what type mufflers to use
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Joined: Mar 2002
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From: Boise, Idaho
Originally Posted by fatfenders
Flowmaster 40s with 2 1/4 pipe. Love them at idle and WOT. Hate them at a certain highway cruise RPM. Too much resonance.
From what I've heard, you've got the right size pipes for a 302, but I think using the exact same mufflers on both sides is a problem; they'll resonate.
Mustangs come from the factory with different mufflers for this reason. When I took my 86 Mustang 5.0 to the muffler shop, I insisted on getting different mufflers. I got an argument from the muffler shop owner (which I don't understand - please do as I say and take my money), but I got different mufflers and they don't drone.
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Joined: Mar 2002
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From: Boise, Idaho
Bobby,
Yes, if you make both sides of the exhaust system identical, it will resonate at the same pitch and make a 'drone', usually somewhere near the 2500 RPM range, which is where vehicles cruise. The trick is to make sure the two sides are tuned to different frequencies. Different size mufflers, different shaped bends in the pipes.
Yes, if you make both sides of the exhaust system identical, it will resonate at the same pitch and make a 'drone', usually somewhere near the 2500 RPM range, which is where vehicles cruise. The trick is to make sure the two sides are tuned to different frequencies. Different size mufflers, different shaped bends in the pipes.
Senior User
Joined: Jun 2005
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From: Somewhere in da corn,Iowa
I know a buddy of mine is running a 302 in his 55 with a full 3'' exhaust w/an X-pipe and shorty headers, he put a set of Flowmaster 40 series on the system and it sounds b-e-a-utiful. I'm either gonna go with a set of 40 series or the hushpowers from flowmaster, I got a buddy that does custom exhausts at his shop and he sells flowmaster.
Post Fiend
Joined: Feb 2001
Posts: 6,328
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From: Iowa
For those of you set on Flowmasters, be aware they make a lot of different styles. Flowmaster has/had a nice description of the different models on their website. I suspect a lot of people make their muffler selection from hearing them on another car. I know I have done that. The 40s are sweet until you are sitting in the cab at cruise. Very annoying if the windows are down. You can get a flowmaster muffler that is nearly as rowdy sounding as a 40, with far less drone (interior resonance).
And hello Paul. I am doing pretty well. Thanks for asking.
And hello Paul. I am doing pretty well. Thanks for asking.
Cargo Master
Joined: Apr 2005
Posts: 3,337
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From: Harpswell Maine
I want to go stainless if possible on my truck. I had a 73 F100 running a 360 with cherry bombs that I really liked. Does anyone know if they are available in stainless or what is stainless that others like. I want some outside the cab noise not inside.
Roast em' if you got 'em
Joined: Mar 2005
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From: Rio Rancho, NM
Originally Posted by pcmenten
Bobby,
Yes, if you make both sides of the exhaust system identical, it will resonate at the same pitch and make a 'drone', usually somewhere near the 2500 RPM range, which is where vehicles cruise. The trick is to make sure the two sides are tuned to different frequencies. Different size mufflers, different shaped bends in the pipes.
Yes, if you make both sides of the exhaust system identical, it will resonate at the same pitch and make a 'drone', usually somewhere near the 2500 RPM range, which is where vehicles cruise. The trick is to make sure the two sides are tuned to different frequencies. Different size mufflers, different shaped bends in the pipes.
For the time being I will be running the stock exhaust manifolds with plans to install the headers after I refabricate my steering intermediate shaft for clearance.
this is facinating stuff
Bobby
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Posting Guru
Joined: Mar 2002
Posts: 2,070
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From: Boise, Idaho
Originally Posted by bobbytnm
Does an equalizer pipe have any effect on the drone? How much difference does there have to be?
For the time being I will be running the stock exhaust manifolds with plans to install the headers after I refabricate my steering intermediate shaft for clearance.
this is facinating stuff
Bobby
For the time being I will be running the stock exhaust manifolds with plans to install the headers after I refabricate my steering intermediate shaft for clearance.
this is facinating stuff
Bobby
Let's be clear that I am not an exhaust engineer. But I've paid attention when people explain how things work.
Exhaust system tuning depends on the size of the engine. If the exhaust pipe is too large, you lose the benefits of a tuned exhaust. 3" is way too big for a 302/5.0. If you do a net search, you'll find that there are formulas for exhaust header and exhaust system size.
I think Ford Mustangs used a 24" muffler on one side, and a 21" on the other side. The crossover is very important to both performance and sound. Its location along the exhaust pipe is also important. Get it right and you make free torque. Get it wrong and you lose power and economy and it's too loud.
Bigger is not better. Right is better.
Posting Guru
Joined: Mar 2002
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From: Boise, Idaho
Originally Posted by imlowr2
Is that the reason for the unequal headers?
The Mustang intake has unequal length runners; the front intake runners are longer than the back runners, and no more than two runners are the same length. The exhaust headers are the same way. The front primary pipes (cylinders 1 and 5) on the Mustang headers are the longest, just like the front intake runners are the longest. What it looks like is that the front cylinders are tuned for the same RPM range, the next pair (cylinders 2 and 6) are tuned for another RPM range, and so on.
With these four pairs of tuned cylinders, each pair tuned to a slightly different RPM, the torque band would have a wider sweet spot. Maybe slightly less peak torque, but certainly more average torque and over a wider range.
That's my theory and I'm sticking to it.
Last edited by pcmenten; Nov 4, 2005 at 08:04 PM. Reason: typo
Freshman User
Joined: Oct 2005
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Flowmasters website lets you listen to the sound of the exhaust, while it's not the real thing, it does sound cool when you crank up your PC and let it go.
I had a 350 dueled out and dumped it under the bed, very loud, in-fact my neighborhood association wrote a letter to my parents asking me not to drive after 10pm. That didn't happen! I liked them, they sounded tough, but I wouldn't get them now, the resonance was too much. Insulation and sound deadening material would help a lot.
Please keep talking, I am learning things I never even considered.
I had a 350 dueled out and dumped it under the bed, very loud, in-fact my neighborhood association wrote a letter to my parents asking me not to drive after 10pm. That didn't happen! I liked them, they sounded tough, but I wouldn't get them now, the resonance was too much. Insulation and sound deadening material would help a lot.
Please keep talking, I am learning things I never even considered.
Postmaster
Joined: Apr 2004
Posts: 3,005
Likes: 2
From: Santa Clarita
Although I went from cast irons to shorty headers, I also went from 2.25" to 2.5" pipes. I'm not running the crossover. I did notice considerable power increase on the highway and the tone of the exhaust was more on the bass tone. Some of you may want to opt for the Magnaflow mufflers. They have some tone, not even close to Flowmasters, but the interior sound is quiet. I guess it comes down to do you want a Streetrod? Go with Flowmasters, do you want a cruiser? Go with something else.
