A few months back, when I told STM that I wanted the lightest, best flowing exhaust for my IX RS that they could possibly make, they did exactly what I wanted! 3" stainless downpipe with turndown, and a 2.25" dump tube. This thing sounds REALLY good with the stock turbo, and has definitely proved it's ability to flow a ridiculous amount of power



So simple, yet so good. When we change something on the car and need to take the exhaust off, it's 5 bolts, drops right down, and goes right back. I love this thing.

We have considered building a rear-section that uses a V-band clamp and an section of aluminum piping to go out of the rear bumper, but for now, this is working just great!

Here is a sound clip of what it sounds like at idle and slight revs. At WOT, it's very loud

http://www.youtube.com/watch?v=ruT7WIjfb-c

 

Lots of low load, high RPM negative timing and rich AFRs FTW!

 

its not annoying taking the housing bolts off with it in the car? ive never tried but its a tight fit up there.
looks like a nice peice though. im just not a fan of the straight pipe sound.

 

I have a tube frame front end, half radiator, and no power steering, so you can stand in there and remove those bolts if you wanted too

 

Video of 2step and lauch is a must if you want to claim coolest exhuast, haha. Also you didnt notice a big lose in tq? I took off my catback and ran open dp on a stock 8 turbo and lost over 35wtq, but did gain 10-15whp.

 

Looks good props for stm on that custom piece..

 

I have no direct comparison for torque loss, but my setup in general is very lacking in the torque department. I only make 365 ft/lb where I make 412 whp. This is at least partialy due to my huge cams, huge intake plenum, and maybe also the exhaust.

--mark

 

That is nice, but I like the exhaust to end about the same place as the dump tube. With it up by the front of the motor it really eliminates the vibration and noise from a turndown with all the light weight benefits. I can only imagine the possible downside would be heat in the engine bay at low speeds but I think if it goes below the subframe and you arent sitting idling for hours I am sure it would not have a detrimental effect.

 

w/o a retune for example?
The turbo it self should provide all the back pressure needed for torque.... the point of your exhaust to be huge is to reduce all the back pressure possible post turbo... if your exhaust's backpressure is giving you torque, probably something is wrong.

In addition, going to a straight short pipe should increase spool, so now your peak torque curve has changed vs rpm and unless your fuel and timing maps change with it how do you compensate for make power/tq?

 

Thats a nice piece! I bet it will sound like a hungry beast with cams!

 

Being tuned for both, the open dp was down almost 40wtq forgot the exact number. Please dont turn this into a back pressure thread as theres evidence to prove some back pressure after the turbo is good an will Improve spool and peak tq.

 

very nice.

 

i had something like that custom made from road race engineering back when i had my 2g dsm in 2004 or so, loud as hell WOT, and people get confused because it sounds like a v8 lol. mine was really short tho, just enough to throw the exhaust away from the rest of the stuff for track. that one looks really nice. mine just attached to the o2 tho where the downpipe did so it was just a little 12inch long downpipe shooting to the ground.

its amazing how much difference a 4g63 will run with no exhaust, you get faster throttle response, faster spool, and more power.

 

You must have had a very restrictive exhaust. Please read this https://www.evolutionm.net/forums/ev...-vs-hp-tq.html it gets good around pg 5 when busuchur starts posting.

 

I did say 2004 .... It was restrictive yes. It was a apexi n1 setup and the car was a fwd 2g, so it was the catback that has the 2" dropped resonator lol. so ya i guess that didnt help.