choppedtop
Well-Known Member
"mmmm"
Header Design & Build
- Thread starter Indycars
- Start date
"mmmm"
old round fart
Well-Known Member
I don’t think you would never have the neighborhood choir stop at your house at Christmas! That may not be a bad thing.
Indycars
Well-Known Member
Can you wait awhile, GP Headers received my mockup kit yesterday, Be nice to see how they turn out !!!
old round fart
Well-Known Member
Did they have anything to say about them? I wonder if they have ever seen a more complicated project.
Indycars
Well-Known Member
They sent me an email yesterday that they had received them. After they got them unboxed and looked
them over they would call. No call so far.
This morning I returned their form with the requested details, plus I included my document
with the details I wanted them to know, plus the Pipemax dimensions.
Ooops, just noticed I forgot the photos they wanted, just sent 19 photos to them.
them over they would call. No call so far.
This morning I returned their form with the requested details, plus I included my document
with the details I wanted them to know, plus the Pipemax dimensions.
Ooops, just noticed I forgot the photos they wanted, just sent 19 photos to them.
old round fart
Well-Known Member
When did you decide to use a megaphone for the collector? Have you got an idea of fitting a muffler?
Indycars
Well-Known Member
Not sure of exactly when I decided to use a megaphone, it's always been on the table. But it
became firm when I decided that I could use a spiral baffle and cut it down to fit the taper. If
I need to reduce the noise even more, then I will pack some SS steel wool between the spirals.
became firm when I decided that I could use a spiral baffle and cut it down to fit the taper. If
I need to reduce the noise even more, then I will pack some SS steel wool between the spirals.
Always wondered if those spirals worked. Looking forward to your experience. Muffling is a fascinating business, particularly when we don't have room for the big under-car exhaust systems. We need some quantifiable way to measure our results. I have a Radio Shack sound level meter, but it's apparently no longer available (RIP Radio Shack; spent many happy hours there), however Amazon has a bunch of inexpensive ones.
choppinczech
Well-Known Member
They were so great 30 years ago. Like a candy store.
Maybe I'm being simplistic, but my ears are the best sound meter I've got. If the "tone" is pleasant and not too loud, I'm happy. Fortunately, the local constabulary does not seem too concerned with dB levels, and of course I do my part by not getting on the gas too much, at least not within their earshot.
old round fart
Well-Known Member
Looking at the Cone Engineering site their muffler kits are the absorption style. I’m thinking about fitting something like that in mine. My Sanderson headers had what looked like a glass pack muffler welded to a flange that went between the collector and the turnout. Might be a way to make several different mufflers to get the sound you like.
Some more reading:
muffler design (2).pdf
Note particularly the part about changing the cross-section area. Here's an add-on piece for bike pipes:
It creates an expansion chamber using the pipe as the outer wall. No idea of how effective it is.
Made by Fuel Moto, which has some other parts that might be useful.
muffler design (2).pdf
Note particularly the part about changing the cross-section area. Here's an add-on piece for bike pipes:
It creates an expansion chamber using the pipe as the outer wall. No idea of how effective it is.
Made by Fuel Moto, which has some other parts that might be useful.
Kevinrevin
Member
These look like the same design Lobak mufflets that were spec'ed for our Limited Late Model class back in '89 - '93.
I used to have a pair that were doubled - a 3.5" inlet split into 2 tubes with the spirals 16 inches long then back to a 3.5 outlet.
Our team broke up before I used the mufflers, and they later disappeared before I ever installed them.
Indycars
Well-Known Member
I expect the spiral design will be louder than I want, so I'm hoping that I can help out with
SS packing around the inner tube(between the spirals). I'm concerned about the back pressure
and the effect on performance, but it should be easy to remove from the megaphone since it's
a taper. With V-Band clamp on the turnouts, it will be easy pease to remove the spiral baffle
when i feel like going faster.
SS packing around the inner tube(between the spirals). I'm concerned about the back pressure
and the effect on performance, but it should be easy to remove from the megaphone since it's
a taper. With V-Band clamp on the turnouts, it will be easy pease to remove the spiral baffle
when i feel like going faster.
Indycars
Well-Known Member
What book what that taken from, what you posted seems to be only part of the whole article.
From your article it says .....
The maximum back pressure allowed for a Continental O-150 or a Lycoming 540 engine
is 1 psi. Typical mufflers of the type shown in Figure 3.1 generate minimal back pressure,
while those of the type shown in Figure 3.2 were measured during this study as having
1.4±0.2 psi of back pressure (see section 7 for details).
I measured about 4-5 psi back pressure and I was probably ~ 1500-2000 rpm from max where
the back pressure would be even higher.
I captured the image below from the video.
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