All Small Six straight thru muffs

[chad]

Moving deeper into completion.
I've all ways stood by turbo muffs for street performance. Recently I C straight thru from some of the major manufacturers and the ol turbos getting glass packed. Never saw the 'straight thru' on anything but the track cars. Might this be the new performance over the turbo? This is all research as the 'straight thru' never come into the shop. My folks dont even have the 'fart cans' on their tuned Japanese rigs (thank ye gods). Thnx for facts AND opinions, helps when U make it obvious or state which~

 

[B RON CO]

Hi, Smitty"s glass pack mufflers have been around for decades. I have them on my Flathead V8. I think I had some Cherry Bombs for a few months way back when, but changed them to the tried and true Thrush Hush. Good luck

 

[powerband]

Here's the "Smithys" mentioned

Performance Mufflers & More at Summit Racing

Give your ride the performance sound you want with direct-fit or universal-fit mufflers. Shop everything from performance mufflers with 2.5 inch inlets to chambered, turbo, or glasspack mufflers & more!

www.summitracing.com

I have them on my '61/250 TriPower with dual out long tube Hooker headers. To me they are less raspy than typical steel glasspacks' and throaty with throttle.

'Had glasspacks on the mild 170 build but too much drone for DD. A pair of OEM stock mufflers make cruising mellow with 1/2 the backpressure. ..... ( mufler BP / 2 = 1/2 muffler BP...

have fun

 

[John Ha]

The Engine Masters TV show did a couple of tests for noise and horsepower that you may find useful. Here are links to their "cheap muffler test" episode and their "Muffler Showdown" episode.

The general conclusions seem to be that the straight through mufflers are louder and don't lose much engine power while the baffled mufflers are quieter at the expense of a little less power at the rear wheels.

 

[Soldmy66]

Ideally, muffler selection should be based on their flow (CFM) rating, and so should exhaust pipe diameter sizing. If that was the case, the muffler design would have little impact.

IIRC, there is (or at least used to be) one after market muffler manufacturer that listed each muffler's flow rating. By using muffler flow ratings and exhaust pipe diameter that is closest to optimal (calculated based on engine flow within the expected operating range) you could design a zero loss (or almost zero loss) exhaust system that would be large enough, but not so large that you would lose exhaust gas velocity (a loss of exhaust gas velocity reduces exhaust gas scavenging). Bigger is not necessarily better.

Intuitively, the more direct the exhaust gas flow, the greater the CFM - however CFM capability that by far exceeds your actual CFM requirement provides no additional gain.

A larger muffler (maybe even one with slightly larger inputs/outputs), could be used to keep things quit(er), if everything was based on CFM - meaning you could select a muffler that was not obnixiously-loud so long as it had the right CFM.

I did nothing to answer your question, I realize.

 

[King_Kong]

"Straight Thru" mufflers are usually resonators, but marketed as mufflers.

Resonators don't muffle the sound, instead they take the high-pitch & raspiness out of the tone of the exhaust & leave a deeper tone. Btw, when you hear that raspiness in a Honda, it's because they removed the middle resonator.

Either way, turbo mufflers (versus a straight thru muffler, or straight pipes) are generally better for torque on most street cars. I don't understand the physics of it all, but some of the guys on this board can probably explain exhaust pulses. But in a nutshell, the overlap of most street cams are not engineered to have a straight thru exhaust system & something bad happens with the exhaust reversion & filling of the cylinders...again, I can't explain the physics, but 99% of the time, when a person throws a straight thru exhaust onto a street-driven car or motorcycle, tuning becomes a nightmare & cause driveability issues due to lack of torque.

Btw, you can get a cheap, high-flowing, high-quality, stainless steel resonator of the junkyard for cheap on modern trucks, luxury cars & foreign cars.

 

[King_Kong]

The Engine Masters TV show did a couple of tests for noise and horsepower that you may find useful. Here are links to their "cheap muffler test" episode and their "Muffler Showdown" episode.

The general conclusions seem to be that the straight through mufflers are louder and don't lose much engine power while the baffled mufflers are quieter at the expense of a little less power at the rear wheels.

Dynos measure power at WOT. And this number is usually over 3k rpms or so.

Dynos can't measure what the engine would feel like at part throttle on the street.

Sometimes parts make better numbers on the dyno, but in real world street driving, the car is slower.

 

[John Ha]

Dynos measure power at WOT. And this number is usually over 3k rpms or so.

Dynos can't measure what the engine would feel like at part throttle on the street.

Sometimes parts make better numbers on the dyno, but in real world street driving, the car is slower.

All true, but the OP asked about noise level too - and the tests done did include noise measurements in db. So it seemed relevant, in addition to providing information generally about the baffled vs. straight-through configurations.

 

[78_200_C4]

I recently drove my daughter's Ford Ranger 2.3 16 valve for a couple of weeks while working on my Falcon.
The 16 valve 2.3 has 143 net horsepower vs 86-89 net hp of a stock large log 200.
The Ranger 2.3 will out run and out rev a large log six using the stock Ford Ranger muffler and a stock exhaust tail pipe smaller than 2.00. The exhaust tail pipe pipe measures around 1.90 outside.

 

[chad]

Thanks guys.

"...OEM stock..."
too long, whole system is abt 3, 4 ft from Y at "6 into 2' to tail pipe. I like it tho (hada pin hole
in mine and it had just the right sound down shiftin. engine brakin, dwn a hill).

"...the baffled..."
yeah I saw that. I got: chambered, turbo, straight thru, what's this 'baffled'? Another full design?

"...stainless steel resonator..."
I know resonators well (they seem to B coming back) as a restorer 50/60 yrs ago w/european 'sports cars' of the'50s/60s. Used w/muffs makes a sound I like. I will not uses a SS muff (altho rest of system is) due to tinniness sound.

As U C in the avatar this is not a race car. Shooting for low rev tq w/almost every consideration (large 1v carb, the cam, etc). Would like a nice burble, not sure the 6 would give that. Anyway turbos seem out for performance now (got glass packed... and 'straight thru' might have stepped into its place). Could be too loud for me tho. Will research this 'slanted baffle' or baffle design. Never heard of it (now 4 muff designs I guess?). Off explorin~

 

[John Ha]

I am not an expert but maybe this would help you? https://www.onallcylinders.com/2012/06/29/sound-advice-a-quick-guide-selecting-right-muffler/

 

[chad]

that one is good, need more detail tho. They post '3 styles'. I'm thinkin we got 4 now, not sure.
Most have the glass pac, not chambered tho...
Straight thru has historically been cherry bomb. Not what I seek. May B still go w/turbo for most low rev tq (sought on all choices since
cam, carb, transmis decisions).

 

[John Ha]

They post '3 styles'. I'm thinkin we got 4 now, not sure.

I don't know either. I only know two styles - quiet and annoying (too loud)

 

[100_2023]

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