Up pipe, down pipe questions

[dvancleve]

Howdy folks.

 

I never thought I would bother going past stage I on my ‘07 OBXT, but lately I’m thinking I might tweak it a little and keep it a while longer. I don’t know anything about up pipes or down pipes, so one or more of these questions might be dumb...

 

Is the up pipe still needed/beneficial on cars that never had a cat there? What are the best bang-for-the-buck UP and DP? I don’t care about cosmetics at all but would prefer to avoid Chinese parts (unless, I suppose, they are great and by far the best deal). I also don’t want to remove any cats, does that affect my downpipe choices?

 

Thanks, Doug

 

P.S. Probably well into the “duh” category, but are there STi OEM parts that would be a good, cheap upgrade? I doubt any mods I do will surpass a stock STi, so if the parts are good enough for that they should be good enough for me…

Edited April 14, 2020 by dvancleve

[Max Capacity]

Your up pipe is catless, leave it in there.

 

Invidia catted DP is what most of do. You'll want to cut about a 1/2" off he divorce plate before you install it.

 

Getting the stock DP off is the hardest part.

 

You might want to replace the oil return hose while your down there.

 

Grimmspeed 2X thick 3" gasket will seal the joint to the stock mid pipe. Red RTV bead on both sides of the gasket can help too.

 

Use anti-seize compound on all the threads when going back together.

 

Check the turbo for shaft play.

 

What version Cobb AP do you have ?

[shralp]

What Max said, Cobb makes a nice DP as well, no modification needed.

[dvancleve]

Thanks guys, so no worthwhile performance benefit replacing a cat-less factory up pipe? If yes, that’s cheap and easy Edited April 14, 2020 by dvancleve

[shralp]

No real huge benefit going aftermarket UP unless you're going to substantial power increases. Because a new UP from Cobb, Grimmspeed, Etc. is relatively cheap, if you're handy and can do the work yourself, it wouldn't hurt if you have tons of miles on our OEM one. Forced induction motors create tons of heat and over time stuff can and will fail in this dept. That said, if you're not seeing any issues your probably fine.

[dvancleve]

My AP is V2, Which I recently read may or may not be obsolete. That would be a bummer, I’d rather spend multiple hundreds of bucks on parts rather than replacing it... dumb question time, can my car be tuned without an AP?

 

My car is at about 82K miles and hasn’t been driven particularly hard. As mentioned, up pipes aren’t that expensive and it seems like you’re taking apart the same things required to replace the downpipe, maybe it makes sense just to do both. Also, Perrin claims +10 hp even compared to the non-cat up pipe. They have dyno charts that seem to support it. What do you think?

Edited September 30, 2020 by dvancleve
Typo...

[shralp]

Unless you move to something like an open source tune, (you don't want to....) then yup, need to have the AP on to be tuned. Best to check with a Cobb Certified tuner most of them have a trade in credit on the V2 if you buy a V3 from them. Still a bit pricey, I know, but its pretty much the gold standard for tuning in the Suby world, for good reason. As for Perrin's claims, meh, debatable as there are so many factors and mods that come into play that I'd be hard pressed to believe +10 HP. Possibly a bit quicker spool because it flows a bit better than OEM. That said, their stuff is well made, I've had their UP on one of my cars for many years.