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Project Gen 3STi: Testing the COBB Down Pipe and Exhaust Project STi AccessPORT COBB Tuning AMS automotosport rallysportdirect proto down pipe GR cat-back exhaust MotoIQ Certified Legit
Our trusty AccessPORT allowed us to re-flash our ECU to safely use our new mods in roughly 3 minutes.

 

After putting the car back on the ground we used our AccessPORT to upload the Cobb Stage 2 93 octane map, the car fired up without issue and I finally had a chance to hear the Cobb exhaust for myself. I was pleasantly surprised at the lack of racket! A nice low tone and just a hint of the Boxer rumble. We took the car out on the road to get it up to temp and then returned to let the car cool down. so that we could double check the torque on the downpipe and exhaust joints. So how does it really sound? Daily driving the car the exhaust is easy to live with as it has almost no drone even when cruising at highway speeds and it actually sounds good at WOT. Having heard quite a few Subaru exhausts in the course of auto crossing and running HPDE and time trial events, I can honestly say this is my personal favorite. I also prefer the look of the Cobb muffler as it resembles the stock layout rather than the tilted grapefruit launcher approach. The goal of this car is to create an all around performer that also functions as a family car when it needs to, thus the Cobb exhaust is the perfect fit!

Project Gen 3STi: Testing the COBB Down Pipe and Exhaust Project STi AccessPORT COBB Tuning AMS automotosport rallysportdirect proto down pipe GR cat-back exhaust MotoIQ Certified Legit
Our installed turbo back exhaust! The cleaning paid off as after a few weeks of use the exhaust is getting a nice golden hue. 

 

We once again called upon our friends at AMS to have Mitch help us with a baseline with the new Cobb stage 2 MAP as well as an AMS pro-tune. After the last instalment our STi was making 245 Horsepower and 271 LB FT of torque to the wheels with the AMS optimized MAP on their AWD Mustang dynamometer. After strapping down the family wagon Mitch hooked up the AEM wideband and got out his trusty laptop. Using the Cobb stage 2 93 octane base map the car made 256HP and 294 lb ft. The Cobb map worked very well and removing the downpipe and exhaust restriction really allowed the turbo to come on sooner and allowed us to hold boost all the way to redline, whereas before the car would die up top as the boost fell off. Mitch then let his fingers do the walking and after a few pulls and logs the car was able to put down 261hp and 301lb ft. We were also able to make a good amount of power in the area under the curve through optimizing the AVCS. Instead of talking about peak # this and that I will let the dyno charts do the talking. 

Project Gen 3STi: Testing the COBB Down Pipe and Exhaust Project STi AccessPORT COBB Tuning AMS automotosport rallysportdirect proto down pipe GR cat-back exhaust MotoIQ Certified Legit
The first sheet shows what one can expect with simply using the Cobb AccessPORT base maps. Real world results of our baseline pull, Cobb Stage 1, and Cobb Stage 2. It is important to note that we have the stock intake and OEM filter still on the car. 
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Comments
Adventurevirus
Adventureviruslink
Thursday, May 24, 2012 3:13 AM
I love how that downpipe is comparable with any kind of exhaust. But if you have Cobb up front I'd go Cobb all the way...
Adventurevirus
Adventureviruslink
Thursday, May 24, 2012 3:14 AM
Compatable*
spdracerut
spdracerutlink
Thursday, May 24, 2012 8:30 AM
The muffler sure is shiney.... you can see Wes taking the picture in it! I can't believe how crappy the stock downpipe design is. I wonder if it's the same deal as the Evo X downpipe where they have a nasty inlet section due to having to be compatible with RHD.
Wes Dumalski
Wes Dumalskilink
Thursday, May 24, 2012 9:31 AM
I laughed out loud when I removed the OEM downpipe Khiem. Holy new level of OEM suck! I DO like the use of the OEM donut gasket and bolts at the down pipe to exhaust junction. Honestly the car is pretty darn quick as it stands. Time to plan the power mods. but get BUSY with bushings and suspension.
x01011000x
x01011000xlink
Saturday, May 26, 2012 12:47 PM
You probably already know, even though the Cobb system necks down to the 2.5" OEM size at the donut gasket, you can still make great power.

Another bonus about Cobb parts, at least for the Subaru community, they seem to hold their resale value really well and are bought quickly on the forums. I think that says a lot about the quality level that Cobb puts into them. Makes them desirable even used.

HKS used to make a Subaru down pipe for the GD. It was 3" non-catted, but it had the stock flat flange at the turbo. I guess it would be good for an external waste gate setup.
Wes Dumalski
Wes Dumalskilink
Saturday, May 26, 2012 1:17 PM
Ya know I am kinda surprised someone hasn't modded the stock down pipe to separate the wastegate flow...
Dan DeRosia
Dan DeRosialink
Saturday, May 26, 2012 6:21 PM
Hmm. I have a TIG welder... maybe when I got stage 2 I could try for grins. Although the stock bits are just mild steel or something, no?
King Hax
King Haxlink
Thursday, March 14, 2013 4:37 AM
The Bends are more gradual and it helps to prevent boost creep but also allows the COBB downpipe.abwe
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