I was wondering if anyone had any recommendations or insight on exhaust manifolds for the 2004 STi. I'm looking at getting the Gruppe-S exhaust manifolds but i can't decide if I need to get it with the Jett Hott Coating or the uppipe. Any insight that i could get from my fellow I-clubbers would be greatly appreciated. Thanks in advance.

 

Please get it Jet Coated... you won't regret it.

 

ooOOoo headers....gonna totally change the exhaust sound....more "rally car" sound...from what i've heard....

 

If I got a header, I'd probablt get an equal length one for the "rally car" sound

 

Changed the sound of my exhaust for sure...both of these are 1:3/4 length meaning one side is 3/4 the length of the other...let's a bit of the boxer rumble through but smooths it out quite a bit...I believe the Gruppe S headers are similar...the Borla is more like the stock exhaust manifold...

I think the equal length ones (invidia etc.) will eliminate the boxer rumble totally...haven't heard one yet though...

If I were to do it again, I probably would have it Jet Coated on the outside only...but as it is, I don't have it wrapped and it's not coated...I do have the plastic shield on the bottom...

The tone of the exhaust went from the low rumble of the boxer, to a higher pitched, smoother rumble...the rally car sound is true...it's pretty cool...

I have the APS 3.5" TBE on with it right now and it outright WAILS at the upper RPM's...I really like the way it's change the way my car sounds and performs...

BTW: Remember to REPLACE ALL GASKETS!!! I learned the hard way and tried to reuse them...BAD IDEA! I had to remove DP/Header/Up-Pipe twice because of this...what a bunch of wasted time!

 

I've also got headers and up-pipe on my rex. Sounds sweet but since you have an STI, don't waste the money on an up-pipe if you don't have to. Your up-pipe is already straight through so I wouldn't get the u/p unless the headers you want requires you to use their pipe

 

but, my header required me to use their up-pipe...

 

gt spec gen II manifold

this is on my list, but it's some dollars.

 

Thanks for the replies fellas. So far I only got one recommendation for the Jet Hot coating. Is the heat coating required? How much of a horsepower gain can I expect if the manifold is heat coated? I don't want to pay extra for something that will only see minimal gains. Thanks again for the suggestions.

 

heat coated or wrapped, but you should do it to keep the heat in the manifold where it should be. It's this heat in part that drives the turbo. Also the coating or wrap will keep the engine bay temp down which is always good for everything else.

 

^^^ What Sykosis said, coating is to prevent overheating, keeping the exhaust gas hot on the inside to spool the turbo quicker. It's not going to add hp to the car.

 

mad dad has great products, and after reading your post, you want maximum HP gains, so you don't mind the loss in torque?

 

I was hoping for the best of both worlds if at all possible. Good torque and HP gains. Sounds like the heat coating or heat wrap is highly recommended. Anyone know where I can get the heat wrap?

BTW I've got the mechanical apptitude of a trained monkey and I'll probably need some help during the install of the headers. Thanks again fellas.

 

sorry I won't be home till Oct. It was a b*tch putting mine on for the first time, but I think it would be a lot easier now...Thanks again Jeremiah

 

i don't think the headers will be a problem, go underneath the car and look at it, but the up-pipe on the other hand may lead to headaches...
one more brand to check out magnus, the dyno on the intake manifold claims 35 HP!! and each one is custom made