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Exaust / Muffler questions
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Author:  brian72valiant [ Sat Jun 19, 2010 8:18 pm ]
Post subject:  Exaust / Muffler questions

hello all.
today I had the notion to change my old as heck muffler on my 72 valiant with a 225 / and single factory style exaust

so I got under and checked out the system - mine happend to be all held together with those muffler clamp jobbers - so I un bolted it and took it with me to pep boys for a replacment unit. - inspection of the old muffler and piping - it was badly carbon deposited - so changing the muffler was probly a good idea anyways.

I was hoping to get a muffler with a slightly more performence tone but not obnoxiously loud like my corvette was with flowmaster 40 series was that was almost un bearable at 2k rpm...

so I ended up getting a "cherry bomb turbo" muffler part # 87703
http://www.cherrybomb.com/products/turbo
and got it installed with no problems as it was basicly the same shape / style as the one that came out of the car...
but
I was definatley not impressed with the exaust sound. it was basicly as quiet as it was before - wich was barely audable by my deaf ears....

so this has me thinking....
have any of you guys here run any "extreme" mufflers and had that deeper growl type exaust note from your slant's ?
should I go ahead and rip out the 1 7/8" exaust pipe from the manafold back and replace with 2 1/4" or 2.5" ? and try and run a welded style muffler ?

or is the smaller diamater exaust tubing giving me nice torque from having propper back preassure...

my engine is basicly a stock 225 with a 1brl holley 1920 on it - but its not a slouch when I give the gas pedal a romp.

I guess basicly I feel slightly defeated by purchacing a turbo muffler and expecting it to sound a bit more meaty than it actually does.
please advise
thanks

Author:  Joshie225 [ Sat Jun 19, 2010 10:57 pm ]
Post subject: 

There is no such thing as "proper back pressure". Velocity is something else all together. If an engine or car/engine package runs better with measurable back pressure then something else is wrong with the combination.

I very much like my 2 1/4" exhaust and Walker Dynomax Super Turbo muffler. It's not very loud, but it does sound nice. You can hear it in my burnout video. http://www.youtube.com/watch?v=MxyNFXuDUTs And in the dirt track video. http://www.youtube.com/watch?v=g4fv0N3LvAw

I used a welded Dynomax 3" muffler on my '74 318 Satellite and it was louder, but not obnoxious. I used to have a sound clip of that, but I don't know what happened.

If you want louder a bigger pipe is almost always louder. An earlier opening exhaust valve is louder.

Author:  olafla [ Sun Jun 20, 2010 12:35 pm ]
Post subject: 

The super-sixes got a 2 1/4" pipes, as did the 'Feather Duster' in it's time. It doesn't hurt to breathe better, have the same size pipe all the way for more sound, I have an old Trush muffler, makes lot of nice sound, but gives a really bad booming noice inside the car at highay speeds.
Olaf.

Author:  ESP47 [ Sun Jun 20, 2010 7:41 pm ]
Post subject: 

I have a flowmaster 40 on mine with a 2 1/4" pipe. It sounds great to me. Nice deep tone but it's not super loud either. No drone at all at highway speeds as well. Remember that flowmaster 40 is going to sound a lot different on your inline 6 than whatever the Corvette had in it.

I used to have a cherry bomb on mine and it sounded ok for the first year. After that it sounded horrible. Was way too farty for my taste.

Author:  brian72valiant [ Sun Jun 20, 2010 8:25 pm ]
Post subject: 

alright thanks guys,

I probly had read somewhere and only remembered hardly anything about engines needing some sort of back preassure to be more torqy I guess..

so the pew plan will be to install 2 1/4" or 2.5" exaust piping leading up to a welded / chamber style muffler wich will have to happen after I re do the rear end setup of the car - as I plan to eliminate the leaf springs and switch up to a triangulated 4 link - so I can lay the rear of the car out until the rear axle hits the intigrated frame rails.
( my car has the hydraulic suspension setup in it )

but thats the plan...
and I also had a pair of the glass pack tube type mufflers on a old pontiac that was my daily - it sounded realley harsh and raspy. not at all nice and deep growl like a flowmaster 40 did on that car. it was verry high pitched and just all round realley yucky sounding... definately aint gona go with glasspacks ever again.... lol

and I dont feel so badly as the muffler swap only cost me $60 in stuff to do it.... and the existing muffler on there was definately junk.

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