Anyone have gruppe s headers on their sti? how does it sound and perform?

 

I just had Gruppe-S install their headers on Monday. I already had the APS 3" TBE. They told me that they may be good for an add'l 10-15 hp, and I can neither confirm nor deny that. They do generate a little turbo lag (just enough to notice). Once the boost builds, of course it takes off and seems to generate a little more power, but it might be a faker outer on the perceiver (in the brain) because of the steeper torque curve. Know what I'm sayin'? So...in conclusion, I can't say for sure that there's more power over my existing set up...maybe 10-15 hp at the most, if any.

Regarding the sound, it has increased the sound level down the exhaust...at the end pipe. I would've expected to hear a little more at the motor, but it's just made the exhaust a bit louder. My 3" APS exhaust sounded great, and was just loud enough...but not nearly as loud as others I've heard (which is fine with me). The headers jacked it up a bit, but not too loud that I'm upset about it.

I had them install the headers, more so because I knew I'd eventually be upgrading the turbo, etc. Their benefit will surely be realized then.

 

I have the GT spec II with the Jetcoat. I had them installed and tuned by Nate at Subaru Specialists. They also tune on a Mustang Dyno. On the stock turbo and injectors, we ended up gaining 13 whp and believe it or not 33'# of torque. The previous tune was for the invidia N1 turboback: numbers were around 210 stock for both whp and tq. That jumped to 257 wp and 277 tq. The finall numbers were 269+whp and 310 tq.

As for the sound.............loud yes, I just got pulled over today and was issued a fix it ticket.

Subaru Specialists rocks. The torque gain they got out of the tune was awesome. I highly recommend this shop of you can afford the extra drive from the bay.

 

Oh yes...I should say that the car has not been dyno tuned... I've got the Cobb AccessPort Stage II amp runnin'...

 

I have the gruppe-s jet coat headers on my 04 STi and i love them. I got a HUGH mid to hig range power gain that put me in a class where i can pull away from or hang with the big V8's. Up till then at about 85 MPH i would always start falling behind.

No, tunning just had them put on with my HKS carbo fiber and helix down pipe and it was a great improvement. A little louder, but the big difference is the boxer sound which i lkind of liked almost disapeared. Sounds like a regular big block now. Not bad just shocked at the difference in the type of sound.

I have heard of people saying you loose this kind of power or that. I dought they have them on there car if they say that. All i have seen are real world improvements. All pro's, no neg's in my book!

 

That's true...the guy at Gruppe-S told me that because they were unequal length, they would retain the boxer sound, but it has diminished quite a bit. It's not that big of a deal, but I liked the boxer sound too. I can't say that I think it sounds like a big block though...

 

I called Cobb about those Gruppe-s headers, and was told that with a Stage 2 the headers would actually make you lose boost.....

 

Does that mean that it should be retuned and have the boost upped? If so, then there's more power there.

Again, I think the headers' benefit may truly only be realized with a larger turbo and IC.

 

Then use the HWG maps.

 

Headers on smaller displacement cars such as ours lose low end and gain high end. You may gain 18 on the top end but lose 8 on the low. That of course is without tuning, some tuners if you can get a custom dyno tune can fix such a radical curve to be helpful across the board. The reason Cobb said that you may lose power is because the computer is tuned for one thing and may go to a safer A/F ratio when it detects the headers.

Cheers
Rush

 

I just recently installed the Gruppe-S headers on my car. Be careful though if you install it yourself. I installed mines and ended up damaging the O2 sensor. Im in the works of replacing it now. It costs a lot more to replace than to have gruppe-s install it. As for the sound, it still has the boxer engine but it does give it a more "rhapsy" sound.

As for performance, I notice a little more top end power but not low end. However, my boost did go down. Im not sure if's because my o2 sensor not working properly and may be running too lean/rich.

 

Does that mean.....? You can't hit target boost? Do you have a stage 2 cobb on your STi? Is your car just not fast as it was before?