Quote:
Originally Posted by soundman98
curious if you've got more info on this somewhere? i'd like to read it
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There are 100's of papers, multiple how too's and other various guides on how to design and build a exhaust header.
The whole "tuned length" bit seems to get pushed out with good marketing.
Give them a read, all about torque curves, rpm, hp, primary lengths, secondary lengths, collector design, yada yada yada.
Every single one states to attempt to acheive a equal length in runner length to help with flow.
Lots of talk about reversion, sound waves, pulses, 4:1, 4:2:1, exhaust temps and other groovy stuff.
I actually had a play with a Tomei UEL header vs a OEM header with the cat punched out.
I found the OEM header performed better.
And that is a OEM header with the compromises in the pipe lengths due to the need of fitting in a cat.
It wasn't until the WRX STI turned up that the sound of a poorly designed exhaust header became fashionable.
Prior to the Rex the only other car that sounded like that was a VW beetle, who's exhaust was designed that way because of packaging and cost.
Opinions may vary
Why was the WRX STI header designed this way, from talking to some old rally guys it was about packaging and available room.
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Why do the ACE headers and other top of the line headers feature so prominently in motorsport?
Hell, a UEL header is basically a excellent example of how "not" to design a exhaust header.
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Our racing series here, they all run EL.
The Jap STI, EL.
Nearly every man and their dog swaps the UEL header on the EJ for a EL.
Why do manufacturers still sell the UEL header? the sound....and the fact that with enough good marketing, some companies sell a exposed pod filter and call it a performance upgrade.
Disclaimer: opinions may vary