Manifold vs Log vs Header?
06-13-2014, 11:02 PM
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Manifold vs Log vs Header? So here is a question when comparing all the different types of exhausts say with a well built TT 427 that will make a easy 1kwhp if cranked up how much difference in power are we talking between the mani's, logs, and tube headers?
I have some SS tube up and forward headers but dont think they will clear so i been thinking of building Twin logs and the benifit is they will hold the turbo's well being they are thicker unlike the thinner headers i just dont want the motor to suffer that bad even mani's make great power just worried about cracking holding turbo's.
I have some SS tube up and forward headers but dont think they will clear so i been thinking of building Twin logs and the benifit is they will hold the turbo's well being they are thicker unlike the thinner headers i just dont want the motor to suffer that bad even mani's make great power just worried about cracking holding turbo's.
06-14-2014, 01:29 PM
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I like the SW headers but they stick forward to far the ones i have are even with the head so i have more room to package the turbos and if i were to make logs i could keep them real compact. I think if they are swept correctly they will flow better than mani's but maybe not as well as headers but i think really it's a very small amount of power were talking about and probably above a certain Rpm which i dont plan on spinning past 7K.
06-15-2014, 10:29 PM
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06-16-2014, 01:23 AM
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06-16-2014, 08:44 AM
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06-16-2014, 08:01 PM
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I'm going to hang on until the motor is sitting in the frame and try the headers i have before i jump the gun i just wish they were 1 7/8" instead of 1 3/4" primary's even though i dont think it will matter much being boosted!
06-17-2014, 01:17 AM
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I recall seeing an import article once on Honda engines that gained 10% by using race quality well designed headers into merge collectors, much like Tom Nelson does on most of his twin turbo packages.
There's no doubt if maximum power is the goal, race headers still have the edge, not sure if it'd be 10% gain on a big engine.
On the other hand, what works in all out race does not mean it is best for all combo's. There are some on this site that will swear that at lower boost pressures stock manifolds and smaller exhausts run quicker than headers.
I'm not convinced stock exhausts are ever better than proper headers, but I could be wrong about that, and can't argue if someone has tried both and proved this in their combination.
I am convinced that stock will spool earlier than a high volume exhaust like headers, but that is not always a consideration if headers still spool quick enough. Logic would say stock will boost at lower rpms but should cost some top end, but logic and experience can differ lol
Clearly both options or a decent log will all get you to 1000rwhp
There's no doubt if maximum power is the goal, race headers still have the edge, not sure if it'd be 10% gain on a big engine.
On the other hand, what works in all out race does not mean it is best for all combo's. There are some on this site that will swear that at lower boost pressures stock manifolds and smaller exhausts run quicker than headers.
I'm not convinced stock exhausts are ever better than proper headers, but I could be wrong about that, and can't argue if someone has tried both and proved this in their combination.
I am convinced that stock will spool earlier than a high volume exhaust like headers, but that is not always a consideration if headers still spool quick enough. Logic would say stock will boost at lower rpms but should cost some top end, but logic and experience can differ lol
Clearly both options or a decent log will all get you to 1000rwhp
06-17-2014, 07:02 AM
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I think headers will provide better scavaging that a log or stock manifolds that should keep it in boost better plus if i use the headers i have they are not huge so they should help also in the spool dept!
06-17-2014, 07:32 AM
#14
Scavenging is a non issue with turbo headers. It is purely about heat transfer and exhaust gas velocity. A 2" crossover pipe can handle upwards of 1000hp. This is why iron manifolds do so well. They retain heat and keep velocity up. Going to a header is not needed until a 2.5" crossover is not enough and a 2.5" crossover will flow a TON. 1500whp+.
The only reason to go to a header under 1000whp is looks and/or fitment. This doesn't mean you should use just any manifold. The ones with the smoothest transitions and merges would be ideal.
The only reason to go to a header under 1000whp is looks and/or fitment. This doesn't mean you should use just any manifold. The ones with the smoothest transitions and merges would be ideal.
06-18-2014, 09:36 AM
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Headers are the optimum solution as you can design them to your requirements including size, shape, length and most importantly where the turbo sits! Ever single high end race car (and not just drag racers) car I have seen all use headers. With decent support most last years to!
Cast manifold are great for a cheap solution that will work. They are strong and easy to work with. Are they the BEST solution? No but they are adequate for 99% of people.
As for performance a designed header (not just mocked up) will out perform a OEM cast manifold any day and in any area you want it to! The advantage is you can design it to do what you want. Want fast spool use a smaller header, want top end go larger. You can even fine tune the pulse length to give you performance were you want it.
Cast manifold are great for a cheap solution that will work. They are strong and easy to work with. Are they the BEST solution? No but they are adequate for 99% of people.
As for performance a designed header (not just mocked up) will out perform a OEM cast manifold any day and in any area you want it to! The advantage is you can design it to do what you want. Want fast spool use a smaller header, want top end go larger. You can even fine tune the pulse length to give you performance were you want it.