Exhaust - let's talk about this one!
 

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:

i love my vibrant its a full 3" and midpipe in one for a great price and sound

I have just the stock exhaust but a turboxs downpipe/racepipe (catless), it sounds perfect for me. Sounds mean as hell @ wot.

go full catless and don't look back

But that's not legal in many states though right? Might cause exhaust to smoke also?

I'd rather not go catless. Never know where tomorrow may take me. I may one day end up in a state that does actually run emissions testing and i'll be in a totally new ballgame.

hmmm this is also been a question i have always wondered. i'm fully bolted and dynoed 310whp but the only thing i never upgraded was the CBE. i wonder if it would really make a difference if i upgraded it to a full 3" tbe

u lost me at the second paragraph

i have a vibrant 3 inch cb with a hi flow mid pipe. Minimal sound increase and +17 whp. No smoking issue at 19k miles.

Harry

I have a Corksport down pipe and "test" pipe with a Magnaflow cat welded on to it, with the stock cat back.
In my opinion the down pipe and test pipe would be your best bet for performance gains and from what I herd about turbos a divorced waste gate pipe is the way to go. The Corksport is the only option with a divorced waste gate pipe. I'm sure the cat back will free up some power but I bet it's minimul.
I would free up exhaust flow after the turbo first then if you wanted add a cat back.
Just my 2 cents worth.

Silver,
There is quite a lot of dyno's showing the performance gains from downpipes on the speed3 and speed6's. The torque increases are absurd.

Just for debate, here's a stock exhaust system, vs a full CP-E catless turboback (DP to tip).

http://www.cp-e.com/imgs/MazdaSPEED3...Horsepower.jpg

http://www.cp-e.com/imgs/MSP3CATBACK_Torque.jpg

Now of course many people will say that's not an owner dyno (a manufacturer dyno), but I'm just posting here for "general" discussion of gains.

I've talked to quite a few local owners in person, and asked them which modification they felt gave them the most gain or difference.

(These are on cars with...intake, tip, bov, fmic, fuel pump, DP/catback).

#1 answer was DP. To paraphrase one fellow "Completely changes how 4th gear pulls".
#1 answer was also fuel pump. "I wish I had done it sooner...everything is so much smoother after it"

Most of them felt that the intake difference was very minor compared to the exhaust modifications.

Now I'm in the same boat as you. I've done pretty much all the intake modifications (beside working on intake manifold, or installing meth). Now I'm deciding whether to do a racing beat catback and streetunit test pipe, or to put on a CP-E catted DP.

The primary benefit of the DP is removing restriction post turbo, which allows the turbo to spin-up faster, and expel exhaust gas more easily. Technically the DP/exhaust mods should also net you mileage gains.

My crossroads is basically that if I'm going to do the DP, I might as well do the manifold at the same time, since it should only be another hour or so of work...instead of having to pull everything apart again later...which makes a DP/manifold cost like 1500 bucks...ouch...which is why I'm leaning towards the RB catback (525) and a streetunit test pipe (200) ish. Which saves me a buttload and should net about 15 whp or so.

I'm curious if anyone has a comparison of the testpipe catback torque vs stock exhaust.

Consider a boost activated cutout... all you need is a DP (and a mani if you desire). use a 4psi WGA on the cutout and your golden. Anytime you hit 4psi the cutout will open and you have all most ZERO back pressure.

I believe that the boost activated cutout (BACO) is better for our cars then the electronice cutout (ECO) due to the face that the BACO will always open providing the same conditions each time where as the ECO will not always be active.

http://www.atpturbo.com/Merchant2/gr...CS-010_450.jpg

I'd go with a racepipe and CBE. I picked up a SpeedAction racepipe for $140 last week. The gains are noticable with the stock exhaust, both power and sound. Definitely worth the $140. I know that a full catless TBE would net huge gains, but to me it's more trouble than it's worth IMO with the install and dealing with warranty issues. I'm hesitant getting a CBE just because of having to cut the stock exhaust in two in order to get it out. I'd like to be able to put it back in if I had to without obvious signs of tampering. The DP and midpipe are the bottlenecks, so once you open those up, you'll see more gains from a CBE. If you just want a little more "character", again, I vote for the racepipe and CBE.

aw man that is f'ing sweet! I want to buy that

HAHA waste money on replacing good pipes. Good idea.

Psst it is not the pipe.

E-cutout FTMFW

I'm expecting to have some decent gains on mine once installed. I live around a local shop to Atlanta and will have a full 3in pipe soon.

3 inch FTW

Where to buy speedaction racepipe? a pipe is a pipe so less money ftw!

I got it on Ebay.

Testpipe Test Pipe Mazdaspeed 3 MS3 Mazda Speed 3 Turbo:eBay Motors (item 110347737860 end time Jun-05-09 18:36:02 PDT)

if you want sound and power get a catless dp, i have it and love it, and the only thing that doesnt give much performance gain is the catback but trust me the dp was a huge gain for me

CS Downpipe and Racepipe, stock catback is the way I would have to go. It's not retarded loud, but has a great throaty sound to it. I still get compliments on it almost everyday. Plus I've had numerous people ask if I swapped a subie motor into my car which is just funny.:biggthumpup:

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.

waste of money imo

That's the whole point of my thread - people have this opinion such as yours that the exhaust does absolutely nothing. And I think I pointed out pretty accurately that people get exhaust typically for sound first, then gains second. And exhaust, regardless of brand for our cars, sounds pretty damn good and has typical "average" gains.

For the same amount, I could get an AP and mess with tunes when I do not drive hard enough or far enough to justify having a portable tuner that could do more harm than good for a complete novice like myself. But, I think this is going to be a great addition to the car. Who knows, maybe it'll add to the resale value by having MS parts? Doubtful, but you never know.

Since I'm from Maryland, I'm going to go with the CP-E Catback. Then when SU Mark runs another special on the SU Test Pipe, I may spring for that too.
Maryland has emissions testing, so I need to make sure I can swap the cat back in if needed.

Also, got this useful information as well:

Now the question being, would you like to see one with a cutout? We have jigged the mid pipe to run a cut out but we could do the DP as well. How many would like to see something like this?

OP, get the downpipe and keep the factory exhaust system. This will be your best bet for gains vs dollar spent.

The stock exhaust has an annoying drone. It sounds fine at WOT, but the droning gets on my nerves after a while and honestly, with the race pipe in there, I think it has gotten worse.

PaPaSpeed,

All Maryland does is plug into your ecu, and checks for cels, and does a readiness test. Takes like 5 minutes through a drivethrough.

Nobody opens your hood, or looks under your car. Heck stretch is in MD too, and he has a completely catless sti, using tuning software to hide his cat cel, he's passed emissions twice! lol. MD emissions is a joke!

Now VA has inspection, thats a whole different story.

They do this in Jersey also, BUT they wheel a mirror on a stick under the car and look for a cat.

I guess I just worry too much. I also talked to CPE and they said I'd pass with no problem with the catback. SU Mark had a pretty good deal on them now, so I went for it.
I'll wait a bit for the test pipe to see if I can get a good deal.
Thanks for the info.

i'm in very similar shoes.

i have 15k miles on my car and haven't been to the dealer since around 2k. however, with a DP, of course i'd get more gains, but i don't think it's worth the hassle. since i'm not driving a racecar, i don't mind better sound with less gains i.e. CBE.

i'm pretty sure i'm going to go with the HKS CBE very soon. i gutted my 2nd cat a couple of months ago so a test pipe would be a waste for me. i notice a slightly different sound with the gutted cat as well.

good luck on deciding.

lets back up to the original comment for a minute, because this needs to be made crystal clear, anyone who thinks the exaust or a downpipe is the cause for a smoking turbo doesn't understand the way turbo seals work. the seals either seal or they don't, they don't rely on any kind of backpressure to keep sealing. the reason why people might have smoke after installing exhaust or a dp, is because the turbo was already smoking, and the two cats in the stock exhaust had been burning the oil off so that no smoke makes it out the tailpipe.

i have a cpe downpipe on my car, and i have never had any smoke. after driving hard i can smell the burnt oil smell coming from the exhaust, but there is never any smoke. i think the burnt oil smell is gone now that i've gone to 10w/30 instead of 5/30, but i can't be for sure because that was sunday and my nose is messed up because i've been sick all week.

damn i think i will add a su tp when they cut em on sale again. i have been happy with my GReddy TI-C cbe. it made the spool seem to happen sooner and i love the look and sound. i had a rp on there once but god it made it horrible. i like to think it had a leak but i will find out later. but the TI-C is staying and i never regret that purchase gives the car character, and helps me stand out from the other speed 3's with stockers. i know might have got 5-7 hp if that but to the op. its your car do it if it feels right.

anyone ever dyno just a testpipe? im interested to see what gains that alone yields.

I have the CP-E Cat'd dP, and muffler only exhaust, no smoke at all, except the carbon, no blue smoke at all only black and it is very minimal and only full throttle, thats just because its running rich, but my car runs great.

my opinion based on your driving description, I would go with a CP-e Cat'd DP, and SRI of sort befor ever spending mulla on exhaust, you dont drive hard enough. I think you will feel more from your intake, and maybe an inlet pipe, (just cuz stock one sucks).

Got an intake, love it.

"Stock inlet sucks"...how so? Just because it looks smashed? No one has done any testing or proof to say that a new inlet would improve anything. Not trying to be a jerk, but seriously, I haven't seen one piece of evidence.

well, my buds has come loose 3 times, so we changed the clamps, but still its plastic and very weak.

have you read the cobb tuning thread on the cover page. it talks about how the inlet pipe is a piece of junk......

Link please?

I've checked my inlet pipe and it's not moving.