Questions on stage 2 upgrade (downpipe/ap)

[pauller]

I have a 2013 WRX. I'm currently getting a nameless axle back muffler delete as my first mod. In the coming months I would like to do more. Definitely getting a cobb ap, but then looking at downpipes. An invidia catless dp is only about $300 whereas a cobb dp is about $600. I'm not looking at the cobb because it's too expensive. So could I use the invidia catless dp with a cobb ap map or would I have to get a custom map/tune? Also, I'm in Florida, so there's no emissions testing
And how loud would a muffler delete be along with a catless dp? What kind of performance increases would I be looking at too? Thanks in advance

[starkall]

You'd need a tune, and muffler delete with catless will be pretty loud. But you'll see pretty good gains and will notice a lot more power.

[11blackwrx]

I say do it lol, im running an invidia catless dp and an N1 race which has no resonators and just one muffler. its loud and sounds great i have yet to get in trouble for it

[pauller]

So I'll get the DP and get a tune, but then will any maps from the AP work with the DP? If not, where do I get them?

[11blackwrx]

the map i went with was a stage 2 from torqued performance, i would be cautious with a catless dp because it can lead to boost creep, i just a few weeks ago installed my catless dp and im going to have a local tuner help adjust the tune to avoid boost creep. but im sure that torqued performance can tweak the tune to avoid this as well

[matsayz]

You should get a pro tune if you put the downpipe on. Also, have you heard this exhaust in person? It's highly suggested, try to find someone at your local Subie meet up. I bought a 2nd hand Namless with the Magnaflow and it sounds great, louder than stock but not obnoxious. If you want an idea on how loud your car will be, drop your stock muffler setup and drive around the block... It'll sound like a rally car.

[pauller]

Boost creep! Forgot to mention that. So how big of an issue is it? (Sorry for the bombardment of questions...)

[wrxtreme06]

IIRC, the OTS cobb stage 2 map is designed for catted downpipes. not sure about any other stage 2 maps though [torqued performance, perrin, etc]

might be best to ditch the AP altogether and just get an opensource tune or if you're set on getting the AP, get a protune like the others suggested.

[Calvinball]

Boost creep! Forgot to mention that. So how big of an issue is it? (Sorry for the bombardment of questions...)

On the 3rd gen cars, a catless dp often leads to boost creep. You don't want that happening, as it could get into dangerous levels of boost.

[pauller]

I'm guessing it'll be pretty damn loud. I think I'll like it though. I'll look around and try to hear a similar setup. I have time to make sure I really like it too (about a month til I actually order it.)

[pauller]

Can a tune prevent it at all? Or is it always going to be there.. I picture it as something insidious

[Ruh Roh]

On the 3rd gen cars, a catless dp often leads to boost creep. You don't want that happening, as it could get into dangerous levels of boost.

this is mostly an issue on third gens? how about bugeyes-hawks?

[Calvinball]

Can a tune prevent it at all? Or is it always going to be there.. I picture it as something insidious

From what I understand, a tune can put a bandaid on it, but that would be by limiting the tune. I'm no expert though.

this is mostly an issue on third gens? how about bugeyes-hawks?

From what I've read, its just more likely to happen with the 3rd gens, but can happen with anyone.

[Ruh Roh]

From what I understand, a tune can put a bandaid on it, but that would be by limiting the tune. I'm no expert though.



From what I've read, its just more likely to happen with the 3rd gens, but can happen with anyone.

ahh yea i was going to put a catless dp on and im still using the cobb ap stg 2 maps..but isnt there a map like high wastegate or low wategate that has something to do with boost creep issues? or maybe not hitting full boost issuse..hmm opening up another topic there so nvm

[zax]

ahh yea i was going to put a catless dp on and im still using the cobb ap stg 2 maps..but isnt there a map like high wastegate or low wategate that has something to do with boost creep issues? or maybe not hitting full boost issuse..hmm opening up another topic there so nvm

Boost creep [most often] means that the wastegate is not able to open completely or is sized too small for the amount of air the motor is flowing, allowing the boost to continue to build past the target boost. With the WRXs prior to 2009, the Mitsubishi turbos have an adjustment on the wastegate actuator arm. However, VF series turbos do not have this adjustment. There are a few ways around this:
1.) Replace the IWG with EWG (this requires a tune regardless)
2.) Replace the IWG spring (there are threads on how to do this with STi turbos, the same concept applies to the VF52)
3.) The boost control is a PI (proportional, integral) closed-loop control system. There is an equivalent to anti-windup within the Turbo Dynamics tables. Tuning this MIGHT remove the boost creep. However if the boost creep is truly caused by the wastegate not opening completely, there's not much you can do from a tuning perspective.

Truly, the best solution is to add a little bit of back-pressure (i.e. high-flow cat) to decrease the pressure differential across the turbine. Running a LWG or HWG map is only for target boost, not for boost creep/wastegate creep (which can be easily tuned out with Turbo Dynamics)