2G Any reviews on the STM 3" full SS awd exhaust ?

[AdR]

I have been looking for a real 3" turbo back system for my DSM. Unfortunately these are now extremely limited and impossible to find. Most exhaust systems I see have the ridiculous 2.5" reduction in the downpipe section and even some catbacks reduce to 2.5" to mate to the catalytic. I have a few requirements:

1. Full turbo back has to be 3" including the flanges.
2. Only mandrel bending (reason why I don't just go to a muffler shop)
3. Don't need a catalytic but would like to have the ability to add it just in case.

The only system I've seen that meets that criteria is the STM system. Does anybody own STM's turbo-back exhaust system? Any reviews? Have searched everywhere and have found nothing.

 

[FIBA M - EC17PSE]

Is there a reason why you need a 3" over a 2.5"? As you know most just do a 2.5" DP and a 3" back system. If you kept it 2.5-3" and you need a full 3" then you must be running alot of power to have out grown it!

Don't forget the o2 housing aswell then, your going to need a 3" housing to stop restriction of all that power .

In all honesty to need a 3" full system you need to be pushing around the 600hp mark give or take a few ponies not only that you also have to have planned around boost creep and if your able to resolve it or have a different turbo which does not get it.

I only ever plan to run close to 500hp myself and I'm not going to restrict myself if I stuck with my 2.5"-3" system at all, it's the best of both worlds and does good

 

[AdR]

I'm fully aware of what most people do, most do it because that's what's available in the market and they just buy what's easier and convenient. My O2 is a 3" unit already. I am not planning on downsizing to a 2.5" downpipe to create a turbulent restriction at the flange so close to the turbo. Currently have 0 boost creep with my setup and already run a 3" turboback exhaust (alas it's crush bent at the end so it reduces about 1/4" in diameter at the bend near the muffler. Usually those that suffer boost creep are running an internal/external wastegate system that cannot keep up with the turbine flow when it's permitted to breathe (unrestricted by the exhaust). I'm not one of those unfortunate souls.

Don't want to sound like a ****, but the question was, has anybody used this system, not lets debate boost creep and exhaust sizing vs whp goals yet again as it happens here every single week. I really rather not enter into the usual size matters debate. We all have beaten the dead horse on that topic, discussing it again won't really yield any different results.


Cheers!

 

[FIBA M - EC17PSE]

Haha no worries, I know you wanted reviews and info etc, it was just a nice way of saying why spend your money when it's not needed or along that path anyway,

Sorry I was no help and a pain haha

 

[AdR]

Haha no worries, I know you wanted reviews and info etc, it was just a nice way of saying why spend your money when it's not needed or along that path anyway,

Sorry I was no help and a pain haha

Haha! No worries. To answer your question. My build will eventually get bigger and want an exhaust system I can grow with it instead of needing to change again down the road. Unfortunately mine has some "interesting welds" and it keeps cracking requiring maintenance. I rather just get a good quality system instead of dealing with this anymore or chancing it on a flebay system. Figured, Apexi, Thermal and the rest cost just about the same as STM's including the downpipe and test pipe but I can't find a single review of it.

Cheers!

 

[19gsx91]

@Fox1486

I believe you are much more familiar with this, I cannot provide much more help though unfortunately.

 

[Fox1486]

I can only speak to my experience with the STM exhaust systems. To date I've had three for my car (1st: FWD SS/Aluminum, 2nd: SS/Aluminum AWD destroyed in accident on the way to the DSM Shootout, 3rd: Current SS/Aluminum version).

I've loved every variation that has been on my car. They were all custom made/designed to my specifications (which route to take/mufflers to use). The production version of the STM SS awd is quite similar in design, but obviously is a full SS system. My car has always ran small frame turbo setups (16g, FP68HTA v2.0), so I'm pretty picky about sound anyways. Because of the smaller framed setups, I've stuck with OEM O2 housings, so all of my downpipes have had stock size flanges at that end in order to mate up. After the flange however, widens out to the 3" spec your talking about. I opted for two mufflers this time as the car is mainly a street car. To cut down on some noise, we decided on one SS race muffler right after the downpipe section, that feeds into a vibrant aluminum "race" muffler once we get to the aluminum section. Other than that, the system is pretty straight forward although I opted for a dual tip exit on my last two versions of the exhaust.

I'm extremely happy with the level of noise that the exhaust emits. Very quiet and subtle when cruising, but can get pretty LOUD when getting into it. The best of both worlds in my opinion. I always get compliments on it, as it doesn't sound like "just another rice burner" as one observer pointed out. As far as flow/performance of the exhaust goes.... I assume it's doing what its supposed to. The turbo is not being pushed just yet, but with a basic tune on the STM dyno this past August, the car had zero issues and plenty of room to grow. I don't think the exhaust will be an issue at all moving forward. The only change I may make in the future is installing one of those nifty looking STM O2 housings!

I will also mention that I was able to spend some time around the full SS awd production version of this exhaust, this past August on the way to the DSM Shootout. We caravanned down from the STM shop, and I ended up driving ride along/behind Cory at STM @eviltsi for a good majority of the trip. He was in his latest DSM, a '99 GSX. To my knowledge the car is still on a T25, but Cory had installed a set of 272 cams (Kelford?). There were some noticeable differences in tone between the two systems. Cory's SS exhaust seemed a bit more dense/deeper when compared to mine. It seems that the exhaust noise is able to easily "escape" an aluminum setup a bit more easily throughout the system. Whereas a SS system does a very efficient job at channeling and directing that sound all the way through to the exit of the system. So basically, more of that deep exhaust note could be heard from the back of his car. This could be also due to the fact that the production model has the muffler towards the rear of the car. Both of my mufflers are towards the front of the car, and cannot be seen unless you got on the ground to look underneath. I don't believe Cory's setup would hinder any performance that his car has currently, especially with the smaller turbo. I remember seeing the car on the lift as they were building the exhaust. They are very well put together systems in my opinion, and I don't think the quality/sound would be a disappointment for you!

Here's the first version I had created, when my car was FWD: http://www.streettunedmotorsports.com/z/brad_gst/brad_99_gst.htm

STM SS AWD Production version: http://www.streettunedmotorsports.com/parts/stm_dsm_2g_awd_stainless_turbo_back_exhaust.htm


I hope some of that info helps! Thanks for the tag @19gsx91

 

[Aproductions]

I have a full STM exhaust including their o2 housing.

 

[Archer Fabrications]

I'm all about planning for the future, do the full 3" even if you are running a 16g the more free flowing exhaust the better. I dont have personal experience with the STM exhaust but i have had some experience with other products from them and they always do amazing work, i wouldnt think twice about passing it up if i was in the market for one, but i run a 3.5" side exit

 

[AdR]

Thanks @Fox1486 for your input. I really appreciate it.

I have a full STM exhaust including their o2 housing.

What's your experience with it? I have the O2 housing (reason why I am leaning to get the rest of the exhaust).

 

[Aproductions]

I currently am opposite from you. I ordered and installed the full exhaust and then realized my o2 housing did not bolt up. I should get the STM o2 housing in the mail any day now haha. The fitment is perfect and I love how its a full 3" with straight through muffler design.