First off power: (all mods should be done with engine management in mind)

Up pipe is just the pipe that goes from the headers, which connect to the engine exhaust ports to the turbo. A aftermarket up pipe is usefull for faster turbo spool up which means better throttle response. (not much gains here)

The down pipe goes from the turbo down to the mid pipe. This has two cats and its a tad restrictive with the plate design. Swapping this for a bellmouth or a divorced downpipe design frees up the turbo for more power. (good gains here)

catback has moderate gains being its the portion from the downpipe and back.

Opinions:

Go with a downpipe first or a turbo back exhaust for gains. You wont see good gains until you flash your ECU to handle the increased flow. Stage 2 is a definite improvement over stock so thats what i'd aim for.

Stage 2 basically consists of a downpipe and a proper engine management flash like off an accessport. More exhuast components added will increase your power moderately after the downpipe.

Noise?

Catless is LOUD and so are alot of single tip designs. One quiter more stealthy model is the borla hush twin tip. I'd choose it becuase its cheap easiley adapats and bolts on plus i like stealth.

More than likely you will hear your turbo spool up with a full exhuast unless you keep the stock cats. (unsure on aftermarket cats total noise)

Addition:

Search the forums for exhaust clips i'm sure you'll find a fair share of opinions on different model tastes.

 

Thats really close to saying I'll have 1/2 a dozen... no wait, give me 6 instead.

downpipe + catback = turboback.

The less cats (and to an extent) the wider the pipe, the happier you're turbo will be. Its all a matter of how loud and illegal you want to be.

As for an ECU flash like Roadspike says, sure it does wonders, but its not necessary. You can get substantial gains from just the boltons... I wouldn't worry abotu it until you're sure you're more serious about hopping up your car. However, you'll about double the gains (and the price) by getting ECU enhancement. Personally, I prefer a UTEC because you get an actual device you can sell later on, you can tune it yourself, you can tweak it without needing a tech or buying a second piece of equipment. If you really want to learn about tuning and be the master of your car, get a UTEC. If you want plug and pay...and pay and pay and pay... get the Ecutek or accessport.

jason

 

Actually it depends on what DP you get to whether it removes one or two cats. DP's sold by some manufactures include both cats however many / most only include the one that exists in the actual DP, not including the mid.

Ecutek is a fantastic option however it is reflashing your existant ECU, the software that it used to tune and load maps is called Delta Dash and is loaded onto a laptop and attached via the console port.... very easy.


Good luck


-K

 

Single cat is a waste of money. They are always race cats. Race cats hardly do anything for emmissions and almost nothing for keeping the volume down. And, they are still illegal because you have modified a D.O.T. approved emissions system. It won't save your *** at the DMV. It hardly helps you preserve the environment. It won't keep cops off your back. Waste of money. That's why I didn't even consider it in my previous post. When you modify a cat'd system at all, you've already made your car illegal. Why waste extra $ to remain illegal?

The only reason to get race cats is for organized race rules that require a stock(ish) setup for various competition groups.

jason

 

It is legal to change a cat when the car has 80,000 + miles on it.

Here are a few different things to help you out.
1. Up-pipe: better flow before the turbo to get spool. No one will be able to look for it (i.e. cops) and you still have 2 cats and should pass emissions if your state requires them. This is the most difficult part to install out of the three.
2. Downpipe: There are some major power gains for the cash here. For a non-catted, bellmouth, 3" diameter pipe you can get it for around $295 from Helix. It will make your car louder, but if you run the stock cat back it will just have a louder grumble and most likly not too noticble to others.
3. Cat Back: This is the only one listed that will keep your car smog legal. It will make the biggest difference in sound and looks.
4. When you remove your cats you will need to buy cel eliminators so that your check engine light wont be on. They range from $15-40.

I personally would go with an up-pipe and downpipe with a stock cat back. I did this on my 03 WRX, it sounded very nice and had a very noticible power gain. Then I bought a cat back when I could afford it. Hope this helped, and good luck.

Nick

 

I was under the impression that by adjusting the settings on the left you could in effect change the settings on the right?... is this true?

What is the software or device used with the utec?..

Thanks for the clarification.


-K

 

They can actualyl void the entire warranty for basically any mods. You have to check otu the dealer and see if you can get something in writing for them and try to figure out how easy going they will be about mods. some are cool and even sell them, some are asses. look at the threads of note sticky in this forum and click the "some helpful diagrams" link.

 

Cool.

Thanks for the lesson bro.


I would love to have he ability to "play" at the cel level however without the proper knowledge and or expieriance im afraid that i would do more damage than good. I wonder if there is a class that we none preofessional tuners can take to educate ourselves on how this technology works; almost like a road tuners guide to success.


food for thought.



-K