dyno testing mufflers on my 496 - Chevelle Tech
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post #1 of 29 (permalink) Old Feb 15th, 20, 5:51 PM Thread Starter
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Bob
 
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dyno testing mufflers on my 496

recently had a chance to compare my flowmaster to some Dynomax. the mufflers are different in that the flowmasters are offset/offset and the dynomax are offset/center. at low RPM the Dynomax seemed significantly quieter but I wasn't able to get a free decibel app to work right.
I have said before that I see .35-.28 improvement in my ET when going down to a mid pipe (necessary for my Fitech). My results confirm that my mufflers are killing a decent amount of power.

https://youtu.be/vPue52BBAaU

Bob
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post #2 of 29 (permalink) Old Feb 15th, 20, 6:03 PM
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Jeff
 
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Re: dyno testing mufflers on my 496

Wow, those FM are killing HP big time! Damn!
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post #3 of 29 (permalink) Old Feb 15th, 20, 6:26 PM
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Hard to see results on iPhone. How much did you lose ? As I remember, Flowmaster 40 was the gold standard for HP. Wonder how they lost the lead when they had it wrapped up ?
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post #4 of 29 (permalink) Old Feb 15th, 20, 6:41 PM
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Re: dyno testing mufflers on my 496

Quote:
Originally Posted by Reelysalty View Post
Hard to see results on iPhone. How much did you lose ? As I remember, Flowmaster 40 was the gold standard for HP. Wonder how they lost the lead when they had it wrapped up ?
I saw 622 (FM) vs 676(DM). Seems like a massive HP difference?
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post #5 of 29 (permalink) Old Feb 15th, 20, 6:43 PM
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Re: dyno testing mufflers on my 496

Quote:
Originally Posted by Supernova72 View Post
recently had a chance to compare my flowmaster to some Dynomax. the mufflers are different in that the flowmasters are offset/offset and the dynomax are offset/center. at low RPM the Dynomax seemed significantly quieter but I wasn't able to get a free decibel app to work right.
I have said before that I see .35-.28 improvement in my ET when going down to a mid pipe (necessary for my Fitech). My results confirm that my mufflers are killing a decent amount of power.

https://youtu.be/vPue52BBAaU
Were there any other changes between the two muffler tests? Same size inlet/outlet between muffs?

Jeff

64 El Camino Pro street, 496, T-400, 9" 3.73


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post #6 of 29 (permalink) Old Feb 15th, 20, 7:04 PM
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Quote:
Originally Posted by fr8dog View Post
Quote:
Originally Posted by Reelysalty View Post
Hard to see results on iPhone. How much did you lose ? As I remember, Flowmaster 40 was the gold standard for HP. Wonder how they lost the lead when they had it wrapped up ?
I saw 622 (FM) vs 676(DM). Seems like a massive HP difference?
WOW, yeah, in my opinion huge difference !

Not to ? the test, but something’s off. Did a rat build nest in one of the FM’s. ? 😁
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post #7 of 29 (permalink) Old Feb 15th, 20, 7:20 PM
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Re: dyno testing mufflers on my 496

Dyno MAX and Magna flow are straight-through mufflers regardless of input and output pipe location, Flow masters don't stand a chance as they are chambered mufflers.
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post #8 of 29 (permalink) Old Feb 15th, 20, 7:31 PM
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Chris
 
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Re: dyno testing mufflers on my 496

That's the mufflers I ran in my full exhaust in my sig.
Results from the dyno are pretty depressing if your using FM but has been known for a while.
They do get a smidgen louder as they age but not too bad.
Was he blipping the throttle for your db test or just a habit of his?

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post #9 of 29 (permalink) Old Feb 15th, 20, 9:53 PM
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Alan
 
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Re: dyno testing mufflers on my 496

Cool test.... just validated what most people have known for years.....if you make over 400hp, you are losing power with a Flowmaster....PERIOD.

If you are making 600hp and still running Flowmasters, you obviously donít care about making power.

Flowmasters, Spin Techs, Violaters, any of those ďnoise makerĒ type mufflers, are gonna to kill power. Thatís all there is to it.

Basically, if you canít see through it, then you canít flow through it.
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post #10 of 29 (permalink) Old Feb 15th, 20, 10:01 PM
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Re: dyno testing mufflers on my 496

I could see through my 3" violators, have a pic in this laptop but all pics went to dates for some stupid reason
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post #11 of 29 (permalink) Old Feb 15th, 20, 11:12 PM
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Re: dyno testing mufflers on my 496

Anybody ever dyno Super turbos at that power level?

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post #12 of 29 (permalink) Old Feb 15th, 20, 11:22 PM
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Re: dyno testing mufflers on my 496

Quote:
Originally Posted by 77 cruiser View Post
Anybody ever dyno Super turbos at that power level?
Interesting that you should ask!

I tested 17665 Dynomax Super Turbos on my 505 that was making 640 HP at the time. With the mufflers it made 631 HP.

Different engine, different dyno, different phase of the moon, but those were my results.
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post #13 of 29 (permalink) Old Feb 15th, 20, 11:30 PM
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Re: dyno testing mufflers on my 496

Quote:
Originally Posted by shovelrick View Post
I could see through my 3" violators, have a pic in this laptop but all pics went to dates for some stupid reason
Violators are similar to the DynoMax Ultra Flo and Magnaflow. A straight-through perforated pipe with a roving or packing material inside the case. They should perform similarly.
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post #14 of 29 (permalink) Old Feb 16th, 20, 12:04 AM
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Re: dyno testing mufflers on my 496

I'd like to see some Horse Power vs. Decibel Levels per muffler to help find some kind of middle ground.

I love a high level of responsive performance (horse Power), but The Wife prefers a subdued muscle car sound. I had FM 40s but they did NOT pass The Wife Test. I'd like to find a pair of mufflers (oval, 2/5 inlet, 2.5 outlet) that are docile when I drive like there's a cop car behind me, but will not rob horse power when I'm dickin' around.
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post #15 of 29 (permalink) Old Feb 16th, 20, 1:01 AM Thread Starter
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Bob
 
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Re: dyno testing mufflers on my 496

Quote:
Originally Posted by fr8dog View Post
Were there any other changes between the two muffler tests? Same size inlet/outlet between muffs?
3" on either end. Everything else was the same. The barometer was dropping between tests. I think all of that gets corrected though.

Quote:
Originally Posted by Reelysalty View Post
WOW, yeah, in my opinion huge difference !

Not to ? the test, but somethingís off. Did a rat build nest in one of the FMís. ? 😁
I did not see a performance difference with open exhaust until I went above 650 hp. I might cut them open to see if there is an obstruction.

Bob
1972 Nova
496 AFR315
Straub Custom HR 258/260 108 lsa
MT 255x60x15 drag radials, Fitech 30012 power adder
1/4 10.067 10/24/2018
1/4 138 MPH **NEW** 11/24/2019 (100 shot)
60' 1.446 10/24/2018
Best 1/8 - 6.404 10/24/2018
Best 1/8 110.11 MPH **NEW** 11/24/2018
Dragweek 2015,2017,2018 SME
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