Re: Mufflers-another scam item

[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

>