Exhaust - let's talk about this one!

[Silver Ecstasy]

I'll have to admit - I was always against exhaust on our cars. And I'd fight tooth and nail saying the exhaust was almost 100% to blame for smoking turbos because almost (keyword: ALMOST) everyone who had a DP/RP/CBE (not in any particular order) was eventually posting about a smoking turbo.

I don't drive my car obnoxiously hard, and I have a short trip to work. But summer is near, and I want something that I can enjoy installing and also add a little "character" to the car. Obviously, i'd like to see some performance increase. But maybe that's wishful thinking? That's what i'd like to discuss.

Exhaust Gains on MS3's
It's been said that the 2.5" exhaust on our MS3's are fairly well engineered, with hardly any extreme bends and a pretty appropriate amount of flow for the car. A majority of this evidence has been from magazines and their parts testing, as well as people and their own personal "lack-luster" feedback that the exhaust was a nice mod but had no major gains. It's also been said that a 3" exhaust is really not necessary for our cars unless you're in the 300hp+ range.

Forced Induction and Exhaust
It's been my understanding that exhaust and exhaust backpressure are always a good thing to have when it comes to NA (naturally aspirated/non super/turbocharged cars). However, when it comes to our MS3's being turbo-charged, the rule should technically apply in any level that opening up our exhausts, freeing up flow on the exhaust side of an even greater scale and lowering EGT's will be a beneficial and positive addition to our cars, or ANY turbo car for that matter.

The Debatables
Ultimately, exhaust gains are always subtle and minimal on any car. However, no one has really ever done any hard proof on just how much this improves the car and that seems to add to everyone's doubt that the exhaust is NOT worth it other than just for sound. Let's all be honest, that's technically the #1 motivating factor for purchasing an exhaust system is changing/enhancing the sound anyhow. And the aftermarket exhaust manufacturers will do what they can to squeeze dyno-proven gains out of their exhausts using their specific ingredients combined with their unique sound to capture the minds, hearts, and all-mighty dollars of car enthusiasts.

The other thing I have noticed is there is a significant lack of paper proof when it comes to exhaust modifications. No one has really done a dyno to prove whether or not their hard-earned money has done anything. But what about EGT's?

Technically, a Catalytic O2 temp sensor on the Dashhawk could be a reliable gauge for EGT's right? For example, during normal driving, I hit 1200*F. When I am stepping into the boost or am on the highway, I see 1500*F+. I'd imagine that someone with an aftermarket exhaust could monitor these #'s during their normal commutes and report back?

From my imagination, i'd also bet that a CAI/SRI would also be complimented by a CBE. And a turbo inlet would also be complimented appropriately by a downpipe. Freeing up intake restrictions along with your exhaust. Freeing up restrictions in the inlet (directly attached to the turbo intake), and match it up by freeing up your downpipe (directly attached to the turbo's exhaust). Isn't that decent logic for modding our cars?

Any and all information would be fantastic guys. I think this is something that could be real beneficial to existing and new MS3 owners alike.

Exhaust Options Available

-MAZDASPEED cat-back exhaust
3" exhaust piping
4" polished tip with MAZDASPEED engraving

-HKS Hi-Power cat-back exhaust
2.95" (75mm) exhaust piping
4.5" offset polished tip

-Greddy Ti-C cat-back exhaust
3.14" (80mm) exhaust piping
?" offset with heat-treated tip

-Corksport cat-back exhaust
3.14" (80mm) exhaust piping
?" exhaust tip with CS insignia plating

-CPE cat-back exhaust
3" exhaust piping
?" exhaust tip

I know there is GHL, Vibrant, AutoExe, Cobb (discontinued) and Borla but I didn't think those really played a key role in the majority of exhausts purchased.

*EDIT*
Also, got this useful information as well:

From Tuner Performance Reports - TPRMag.com - Featured Article - The Turbo Exhaust

Objectives of the Turbo Cat-Back

The objective of a properly-engineered, aftermarket cat-back exhaust system is to provide additional performance while still delivering adequate sound control. Unlike an all-motor exhaust system, a turbo exhaust system suffers no ill effects from going as big as possible. Bigger is better in this case. The bigger or larger diameter exhaust pipes allow the back pressure to be significantly less than the factory exhausts system. As a result, the difference in exhaust pressure before and after the turbocharger is increased. The increase in the magnitude of the pressure difference allows the turbocharger to reach higher shaft speeds at lower engine operating rpms. As a result, boost response increases and boost pressures increase. More boost pressure at the intake manifold results more power at the wheels. Can a turbo exhaust be too big? A turbo exhaust is too big if it drags on the ground or is too large to provide adequate sound suppression. For peak performance, most aftermarket turbo exhaust manufacturers will use the largest diameter tubing that can be properly routed underneath the vehicle. A muffler will be matched that allows an adequate amount of sound suppression.

 

[bigdaddy]

how loud do you want it to be? I do not know from personal experience, but I think that the HKS is loud. I have the Mazdaspeed CBE and I love it. Perfect tone, nice and deep, and very little drone. It is also aggressive when you want it to be. Its not obnoxious on the highway. I think it adds between 8-10 WHP. Plus, its made my Mazda...so you cant go wrong there.

 

[Silver Ecstasy]

I do not want it to be excessive. I've heard the MSCBE in person and I liked it, but I also thought it was pretty conservative. Atleast, there's potential to make it louder with a testpipe or dp eventually. But for a start, it's great!

HKS seems so loud and "gutter" sounding, raspy, harsh. I dunno.. Any pics of your setup? Vids?

 

[MM BOOST]

I wished someone would buy an HKS catback and then trade me for my racing beat catback. I have the racing beat catback along with the turbo xs catless downpipe and race pipe, and it sounds AMAZING...I just want something louder. I was going to get the HKS at first but then decided against it and I don't know why. If someone wants a toned down aggressive sounding exhaust, get the racing beat catback. great build quality, looks great, and has zero drone. I just want some more noise, I am all about hearing that gurgle from the exhaust. I am a audiophile, i like everything loud.

 

[turbo 4]

I have the HKS exhaust and i love it and it sounds very nice. Even when i go to car shows people seem to notice the sound on it and they say its a very nice gt sounding exhaust. I would not trade it for any other exhaust out there.

 

[240ka]

There's a guy down the street from me with the hks and its about as loud has our stock exhaust with the two resonators before the "muffler" deleted and a testpipe. Maybe iits not as loud. But its audible but not loud.

I love the way my exhaust sounds with both resonators gone and a tp. Can't wait to heear it when I get my dp.

But the best sounds exhaust I've heard so far is the cs dp, tp cbe. Sounds nasty. As well as a dp, tp combined with an Apexi can. Of course the apexi is loud, take a listen

http://www.youtube.com/watch?v=RchxuRTEbKQ

 

[mazdaspeed32007]

i had a custom 3" tbe with the corksport dp and it was way to loud for me. on the highway esp if your doing a lot of highway driving the drone is annoying and hard to talk over. anythiing above mid throttle gets loud and above that your def LOUD. i left ont he cp dp and put back on the stock cbe. i love the way it sounds with the dp. its a nice performance hum without the extra "noise" associated with the no resinator exhaust. it was to my understanding that a while back someone did a cbe and checked what it did for hp and it was something along the lines of a 5 whp gain. nothing for me to care about personally but with my sri, inlet, and dp, i would like to have the mscbe but then again, 0.5 an inch would not yield as much gain as i would like esp when this is my daily driver and the exhaust sound with the dp put me in my comfortable sound range. with that said, if this is your daily driver and you travel on the highway, i say stick with the stock cbe and get yourself a dp and see how that compliments the sound and hp. then work from there. otherwise you might find yourself in a tight spot like me where you started from the back and went forward, and lost money piecing it all back tgether. good luck!

 

[verbalink]

i have a cpe-catted downpipe with stock catback and the exhaust is definitely audible. sort of a soft purr that opens up more as you ease into the throttle. the off throttle drone around 3000 rpm can be annoying for people in the backseat though. ive been looking for an exhaust that maintains an aggressive note without the off throttle drone.

i hear good things about the magnaflow...

 

[PCspeed3]

Atleast get the Cobb downpipe

http://www.youtube.com/watch?v=qNq3XSN0v_A

 

[mazdaspeed32007]

i have a cpe-catted downpipe with stock catback and the exhaust is definitely audible. sort of a soft purr that opens up more as you ease into the throttle. the off throttle drone around 3000 rpm can be annoying for people in the backseat though. ive been looking for an exhaust that maintains an aggressive note without the off throttle drone.

i hear good things about the magnaflow...

thats how i feel, but i still have yet to hear a complaint about the back seat....my exhaust was so loud before that i think its great compared to before. but that purr is sweet with the stock cbe and dp

 

[Sport6]

There's a guy down the street from me with the hks and its about as loud has our stock exhaust with the two resonators before the "muffler" deleted and a testpipe. Maybe iits not as loud. But its audible but not loud.

I love the way my exhaust sounds with both resonators gone and a tp. Can't wait to heear it when I get my dp.

But the best sounds exhaust I've heard so far is the cs dp, tp cbe. Sounds nasty. As well as a dp, tp combined with an Apexi can. Of course the apexi is loud, take a listen

http://www.youtube.com/watch?v=RchxuRTEbKQ

Might sound okay but it looks terrible...

 

[verbalink]

thats how i feel, but i still have yet to hear a complaint about the back seat....my exhaust was so loud before that i think its great compared to before. but that purr is sweet with the stock cbe and dp

i guess to be honest, they werent explicitly complaints, more that they were surprised how loud it was in the backseat (particularly off throttle). i thought about getting a custom exhaust built.

 

[MSMS3]

I got the same hp and torque numbers whether the stock CBE was attached to my race pipe, or disconnected and just hanging by one bolt. I did an ECU reset between, but understandably cound not drive around with the open setup for a "relearn" period because the noise was enough to wake up the dead.

I just don't think there's any power to be gained from any of the CBE options until the engine is producing well north of 300 whp, or I'd be running one. The power gains, and they are nice ones, come from opening up the exhaust ahead of the CBE.

 

[Silver Ecstasy]

Well I think the way to go is the MSCBE for me. I really like the fact it's subtle yet throaty. It's not much louder than stock at all, but i've heard nothing but fantastic things about adding a test pipe with this exhaust.

From a performance standpoint, I really would have liked to dyno my car before and after, but I don't know if i'm going to have the patience to wait and find a dyno, then install it, then re-test.

I will definitely provide feedback as soon as I get it.

 

[jeff4880]

There's got to be some gains from a cat back even if minimul.

 

[screaminMS]

anyone thought about the Turbo XS TBE?

http://www.youtube.com/watch?v=05jIoDnrVts

 

[MSMS3]

There's got to be some gains from a cat back even if minimul.

Why is that? If the CBE flows more CFM (cubic feet per minute) than the air coming into the engine and the CFM of exhaust being discharged from the turbo exhaust side, then it's the equivalent of an open pipe.

 

[jeff4880]

Why is that? If the CBE flows more CFM (cubic feet per minute) than the air coming into the engine and the CFM of exhaust being discharged from the turbo exhaust side, then it's the equivalent of an open pipe.

I'm talking about a performance cat back compared to the stock cat back. I find it hard to belive there arre no gains at all.

I dynoed a hayabusa with a turbo and a muffler and could not get over 350 h.p. with it until I put a dump pipe on it. The bike gained 30 h.p. just from the exhaust.

I'm not saying the Speed will see a 30 h.p. gain but there got to be something?

 

[MSMS3]

I'm talking about a performance cat back compared to the stock cat back. I find it hard to belive there arre no gains at all.

I dynoed a hayabusa with a turbo and a muffler and could not get over 350 h.p. with it until I put a dump pipe on it. The bike gained 30 h.p. just from the exhaust.

I'm not saying the Speed will see a 30 h.p. gain but there got to be something?

I think you are missing my point. An engine is an air and fuel pump. You can't pump more burned air and fuel (exhaust gasses) out of it through the exhaust than the engine takes in, and you can't flow more exhaust gasses through the exhaust than the exhaust turbine side of the turbo puts out.

Once the exhaust piping flow capacity exceeds those flow rates, any gains by making it larger simply disappear. That's what I'm saying about our stock CBE until we get north of 300 whp.

In your example, the exhaust was undersized for a 350 whp engine. Ours would be too if the engine were making that kind of power and using those amounts of air and fuel. But it is not and cannot with the K04 turbo.

 

[jeff4880]

I think you are missing my point. An engine is an air and fuel pump. You can't pump more burned air and fuel (exhaust gasses) out of it through the exhaust than the engine takes in, and you can't flow more exhaust gasses through the exhaust than the exhaust turbine side of the turbo puts out.

Once the exhaust piping flow capacity exceeds those flow rates, any gains by making it larger simply disappear. That's what I'm saying about our stock CBE until we get north of 300 whp.

In your example, the exhaust was undersized for a 350 whp engine. Ours would be too if the engine were making that kind of power and using those amounts of air and fuel. But it is not and cannot with the K04 turbo.

I'm not missing you point. I have built and tuned MANY engines in my time. I know how they work. The gains might not be in power terms but it could be spool time or the time it takes for the engine to build to max power. It could also just flatten out the torque curve some more.

In my experiences you almost always benifit from a free flowing exhaust (post turbo) on a forced induction engine