Long Tube Header Dyno results & Photo

[CASTREX]

Hey Richard,

Would you care to educate us a little bit on the theory behind this long tube header design.
You have explained a lot about the theories involved in the Intake manifold tuning and such...

We all know the main idea of an aftermarket header is to improve the flow of the exhaust gases into the exhaust pipe. People often debate also between the pro's and con's of 4-1 vs 4-2-1 designs.

So what is behind this long tube design of yours?

[richardholdener]

Headers operate on the same principle as intake manifolds. The primary length is tuned to optimize scavenging (using a negative pressure wave reflected back to the open exhaust valve) that helps draw more intake charge into the combustion chamber. The header does not simply allow the exhaust to flow better than the stock ex manifold (this is the case with a larger diamter, shorty style header), but the gains are miniaml compared to teh long tube since the stock header is not terrbibly restrictive to flow. Gains from changes soley in exhaust flow are minimal as indicated by the gains offered by dropping the whole exhaust system (cats and mid pipe-middle line in graph). The real gains come from the scavenging effect produced by the combination of design characteristics of the header. We tried a number of different primary lengths and diamters as well as several collector designs to fine tune the gains. 4:1 and Tri-Y headers can be tuned to produce the same power curves-one is not inherantly better than another at different engine speeds, though each design can offer somehting not available by combinations of the other (usually minor gains in power at distinct engine speeds-but this will be dependant on the engine combination-primarily cam timing, displacement and intake design). The right design for any single combination takes a lot of work. BTW-we tesed the header designs with both the stock and new intake.

Originally Posted by CASTREX

Hey Richard,

Would you care to educate us a little bit on the theory behind this long tube header design.
You have explained a lot about the theories involved in the Intake manifold tuning and such...

We all know the main idea of an aftermarket header is to improve the flow of the exhaust gases into the exhaust pipe. People often debate also between the pro's and con's of 4-1 vs 4-2-1 designs.

So what is behind this long tube design of yours?

[CASTREX]

Thanks

[kou]

more of my money coming your way. i want this.