Exhaust manifold design program

Steel

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I have been kicking around the idea of either making or have made, an exhaust system.
I was looking online at a program to design the header system.

I'm missing a couple of numbers. I was hoping someone could fill in the blanks. Or even point me to a better program.

Primary Header Tube Length and Diameter Calculator

Stroke: (Inches) Bore: (Inches) Number of Cylinders: Exhaust Valve Diameter: (Inches) Exhaust Valve Opening Point: (Degrees ) Exhaust Valve Duration: (Advertised) Exhaust Valve Centerline: (Degrees) Peak Power RPM: Volumetric Efficiency:

Bore 4
Stroke 3.71
# of cyl 3
EVD 1.27
EVOP 41
EVD 232
EVC ?
Peak Power 6500
VE ?

Thanks
 

Pancho

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Gidday mate. I'm from Auckland, New Zealand. I don't own a Rocket yet, but I'm looking at a 2012 same as your one listed in your title, or whatever they call it. Can I ask how you find it and if there should be anything to keep a look out for with them. The one I'm looking at is for sale by a dealer. Pancho (Ady)
 

Steel

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It's great so far. More torque than anything I've ever ridden. Faster and better handling than my M109 was. A bit cumbersome at very slow speeds at first, but it didn't take long to get use to the weight. All around a great machine. You will n not be disappointed.
 

R3Tex

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Steel...can't speak to the math in the calculator because it's not visible. From a manufacturing perspective you will need to have CAD models made if you are going to have a repeatable product...my preference is a program called Solidworks (expensive). Once you have the CAD models the flanges can be CNC machined so that the tolerances can be maintained. As you are aware the Gulf Coast is thick with machine shops and one off type engineering firms so finding someone to do this shouldn't be a problem
 

Power-Tripp

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The Wallace Racing calculator is not the most accurate, based on actual testing. Learry Meaux at Max Race Software wrote PipeMax, and this is a good bit more accurate, as well as serving several other functions. Best $75 you will spend. You will need to alter VE inputs based on actual dyno results for best calculations. Calculating VE based on head flow does not work.

The new version is due out any time, and should be a substantial improvement.

V3.9 - PipeMax version 3.9

I have found that the calculations in PipeMax are not far off optimum based on actual testing, as long as you input accurate data. You must use valve events at .050 inch lift, not .040 inch as many motorcycle cam data is given.

I hope this helps.
 

Steel

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R3Tex:
I hadn't thought about a machine shop. I did meet a guy at the gym a while back that has a machine shop, and he tinkers with race bikes. Thanks for the idea.


Power-Trip:
Thanks for the information. I guess VE would be a difficult number to get. I'm still not sure where to get the Exhaust Valve Centerline Degrees.

I might do better to just save up my money and get the Brute Pipes, so I can spend my time riding instead of building.
 

Power-Tripp

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Do you want the cam numbers, or would you prefer the specs on the primaries and secondary that work best?

The R3 engine is amazingly insensitive to intake duration changes as long as the dynamic compression ratio is good. What this means is that stock cams, an exhaust cam on the intake, or high lift/long duration all tend to want similar specs on primary and secondary tubing. Most exhaust companies and formulas tend to treat a 3-cylinder engine the same as a V or inline-4... this will tend to make the collector larger than the engine wants.
 
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