I was looking at headers for the WRX and I have noticed that there are several different designs.

When I was searching for headers for my other vechicles I learned quite abit about tube length, size, collector method etc. I remember equal length tubes with each bank collecting seperatly to be the best because it would scavange exhaust gases and pull more fresh air into the cylinder.

Here is what I noticed about the different designs on the WRX.

Borla- None equal lenght tubes with a single collection point just before the uppipe flange (probably not the best design but it was the cheapest )

Aqua- Looks like the Borla but better tube length

Cusco- Nice heat shields similar to stock better tube length than the borla and Aqua

Greedy- Looks like some flex joints (which are probably useless) same design as a borla

GTspec- can't tell any thing from the photo any additions here would be great

HKS- Same as borla

Jun- Equal length header which would help scavange gases can't tell if it has an uppipe.

Maxium- Equal length with uppipe looks similar to Jun

Skunk2- Out of all of them this design looks the from the 4-2-1 design. It looks equal length with opposing cylinder joining to one just before where the uppipe flange would be. From the 2 tubes travel side by side to the end of the uppipe where they meet which I would think would be the best design for scavenging gases.

I could be completly wrong because the turbo could cause backpressure and make scavenging completly useless.

Here is a page that has pics of all of the different types but not the best prices.

http://www.wrxtuners.com/parts/default.php?cPath=24

Most of my experience with headers is on non-turbo trucks where tube length determines effective rpm band and torque vs. HP characteristics. So any and all input would be awesome.

:banana:

 

I have the Borla and it works fine.
It looks nice too :banana:

It was inexpensive and thats why I went with it, but it turns out that I really liked it.

 

Here's the reviews

https://www.i-club.com/reviews/showcat.php?cat=8

 

Most of the reviews don't really talk much about performance and what design is the best. Most of the info is from the manufacturer

 

I have no complaints about my Borla. It gave some umph, and it sounds pretty mean. The exhaust pulses are evened out at idle, giving it a nice, low, "blub blub blub blub."

 

you're right about the turbo. the tricky header designs don't make as much of a difference as on n/a cars. I think the hp gains are due to better flow and not scavenging and pulsing effects.

btw, I thought you had to use special cams with a good "pulsing" header to get good scavenging?

personally I'm interested in what headers would allow use of a twinscroll turbo

 

On my truck I don't have any "special cam" but I could really feel the gain in torque down low when I install my headers.

I was hoping to replicate that in my WRX that is why I have such an interest in a header replacement

 

hmm maybe I'm confused by the term. IIRC scavenging is something a cam can accomplish by lifting both the intake and exhaust valves at the same time letting the exhaust help pull in the intake charge.

dunno if this works with a turbo because of the positive back pressure.. I think its more important to have high-lift/slam shut cam like the stock wrx's

 

This guy just dynoed different headers on 2 wrx's and an STI. he's waiting to release the results.

http://forums.nasioc.com/forums/show...hreadid=455046

 

On that link that Scoobystats just put up, someone said that on the larger turbos like the PE series, it is better to run a stock header because it will decrease lag. I was wandering if this is also true for the VF34, even thought it is not the biggest of turbos, it is bigger than stock. Can anyone help? Would it be better to run a stock header or aftermarket for a vf34? thanks

 

The PE series are actually small turbos