OK, it's go time for a downpipe install, but I can't decide if I should replace/gut the up pipe while I'm in there. I've read a ton of install threads and this will mos def be a DIY job with one assistant. Experience = moderate.

I have a Helix DP with hi-flow cat that will be sweet with my existing EVO2 catback. The DP install doesn't seem that bad - it's going to happen in a week or so. Further, I am ordering a Tactrix cable and appropriate reflash s/w to flash the ECU once the install is complete.

Should I also work the up pipe? It seems to have a decent performance advantage, as well as the issue with the stock cat grenading into the turbo over time. But the up pipe install looks like a big PITA for someone who's never done one before. That and the possibility of opening Pandora's box with having to remove/mess with so many components close to the motor makes me hesitant. I'm not willing to risk premature engine failure or large problems for 10 wHP.

My wagon is a daily driver, 30K miles. I track it 4-6 times per year, possibly some AutoX this year too. Is it worth the extra install trouble and risk to change out (or gut) the up pipe? I'd love to hear from some peeps that have done the install - what were your results/issues?

Thanks for the input!

 

You'd better consider an ECU reflash with those mods. They'll make an existing condition worse.
I suggest not modding your daily driver.

 

what problems? He's just asking for advice on the install, and he makes mention to doing a reflash?

I'm looking to go down the same road as shagginwagon, so Im subscribed...

 

I'd do the UP while you're at it. I don't know if its that much more of a technically advanced process, its just a bigger PITA.

 

An upipe/downpipe combo worsens the factory condition of lean AFR. Run too long without a reflash and you'll be replacing a motor.

 

I agree, you HAVE to have an ecu reflash/tune with an uppipe and/or downpipe on the 2004+ wrx. Runs better and safer.

That said, hell yes gut or buy a catless uppipe! More power, better response and no worries of sucking the cat into the turbo.

Uppipe + downpipe + catback + accessport =

Or

Uppipe + downpipe + catback + Protuned accessport =

 

Yes, as I stated in the first post, I am definitely going to do an ECU reflash with DP install, regardless of whether I do the UP or not. I'm not planning to get an AP at this point due to cost.

Instead, I'm going with the DIY solution discussed here, probably with an XPT Stage 1.5 or 2 map (again, depends on go/no-go on the UP). This is a somewhat conservative map, so I'm not anticipating any issues as long as things are installed properly.

 

You'll see far better gains in driveability and usable power with an upipe + reflash than a downpipe/tbe + reflash. So if you're set on the downpipe, I'd highly recommend the uppipe. Besides, you have to remove the downpipe to remove the uppipe so you might as well do them at the same time.

The uppipe install is not all that difficult. I can do it by msyelf in 1-1.5 hours. Even a first timer should be able to do it in 2-4 hours. There are many helpful guides online, but feel free to ask specific advice here. If you really feel like it is too much of a task, then take it to a Suby shop.

Good luck!

 

Can anyone explain the diff between gutting the stock UP vs the STi UP? I've never seen either up close...

 

Well the end result is pretty much the same = no cat. Gutting a cat is a pain in the *** (Ive done it on my old wrx) but a gutted stock uppipe is free, fits perfect and looks oem. Just make sure you get ALL the cat out. Ive heard that the stock STi uppipe heatshield can rattle...but Ive had no issues on my 2004 STi.

 

Thanks for the tips. Since there seems to be a market for people to steal cats off of cars does anyone know if the gutted platinum can be recycled or sold?

 

the only problem you will have is a cat code reading cat on bank 1oxygen sensor effincency too low or you live with or change the setting by the way of flashing

 

The only two O2 sensors in the car are before the uppipe and after the downpipe cats. Changing the uppipe out to one without a cat (or gutting the stocker) has no effect on the O2 sensors or their readings.

Now, the stock EGT sensor may not fit back in an aftermarket uppipe and you'll have to do the $.10 resistor fix. It's a useless sensor anyway.

 

I have a Cobb down pipe and a dcsport exhaust, with a perrin uppipe, im also reflased with a cobb AP running the stage 2 93 oct hwy map and it feels good driveing it around.

 

+1 ECU reflash should be on the top of your mod list.