Intake/Exhaust: better in combination?
 

Hello all,

I have a 2002 WRX (2.0 liter, U.S. spec) and am thinking about replacing the exhaust with a prodrive kit. Details can be found here: http://www.prodrive.com/defaultflash.asp?M=5

There are a bunch of places on the internet where it can be purchased. For example: http://www.prostreetonline.com/buy/p...ormance_packs/

Here's my question: I can buy a cold air intake for a couple hundred bucks. (This: http://www.prostreetonline.com/buy/k...akes/69-8000t/ - for example)
So, would adding an intake onto the exhaust make a significant performance difference or should I just go with the exhaust and skip the intake?

You need to open it up and let it breathe at both ends. The drop in backpressure (you want no backpressure at all on a Turbo car, despite what some people will tell you) will free up some power, but if it can't take in enough air, you won't be able to make any more power tha you do now.

Thanks, that's good to know. I figure I'll have almost 300 hp if I buy both the intake and the exhaust. Upgrade the intercooler and the turbo and I can have myself a burnout picnic, AWD be damned!

isn't the wrx like 227hp? you're not getting 73hp from I/E :)

Having had a 2004 WRX sedan, the CAI on a WRX isn't really going to help it at all unless you are pushing around 400hp. You'd be better off doing a turbo-back exhaust and engine management. This combination will put your car at around 285hp/280 ft./lb. I'd look at Cobb Tuning, I really liked the sound of their exhaust and the AccessPort for engine management was awesome. I had this on my car, and it was really damn nice.

You aren't going to get over 300hp unless you do a turbo swap to a VF-34 or something of that calibur, but then you are going to get an entirely different torque curve...

I'll agree that the benefit of a cai wont be much, but turbo cars do love exhaust systems, get that for sure.

The thing with turbocharged cars is that you don't have to open up the exhaust. Although, it does help. Getting cold air to the turbo, and cooling it off after it's charged(intercooler,) can make a huge difference.
I've never worked on a Subaru, but if you can add boost and fuel, you can add 75hp...the problem is. On most OBDII cars, you can add intake and exhaust stuff, but without being able to scan the computer and change the programming, it isn't going to do much.

Thanks a lot for the advice, everyone. It's really nice to have a resource like this to turn to. :)

I have a MY03 (aussie spec) that I have removed the intake resonator (gives a nice blow-off sound, doesnt cost anything, intake breathes alittle better) and had a ecutek type1 computer upgrade. This has made the world of difference to my WRX. Its been really cheap, given more power and uses less fuel. Its a really good starting point that you can build on later.

DO NOT GET A CAI FOR A WRX. This topic has been beaten to death at www.nasioc.com. The MAF sensor gets all screwed up and it will kill your car. The stock intake is good till roughly 400 horsepower, but at about 350 maybe a bit more the tranny and engine internals will start to let go. Get a downpipe, uppipe and engine manangement and you will be at around 285 or 290 horsepower at the crank and will have a much more fun car to drive. I am at stage two, which is downpipe and engine management and have about 280 horsepower(extremely smooth power curve with no turbo lag), when I get my uppipe and cat back exhaust it should free up a few more hp. Go to www.nasioc.com and search around there, it is the best subaru resource in the world.

I like i-club a little bit better than NASIOC. There is nothing wrong with a properly designed CAI for a turbo Subie, but, as said previously, you are far better off spending your money on exhaust and engine management. Don't forget suspension, traction, and braking.