Exhaust size and muffler type

StarDiero75

StarDiero75

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Howdy guys,

So you all have seen my 2V head now and we've discussed cams, and i plan on getting a nice exhaust too since I'll be putting on my dual out VI headers when the 2V goes on the car.

I'll have 1.5 exhaust valves and the 256H Schneider cam with .420" lift and stock 1.5 adjustable rockers, maybe 1.6s in the future, my dual out VI headers which have collecters of 2.5" and I want an X pipe. The car will never see more than 4000 RPM. I'd like the car to have a deeper sound and be a little more on the quieter side than the crappy cherry bombs i have on now. This is a daily and i want to be able to pull into my neighborhood at night and not be yelled at lol. But i still want it mean enough sounding that small block guys dont scoff at me when i pull up. I plan on having the pipes exit behind the rear tires angled a little downwards.

So now my question is, should i neck down the pipes into 2" or smaller? And what kind of muffler should i be looking for for this? Then after the muffler, does changing the pipe size change the pitch/tone?

I want to make sure i don't have the drone on the highway I've heard of, thats my main concern.

Thanks guys
Ryan
 
You might want to listen to some sound clips of Borla mufflers. Both Borla and Spintech have a nice (to my ear) sound.

As to pipe, size it based on a calculator to ensure that you will have sufficient exhaust gas velocity. Increasing pipe diameter too much will result in reduced gas velocity and less scavenging. You DO NOT need exhaust back-pressure, regardless of what you may hear; but you do need to size the system to make sure you don't reduce exhaust gas velocity.

I've attached a Youtube video that will help explain the "you need back-pressure" misnomer. https://www.youtube.com/watch?v=jjPeP_Nn2B4

David Vizard has written some excellent stuff that explains the concept of a zero loss exhaust system. Yes, it can be quite enough and no result in a demonstrable power loss (compared to an open (no muffler) system). Once you calculate the CFM requirements and the resulting diameter of the pipe(s), you can research the CFM ratings of the muffler(s).

I hope that helps.
 
2 inch in a dual full run set ( for a 200 )
(I'm not up on the X pipe use, but hvve read a lill on benifit).
theres too many opinions on muff sound,
I'd just try a turbo for performance. Save the CB? may B as resonators?
 
I'm using a 18" resonator(glasspack) into a walker quiet-flow and I'm really happy with the sound. I wanted something not to loud. I don't have headers, I'm running a 2" all the way. I fabbed it up myself, all mandrel bends. It sounds good to me. According to an online calculator my exhaust can support 164 BHP, which is probably within the range of what the engine can produce, but it may be borderline restrictive for me. A single 2.25" can support 208 BHP according to the same calculator. When I go up to 2v tbi I'll probably need to up the exhaust to 2.25"
 
Alright so from what I've read, i should roll with 1.75" pipes since I'm running dual. I remember reading that Classic Inlines page, and i liked the other site too.

I'll check youtube again, but a lot of the videos have crappy sound quality.

Does anyone know how much extra an x pipe is? I'm very interested in using it.
 
StarDiero75":woioymne said:
Alright so from what I've read, i should roll with 1.75" pipes since I'm running dual. I remember reading that Classic Inlines page, and i liked the other site too.

I'll check youtube again, but a lot of the videos have crappy sound quality.

Does anyone know how much extra an x pipe is? I'm very interested in using it.
Click to expand...

You might consider a muffler that is the next size up pipe diameter (for ex. the muffler would be 2.0", while the rest of the system is 1.75" -- assuming the size is not just inlets and outlets) to ensure the muffler is not a choke point. This can be done by flaring the pipe end or using a transition. Several articles suggest this so that the muffler flow is equal to the CFM of a the rest of the system's straight pipe, or selecting mufflers based on CFM, not pipe size.
 
'S Y the turbo style is suggested
 
I would do some research on the "X" pipe. From what i understand. It kills torque. Since our engines are all about torque I would consider against it. X pipes perform well for 2500 and above RPM's.

For an all about cruiser street car maybe consider an H pipe. But I am mo expert so do some research first.
 
Matt hasa long history w/exhaust systems frm B4 VI...
Ck out what he has...
 
So i have a dual outlet header run full 2" exhaust into 20" thrush glasspacks followed by about 4 ft of piping then into a set of turbo mufflers, it sounds mean when you get on it but not over bearing when your just putting around.
 
62Cometman":8v5rdlso said:
So i have a dual outlet header run full 2" exhaust into 20" thrush glasspacks followed by about 4 ft of piping then into a set of turbo mufflers, it sounds mean when you get on it but not over bearing when your just putting around.
Click to expand...
Do you think you could send me a video of how it sounds? I'd be real interested to hear it
 
I'm running the original 200 cu in straight six in my 1964 Mercury Comet. Unmodified as far as I know with the exception of a DUI distributor. The original exhaust manifold had split into three pieces (cylinders 5 and 6 had pulled away from the rest. Typical.). So, when I replaced the exhaust manifold, I took it over to the local muffler shop for all new pipe and to have them install the muffler that I provided.

The end result turned out to be 1 3/4 inch pipe from the new manifold to about the front seat. Then they stuffed 2 inch pipe over the 1 3/4 and welded it shut. The rest is 2 inch pipe up over the axle and into the Flowmaster muffler out back (I'd have to think a for a bit to remember which model of Flowmaster). Then it's just a simple 2 inch dump beneath the rear bumper.

This setup made a tremendous change in the way the car breathes and you wouldn't believe how much difference it makes when you put your foot in it to get on the interstate or to pass someone. I do get a little popping when I let off the gas to cruise down the off ramp of the interstate or when I'm in it and suddenly let off but I accept this as being how it is when tampering with any stock setup.

As for noise, I actually get more resonance inside the car than I get rumblings outside the car. Most people think it's a mean machine until I let them know that it's only a 6 cylinder.

My point here is this: No need to go crazy. It's just a simple pipe and a muffler even if you're trying to pump out as many ponies as possible.
 
[T00lbag said:
":1rsthjo4]I'm running the original 200 cu in straight six in my 1964 Mercury Comet. Unmodified as far as I know with the exception of a DUI distributor. The original exhaust manifold had split into three pieces (cylinders 5 and 6 had pulled away from the rest. Typical.). So, when I replaced the exhaust manifold, I took it over to the local muffler shop for all new pipe and to have them install the muffler that I provided.

The end result turned out to be 1 3/4 inch pipe from the new manifold to about the front seat. Then they stuffed 2 inch pipe over the 1 3/4 and welded it shut. The rest is 2 inch pipe up over the axle and into the Flowmaster muffler out back (I'd have to think a for a bit to remember which model of Flowmaster). Then it's just a simple 2 inch dump beneath the rear bumper.

This setup made a tremendous change in the way the car breathes and you wouldn't believe how much difference it makes when you put your foot in it to get on the interstate or to pass someone. I do get a little popping when I let off the gas to cruise down the off ramp of the interstate or when I'm in it and suddenly let off but I accept this as being how it is when tampering with any stock setup.

As for noise, I actually get more resonance inside the car than I get rumblings outside the car. Most people think it's a mean machine until I let them know that it's only a 6 cylinder.

My point here is this: No need to go crazy. It's just a simple pipe and a muffler even if you're trying to pump out as many ponies as possible.
Click to expand...
I'm figuring here, if I have 2" pipes, which will be a neck down from the 2.5" collectors, and then have a really quiet muffler, it'd create enough back pressure to where it shouldn't resonate, but still breathe better, y'know? Or just say screw it and do 2" with a nice sounding muffler. I am also considering spraying sound deadening material on the inside and under the car to help with noise. Currently its pretty loud with no insulation
 
something under the rug is the best approach (unless 4 heat).
I'd go 2 inch pipes (if true duals)turbo construction mufff.
 
StarDiero75":26uxpdzp said:
I'm figuring here, if I have 2" pipes, which will be a neck down from the 2.5" collectors, and then have a really quiet muffler, it'd create enough back pressure to where it shouldn't resonate, but still breathe better, y'know? Or just say screw it and do 2" with a nice sounding muffler. I am also considering spraying sound deadening material on the inside and under the car to help with noise. Currently its pretty loud with no insulation
Click to expand...

Back-pressure does not prevent resonating. Resonating is the result of muffler design. You do not need or want back-pressure, but you are free to have as much as you want - as long as you realize that it works to your disadvantage.

With the right muffler, you can have a system that does not drone and does not cause back-pressure. Also, droning can usually be eliminated (or greatly reduced) by using a simple helmholtz exhaust resonator (basically a tube that cancels sound wave at calculated frequencies). The reading on helmholtz exhaust resonators is pretty interesting (to me).
 
Soldmy66":2icfipaj said:
StarDiero75":2icfipaj said:
I'm figuring here, if I have 2" pipes, which will be a neck down from the 2.5" collectors, and then have a really quiet muffler, it'd create enough back pressure to where it shouldn't resonate, but still breathe better, y'know? Or just say screw it and do 2" with a nice sounding muffler. I am also considering spraying sound deadening material on the inside and under the car to help with noise. Currently its pretty loud with no insulation
Click to expand...

Back-pressure does not prevent resonating. Resonating is the result of muffler design. You do not need or want back-pressure, but you are free to have as much as you want - as long as you realize that it works to your disadvantage.

With the right muffler, you can have a system that does not drone and does not cause back-pressure. Also, droning can usually be eliminated (or greatly reduced) by using a simple helmholtz exhaust resonator (basically a tube that cancels sound wave at calculated frequencies). The reading on helmholtz exhaust resonators is pretty interesting (to me).
Click to expand...
Ok, so no high back pressure. What kind of muffler would you recommend to help prevent resonating? And does the reaonator go before or after the muffler? How do I know what kind of resonator to get?
 
chad":u31nybtq said:
Matt hasa long history w/exhaust systems frm B4 VI...
Ck out what he has...
Click to expand...
and sez.
A resonator goes B4 the muffff. I'd say back to personal prefference ("by ear").
A turbo design has been suggested.
 
chad":2mfm6cxh said:
chad":2mfm6cxh said:
Matt hasa long history w/exhaust systems frm B4 VI...
Ck out what he has...
Click to expand...
and sez.
A resonator goes B4 the muffff. I'd say back to personal prefference ("by ear").
A turbo design has been suggested.
Click to expand...
I did see that several have recommended the turbo style. i was just curious to see everyone's opinion on it.

Thanks for telling me where the resonator goes
 
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