '12, '14
If you remove the heat shield from the manifold used on the Z06/LS9 you will find that it is actually a short tube header made from steel and individual tubes, far better than the mess in the above pic.
Long tube headers suffer from the lack of heat to bring the cats up to temp quickly and hold it there.
Current designs for optimum cat efficiency is to mount the cat right at the exhaust manifold flange. The newest 4 banger GM has the exhaust manifold cast as part of the head.
Long tube headers suffer from the lack of heat to bring the cats up to temp quickly and hold it there.
Current designs for optimum cat efficiency is to mount the cat right at the exhaust manifold flange. The newest 4 banger GM has the exhaust manifold cast as part of the head.
Thread Starter
Race Director
Joined: Dec 2011
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If you remove the heat shield from the manifold used on the Z06/LS9 you will find that it is actually a short tube header made from steel and individual tubes, far better than the mess in the above pic.
Long tube headers suffer from the lack of heat to bring the cats up to temp quickly and hold it there.
Current designs for optimum cat efficiency is to mount the cat right at the exhaust manifold flange. The newest 4 banger GM has the exhaust manifold cast as part of the head.
Long tube headers suffer from the lack of heat to bring the cats up to temp quickly and hold it there.
Current designs for optimum cat efficiency is to mount the cat right at the exhaust manifold flange. The newest 4 banger GM has the exhaust manifold cast as part of the head.
Melting Slicks
Joined: Dec 2006
Posts: 2,186
Likes: 2
From: Woodinville WA
You can see the individual tubes from the inverted image
Last edited by ctusser; Apr 3, 2012 at 09:11 PM.
Safety Car
Joined: Jan 2004
Posts: 4,974
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From: Pinellas Park Fl
St. Jude Donor '08-'09 & '12, '14
If you search for LS7 exhaust manifold in google images I'm sure you'll find a pic of the manifold showing the tubes.
On the dyno they perform just like a short tube header over the standard LS2/3 manifold. You wouldn't know it to look at them, but they do work.
Thread Starter
Race Director
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Mostly emissions and then packaging. You also have to look at durablity.
If you search for LS7 exhaust manifold in google images I'm sure you'll find a pic of the manifold showing the tubes.
On the dyno they perform just like a short tube header over the standard LS2/3 manifold. You wouldn't know it to look at them, but they do work.
If you search for LS7 exhaust manifold in google images I'm sure you'll find a pic of the manifold showing the tubes.
On the dyno they perform just like a short tube header over the standard LS2/3 manifold. You wouldn't know it to look at them, but they do work.
