I just purchased an 04 XT 5 speed and like all speed crazed freaks, I'd like to improve the performance a bit. After talking to a number of people and looking at what's available, I'm confused about where to start. I've heard bigger intercooler, better exhaust, wastegate, bigger turbo, boost controller, EMS, fuel management system, APE ram intake, etc, etc. I'd like to add 30 - 40 horse, preferably with something I can deactivate when my wife drives it (she doesn't know XTs haul butt).

A full exhaust system can yield up to 30 horses. It will also yield up to 15dB !

 

The main thing to note is the turbo up- and down-pipes. Good replacements are far less restrictive. You could replace these and leave the standard cat and silencer on there. HP gain? Maybe ten on a sunny day, but the throttle response will be much better.

 

A K&N (or similar) panel air filter, accompanied by removing any intake silencing could free up a few extra horses.

 

Overboost, and the related fuel delivery upgrades will be more complex and will harm the longevity of internal components.

Thanks for your reply. I was told a larger intercooler will allow me to go to about 15 - 16 lbs of boost with no adverse effects. True or false? I can see where a good exhaust system would help, as there are quite a few bends in the stocker, but 15 db more doesn't sound very appealing.

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how bout putting one of these in

Bigger intercooler? Sure it would help to relieve some of the overboost stress, but it will also add throttle lag.

 

I don't mean that this engine is already so stressed, that it you overboost it will explode. If you want your engine to run 200k miles on nothing more than oil, coolant, and timing belt changes, then stick with normal boost.

 

You could just dismantle the stock exhaust system, and optimise flow in there. Usually there are many edges that can be smooth out. Easiest thing to do is get the pipes welded INSIDE the flanges too.

 

While your in there, a tuned up- and down-pipe would be good, but often you can't fit these into the stock system. You'll need to replace everything, and that brings us back to the noise problem...

 

Bear in mind that this is my personal view. Lots of people spend lots of time (and money!) successfully tuning their engines. Just remember to upgrade your brakes too :-)

I saw a Cobb Tuning Stage 2 kit that supposed to be good for (an over-optimistic) 280 hp. It consists mainly of an AccessPort ECU programmer and cat-back exhaust. It's not terribly expensive but seems to be about what I'd like. It doesn't drastically alter boost or other engine parameters. Any thoughts? Also, I'd like a short ram intake... mostly cause I like the noise. Good or bad?

 

The only thing I've found that I don't like about the Forester is the body roll on corners and curves. Cobb has a suspension kit that seems to address this.

 

Anyone have experience with Cobb parts? Anyone know somebody in southeastern Wisconsin who can install this type of stuff?