Toddcod

iTrader: (8)

So the dynomax race muffler for the resonator. correct???

Do you think the 23 1/2 in will fit. Or do I need to get the 16 1/2 in.

Thanks.

Rafa

iTrader: (22)

Jason, where did you buy your muffler?

Thanks

patsmx5

iTrader: (16)

Those numbers are out of a book called "The Scientific Design of Exhaust and Intake Systems". That book was published in the 60's I think. Had lots of good info in it.

For example, glasspacks reduce the intensity of the sound. Say X=length and I=intensity of the sound. (Note Intensity and dB's are related, but not linearly). The rate at which it reduces sound is something like I*X^1.6. That is, as the glasspacks length gets longer, its affects become more and more evident.

So with that in mind, I did this...


That's 75" of actual glasspack. Two 24" core ones and a 27" core one. I cut the extra 3" off each end so that it's more like one large one instead of 3 small ones. That way if a sound wave is say 5' long, my system catches the entire thing, where if the sound wave is 3', I'll catch it twice. But when you have gaps between them, then part of the wave always escapes.

The 12" rule is just the number they came up with through testing. You want 12" of straight pipe before it exits. No bends. More length is better, but 12" was the point of diminishing returns.

paul

iTrader: (21)

that exhaust must weigh a ****-ton

patsmx5

iTrader: (16)

lol. Yeah it's about as heavy as the old exhaust system was. I don't care though, it sounds good. DEEEEEEP, if you can imagine. Plus I'm still NA, so for 3" NA it isn't bad. It will be even quieter when I get the turbo on.

y8s

iTrader: (8)

mine's the 5x11x22... who you callin peewee, peewee?

PS You can get all these at Summit Racing.

Todd: I used the 12" bullet.

Toddcod

iTrader: (8)

Hmm. Do you think the 18" would be any noticable differance on power. Or not enough to worry about. I doubt it would even drop any. What do you think.

I may order a resonator tonight.

y8s

iTrader: (8)

18inch what? bullet? i doubt there's a 2% difference between resonator and no resonator.... less from 12 to 18

JasonC SBB

"The Scientific Design of Exhaust and Intake Systems"

I know OF that book; I saw it at a local used book shop for some big bux.

So 12" of straight pipe AFTER the muffler helps make it quieter?

Did it say anything about resonated tips?

Hey peewee, mine's quieter than yours because girth is 2.5" and yours is 3".

patsmx5

iTrader: (16)

Yeah, MSU library here has that book. I was gonna buy a copy and it's like 100 bucks used. So I think I checked it out like 6 times last year instead. Yes, 12" helps. They had a reason for it, but I don't remember it. Book said tips are a 100% waste. They do nothing but add resistance and turbulence.

But I would like to get a copy of it one day. Has Sooooo much information in it. It's all you would need to design intake manifold and headers. I was designing a set of headers for a V8 guy on m.net and used that book to determine the specs.