plac

iTrader: (4)

No pics.. not much to show. Easy job, just time consuming the first time.

Summary: Don't be scared to do this simple job. It was one of the most simple jobs I've ever done. I've done V6 timing belts and full suspension, and this was far easier than any of it. When I put the stock back on for smogs every 2 years, i will prob have the swap down to under an hour.

I removed the upper heat sheild a couple days ago so that shaves some time off the start of the job. That task takes about 10 mins at most. I did not remove my intercooler to get the heatsheild out.

The work tonight was very straightforward. I waited until the car was cool. I sprayed the 5 top bolts on the main flange with WD-40. I then easily broke all those 5 nuts/bolts loose with no issue, they came off like new. (Car has 60k miles). Removed the 5 top bolts completely.

Next I had to see what all the other connections looked like. I next removed one 10mm heatsheild bolt. You can see it from the engine compartment down the side of the stock downpipe.

I then moved under the car after jacking it up with a stand under the passenger side of subframe. There are two 14mm bolts attaching the stock downpipe to the car, I did not know about the upper one. You will see one up near the cat itself. The other is the "hangar" bolt people talk about. The hangar has a hook on it so you can hang the pipe while you set it up. I removed both those 14mm bolts.

Finally, I removed the two downpipe-to-catback spring bolts which came off fairly easy. I then unplugged the O2 sensor harness plug and unsnapped the holdowns so it could come out with the stock downpipe.

On install:

The Cobb downpipe looked a lot better than all the pics I have seen. The finish looked more shiny/stainless rather than the ceramic type surface I have seen in some pics. It was also a lot bigger in person than i expected in piping size.

The Cobb did not come with ANYTHING but the pipe. So I reused the gaskets on each side. I might order a new donut for when i bring it back stock someday for smog.

I put the new pipe in from under the car, and hung it on the turbo studs. I then attached the "hook" hangar for it to rest on. I went to top and started all 5 master nuts/bolts, did not tighten. I then put in the hook bolt lightly also. You do NOT use the other upper 14mm mid bolt with this downpipe. Finally, I attached the spring bolts which was the hardest part. I had to use channel locks to get it close enough to get the bolts started. Then I tightened everything carefully. As a last step I screwed in my O2 sensor and tie wrapped the harness nicely.

I then installed my Cobb stage 2 map which I will test tomorrow, been storming here.

Notes:

The donut which connects the downpipe to catback is very tight fit over the downpipe. Both stock and Cobb. I had to pry it carefully off the stock one with a large flathead. Make sure you install the donut on the new pipe before you install it under car. I forgot and it was much harder under the car to get it on all the way.

I would order the 2 gaskets in preparation if your downpipe does not come with them. It's a nice thing to have for emergencies.

I will be ordering a Cobb heatsheild also just to help out on heat.

I can get a few pics later of it installed if anyone really needs to see pics.

plac

iTrader: (4)

Installed the Cobb heatshield this morning. Straight out of the box it doesnt fit very well. It hits the wastegate rod. But after some simple pressure and slight bending, it becomes a perfect fit. I used 3 stock bolts to attach it.

03_Impreza_Al

iTrader: (46)

Congratz.

AngrySubyWagon

iTrader: (9)

that's why i use the cusco heat shield...i had no problems with bending and pressure.

plac

iTrader: (4)

Downpipe is working fine, though i'm already used to stage 2 and getting bored. It's partially my own fault as I don't drive fast all day long, just once in a while. It seems like the stage 2 is mostly good for freeway stuff. Around town theres just too much lag stop and go.

plac

iTrader: (4)

My Invidia uppipe is getting installed tomorrow. I have prepared all the usual perventative measures. I already installed my 5 studs into the new downpipe. I had to buy M10 x 1.25 nuts to install the studs. Those nuts were hard to find, but I found a Kragen/Checkers that had them in the "Help/Dorman" hardware section. I bought both packages of 2. I have done a lot of reading on the EGT sensor regarding whether to use it or not. I was set to use it in the new pipe, but changed my mind recently. I want to make sure it doesnt get damaged so I can reinstall it in a stock uppipe later if I need to. So I also hunted down a M12 x 1.25 bolt to plug that hole. I have not tested the correct thread size, I just went with what I read around here. It is a 25mm long bolt, so it might be a bit too long for the hole. I can either have it stick out a tad, or I can hacksaw off 10-15mm in length so it sits flush. Finally, I bought the 4 new gaskets needed for this job. Upper downpipe, lower downpipe, upper uppipe, lower uppipe. I have all of tomorrow and the next day off, so i will be going slowly on this job. I will attempt the uppipe removal without touching engine mount for no more than 5 mins. If I can't get it I'll jack up the engine.

unstble

Glad to see everything went well!

plac

iTrader: (4)

Did my uppipe this morning. I NEVER want to do that job again. I'm already worried about smog in 2009 or 2010.. (My cars a 2005 California car). I'll have to bring it all back stock to pass smog then, and i prob will just sell the car stock after that point.

One thing that wasnt clear in tons of writeups I read.. I DID have to remove that corner section of the exhaust manifold/header. Well, all but one bolt so i could swivel it out of the way. I also had to do the engine mount bolt and raise the engine at least an inch. That nut is shady, and i finally got it with my impact gun on air. It was a tad soft as people have said.

The job sucked, and i spent about 4 hours all in all. First time doing it though. I'll test drive it later, I'm too tired right now. Started it up, don't hear any leaks.

unstble

yeah, the up-pipe takes a little while to do...

Woodward

iTrader: (7)

Cobb makes a heat shield for the WRX and a different one for the STI. Maybe you ordered an STI one. I ordered one for a friend over the phone and was told the WG arm is in different locations.

karis119

iTrader: (1)

why not re-use the old heat shield? I took a grinder to mine and cut it so it fits over the aftermarket downpipe, but still looks stock.

plac

iTrader: (4)

Instead of making a new thread, I figured I'd just add to this one. Since most people thinking about a downpipe might be interested in uppipes also.

I installed my Invidia uppipe this morning. It came with 5 uninstalled studs, and a EGT bung. You can buy M10x1.25 nuts in order to install your studs ahead of time. The job took a good 4 hours. I already had a Cobb downpipe installed, so at least that's easier to remove than stock.

Install thoughts:

Just as hard as everyone says, huge pain in the ***. Not because of the physical tasks, but because of things that can go wrong.

I did NOT notch out my "O2 sensor cover" like some people do. I didn't need to. My O2 sensor socket fit on it and broke it loose easily. I removed it and then the lower shield fell off.

I didn't realize at first that I needed to unbolt that header section. One bolt seized up, but it was loose enough to swivel. Then it tightened back up ok. It is right under the uppipe preventing it from coming out. Even after I jacked the engine up an inch, I still had to remove that small header section to get the stock uppipe out. (Total of 5 bolts/nuts.) I used an air impact gun to remove the engine mount nut, otherwise it would have rounded off.

The EGT sensor looks exactly like an O2 sensor. I used the M12x1.25 bolt in the EGT bung hole to plug it up.

I used new gaskets and doughnut except for the header piece which I hadn't planned on unbolting. I am keeping my old gaskets in case one breaks in a later job.

I don't know if I would do this job again.

Results:

I did not expect this much difference. It was VERY noticable. It seems to me this is just as much of a butt gain as when I did my downpipe, maybe even more.. I did get stage 2 Cobb after my downpipe was installed. This feels like a lot of lower end gains rather than highs. I felt the difference right when I took off from a stop. This was a very worthwhile mod, although it was no fun during the work. I hope I am almost to stock STI levels now, the car sure feels fast.

Sidenote: Running stock airbox. Stock catback.

plac

iTrader: (4)

so i dont wreck any stock parts of course. the car will be returned stock in a few years when i sell it. anyone buying a used WRX will look for a cut stock heat sheild. dead giveaway.

Woodward

iTrader: (7)

True. Plus the Cobb heat shield is a TON easier to pull off.

wrXmon

I recently did the UP and DP on my '04 WRX, and best thing about it is the way the turbo spools up. I used a STi UP on my car.