[burd]

N O drone on my Borlas. And their straight thru.

[78w72]

Originally Posted by allenga

Interesting. Pypes web site says street pros are louder than race pros. Looks like street pros are just a hollow muffler.

street pros are a chambered muffler just like flowmasters. & race pros are the same basic design as ultraflos & magnaflow, straight through perforated pipe with a fiberglass type packing. most people agree street pros are louder than race pros but as you can tell from the different replies on this thread, everyone is different & every car/engine combo is different. some say a certain muffler is loud or drones & others with the same muffler say they are quiet & no drone at all... that is the case with most things, one person loves something & says its the "best" & the next person hates it or says it "junk."

best thing to do is to try & listen to mufflers you're considering in person at car shows or drag strip etc or watch videos of them. pypes has videos of all their mufflers on their website & youtube has all kinds of vids of different mufflers... but they are all on different combos of engines & exhaust systems so you can only get a general idea of the sound. or the more expensive option is to try a few different mufflers on your car & go with what works best for you. your engine, headers, exhaust system & the gear ratio will determine the sound & what if any drone you get at cruise rpm.

ive had quite a few different mufflers on cars over the years from cheap OEM replacements to many popular aftermarkets listed here, ive had ST on a mild 455 daily driver, flowmaster 40's on a close to stock W72 400, & race pros on a 500+hp alum head OF cam stroker. the ST's are definitely the quietest & had little to no drone. the 40s sound great at idle & higher rpm but do have some drone at cruise. the race pros are very quiet at idle, but once you get into any throttle they come alive & are loud but in a good way to my ears & very little true drone at cruise. you can obviously hear them since its a 2" header with 3.5" collector & full 3" pipe system, but real drone is very minimal. for your car/engine, i would think the ST mufflers will be the best option.

any muffler on a V8 is going to have varying sound levels much louder than a stock system, but to me "drone" is that strange obnoxious sound that vibrates or resonates between your ears & makes things sound hollow or echo'y, kinda like when you humm into a fan, hard to describe but you know when it happens. hope you find a muffler you like!

[allenga]

I've owned two cars in my life in my 20s-30s, with cherry bombs glasspacks. I don't ever remember complaining of drone and I always loved the rattle sound.

[David Jones]

I had some Flowmaster 50 series on the car a long time ago. They sounded all sporty outside the car, inside, you couldn’t hear yourself think. Hold a conversation? Just pull over and shut it off. Resonance.
I bought a pair of 20” case Dynomax Super Turbos (17749?) and OMG, the difference inside the car was incredible. NO resonance. My understanding is that they flow well too.
The pipes are 2.5” mandrel bent with an H pipe.

[Sirrotica]

I try to read most all the muffler threads posted on PY, and I don't believe I've seen any reference to the Aero Turbine XL series. I have a 4 inch XL on my 6.5 turbo diesel dually, and I really like it.

The XL series has a longer body on it than the regular series muffler and incorporates a resonator right into the muffler to cancel drone and excess noise. The mufflers are full stainless and come polished to a mirror finish, lifetime warranty on defective materials.

Link to Aero Turbine exhaust: https://aeroexhaust.com/

I'd just like to hear from someone that has used these mufflers on a classic Pontiac if that person exists. I have a mild 455 that I plan on using on my next project and would like to know how they work before buying a pair of them (they're a little more money than the average muffler costs).

[many birds]

Over the years, I’ve tried a few different systems. Least drone prone was stock with crush bent pipe and transverse dynomax muffler. Next was a basic dual exhaust system a muffler shop put on in the early 90’s with with no H pipe—sounded good, no drone, but restrictive due the small diameter pipe and crush bends.

Worst for drone was the Flowmaster American Thunder system with the 40 series mufflers. It sounded great but was unbearable in the car for anything more than a short drive. Also tried the Flowmaster Force II system with a transverse muffler. It was much tamer, still droned at about 2000 rpm.

Currently, I’m running 14 inch dynomax ST mufflers with Flowmaster 2.5 in pipes with H pipe and factory logs with 2.5 down pipes and Flowmaster tailpipes. The Flowmaster parts are leftovers from the American Thunder setup. And, it still drones at 1800 to 2300 RPM—not terrible but definitely more than I care to have. I think the H pipe, although better than an X-pipe, is adding to the drone.

[1968GTO421]

Originally Posted by Sirrotica

I try to read most all the muffler threads posted on PY, and I don't believe I've seen any reference to the Aero Turbine XL series. I have a 4 inch XL on my 6.5 turbo diesel dually, and I really like it.

The XL series has a longer body on it than the regular series muffler and incorporates a resonator right into the muffler to cancel drone and excess noise. The mufflers are full stainless and come polished to a mirror finish, lifetime warranty on defective materials.

Link to Aero Turbine exhaust: https://aeroexhaust.com/

I'd just like to hear from someone that has used these mufflers on a classic Pontiac if that person exists. I have a mild 455 that I plan on using on my next project and would like to know how they work before buying a pair of them (they're a little more money than the average muffler costs).

Interesting mufflers, I would be intersted in what you discover about Pontiac usage of them.

https://aeroexhaust.com/i-30497610-a...ratesound.html

Thanks

[Sirrotica]

Originally Posted by 1968GTO421

Interesting mufflers, I would be intersted in what you discover about Pontiac usage of them.

https://aeroexhaust.com/i-30497610-a...ratesound.html

Thanks

This is the only reference on PY I found with the search function:

https://forums.maxperformanceinc.com...49#post2859349

Seems C. Cass wasn't impressed with them when they tested them????

[1968GTO421]

^ He didn't sound impressed favorably. When you look at the tips they sell (see below), it does look like "tuner" cars with the "fart can" exhaust note. I may check to see if they have modifired them to sound less "tinny" on V-8's.

https://aeroexhaust.com/c-1389199-exhaust-tips.html

[Sirrotica]

Originally Posted by 1968GTO421

^ He didn't sound impressed favorably. When you look at the tips they sell (see below), it does look like "tuner" cars with the "fart can" exhaust note. I may check to see if they have modifired them to sound less "tinny" on V-8's.

https://aeroexhaust.com/c-1389199-exhaust-tips.html

The one I do have is on a V8 diesel, (6.5 turbo diesel). I like the sound of it, but the exhaust is also running through a turbo, before the muffler. I've listened to sound clips off these mufflers on numerous gas V8s with dual exhaust, but since recording sound on a cell phone, and real life usually are apples and oranges, plus diesels and gas engines don't have the same sound out the exhaust to start with. Not to mention my diesel uses a 4 inch exhaust with a single muffler, as opposed to my planned exhaust for my street 455 would be duals with headers, either an H pipe or an X pipe, and probably a 3 inch set of pipes, exiting in front of the rear wheels.

I also don't know if C Cass listened to a system with a resonator style muffler, or just the un-resonated muffler, he doesn't specify. The clips I have listened to without resonators, are too loud for my tastes. I've had cars with dual, turbo style mufflers, that droned even with full exhaust to the rear of the car, driving the car for 50 miles on the thruway, was torture.

Anyway, I was just looking for an opinion possibly with dual resonated Aeros on a Pontiac street car. It seems no one reading these threads have tried either style of these mufflers. At 67 YO, I don't want loud, nor droning, just a deep aggressive tone on a mild 455 street car. I might have to fork out the money, and find out if they are what I'm looking for.

The Aero mufflers have also have the design to actually increase power over a conventional muffler due to their design, which causes a delta flow, that causes a low pressure area in the exhaust. I know that it increased the power on my diesel over a conventional muffler, without a doubt. I didn't need a dyno to feel the difference between the mufflers. I was looking for the same possible performance advantage on a naturally aspirated gas V8 Pontiac for street use.

I'm too far away from the point where I have to worry about mufflers anyway, maybe by the time I'm ready for an exhaust system someone on PY will have tried the Aero Turbines.................

[allenga]

Originally Posted by moontower69

You're gonna keep chasing your tail trying different recommendations of folks here to "tweak" your muffler set up (X v H pipe, etc). Most of the folks here dont drive their cars daily. If you do, there's no really good drone free option but the Super Turbos - best balance between sanity and power and decent sound.

But just put the Dynomax ST long case mufflers in and problem solved. PERIOD. And they DONT rob power at all unless you're worrying about a tenth of second on the quarter mile race times....I think Jim Hand tested them and showed they dont really rob power at all unless you're making 500 HP or more....

Well, I just gave in after hours of research and ordered Dynomax Super Turbos. Hoping my car does not sound like my mom's Buick.

[Mister Pontiac]

It may be irrelevant now since you've already ordered the ST's (which should be great!), but Engine Masters did a 'Muffler shootout' on an episode a while back. They utilized only the cheap mufflers ($40 or less) but compared the chambered, welded and turbo designs. They looked at HP gain/loss, sound level, etc... It was an interesting watch.

[moontower69]

ST will solve your drone.

I watch Engine Masters and unfortunately they didn't test for drone on the dyno with their "cheap muffler shootout" or deal with daily driver issues.

You're gonna be very happy Allenga with the STs - please report your results back here!

Rule of thumb is any muffler that's not a turbo design (3 chambers inside with 2 "U" turns) like a super turbo (called turbo mufflers after its original design for the turbo Corvair in 60s) and is instead "straight through" design is just gonna drone. It's sound physics. There's no free lunch, anything that has that "flow master sound" or heavy growl does it by being open inside and will drone.

[allenga]

I got the STs delivered today. Noticed they are bare steel mufflers and I have stainless exhaust. Thank may not look nice over time. Should I paint em silver.

[78w72]

Originally Posted by allenga

I got the STs delivered today. Noticed they are bare steel mufflers and I have stainless exhaust. Thank may not look nice over time. Should I paint em silver.

yes ST's are steel but not bare steel, they are aluminized & usually last many many years without rusting. they should look nice for a long time. & if your exhaust isnt fully polished they might actually dull a bit to match it pretty good.

[tom s]

ST had a drone on my bird with a X pipe,changed to a H and went away.tom

[allenga]

I just installed the Dynomax ST and my car has been neutered of coolness.

The drone was reduced significantly but its still there. I find the exhaust note on my car to sound like a 2019 Silverado.

This is just my little rant. Before my new Pypes exhaust system with X pipe and headers, I had stock manifolds, no X or H pipe and Flowmaster 40s. My exhaust note sounded cool. People at car shows said hey, that exhaust sounds cool.

So, I spent $2500 on new exhaust on my car and am completely disappointed.

Sigh.

[Formulajones]

If you have the room, the dynomax ultra flow 17546 is my favorite. 20" case so it helps subdue the sound to some degree, but they sound great, and I've never had drone issues with them.

I run the shorter case version on a mustang here, X cross and 2 1/2" system and they sound really nice, with no drone. I was concerned, since I can't fit the 20" case on this car, but very pleased with the results.

It's why I recommended this muffler right from the start in this thread. The ST's are very quiet, which isn't a bad thing, but they are usually too quiet for most people.

[allenga]

Just wanted to clarify. I appreciate all the input into my muffler journey. The STs did solve my drone headaches. I may look to eliminate the X pipe and go back to a Flowmasters.

[78w72]

sorry to hear you're not happy with them. keep in mind, they will get a little louder over time as the fiberglass packing gets blown out or compacted, or whatever happens to it over time, that was my experience with them.

& i'm curious how or where you spent $2500 on exhaust? pypes system is $400-500 & the mufflers are about $100. plus a few hundred for splitter tips, hangers & install etc, i'm not seeing $2500 worth of exhaust in your pic.