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muffler advice?

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kellysguy said:
No, 1 1/2". IIRC VB only shows one replacement pipe, however; that doesn't nessisarily mean it came with one.

You have a '76?
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I remeasured the pipe, after coming out of the engine and down to the belly of the car it is 2" outside diameter pipe, the section running under the car and to the muffler is 1.75" outside diameter.
 
kellysguy said:
Yep but that's on a 1 1/2" factory pipe. If you have a 2" pipe I wouldn't run a Harley muffler without yet another series of modifications. If you have a 2" pipe with a stock intake and carb you have more exhaust than you do intake. In that case I'd drop back down to 1 1/2" pipe w/ the Harley muffler and baffle mod. I have a 7.5 comp 1500 drawing through a single 40DCOE up front and blowin' it out a punched and modded Harley muffler. It's a straight through muffler with minimal noise. My system is about as free flow as you can get on the street w/ a stock pipe. Folks can't believe it's a straight through muffler when they hear it.
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I have a webber 32/36 dgv carburator on the 9:1 compression engine. Intake is the Pierce manifold for the Weber. Any comments on this for doing the Harley exhaust?
 
recordsj said:
I have a webber 32/36 dgv carburator on the 9:1 compression engine. Intake is the Pierce manifold for the Weber. Any comments on this for doing the Harley exhaust?
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The carb size is fine, problem is you'll have a 2" pipe that will be necked down into a 1 1 /2" muffler. So, you'll have about the same restriction with lower exhaust velocity. Exhaust velocity is what evacuates cylinders and promotes low end toque.

I'm going to over simplify everything as a full explaination would take too long. What you have basically is a "high intake velocity" street carb with an exhaust system that may quite possibly may be considered too big depending on intended use. The 32/36 is a good carb for a 1 1/2" pipe as it's not a "max power" carb. What you're after is a balanced system. Bigger isn't nessisarily better. For instance, you'd lose more low end if you went with an even bigger exhaust pipe.

What I would do is run a 1 1/2" pipe from a non cat factory exhaust manifold to a punched and modded harley muffler ('cause a header uses a 2" pipe). You should (might) see a gain in part throttle torque, milage and around town fun.

Some folk don't like the 32/36, I never had a problem with mine and the afformentioned system is exactly what I had on my car and I liked it.
 
kellysguy said:
The carb size is fine, problem is you'll have a 2" pipe that will be necked down into a 1 1 /2" muffler. So, you'll have about the same restriction with lower exhaust velocity. Exhaust velocity is what evacuates cylinders and promotes low end toque.

I'm going to over simplify everything as a full explaination would take too long. What you have basically is a "high intake velocity" street carb with an exhaust system that may quite possibly may be considered too big depending on intended use. The 32/36 is a good carb for a 1 1/2" pipe as it's not a "max power" carb. What you're after is a balanced system. Bigger isn't nessisarily better. For instance, you'd lose more low end if you went with an even bigger exhaust pipe.

What I would do is run a 1 1/2" pipe from a non cat factory exhaust manifold to a punched and modded harley muffler ('cause a header uses a 2" pipe). You should (might) see a gain in part throttle torque, milage and around town fun.

Some folk don't like the 32/36, I never had a problem with mine and the afformentioned system is exactly what I had on my car and I liked it.
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When you say 1.5" pipe is that the outside diameter?
I did some more measuring and after the exhaust pipe goes down and starts the run under the belly of the car (horizontal with the ground) it is 1.75" outside diameter pipe. Before that point it is 2.00 outside diameter.
 
IMHO the perfect street system would be dual SU's or a single 40 DCOE (or injection), pocket porting with maybe a mild cam, header, 1 3/4" or 1 7/8" pipe(depending) into a fully modded H-D muffer (which would consist of a complete gutting and installation of the same size exhaust pipe with the baffle mod cuts the full lenth of the muffler case inside the muffler.)
 
All measurements are ID. Can you get a pic of the pipe at the mainfold and under the car?
 
recordsj said:
When you say 1.5" pipe is that the outside diameter?
I did some more measuring and after the exhaust pipe goes down and starts the run under the belly of the car (horizontal with the ground) it is 1.75" outside diameter pipe. Before that point it is 2.00 outside diameter.
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Sounds like maybe you have ~ 1 5/8" pipe which should be fine. Changing to an HD muffler would pro'bly be the same restriction wise as just ususng the first muffler you already have, maybe a little less. I'd hack the tube shaped thing off and run a tip straight back from the first muffler. You might not notice anything power-wise but it should sound better.
 
kellysguy said:
Sounds like maybe you have ~ 1 5/8" pipe which should be fine. Changing to an HD muffler would pro'bly be the same restriction wise as just ususng the first muffler you already have, maybe a little less. I'd hack the tube shaped thing off and run a tip straight back from the first muffler. You might not notice anything power-wise but it should sound better.
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You are saying to cut off the tube shaped thing (sitting under the license plate in my picture) and remove the 1st muffler (sitting next to the rear wheel) and place the HD muffler there instead?
 
What are you after, do you need new exhaust or just looking to make an improvment?
 
Then yes, if you have close to a 1 1/2" ID pipe and a bad muffler, I'd hack yours off (both) and install the Harley muffler.
 
Here's the confusion I think. 948, 1098 & 1275's use a straight through pipe that goes back to a single muffler. Later Spridgets/1500's use a muffler / resonator 2 piece system. I think that's the cause of confusion here. Piping is different. The Harley Muffler adapts easily to the straight pipe.
 
Let's call them Harley Pipes. Before the baffles are punched out yes they really do have mufflers. And the muffler designed for exhaust from a single cylinder souece really good when 4 exhaust pulses are fed into it.
 
Jim_Gruber said:
Here's the confusion I think. 948, 1098 & 1275's use a straight through pipe that goes back to a single muffler. Later Spridgets/1500's use a muffler / resonator 2 piece system. I think that's the cause of confusion here. Piping is different. The Harley Muffler adapts easily to the straight pipe.
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I don't think the problem was there, it's that the shape/location was backwards from factory. The round res is supposed to be first (where the 1275 muffler is) and then the "turbo" shaped muffler runs under the bumper. Whoever did this system looks like they put the "muffler" first then the res (which is most likely a glass pack given it's 2" pipe there.)

So hack everything off and install the HD muffler in the same location as Jim. Adapters are optional as per the link.
 
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