[killerkid08]

Originally Posted by 504

Hey guys, first time poster here
is exhaust scavenging effect still existent in the AVO UEL manifold? As far as I know the stock headers on this car come in a 4-2-1 orientation which actually creates a vacuum in the next pistons manifold tube to suck out exhaust gases. If scavenging wasn't occurring was it acknowledged during development and does it affect engine longetivity due to possible build up of carbon in combustion chamber?
Also some people say UEL headers are bad for the engine due to varying back pressure experienced by each piston. I know some Subarus come from stock with it, I just want to know what this community has to say about it

Thanks!
(sorry if this has already been discussed)

I second this.