Do headers make a differnce

[Guest Anonymous]

ive read that on a stock engine, all you really need to do to the exhaust is the actual exhaust and that you really dont need headers unless you do head work? any truth to that?

[Mikelly]

A motor is a big air compressor. It takes in air, ignites it using fuel and spark and then moves it out. If you improve the intake of air, but don't improve the area of combustion and fuel delivery, then you have wasted your time. If you improve on the first three, but not on the headers and exhaust, then you still have wasted your money. An engine should be look at in regards to TOTAL PACKAGE! Hope that explanation helps.

Mike

[Guest Anonymous]

thanks guys, that was exactly what i was looking for!

[pparaska]

Mike, in theory I agree.

 

However, there's a racer and engineer on the IZCC list that's done some engine dyno work comparing the 240Z, 260Z exhaust manifolds and various headers. His findings show VERY MINIMAL improvements over the manifolds. The 260Z manifold was marginally better.

 

I wish I had references to cite, but if you go and ask on that list, his name is Keith.

 

Then again, this is on a dyno. No telling if there might be some improvement on the tracks.

[Modern Motorsports Ltd]

Mike's info is correct. However L6's have fine exhaust manifolds to start with unless you go quite extreme. Quite a few dyno's were done by a race team with different headers etc and its been agreed for a while that no an L6 headers aren't much if any of a bang/buck unless you're doing a stroker etc and even then it might be questionable. Custom exhaust from the downleg to horizontal transition of the OEM manifold rearward is generally simplest and most functional. I love headers but on an L6 I'd avoid the install/maintenance hassles for sure. AIR, a 280ZX manifold has tuned length runners, not sure if 70-78's have same? (ie. would a 280ZX manifold be an up grade to an older L6?). www.zhome.com might have those dyno results listed somewhere. I recall no more than 4 hp variance b/t any of the tests.

[pparaska]

Ross, thanks for pointing out what I meant to say - headers are usually a good upgrade from exhaust manifolds (in the V8 world, this is generally true, unless the manifolds were designed as cast iron headers from the factory on special cars). But in the case of the L6, there's evidence to say that for all but a really high output L6, a good manifold is just as good.

[Modern Motorsports Ltd]

"Ross, thanks for pointing out what I meant to "

 

You did say it fine! I just hadn't seen your post yet while I was composing mine....if you're all quick on the draw today I should get back to work