j9fd3s

iTrader: (3)

i think its a CSC muffler, i've got one here for another car and its really similar in detail.

i've done some experimenting, and i think the tip design is the key piece. with my PP running though a 3" borla, its as loud as you'd expect. but i have this resonated tip thing i clamp on it when i'm around the house, and it makes it quieter than the turbo car, with no real change in performance.

in theory the noise is the difference between the negative side of the exhaust pulse, and the positive side of the exhaust pulse (think of a speaker cone), and with the rotary this is big, as it goes supersonic. what the small diameter tip does is let the pulses stack up, which lets them even out a bit. which really cuts the noise down. if the pulses are damped enough the tip can actually be quite small and still flow enough to not really effect power.

that is my theory anyways, not sure its technically correct, but it seems to work in practice

Jeff20B

iTrader: (13)

I tried my powerpulse muffler on the 20B with a long primary and it flowed fine. Gave it more power than when it had the full 3" and a short collected header.

peejay

Is it still mongo thick material or is it lightweight stuff?

A friend of mine bought a long primary system last fall and he had to do some major surgery to it to get it to fit his car (an '81). I'm wondering if he got a "New" system and they don't have their jigs correct.

wankel=awesome

^ fitment on s 1985 GSLSE is pretty bad with the new stuff. Im helping install one right now. The muffler wants to hang crooked and the center section is rubbing on the body pretty good.

Sh00bs

iTrader: (8)

that full stainless looks great! only issue i would have is attaching it to my steel exhuast, i guess i could V band or flange it :/ would prefer to just weld though

peejay

So weld it. I weld stainless to mild all the time. World hasn't ended.

drdode

Not sure cause I've never held the older rb muffler before. This stainless rb muffler doesn't feel too heavy though.
This long primary system will be going on my 79', so I hope it'll fit right and no surgery involved.

peejay

The old RB rear muffler feels only a little bit lighter than a transmission.

drdode

Haaa! Then it's definitely a lot lighter

wankel=awesome

Haha it's true. I'm convinced what I've heard is true though. This new muffler is light and cheap compared to the old one, and supposedly is straight through designed.

peejay

My SP rear muffler is also a straight through design.

drdode

Then again I've never held a transmission either! Cheap as in the quality?

wankel=awesome

Yup. And a tinny exhaust note. The one on the SE we installed doesn't sound anywhere near as quiet or as good as the 15 year old RB SP system on my widebody.

drdode

Yeah not sure. But I highly doubt RB is going to sell a cheap quality muffler, especially since it's manufactured in Italy. The full sp system will be going on tomorrow, so we'll see...

wankel=awesome

Well its not their fault, the manufacturer changed it, not them. They are still quality pieces but it's built more like the universal now, which I just don't like. It's probably the same after a while, RB claimed the pitch would change as the resonators broke in. We'll see.

Sh00bs

iTrader: (8)

welp, there's a power pulse for a '79/80 on CL for $200, brand new still in the packaging. has some surface rust from water getting in the bag but he assures me it's surface only, think im gonna pick this up, get it welded on and will report back

wankel=awesome

Mine isnt! Mine is chambered, sounds really nice at idle and cruise. Only noisy at WOT.

Wonder when they made the change to straight through?

t_g_farrell

iTrader: (1)

Yep , I got my setup used for $400 bucks but its the older version and its heavy as hell. I just
replaced the header because it burn through. I was thinking about replacing the muffler because
I think its making rattling noises but I wont if the new ones are not the same. I like the sound
I have and it performs very well from what I can tell. It is not straight through either. Can't even
see daylight through it if I remember right.

Jeff20B

iTrader: (13)

I have the newer center section which uses bullet shaped SS presilencers. It's very light. Also the newer muffler that is straight through. It is just two 1" or so perforated tubes split or Y'd apart down to the tips. It is joined internally by the perforated 2.375" inlet tube.

I've tested an earlier one that had the heavy center section and the slant cut tip muffler. It sounded good too.

peejay

I'd be very pissed off if I spent $1200 on a new exhaust and it was loud. That money could have been spent on an Ecoboost swap, which would be not loud.

wankel=awesome

I'm really interested in when the change from chambered to straight through happened. The straight through would be best for anything over a street port...

peejay

I bought my midpipe/rear muffler from Paul Aber around 2013ish. I think. Anyway it was like ten years old when I bought it, so we can use that as a minimum year for straight through mufflers.

Note that ALL '81-82 exhaust systems use the same muffler as the Long Primary (Street Port) exhaust system and NO '79-80 or '83-85 exhaust systems use it.

drdode

79-80 and 83-85 use street port exhaust once you choose to go with the complete street port (long primary) exhaust system, right?

j9fd3s

iTrader: (3)

agreed. if they actually did have a chambered one, it was at least 15 years ago. if there even was a chambered one. my friend has an older (he got it used in 1994!) slanted tip system, and next time i'm up there, i'll check it out

wankel=awesome

This actually explains the differences in opinions I've read over the years using the SP system on bridge and pp motors. 10 years ago, people wrote about bad experiences with that system on aggressively ported engines, but as of late the results have been good, like peejays full bridge.

Maybe the less restrictive muffler design is key to what a bridge or pp will want, but the older chambered design wasn't so good on them.

This actually brings the thread full circle to the original point. Sounds to me that the current stainless/straight through system would be a great match to your half bridge..