Exhaust for my M45 Miata

[bada55mofo]

My factory exhaust has finally pissed me off enough that I'm thinking about getting a new one for it...I am curious what you guys with supercharged Miatas are running for exhausts. I'm really wanting it to be as quiet as possible! Thanks in advance for the help!!

[Tkblazer]

Sounds like you want a racing beat exhaust.. I loved my old one

[Flyin 92]

2.5 straight pipe. The supercharger will muffle the sound.

[Oldekamp]

My buddies M45 SC by Jackson Racing doesn't really muffle the sound that much.. :D

[bogaut]

not sure how a supercharger would muffle sound

[Dandy]

Stay closer to 2.25" for a quieter exhaust with a supercharger. Racing Beat exhausts mentioned are quiet and good quality. The offerings from Thermal have a low throaty sound that I like and are not loud. I'm personally not a fan of Borla exhausts as I think the sound is too raspy. Spend some time at youtube. There are a lot of sound clips that can give you a good idea of what you want.

[bada55mofo]

Thanks everyone, I was actually leaning away from the RB because I've heard people talking about them not lasting with a SC...I was actually leaning towards the FM kit!

[Flyin 92]

not sure how a supercharger would muffle sound

The Skyrim Performance Elder Scroll supercharger kit replaces the "factory" SC internals and are supposed to cut down on exhaust noise.

[Dandy]

FM is a Thermal unit I believe. It is quality and FM is great to deal with.

[BoBo]

I own a Racingbeat exhaust w/ a pre-silencer, and it's probably the best sounding exhaust other than the Magnaflow system that I had on my 94. I had a corksport as well, but even with the turbo, it still sounded crappy. I had the early FM exhaust for the naturally aspirated motor too, but it was generating too much drone. Racingbeat sounded just right.

[etikoner]

Fujitsubo rm01a

[kung fu jesus]

Go custom. Find an independent exhaust shop, tell them what you want to do, ask for mandrel bent, name your material, let them hang it.

2.25" tubing, larger muffler, midpipe resonator.

Custom *might* cost a little more, but it's going to fit better and will probably only have one joint at the cat, so less risk of leaks. A S/C (JRSC) made my exhaust much louder. I had a Borla with that system.

[atank]

http://www.mandrelbend.com/library/P1010210-ed.jpg

Custom = Beauty-FULL Tip........:frantic:

[bada55mofo]

Custom actually sounds like a good idea, less shipping cost lol..I've got a pretty good exhaust shop near me.

[73Bacon]

2.5 straight pipe. The supercharger will muffle the sound.


The Skyrim Performance Elder Scroll supercharger kit replaces the "factory" SC internals and are supposed to cut down on exhaust noise.

Is this the miataturbo.net tryouts thread? Guy asks a straightforward question...

I've got a Borla Dual Sport behind mine, and it's loud as they come. So I'm pretty sure you don't want a Borla solution.

[kung fu jesus]

Custom actually sounds like a good idea, less shipping cost lol..I've got a pretty good exhaust shop near me.


Yeah, I forgot about shipping.


I had a custom 2.5" made when I had a turbo, too. The shop was really cool, glad to be working on other cars besides V8 Americans. They did the whole exhaust DP back for around $400, IIRC. I also had a shop here in Raleigh do the NB midpipe when I reconfigured the exhaust manifold. $250 for a new 2.25" cat, custom 2.25 midpipe, and a resonator to the axle-back RB muffler. I thought that was a great price for not having to mess with a damn thing on it.

[ScratchNSniff]

I've got a Borla Spec Exhaust and while not loud, it isn't quiet if that makes sense lol...running FFS MP62 right now...

[BlitzWing]

While I've only just got the SC on the car I'm using an Racing Beat with the race centre pipe.

[Phatmiata]

FM is a Thermal unit I believe. It is quality and FM is great to deal with.

Yes they are made by Thermal Research out in Cali, a very high quality unit, they make a lot of stuff for import cars. I would say no larger than 2.5 as it will get noisy if you go any larger.

[bada55mofo]

Well great guys...in about the same boat as before!! RB vs FM vs Exhaust shop..lol

[BlitzWing]

well there is no wrong choice IMO fire up you tube and see what sounds best to you. While I love how subtle my RB is I can see the draw of a custom unit that is almost a straight pipe.

[mx54life]

RB on my 94 JRSC M45 well tamed sound and street legal in CA. I believe this is the only CA street legal cat back exhaust if that matters.

[bada55mofo]

Maybe I'll just close my eyes and choose one..lol just don't want to have a repeat of my 95 with a coldside BRP and the eBay N1 turbo exhaust...(insanely loud)

[fwdtamiya]

RB on my 94 JRSC M45 well tamed sound and street legal in CA. I believe this is the only CA street legal cat back exhaust if that matters.

All catbacks are legal, so long as they fall under the decibel limit.

[bada55mofo]

Really leaning towards the ISIS now, I want a RSR but don't want to spend that much on a used exhaust!

[topover]

Here is a sound clip of a magnaflow exhaust (http://4wheelonline.com/Magnaflow_Exhaust.29780) installed in a Miata. Its a great comparison from stock to aftermarket.
https://youtu.be/mMbHGYdVnbM

[kung fu jesus]

A s/c will amplify the exhaust. 2.25" custom header back. 2.25" cat, 18" bullet as a resonator, straight through muffler, 2.5" tip.

[mx54life]

All catbacks are legal, so long as they fall under the decibel limit.

So if they don't fall under the decibel limit (95 in Cali) they are not street legal therefore such catback is...........? I know by experience in Bethesda, MD we were pulled over and given a fix it ticket for a loud custom exhaust in my friend's VW Golf.

The other thing to is the annoying drone in some exhaust system when the hard top is on. So far my RB has zero drone and a the sound even at WOT does not commands attention.

[Greasemonkey2000]

mx54life: Full details on exhaust? (header type, cat type, resonated or non resonated midpipe, power pulse, twin tip or dual outlet RB muffler) I hope mine doesn't drone but different components definitely have a bearing on this I'm sure.

Have no idea why someone would think a s/c would muffle the exhaust as it is on the intake side of the equation and increases air flow/volume thus increasing exhaust volume/flow.

This is why(s/c is still on the table) i want a rather quiet aftermarket exhaust and chose a Racing Beat dual outlet muffler, although i would think the Power Pulse would be quieter option i like the symmetry of the dual outlet. Still have to get a midpipe but finally have a used RB resonated midpipe lined up. Also have a Raceland header but can't decide still if i want a 'high flow' cat or oem type...obviously the oem type would be quieter but how much of a difference i dunno. I know what may be quiet n/a could be too loud, imo, with a s/c increasing volume/flow.

[Slipstreem]

Interesting thread as I plan on going with a supercharger sometime in my next life time. I still have the stock exhaust so I'm no help on the topic unfortunately.

Just like mofo I REALLY like the Isis exhaust but, sadly they haven't made a 1.6 specific unit. I've been thinking about an exhaust system and watching YouTube videos for about a month now and personally I think the best route might be a costume system.

The fact you can choose any size piping you want, the way it bends, and having infinite muffler choices sounds pretty sweet to me. Plus it may save you a couple hundred and who doesn't like saving more money?

[mx54life]

mx54life: Full details on exhaust? (header type, cat type, resonated or non resonated midpipe, power pulse, twin tip or dual outlet RB muffler) I hope mine doesn't drone but different components definitely have a bearing on this I'm sure.

Have no idea why someone would think a s/c would muffle the exhaust as it is on the intake side of the equation and increases air flow/volume thus increasing exhaust volume/flow.

This is why(s/c is still on the table) i want a rather quiet aftermarket exhaust and chose a Racing Beat dual outlet muffler, although i would think the Power Pulse would be quieter option i like the symmetry of the dual outlet. Still have to get a midpipe but finally have a used RB resonated midpipe lined up. Also have a Raceland header but can't decide still if i want a 'high flow' cat or oem type...obviously the oem type would be quieter but how much of a difference i dunno. I know what may be quiet n/a could be too loud, imo, with a s/c increasing volume/flow.

JR header, Carb legal Magnavox Cat, RB power Pulse cat back and the sound IMHO is what is appropriate for the street, zero highway drone with the HT on, Cali street legal and I can't imagine it to be illegal in any other state or county.

The sound of any exhaust is relative to the owner. A friend of mine who has IMO one of the most obnoxious sounding exhaust hears his exhaust as a V8 with a straight pipe lol. What I like about the set I got is that it has a quiet idle but when you rip it the loudness is steady and not annoying. You definitely could hear it that it is not OEM down there. It's the sound that one can feel rather than necessarily hear. Again this is purely relative. I am not deaf and I am not seeking attention. The RB is a bit heavier that other comparable set up but that extra poundage ensures a solid system free of drone and a sound no more than 95 decibels exhaust system. Again I am an older miata owner living in California lol.

[bada55mofo]

JR header, Carb legal Magnavox Cat, RB power Pulse cat back and the sound IMHO is what is appropriate for the street, zero highway drone with the HT on, Cali street legal and I can't imagine it to be illegal in any other state or county.

The sound of any exhaust is relative to the owner. A friend of mine who has IMO one of the most obnoxious sounding exhaust hears his exhaust as a V8 with a straight pipe lol. What I like about the set I got is that it has a quiet idle but when you rip it the loudness is steady and not annoying. You definitely could hear it that it is not OEM down there. It's the sound that one can feel rather than necessarily hear. Again this is purely relative. I am not deaf and I am not seeking attention. The RB is a bit heavier that other comparable set up but that extra poundage ensures a solid system free of drone and a sound no more than 95 decibels exhaust system. Again I am an older miata owner living in California lol.
That actually sounds pretty nice, listening to it of course in my Miata lol, but I'm just worried how loud it'll be with the m45...had a bad experience with my previous Miata with a turbo exhaust and a supercharger...it was horrible. Plus the Isis just looks so damn sexy. Plus I'm still thinking a snail could be in my Miata's future!

[mx54life]

That actually sounds pretty nice, listening to it of course in my Miata lol, but I'm just worried how loud it'll be with the m45...had a bad experience with my previous Miata with a turbo exhaust and a supercharger...it was horrible. Plus the Isis just looks so damn sexy. Plus I'm still thinking a snail could be in my Miata's future!

That is with an M45 in my engine bay lol.

[bada55mofo]

Ohh...well damn that could be a possibility for me...just the Isis is so damn pretty...I wish someone had a M45 and an Isis so I could compare the to..I like the way yours sounds...can you still hear it whine?

[mx54life]

Ohh...well damn that could be a possibility for me...just the Isis is so damn pretty...I wish someone had a M45 and an Isis so I could compare the to..I like the way yours sounds...can you still hear it whine?

Yes that's probably the plus if you want the SC whining. Once it's down there you won't see it. But wait the RB system is a beauty too.....then again out of sight most of the time.

[bada55mofo]

Most definitely don't want it droning, I do a lot of highway runs at around 80-90 for about 45 mins.

[Dandy]

Really leaning towards the ISIS now, I want a RSR but don't want to spend that much on a used exhaust!

You are now looking at the wrong exhausts if you want quiet. Remember you want a 2.25" pipe for naturally aspirated or a supercharger. A supercharger is not going to significantly increase and will NOT decrease or muffle the exhaust sound if you go with a larger than 2.25" pipe. A 2.5" or larger exhaust will be louder and will decrease the performance of a supercharger. The m45 needs a bit of back-pressure to perform efficiently.

[Greasemonkey2000]

Far too many times people put too large of an exhaust pipe size for their application and most exhaust parts manufacturers say it is better to error on the low side. In the end the size is more or less determined by hp and the number i found was 2.2cfm flow per hp.

A square inch of straight pipe being able to flow 115cfm so with those numbers you can figure the proper size based on hp. So here are sizes to hp(estimated):
2.00"<144hp
2.25"<185hp
2.50"<232hp
2.75"<283hp
3.00"<339hp

Info from: http://www.exhaustvideos.com/faq/how-to-calculate-muffler-size-pipe-diameter/

This is similar to the numbers i have seen in magazines, articles, etc over the years but still on the lower/conservative with a difference of around 50hp.

There are so many variables in making a proper exhaust system so i definitely say read up.

I'm certainly no expert but try to read up any time a situation/opportunity presents itself and have always subscribed to various popular automobile performance magazines for the last 15 years including Super Chevy, Hot Rod, Fast Fords, 5.0, Mopar, Super Street, Modified, Grassroots Motorsports and others.

[RustRat]

Useful info right here, Greasemonkey. I take it these numbers work for turbo applications, too, right?

[Greasemonkey2000]

Rustrat: As far as the size yes but again there are many factors like having a resonator(typically a must have for n/a or supercharger if you want to keep the decibels down) or not, muffler type/size and even exhaust tips when you are talking about sound/tone.

Again definitely not claiming to be an expert, just passing on what i have read/learned over the years. I was reading a article the other day that REALLY went into depth about exhaust systems, i think it was in super chevy or hot rod...can't recall but it was online.