Re: Mufflers-another scam item

[ameskg@xxxxxxxxx]

When one tests mufflers, can you be sure that the flow with hot, pulsing exhaust
gas will be the same as a cool, steady flow of air? Or at least comparable from
one muffler to another? 

;)

Ken

Quoting Tom Jennings <tomj@xxxxxxx>:

> On Tue, 17 May 2005, Bruce Hevner wrote:
> 
> > Ahhh, mufflers.
> > Ever wonder which "flows" best?? Which "is louder/quieter than the others?
> > So have I!!
> 
> NO SH*T!!! I didn't even bother to ask casually on the list about
> that stuff I guess because mufflers (and street-type exhausts in
> general) are one of those areas with a knowledge and info vacuum.
> It's been like that for so long I gave up trying. I suppose if I
> was in your shoes I'd be more upset by it like you are :-)
> 
> Summit lists CFM for a few higher-end racing mufflers, but that's
> it. The $29 muffler looks no different in the catalog than the $200
> job. Besides hype, there's got to be some difference, but what that is
> is a mystery.
> 
> Using hocus-pocus and the brains in my ass I decided (not
> determined) that the better brands around $50 in Summit are
> probably the best choice for me. That's the basis for me asking.
> 
> What a way to choose.
> 
> I'll go with dynomax (or closest spelling thereof :-)
> 
> 
> I know that the physics of flow in pipe is well known, and there's
> good rules of thumb for determining losses (diameter, bends,
> length, etc) and a lot of it is obvious, but mufflers need to be
> tested.
> 
> It would make a good article for one of the 'rod mags. Just bench
> flow 'em cold, at least hit the barn door with data.
> 
> And noise, that can't be that hard to test either. Standard pipe
> setup on probably a chevy 350 at two, three RPMs would also hit
> the barn door.
> 
> Bandsaw 'em open, hit the parts with a rubber mallet, guess whose
> will fall apart first.
> 
> 
> 
> 
> >
> > Read an article in one of the car rags a while back comparing a few of the
> > leading brands. They made an interesting statement. Their comparison
> showed
> > that matching a mufflers "flow" to your engines size and HP output is
> > important. And that although a mufflers internal design affects sound,
> > matching a mufflers "FLOW" is the important part. So WHY aren't mufflers
> > rated in FLOW so we know which one to choose?? Turns out the exhaust
> system
> > industry as a whole IS fighting publishing flow ratings for mufflers.
> There
> > IS a formula for choosing the approximate flow rating for your muffler. If
> I
> > can find out what I did with it I'll post it.
> > And WHY isn't there some kind of standard "Noise" rating for mufflers? As
> > it is now unless you have actual experience with a muffler you have NO
> idea
> > how quiet they will be. I DO realize that the installation affects the way
> > they sound.
> > I have tried finding a source that has compared mufflers that does not
> > actually SELL them. The only place I've found so far wants $65 for their
> > book.
> >
> > In my opinion mufflers should AT LEAST be rated in FLOW! That way we could
> > at least get some kind of idea of which one to use for the performance we
> > are looking for.
> >
> > But HEY,,, that's just me.
> > Bruce Hevner
> >
> 
> >
> 
> 
> 
>