The mini-controversy surrounding views on glass fibre filled mufflers stirred me to Google.

http://researchnews.osu.edu/archive/fibrmufl.htm

Seems like it could be a good idea.

Of course, its in the nature of fora such as these for facts to get lost in the swirl of opinion, exaggeration and hyperbole, but sometimes it could be a good idea to back up assertions with some measurements. Sticking a thermocouple up the tailpipe could settle some arguments about exhaust temperature.

"If you can't measure it, you can't understand it. If you can't understand it, you can't control it. If you can't control it, you can't improve it".

 

Link didn't work... here's another one: http://researchnews.osu.edu/archive/fibrmufl.htm

Interesting reading.. thanks labrat

 

Ahh, labrat, we could have done with your calm 'measured' approach a couple of days ago. :D

Can someone explain this to me then - if the OEM muffler contains metal baffles (am I even right so far :o ) and the Hymee mufflers contain glass fibre, why does the Hymee catback emit more noise than the OEM set-up?

Remember, use small simple words so the lawyer can understand.

 

Resonance?

I don't know the answer; but do know it is the design of the piping.

As the article says - the best silencer is a potato at the tail end; so I take it as less flow, less sound.

He also talk about back pressure too. So as I observed less flow, more back pressure, less kW, less sound. Reverse is true in Hymee.

You guys just have too much time arguing.... people paid $3000 for a titanium muffler that last only 3 months and never complain.

 

hehe, Taka if you think $1,000 per month is good value for muffler alone you have been looking at dead people too long. :p :D :D

 

Not me personally but some people do. They know that all mods does not last long. They are not meant to last a century, but the duration of time they have the car for....

Incidentally the guys only had his car for 3 months

Moral of story is: if you want to keep your 8 for 20 years, don't mod or expect to mod and change stuff a few times.

 

And this from someone whose workaday speech is bespattered with Latin?

The answer is gee, I don't know, I'm a chemist not an acoustics engineer. But it seems to me that if academic engineers get involved, it must be a complex field. Perhaps Hymee's is designed more to reduce back-pressure than to reduce noise. I haven't seen a cross-section diagram of what a glass fibre filled muffler should look like. I have this mental picture (probably wrong) of something like a silencer used on pistols - sort of a mesh or perforated tube around which the fibre glass is wrapped surrounded by a metal shell. I guess that the amount of noise reduction could depend on the depth of the glass layer and how loosely or tightly its packed.

 

Thanks for taking a stab at it for me.

As for latin - I detest lawyers who overuse it. It does have its uses as a shorthand way to communicate sometimes complicated or unwieldy concepts but it is gradually dying off.

Not being one of the GPS set I never did learn it at school. This has it's uses.

I had a Joe Blow client in the witness box one day whom I was questioning in order that he might give evidence in support of his claim (evidence-in-chief - not cross examination). The pompous judge (his nickname is 'The GILP' - Gorilla in Lace Panties - because he's fat, hairy and bats for the other team) decided to interrupt me and spew forth some fluent latin, no doubt to demonstrate his inordinate wit. I was temporarily baffled and could see my already nervous client getting even more uptight. So I turned to his Honour and said:

"My apologies your Honour but neither I nor my client had the privilege of attending the kind of school which taught latin and consequently you have us at a disadvantage."

The GILP back-pedalled furiously, apologised to my client and ultimately gave him the benefit of the doubt on some pretty dodgy issues. A good example of how one small episode can turn a case.

It also demonstrates that it is better sometimes to disarm than attack. :p :D

Oh ****, I'm telling war stories now. Apologies - it's been a long day in the trenches. :o :o

 

Having seen the Hymee exhaust production line, that description is exactly what the inside of the muffler looks like.

Hymee, correct me if I am wrong, but that is what I remember it looking like. Also, delete this post if I have just given away the secret to the sweet sound of the Hymee catback!

 

No worries Wildcard, as you didn't tell them the shape

Cheers,
Hymee.

 

Something that the exhaust specialists here could wise me up on: is it possible to have too little back-pressure? I have heard stories that with conventional motors, too little back pressure can cause valves to burn. True?

BTW, what is the cause of the crackling and popping that some enthusiasts like so much? Does it have to do with combustion outside the engine? Could this be associated with exhaust back pressure?

 

I might continue this in the lounge - I don't want to get flamed for causing off-topicness.

 

Yeah - sorry about that.

What a tool I am sometimes. :o :o :o

Maybe I should delete it.

 

Don't apologize: it was interesting and funny. It must be a great profession for turning out one liners.

 

hehehe, the drudge and tedium can make the most pathetic bon mot appear hilarious.

On the flip side, there is nothing worse than a judge who believes he is funny.

Hmm, I think we better get back to mufflers before said flaming begins (pardon the pun Hymee).