[bird72]

Good thread and timely. Now that I have the 455 going, the inherited system on car with Flowmasters is wayyy too loud. I may try the Dynomax Turbo as recommended here. Rest of system is nice pipe and going to hopefully change out mufflers only (?). Has X pipe.

[76TA462]

I went through trials and tribulations too, when searching out a muffler for a built 455. I am using Pypes X-Pipe with a pair of DynoMax Ultra Flo Welded p/n 17222. Really happy. No drone, not loud but loud enough.

[n2ogpsj462]

my experience with race pros with virtually the exact same combo but different cam.. sounded wicked with my 3" x-pipe and turn downs right before the axle but got annoying in certain driving situations so right before a long trip to a car show in new jersey I went and had 3" tail pipes installed. Nice idle but sounded like garbage under any throttle. raspy like glasspacks. the minute I got into town for the car show I found a local shop to remove tail pipes. it was that bad. from there flowmaster 3 chambers which were a predictable sound and now hooker straight thrus for the turbo with the same tail pipes and they sound great. heres a clip of the race pros with turn downs. awesome sounding but pissed my neighbors off
https://www.youtube.com/watch?v=cGiy_itsXPY

[HWYSTR455]

I ran the Goerlich Xlerators on the last config and really liked them. They are louder at WOT than the Super Turbos, but very close to same at under 3000k. I liked the fact that they were louder at WOT in some ways, and am on the wall if I'm going back to them. I plan on spending more time on trips in the car, and with the windows down, the Super Turbos are the best.

.

[Formulajones]

Originally Posted by HWYSTR455

I plan on spending more time on trips in the car, and with the windows down, the Super Turbos are the best.

.

That's pretty much where I'm at these days. And since the OP started this thread asking about his convertible, it really becomes an issue. We drive 90% of the time with the windows down (sold the convertible) and we drive them daily, so exhaust sound levels are more critical for us than they used to be 30 years ago. Or maybe we are just getting old, lol.

I simply can't do dumps in front of the axle on anything anymore. Last car I had like that would set off car alarms at the grocery store just idling up and down the isles. My head can't take the drone inside the car anymore either. Everything here has to have tailpipes.

[lfdsteve]

Started with Race Pros. Too loud for my taste although they sounded wicked at idle. Running VT’s now. Love them but understand they may be no longer available?

[HWYSTR455]

A little noise is a good thing, keeps critters out of your path. 2 weeks ago in my ranger beater truck, deer darted back and forth in from of me, and right as I was beside it, it darted 'back', and ran into the side of the bed.

In that thing, I never took my foot off the gas, and never hit the brakes. Girl that was with me freaked, and couldn't understand why I wasn't shaken. I have like maybe $2500 in that whole truck. That's why.

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[n2ogpsj462]

Originally Posted by Formulajones

That's pretty much where I'm at these days. And since the OP started this thread asking about his convertible, it really becomes an issue. We drive 90% of the time with the windows down (sold the convertible) and we drive them daily, so exhaust sound levels are more critical for us than they used to be 30 years ago. Or maybe we are just getting old, lol.

I simply can't do dumps in front of the axle on anything anymore. Last car I had like that would set off car alarms at the grocery store just idling up and down the isles. My head can't take the drone inside the car anymore either. Everything here has to have tailpipes.

funny how that happens. had my race pros with turn downs in my earlier 20s and loved setting off peoples alarms or cruising in center city with the drone off the skyscrapers. that video says 06 so I was 24! seems like yesterday but best thing I did to my car was tail pipes and 3.42 gears with the 700r4 it cruises just below that drone rpm. once I get mine back together ill post a vid but with the turbo and dual 3" muffler and tail pipes its incredibly quiet

[Formulajones]

Originally Posted by n2ogpsj462

funny how that happens. had my race pros with turn downs in my earlier 20s and loved setting off peoples alarms or cruising in center city with the drone off the skyscrapers. that video says 06 so I was 24! seems like yesterday but best thing I did to my car was tail pipes and 3.42 gears with the 700r4 it cruises just below that drone rpm. once I get mine back together ill post a vid but with the turbo and dual 3" muffler and tail pipes its incredibly quiet

Yep, I've found that once tailpipes are done, it really comes down to the muffler choice to really hone in on the noise level you're looking for. Or vice versa....

If that's not enough for me, lately I've also been adapting stock sized tailpipes onto the performance 2 1/2" or 3" systems. I find this tones it down just a bit more and it's not that much of a performance hit that far back in the system.
Did this on our 69 Z recently. The 2 1/2" Pypes SGF70 transverse system was just still a bit too loud. Transverse muffler choices are limited, and not adaptable to the Pypes configuration anyway. So I pulled off the 2 1/2" tail pipes and installed a set of factory 2" tail pipes, not only does that give the car a stock appearance out back, but it made the noise level just about perfect. Still makes noise on the gas, but the level inside the car is very comfortable. Standing in front of the car it's pretty quiet, standing behind the car it has a nice rumble. So it doesn't draw a lot of unnecessary attention.

[TransAm 474]

Here is a video of my 1978 Trans Am with a 461 and Dynomax Ultra Flow 17229 mufflers, 3" mandrel exhaust with Dr. Gas X-Pipe, and Pypes 3" tailpes.....

https://m.youtube.com/watch?v=3DqLBfQMaCs

[gto65lvr]

manifolds or HO manifolds, 2.5 pypes system with X pipe and custom 18 race pros on both my 66 and 67 GTOs with built motors. can hear the fan spin at full throttle almost and can hear music and talk on this set up. if I could fit the 18" on my 68 FB Vert I would. it has flowmaster on it now and its too loud but the 16" case is all that fits in there running dual mufflers. Race pros are normally 14inch I think so it makes a big difference. Although I am sure if I had headers with the system it would get considerably louder.

[peppergreen]

I had PYPEs 2.5" XPipe with the Street Pros. Awesome idle and cruising sound. But the drone on highway drove me nuts. Picked the Dynomax VT's from searching this forum, I love them. Same idle, great sound at all speeds.

[ponchjoe]

Whenever I see this inquiry in the future I will just post a link referencing Jim and Tom Hands work in their book. It is real world testing that includes measuring of sound and flow.

http://www.pontiacstreetperformance....p/exhaust.html

[Formulajones]

I've mentioned using smaller tail pipes quite a few times in threads like this to reduce some of the noise level. I've done this a few times with good success.

What's interesting in that test, and what I've been saying, is that the smaller tailpipes aren't hurting performance "that" much, and what performance it does hurt, that test shows it can be picked right back up by removing the "H" switching to an "X" pipe.

[Formulajones]

Originally Posted by gto65lvr

if I could fit the 18" on my 68 FB Vert I would. it has flowmaster on it now and its too loud but the 16" case is all that fits in there running dual mufflers.

I mentioned this in post 8. When we had our convertables we preferred them pretty quiet. Otherwise top down driving was miserable.

On the F-bodies, I prefer the transverse systems. Can't fit the larger dual mufflers under the car all that well, and the transverse systems not only provide better ground clearance, but have decent sound control. Todays aftermarket transverse systems perform just as well as dual muffler setups now.

Another benefit to the transverse setup, is that the tailpipes are very short, maybe 18" and they don't go over the axle, yet installing smaller factory style tail pipes has a decent effect on the noise level without hurting the performance. I've done this on the Pypes SGF70 transverse system with good results. I also like the Thrush/Dynomax transverse system as a much cheaper and slightly quieter alternative.

[David Jones]

Dynomax 17749 Super Turbo.

H pipe.

[Murf]

Originally Posted by ponchjoe

Whenever I see this inquiry in the future I will just post a link referencing Jim and Tom Hands work in their book. It is real world testing that includes measuring of sound and flow.

http://www.pontiacstreetperformance....p/exhaust.html

What I find interesting and I think some people miss, is that those test were done with a single muffler.

Makes me think that almost any decent dual system should flow well enough for the street/strip set-ups most have.

Murf

Sent from my Z936L using Tapatalk

[Formulajones]

Originally Posted by Murf

What I find interesting and I think some people miss, is that those test were done with a single muffler.

Makes me think that almost any decent dual system should flow well enough for the street/strip set-ups most have.

Murf

Sent from my Z936L using Tapatalk

That was only the first test. After that he went back to a dual muffler setup to test his tailpipe and crossover pipe theories.

If you look at the ET's and MPH's, the single muffler had a very drastic affect on the car. It only ran low 13's at about 102 mph.
When the dual mufflers went back on the car it was running mid 12's at 108 mph.

[Murf]

Thanks for clearing that up for me!

Reading comprehension isn't my strong suit.

ETA, I went back &looked again. It still looks like only 1 ten & 1 mph difference between open & 1 Dynomax muffler. Am I reading this wrong?

Sent from my Z936L using Tapatalk

[Formulajones]

Originally Posted by Murf

Thanks for clearing that up for me!

Reading comprehension isn't my strong suit.

ETA, I went back &looked again. It still looks like only 1 ten & 1 mph difference between open & 1 Dynomax muffler. Am I reading this wrong?

Sent from my Z936L using Tapatalk

Those blocks are very small for me on my screen but I'd say yeah you're seeing that right.