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[Lonely_Driver]

So I'm in the market for a new header for my Legacy since all the stock heat shields are rattling like a mofo and I cant be bothered to work on it without upgrading. One of the most popular options for us is to port and polish the stock manifolds.

Now inside the pipes are weird steps, and it always made me wonder why Subaru did this, there has to be a reason why they are cast this way, so I did some research and it has something to do with the firing order and to help the exhaust pulses and such. Also the stock manifold diameter is a perfect match to the cylinder head and turbo exhaust inlet, only the gasket size is bigger for some reason.

Anyways I'm still set on buying a EL header but most of my knowledge on the subject is all from NA designs which I found out lately is totally different when you are turbocharged.

I was hoping to hear some input from the rest of you guys with different platforms to see what others are doing to decrease spool up time and keep pressure in the exhaust system before the turbo.

Here's what Ive read regarding Subarus on the subject. (copy pasted my post from WSC)

Starts at post #15
http://forums.nasioc.com/forums/showthread.php?t=2271466

Found another one too, stock manifolds are already an exact match to the cylinder head.
http://www.iwsti.com/forums/gd-exhaust/170...ld-porting.html

Another good post by KillerB

http://forums.nasioc.com/forums/showpost.p...87&postcount=26

(KillerB makes the best header for single scroll Subaru's, its called the Holy Header)

[s12drifter]

i dont know what you subbies do but a lot of times us Z31 people ceramic coat the manifold heat wrap and heat shield lol.

[sideways]

Not a fan of header wrap on street cars personally. But im also not a fan of exhaust leaks

[HorizontalMitsubishi]

Crystallized headers tend to not seal very well.

[SolidSTI]

Unless you are going with swaintech coated killerb headers go with ported subaru factory manifolds. Many of us, myself included, have tried the various aftermarket solutions to wind up with a cracked header. The EL vs UEL debate is like beating a dead horse. EL will get you maybe 300rpm lower in spool. It is hard to compare since tuners could have just enriched the bottom end.

[chillined]

The only thing is, equal length headers not only increase spool time but overall power throughout the whole rev range.

[RedsunsF1]

I would stay with the oem headers honestly for a DD. You might have known this already about equal length headers but i'll still say it, if you go equal length headers you will lose the rumble sound of a Subaru.

[chillined]

I'll be going with equal length headers on my GM6, thanks. I don't need to have that rumble sound, because every other freakin' Subaru has it.

[sometrueno]

i didnt read your post but whatever you do, get unequal length for cool noises