First Modifications - what to do and not to do

[plunker23]

I have a stock 2004 wrx and i am thinking about upgrading to an 18g turbo. What all would I have to replace if I made that mod. The only mod to current date is an short RAM intake. Any advice/help would be greatly appreciated.

[Mikie13]

Go two posts up from here...see the link in SD GR's sig.

[Bucky]

Thanks guys, thats allot of info to look into. I'll post back on here what I do and put some pics up soon.

[Undead]

My first time looking at this thread and saw something that scared me! The uppide cat breaking apart and destroying the turbo?! I really want to take care of this but is it legal in California to replace the uppipe with a cat-less one?! I doubt it with our stupid strict emmision laws out here....

[EJ257]

My first time looking at this thread and saw something that scared me! The uppide cat breaking apart and destroying the turbo?! I really want to take care of this but is it legal in California to replace the uppipe with a cat-less one?! I doubt it with our stupid strict emmision laws out here....

It is illegal to tamper with emission control devices in any state.

If you're really concerned, gut it (looks stock, but catless)...

[Undead]

It is illegal to tamper with emission control devices in any state.

If you're really concerned, gut it (looks stock, but catless)...

Thanks for the advice, you really think I should do this? Will this also allow for better airflow? Won't that mess with the computer, a.k.a. will I have to tune it? Sorry for the ?'s I just don't know anything about this little mod...

[SD_GR]

See the link in my signature for any/all info. In short you will generate a CEL, that must be corrected or your car will not pass emissions. To do so you will need to implement the resistor fix (search that term specifically) or use an ECU management scheme to dismiss the code while allowing the sensor to report "ready" since a sensor that doesn't report ready is just as bad as a CEL with respect to smog checks.

Incidentally, your cat is not guaranteed to dislodge and destroy your turbo. My guess is that most in fact do not.

[EJ257]

Thanks for the advice, you really think I should do this? Will this also allow for better airflow? Won't that mess with the computer, a.k.a. will I have to tune it? Sorry for the ?'s I just don't know anything about this little mod...

It's up to you. A friend of mine had the cat dislodge and get sucked into the turbo on his '04.

Yes, it will allow for better airflow, resulting in better spool and power. Total cost for gutting the uppipe is ~$100, if you don't already have the tools. Because an uppipe install can be a bear, I recommend purchasing an OE uppipe in the classified section and gutting it at your leisure. This will allow you not to rush (possibly missing cat material that in turn can be sucked into the turbo), and should help reduce vehicle downtime (if there are complications with the uninstall / reinstall, you don't have the time factored into gutting the material to add to it). After your install, you can sell the one off your car to recoup all / most of what you spent on your second one.

[mycologist]

IMO an aftermarket uppipe is nearly impossible to spot on a normal inspection and you don't have to deal with the extremely toxic crap you will be gutting. No guarantees though.

[Undead]

Wow, thank you so much guys! I have a lot of thinking to do...

[Undead]

Oh, and happy Thanksgiving!!!!

[Sevier2]

I live in California also and i have a catless up pipe. Not gutted or anything I just purchased an Invidia catless up pipe and it's fine. what you have to do is put your STOCK down pipe back on when you go to get smoged. (this means you need to set your ecu back to stock mode with your cobb ap if u have it or anything like it.) After doing that i passed easily with no questions. took it back home and was back to stage 2 within the hour. Just remember when switching the Down Pipes you NEED to tune accordingly. good luck!

[Kemy704]

hey man I have an 2011 Rex 2.5, wanna get the most HP out of it.... What should i get and what has to be done, Please let me know. I wanna make it as fast as i can without none of the Downfalls, need help bro thanks.

[mycologist]

hey man I have an 2011 Rex 2.5, wanna get the most HP out of it.... What should i get and what has to be done, Please let me know. I wanna make it as fast as i can without none of the Downfalls, need help bro thanks.

I have no experience with 2011 - maybe someone else can point out if there are any significant differences from the mod path outlined in the OP.

[Mikie13]

hey man I have an 2011 Rex 2.5, wanna get the most HP out of it.... What should i get and what has to be done, Please let me know. I wanna make it as fast as i can without none of the Downfalls, need help bro thanks.

WRX or just a 2.5i Impreza?