NA exhaust, need opinions!

[11110000]

Don't know how helpful this will be for you, but I can offer my own experience with loudness. I have a B23F w/K-cam, OEM exhaust manifold, head pipe and 2" cat. From there, I use the 240T 2.25" piping all the way back to a Pep Boys Cherry Bomb (27" long) in the stock rear muffler location. Between the cat and the cheap glasspack, I get a fairly rich sounding exhaust that's actually really quiet under part throttle, and rather badass under WOT.

What this suggests to me is that you will have a difficult time getting acceptable noise levels with a side exit setup, because you have a proper header with a larger diameter exit and no cat.

I've seen some cars with side exit exhausts use a 'S-path' arrangement, where you might run through a long glasspack from the header towards the rear axle, make a 180° turn, run through another glasspack, make a 180° turn, then out the side. The directional changes are clearly not optimal performance-wise, but this arrangement might work for you if you're dead-set against a rear-exit system.

[Dauntless]

Ahh ok.

I had a 22" long 2" louvered core oval muffler and bullet muffler in stock locations before, and it wasn't particularly loud, I think it was almost as loud inside as outside though, for some strange reason.

With a stock resonator and then the same bullet muffler at the of the system just next to the tank on the RH side of the car, it is very quiet inside, almost like stock.

That S-path setup is definately out of the question.

[Dauntless]

Does anyone have any experience/opinions on these?

Jetex TUBEX Silencer box, Round 100mm / L=625mm
http://www.jetex.co.uk/website/images/U446300box.jpg

Flowmaster Hushpower II 18" - Anyone know roughly how thick they are?
http://www.flowmastermufflers.com/hp2.html

*edit*

Got a reply from Jetex, he recommended one of these:
http://www.jetex.co.uk/website/images/07.1047box.jpg

What are your thoughts on these?

[AJS]

[QUOTE=Dauntless]Getting a stock 240T exhaust from over there to here would be extremely expensive, because I would have to source one from USA or Europe.

QUOTE]

Local non OEM Volvo shop down here. Got a quote awhile ago. Front pipe 132 (think this is from the headers to cat), Cat 415, front muffler 90, Over axle pipe 36, rear muffler 86, Tail pipe 20. From memory he could get the turbo pipes. Now these were not OEM but the quality would at least meet most most after market systems. Just an idea as this was bolt on. Not what you want but...... (im going to go in on thursday so will ask about the turbo pipes)

I think if you look hard enough you will find the exact muffler you are after (having seen them somewhere). Noise is a funny thing. Even having the exit at certain points, angles or within the body line can cause resonance inside the cabin. Even the tip is important. Needs to be straight and clean or you can get noise.


My ideal system would be throaty at over 3000RPM but quiet inside this. noise on full throttle but not much at low revs. You know, I hate exhausts. I really do. Next to impossible to find a decent shop and someone who has half an idea.

[stickman]

Originally Posted by JW240

ok. higher velcity in the exhaust.
The high verlocity in the downpipe is created by reducing the cross section of the exhaust at the point of the valve. Wat is the effect of this high speed? (to create the high speed, some backpressure is needed, p=0.5*rho*v^2, or not?). Does the higher speed cause a resonance that allows better breating, or the higher speed makes the gasses 'fly' out of the exhaust?

OK. After seeing an equation being thrown out there, you almost had me digging out my old fluid dynamic books and wind tunnel notes...

[BDKR]

Originally Posted by Dauntless

The bullet mufflers I referred to earlier are the brand Berklee, they don't have a website with any info or pics. Apparently they're good, but I've never used them before.

Being that you are on a differnet land mass, Berklee may be domestic to you.

Originally Posted by Dauntless

Are Moroso Spiral Flow Racing Mufflers worth looking into?

I think so. Of course, what works for you in terms of noise may be different then someone else, but it may worth looking into.

Let me interject something else here since we're both driving 244's and building side exit's. I barely have enough room for 1 cat and the 1 Moroso ( Spiral Flow I mentioned earlier ) to run a 90 degree bend and exit at a good location. If you aren't going to be running the cat, then it's not as much of an issue. However, some of this depends on where your cat or first muffler is. My cat is just BEHIND the crossmember for the tranny. You could prolly move it in front of the crossmember, but it will be right next to the tranny and I'm not too sure how good of an idea that is. Another option may be to put one of the bullet mufflers in front of that crossmember then run the cat and the second one after it (assuming you're running a cat). Lastly, you could run on bullet before and one bullet after (assuming you aren't running a cat).

Hope all that makes sense.

Back to the noise thing. The spiral flows do have a straight through core, so the db level won't be as quiet as it could in something like a turbo muffler or those crappy chambered mufflers that people around here (in Florida. Not TB'rs) seem to think are so cool. My system previously was a huge Dynomax Turbo muffler in the rear and the spiral flow in the resonator section. When the car was in N/A, it wasn't noticeable at all to people around me, but as the RPM's climbed, it had a really nice tone that could be hear without being obnoxious.

However, putting the turbo on the car made it a good deal quieter. Too quiet for my taste. The turbo has a tendency to dissipate the pulses thereby making it quieter and also eliminating the possibility of boominess you can feel inside the car with some large diameter turbo mufflers.

There are also the straight through stlye bullet mufflers that seem to have some fiberglass packing around them. Those can help get rid of the raspiness and buzzy higher pitched stuff. The spiral flow will take care of a lot of the lower frequency stuff, but will do it at the expense of flow.

Here's a pic of the spiral flow:



http://www.jegs.com/webapp/wcs/store...tegoryId=13917

I have to admit that i loved the sound of it when you put your foot into it. As the car got into a particular RPM range, it would seem to resonate and sounded like a thousand glass goblets banging against each other.

Hope that helps. This is by no means the gospel. Just some of the things I've noticed and found.

Cheers

[740TurboPerformance]

Don't listen to people saying you need backpressure. That's rubbish, it comes about as a result of people not knowing what they're talking about; the less backpressure the better. ;and the backpressure comments

hahaha, well I guess I never did a freeflowing muffler and glasspack on an NA where I was dissappointed to experience a noticable loss of off the line umph. I've talked to others who have experienced this as well with other vehicles so it aint BS. Anyway, I don't know what I'm talking about although I witnessed it first hand . . . .

Just because it's louder doesn't mean you've actually achieved some gain in performance.

Like I've said though, if you are running an aftermarket cam it may not be so bad or bad at all, you are running an H cam you said so you'll probably be fine.

[Dauntless]

Originally Posted by BDKR

Being that you are on a differnet land mass, Berklee may be domestic to you.



I think so. Of course, what works for you in terms of noise may be different then someone else, but it may worth looking into.

Let me interject something else here since we're both driving 244's and building side exit's. I barely have enough room for 1 cat and the 1 Moroso ( Spiral Flow I mentioned earlier ) to run a 90 degree bend and exit at a good location. If you aren't going to be running the cat, then it's not as much of an issue. However, some of this depends on where your cat or first muffler is. My cat is just BEHIND the crossmember for the tranny. You could prolly move it in front of the crossmember, but it will be right next to the tranny and I'm not too sure how good of an idea that is. Another option may be to put one of the bullet mufflers in front of that crossmember then run the cat and the second one after it (assuming you're running a cat). Lastly, you could run on bullet before and one bullet after (assuming you aren't running a cat).

Thanks for your response. I'm definately not running a cat, as it is legal to run without one.

Also I can't put a muffler in front of the crossmember because the headers end pretty much right underneath the crossmember.

Originally Posted by BDKR

Back to the noise thing. The spiral flows do have a straight through core, so the db level won't be as quiet as it could in something like a turbo muffler or those crappy chambered mufflers that people around here (in Florida. Not TB'rs) seem to think are so cool. My system previously was a huge Dynomax Turbo muffler in the rear and the spiral flow in the resonator section. When the car was in N/A, it wasn't noticeable at all to people around me, but as the RPM's climbed, it had a really nice tone that could be hear without being obnoxious.

There are also the straight through stlye bullet mufflers that seem to have some fiberglass packing around them. Those can help get rid of the raspiness and buzzy higher pitched stuff. The spiral flow will take care of a lot of the lower frequency stuff, but will do it at the expense of flow.

Here's a pic of the spiral flow:

http://www.jegs.com/images/photos/71094050.jpg

http://www.jegs.com/webapp/wcs/store...tegoryId=13917

I have to admit that i loved the sound of it when you put your foot into it. As the car got into a particular RPM range, it would seem to resonate and sounded like a thousand glass goblets banging against each other.

That's interesting, thanks for that. I could definately fit a pair of them in there. I'll look into it, but not commit yet. Thanks mate.

[JW240]

Originally Posted by stickman

OK. After seeing an equation being thrown out there, you almost had me digging out my old fluid dynamic books and wind tunnel notes...

haha post whatever you want. Interesting stuff for my jetengine..
I have a exam tomorrow about this kind of stuff (not exactly fluid dynamics though, as i already had that exam, but its close related to it)

[SteveMD]

Too bad there aren't any aftermarket N/A headers here in the US. While the stock exh. manifold may flow good, it IS heavy.

[klr142]

Originally Posted by stevemd

Too bad there aren't any aftermarket N/A headers here in the US. While the stock exh. manifold may flow good, it IS heavy.

Stahl, $600 I think now?

[Dauntless]

Just for the record, I think Hurricane headers are about $300USD these days. Group buy? Haha.

Anyway, back on topic please

[mikep]

Remember, butt-dynos don't count.
I have seen dyno tests with Supertrapps that showed certain combos liking a certain number of plates in the stack, but that is probably shifting the resonance peaks around. And it was a small enough change for me to ignore.

The way I feel, if it's quiet it's more enjoyable for a longer time. If it can be quiet with no power loss, cool. And plenty of race cars have mufflers.

2.5 is plenty big, Who knows if a 2.25" would gain torque. But the header is 2.5", so go with 2.5".
The Miata had a spiral muffler for a while, it was too loud.

[Dauntless]

Ahh ok, thanks for the info Mike.

My latest idea was trying a pair of spiral flow mufflers together, and if that is too loud, using the Jetex db-killer insert. in the side pipe just before the tip.

Is that a good idea?

[Dauntless]

So I could do the above, or;

One Moroso Spiral Flow muffler, one normal bullet muffler, and the Jetex decibel killer in the side pipe. It might sound nicer if I do that.

What do you think?

[AJS]

[QUOTE=740TurboPerformance]Anyway, I don't know what I'm talking about although I witnessed it first hand . . . ."

You know, I would tend to agree.....


Or were you being sarcastic?

[faster4_tec]

sorry to crash the topic, but might as well stick it in here rather than a new topic

for my turbo project, I was thinking of doing a home made stainless 3" exhaust

although from what I've gathered from previous cars is that NA engines DO need something on them to provide a bit of back pressure, so something that flows, but basically something that is NOt an exhaust (like just taking the top pipe out), overwise they melt down (in the case of 2strokes), and don't perform great, not sure on actual figures but the same car as mine (not the volov a fiat), with a poo exhaust on, just felt breathless and didn't really feel like it had any compression to it

Right heres my figuring for the turbo, the turbo is already causing a lot of flow disturbance, and creating quite huge back pressure (e.g. exhuast manifold glows like a steel works at 3am in the morning), so heres what I want to know. Will a 3" exhaust from turbine housing back actually do anything? Or will it just help with heat dissapation?

also due to the expensiveness of silencers, I was thinking of copying the guy on here with his homemade 3" job, JUSt how loud is a 3" straight thru exhaust
or should I make it as a straight thru (probably about £50+someone to weld it), then if its ridicolously abnoxiously loud I will cut the end off and put a silencer on (would stock silencer be good enough, as its basically new).

[Dauntless]

Yeah thanks for the threadjack haha.

No worries though, maybe someone will answer my question soon.

[klr142]

Originally Posted by Dauntless

Yeah thanks for the threadjack haha.

No worries though, maybe someone will answer my question soon.

It appears you don't really have any other options. No one has done what you're thinking about doing, so no one can tell you to do two spiral flows or one and one bullet. Do either one.

[Dauntless]

Yeah I know mate, it's just speculation. Thanks for the reply though. All input is welcome.

[stylngle2003]

Originally Posted by faster4_tec

Right heres my figuring for the turbo, the turbo is already causing a lot of flow disturbance, and creating quite huge back pressure (e.g. exhuast manifold glows like a steel works at 3am in the morning), so heres what I want to know. Will a 3" exhaust from turbine housing back actually do anything? Or will it just help with heat dissapation?

also due to the expensiveness of silencers, I was thinking of copying the guy on here with his homemade 3" job, JUSt how loud is a 3" straight thru exhaust
or should I make it as a straight thru (probably about £50+someone to weld it), then if its ridicolously abnoxiously loud I will cut the end off and put a silencer on (would stock silencer be good enough, as its basically new).

a 3" exhaust on a turbo application will help you make maximum power by reducing the work the turbo has to do to acheive comparable boost levels. a stock muffler is too small if you're going with a 3" exhuast, and isn't straight-thru either, so it will hurt performance. i would go with either a straight thru muffler and bullet style resonator, or just a straight thru muffler. 3" by itself is pretty loud.

also, if you have to run a catalytic convertor, get a high flow 3" model fitted with your 3" downpipe. that way you will have the lowest amount of restriction possible.

A question:

why do you HAVE to go side exit?

To me, limiting yourself to a side exit setup is false economy.

To reply to a few of your questions:
...the Moroso Spiral Flow is not sufficient by itself. I doubt that two in a row would be either. But you are welcome to give it a shot.
...2.5in will do fine. BTDT on a couple of NAs: 2.5in from the front pipe to the rear bumper. One [B21F] has a Dynomax turbo muffler. the other [B23F] has a Spiral Flow and a Dynomax turbo muffler.
The turbo mufflers on both are in the stock rear muffler location. The Spiral Flow is where the front muffler would go. No cats on either; but those could be added in easily enough....in the stock location. Both are underaxle setups: 2.5in mandrel bends.
...That tip you linked to is unfamiliar.
...if you want to take the "bark" off the tailpipe, and reduce the drone at cruise, then go with something like a Hedman Hedders Hot Tip, that splits the 2.5in into two smaller diameter outlets. The Hot Tip really helped on the NA with the single turbo muffler. [To finish the job of getting the quiet back without losing the flow, I will have to retrofit a Spiral Flow into that system. I'll do that when I swap the B21F out for a B23F.]
...the further back you mount your mufflers, the easier it is for them to muffle without killing the flow.
...a bullet muffler will not be quiet; and what quiet it does do will start to diminish from the git-go. The packing will start to compact on itself from the first time you run it. It will get noisier as the days go by. BTDT

Another question:
...can you get Flowmaster brand exhaust products there?

good luck

Thomas Fritz
...the stealth FTi

[badvlvo]

Try looking at the Dynomax Ultra Flow Bullet mufflers. I have had great experiences with these. Also the round Magnaflows flow well. Any of the 'bullet' mufflets will have a minimum of sound deadening. The Dyonmax U;tra Flow Ovals flow great, sound nice and mellow and aren't all that expensive.

EDIT: Flowmaster's don't 'flow' all that great, have horrible resonances and are heavy.

[DAVO240]

Dauntless,
You may have to yet go to a rear exit, fairly sure that a side exit is illegal in Australia, Could be wrong but I’ll ask my cousin for you (he’s a cop in NSW). Something to do with exhaust entering the cabin :S

Hooray for nothing to do with mufflers!

Cheers
David

[Dauntless]

Yeah, I know side exit is illegal.