Quiet Exhaust

[Oricle]

i just bought a mazda 3, 5 door and I am in the market for a performance exhaust system (cat back). i want one that is relitively quiet because all those hondas that have the damn 6 in. exhaust sound like crap and allow too much valve chatter through. i just want somthing that will give the car some kick, but not get too loud on long drives. any recomendations? thanks

[goldwing2000]

People have had good luck with simply removing the forward resonator and replacing the stock muffler with a magnaflow unit.

If you don't mind taking a chance on having your warranty voided, VRS Exhaust is selling a stainless system that bolts on but removes the 2nd cat. There's a thread on here somewhere about it.

[Da 6]

before you go in for service crawl under and yank the system(2thumbs)

[goldwing2000]

before you go in for service crawl under and yank the system(2thumbs)

That's not really an option. You have to cut up the old system to get it out (unless you enjoy disassembling your rear suspension... alot)

[jbass]

I own a 3 and i like it very much. It is really an amazing car to drive. For your question, I have installed a magnaflow pipe and someone made me all the piping necessary in order to have cat-back. It sounds really nice but it is not annoying like those civics with pipe. It has a subtle sound from 2000 rpm to 3500 and after it is quiet nearly as stock pipe. Then if you find it is not enough noisy, take off the resonator. Ive done it and I personally find it really nice. The car is a bit peppier and it makes a great sound too.

[Oricle]

when removing the second cat i would assume that my car would not pass smog (california). but i guess that i dont have to worry about that untill 2009.

[Da 6]

09....I wish I had that much time in between testing...(shocked)

[brett_32i]

whats is the pipe diameter of the exhaust?
is it the same all the way through?

[Da 6]

on an n/a 4 cyl car under 500 ponies you should never go past 2.5 piping

[brett_32i]

ill try again.
what is the pipe diameter of the exhaust?
std car without 500hp. as it left the factory

[goldwing2000]

ill try again.
what is the pipe diameter of the exhaust?
std car without 500hp. as it left the factory

Do you have one? Go out and measure it. (dunno)

[brett_32i]

if i did, i would.
its due to arrive in september.

[goldwing2000]

So are you just trying to get parts in advance or something?

[AzMz3]

on an n/a 4 cyl car under 500 ponies you should never go past 2.5 piping


Where did you come up with that?

--Herb--

[brett_32i]

So are you just trying to get parts in advance or something?
yes.

[Da 6]

you can run 3.0 exhaust piping on a N/A 4 cyl if you don't like your low end

[brett_32i]

does anyone know the standard exhaust size for a mazda 3?

[AZhitman]

Hey guys! Great forum.

There's also a catback for the Mazda 3 available from a company called BRM Exhaust. Their website is www.brmexhaust.com - Hasn't been updated in a while, but their system for the Mazda 3 is really sweet. Great sound, and affordable as well!

Available in 2.25", 2.5" and 3" piping, aluminized or T-304 stainless.

Email me for pics and pricing.

Take care!

[crossbow]

What I find most interesting is how restrictive the 3s's exhaust looks. But then you look at the 6i's exhaust (which looks hella less restrictive), and yet both car's dyno exactly the same.

This leads me to believe that you aren't going to see any major power gains from exhaust modifications. (You guys have headers stock)

Here's some photos for comparison.

Mazda 3s
http://www.wam.umd.edu/~greghess/3snoca.gif

Mazda 6i
http://www.wam.umd.edu/~greghess/scans/exhaust/6iexhaust.gif

[AzMz3]

How do you come to the conclusion that the 6i is more restrictive. I'd say that the 6i has smoother bends than the 3. I know that the mazda3 has a really sharp bend (almost 90*) under there.

--Herb--

[crossbow]

No I said that the 3s looked alot more restrictive, but yet dyno's the same as the 6i (which has a less restrictive exhaust).

Thus my argument is that because the two engines have two totally different exhausts, and yet dyno exactly the same, that exhaust mods will not result in any substaintal power gains.

And upon reading my statement, find it flawed in so many ways, that I have no excuse but to say I was drunk.

[AzMz3]

No I said that the 3s looked alot more restrictive, but yet dyno's the same as the 6i (which has a less restrictive exhaust).

Thus my argument is that because the two engines have two totally different exhausts, and yet dyno exactly the same, that exhaust mods will not result in any substaintal power gains.

And upon reading my statement, find it flawed in so many ways, that I have no excuse but to say I was drunk.

Gotcha, I read that wrong.

I feel there will be some substaintal power gains with the exhaust mods. The Focus 2.3 basicly has the same exhaust set-up as the Mazda3 and has produce great gains with a full exhaust. I would say we will get better than the norm for a 4cylinder, if there is such a thing. Just look at the sizing of the pipe, it is what 1.75 - 2.0" LOL...2 cats, a factory resonator and muffler. And the Focus has been dyno tested to show more gains through out the powerband with the bigger 2.5" exhaust, that tells me that this engine like to breathe. SInce there is no raceheaders, or even exhaust out yet this is purely my opinion. But I think we will surprise alot.

--Herb--

[Da 6]

doesn't the 3 have 2 cats?...

also what he means by less restrictive is the piping in the box marked L3 engines is the exact same setup " from cat and all the way back" of the V6 model.... the restriction with ours is the y pipe but those of us with lip kits/sport bumpers aren't willing to give up the 2nd muffler....

[AzMz3]

doesn't the 3 have 2 cats?...

also what he means by less restrictive is the piping in the box marked L3 engines is the exact same setup " from cat and all the way back" of the V6 model.... the restriction with ours is the y pipe but those of us with lip kits/sport bumpers aren't willing to give up the 2nd muffler....

The 3 does have 2 cats!
I don't understand the rest of your post, what are you trying to say?

--Herb--

[Da 6]

aour restriction isn't the headers or cat..but the y pipe that splits into 2 mufflers. the catback systems for the 6 are the ame from both engine platforms. Perfomance 4 and V6 have the same cat back.

[AzMz3]

aour restriction isn't the headers or cat..but the y pipe that splits into 2 mufflers. the catback systems for the 6 are the ame from both engine platforms. Perfomance 4 and V6 have the same cat back.


I don't know about that, how many cats does the 6 have. It looks as if you have a better header? I'd take that y pipe over the sharp bends on the 3.

--Herb--

[Da 6]

I don't know about that, how many cats does the 6 have. It looks as if you have a better header? I'd take that y pipe over the sharp bends on the 3.

--Herb--6i has 1 and 6s has 2 and crush bent headers. only thing I might get rid of is the resonator on the stock exhaust..I found a shop that will use ss piping so it won't corode once the salt hits the ground. I don't know if our header will bolt directly up w/o clearance issues with heat shield. I still hate that holow exhaust note of the 6i (anoying frequency heard in cabin)with a passion so the headers will stay "as is". if it takes a spooling ebay turbo wistle to cover up that sound placed (just after the header).....i'm almost temped to go that route...

[AZhitman]

We saw 9hp peak gains in testing and development of our catback for the Mazda 3.

The primary area of restriction appeared to be the factory muffler, the added benefit is a weight reduction of approximately 25 lbs. Elimination of the severest bends, coupled with a straight-through resonator and muffler design, and mandrel-bent tubing helped matters as well.

Herb was right on the money - We actually found the 2.25" to be perfect for this engine.

Sound is spectacular. Quiet as stock at idle, but a throaty roar at WOT. No "ricey" high-frequency sounds, no raspiness, just a threatening growl... Quite impressive, but then again, we spend a TON of time fine-tuning for sound quality.

[AzMz3]

We saw 9hp peak gains in testing and development of our catback for the Mazda 3.

The primary area of restriction appeared to be the factory muffler, the added benefit is a weight reduction of approximately 25 lbs. Elimination of the severest bends, coupled with a straight-through resonator and muffler design, and mandrel-bent tubing helped matters as well.

Herb was right on the money - We actually found the 2.25" to be perfect for this engine.

Sound is spectacular. Quiet as stock at idle, but a throaty roar at WOT. No "ricey" high-frequency sounds, no raspiness, just a threatening growl... Quite impressive, but then again, we spend a TON of time fine-tuning for sound quality.


Whooo there, I never said 2.25" being perfect for this engine. I'd be willing to bet that the 2.5 will show better gains all throught the power band.

---Herb---

[Da 6]

open the engine up a lil bit then 2.5 start droping in cams and bore out head and then go 3.0....unless there is a big restriction hanging off the header(TURBO) going large exhaust piping won't always yield the gains you are trying to get. remember the exhaust gasses need to be hot when exiting the vehicle cause when you get large exhaust it gives more space for the exhaust to cool down and become more heavier that stock and that puts a strain on the engine. If you want to get the 3.0 exhaust I'm not stopping you. Please post results and soundclip when you do

[AzMz3]

open the engine up a lil bit then 2.5 start droping in cams and bore out head and then go 3.0....unless there is a big restriction hanging off the header(TURBO) going large exhaust piping won't always yield the gains you are trying to get. remember the exhaust gasses need to be hot when exiting the vehicle cause when you get large exhaust it gives more space for the exhaust to cool down and become more heavier that stock and that puts a strain on the engine. If you want to get the 3.0 exhaust I'm not stopping you. Please post results and soundclip when you do


Huh? I never heard it explained that way....and I'm pretty sure you are wrong with the way you worded that....
Like I said the 2.3L focus has shown gains with the 2.5" exhaust over the 2.25" and I don't see why we wont get the same or better. ANd if you went full N/A you could get gains off the 3.0" exhaust. You are right that going with a larger diameter pipe won't always yeild better gains, but I believe they will here. A 9HP gain with the 2.25" is very nice, I'd like to see the dyno graph for that.

--Herb--

[Da 6]

Huh? I never heard it explained that way....and I'm pretty sure you are wrong with the way you worded that....
Like I said the 2.3L focus has shown gains with the 2.5" exhaust over the 2.25" and I don't see why we wont get the same or better. ANd if you went full N/A you could get gains off the 3.0" exhaust. You are right that going with a larger diameter pipe won't always yeild better gains, but I believe they will here. A 9HP gain with the 2.25" is very nice, I'd like to see the dyno graph for that.

--Herb--If you wish to try the 3.0 on for size then by all means...I'm also pretty shure they tested the 2.5 out as well before they settled with 2.25 but that I can't confirm. You would have to ask him that for yourself once he sighns back on.

[AzMz3]

If you wish to try the 3.0 on for size then by all means...I'm also pretty shure they tested the 2.5 out as well before they settled with 2.25 but that I can't confirm. You would have to ask him that for yourself once he sighns back on.


Only the 2.25 was test, I already asked. I will get the 3" but not until I build a new block for a turbo. So a 2.5" will do for now.

--Herb--

[Da 6]

save up and do exhaust last if you are DEFINATE on boost. I thought I was too. just because you have the parts doesn't mean you will go thru with it. also if you plan on going totally custom...plan on getting a $500 daily driver cause the 3 will have alot of downtime. as stated before this isn't a sausage kicking fest by no means...

[IllBinfrontofya]

What do you mean the 3 will have a lot of downtime??? Are you saying that if we go the route of boosting the 3, it will have a lot of problems? I thought that the engine would fair VERY WELL with forced induction?

[AzMz3]

What do you mean the 3 will have a lot of downtime??? Are you saying that if we go the route of boosting the 3, it will have a lot of problems? I thought that the engine would fair VERY WELL with forced induction?


I don't think he knows what he is talking about! (help) (mj)

--Herb--

[Da 6]

turboing a non turbo car takes more than a few days to fully tweak out the bugs especially if you decide to work from scratch with a custom turbo setup...plus if you need parts...unless you want to put the car back together you would need a 2nd(daily) driver. didn't say get a BMW or Lotus...just something reliable.

[AzMz3]

turboing a non turbo car takes more than a few days to fully tweak out the bugs especially if you decide to work from scratch with a custom turbo setup...plus if you need parts...unless you want to put the car back together you would need a 2nd(daily) driver. didn't say get a BMW or Lotus...just something reliable.

I don't consider that downtime. And it does not always take a few days to install a turbo, and you most likely will be tweaking with it for alot longer than that. And it would be kinda stupid to start a turbo install with out all of the parts.
And as for another car I have one.

http://www.imagestation.com/picture/sraid118/p3d4945508648669baafe648791336d84/f88a2161.jpg

--Herb--

[Da 6]

sometimes things get lost, stolen (chair), or broken. shit happens