Exhaust reccomendation

**D's WRX** · 11-19-2012 01:29 AM

I've already purchased an Invidia Catted down pipe and an Agency Power Cat-back exhaust. Before installing them, my tuner recommended replacing the Invidia pipe for something else (possible boost creep issues). Does anyone have experience with the nameless downpipe? I've been looking real hard at a complete Nameless Turbo-back exhaust with 5" mufflers. I see a lot of threads with nameless axle-backs with positive reviews, but no reviews of their down pipe.

**Mf645** · 11-19-2012 04:07 AM

Boost creep is rare with a catted DP. I bought a catless DP based on the word of my tuner, STI Mikey who basically told me that he had never seen a DP failure and buy whatever one I want. Boost Creep can be tuned out and when he is done tuning I won't have a problem

**Ruh Roh** · 11-19-2012 05:11 AM

Originally Posted by Mf645

Boost creep is rare with a catted DP. I bought a catless DP based on the word of my tuner, STI Mikey who basically told me that he had never seen a DP failure and buy whatever one I want. Boost Creep can be tuned out and when he is done tuning I won't have a problem

^^Wrong. Thats the second time ive heard someone say that about STI Mikey...Ill let another member get into how boost creep IS NOT "tuned out". Its the mechanical devices that are causing the problem, not the tune. (correcet me if im wrong) There are solutions like EWG or porting out the internal wastegate. Ill look for a thread thats a few days ago about the same topic..Stay with a catted downpipe. Wait for some 3rd gen owners to chime in on the Invidia DP's

**Ruh Roh** · 11-19-2012 05:18 AM

check out this thread D's

Questions on stage 2 upgrade (downpipe/ap)

**Mf645** · 11-19-2012 08:21 AM

Originally Posted by Ruh Roh

^^Wrong. Thats the second time ive heard someone say that about STI Mikey...Ill let another member get into how boost creep IS NOT "tuned out". Its the mechanical devices that are causing the problem, not the tune. (correcet me if im wrong) There are solutions like EWG or porting out the internal wastegate. Ill look for a thread thats a few days ago about the same topic..Stay with a catted downpipe. Wait for some 3rd gen owners to chime in on the Invidia DP's

I really don't know a whole lot about it, other then I installed a CNT racing catless DP ($179 from Kronos) and Had Mikey tune the car. Boost spikes to between 17.9 and 19.1 at about 3400 RPM, settles to between 18.2 and 18.6 and slowly falls off into the mid 15's as RPM climbs toward redline. Other then CEL 0420, had no problems. I first contacted Mikey to tune my stock car and he suggested adding a DP before he gets there to really wake up the car. I asked if there is a specific brand or model he likes and he said he has not seen any difference between any DP's and since I am in Florida, get a catless one. I ordered a Tsudo DP but the distributor was out of stock and they sent a CNT racing in place of it.

**Calvinball** · 11-19-2012 09:34 AM

Ok. So, we all know the turbo is run by exhaust gasses. The wastegate is literally a little flap that opens or closes a certain amount to let the correct amount of exhaust through to have the turbo spinning at the rate it should. Here's a good pic:

When a car's exhaust is changed to be more free-flowing, then there can be a point where the exhaust is moving so fast that even with the wastegate fully open, bypassing as much exhaust as possible, there is still too much hitting the turbine. This causes the turbo to boost beyond what it should according to the tune.

There is no way for the ECU to make exhaust slow down that I can think of, it is a mechanical issue. I still can't figure out what a tuner might be doing that could possibly put a bandaid on boost creep, but whatever they might do I don't think it would be good for the car. The only thing I've seen is that they might just tune the car so that the higher psi caused by creep is the map's target boost. Problem with that is that you're still possibly pushing more boost than is generally considered safe for our engines.

**Mikie13** · 11-19-2012 12:13 PM

Too shorten what Will said, Boost Creep is a 100% mechanical issue. Only thing that can be "tuned" for it is to raise boost, remove the fuel cut that happens when overboosting...and change wastegate duty cycles.