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Cary,
Ed came to the rescue (once again) and reminded me that was a conversion of inlet speed of 120.58 mph to seconds a minute. I adjusted the attached info sheet, to reflect this information).
The maths isn't a problem, however Ed has a knack of knowing how to approach and work through a problem, whereas most of us wouldn't bother. This must be how the engineers do it to get to a start point.
I don't know of anyone needing to go to 8,000 rpm and if they did they might need another ratio reduction drive, in that case they might need a slightly larger inlet. However greater VE would need to be driven by a greater inlet velocity and a bigger inlet has a reduced velocity, but I'm sure 120% VE is achievable in the racing game and much higher rpm, much as I would love to see it at our rpm. Then again I would love to be proven wrong. Perhaps with the higher peak inlet speed Tracy indicated was available. We won't know until we get mare data, perhaps from bill, down the track.
Knowing how you love to dabble in things, ( nothing wrong with that) I included a calculation for inlet tube length, in this latest attachment - mind you their only ball park figures, but to me it gives a rough start point and an understanding of the processes involved.
Hope that helps.
I do have some figures on exhaust speed if your interested.
George (down under)
Hi George;
What is the meaning / origin of the value "176.85" in your "Diameter of Inlet" calculation?
You should also try running your calculation with 8000rpm and 120%VE.
SAE900032 has a bunch of useful intake and exhaust info including volumetric efficiency charts versus Pport sizes and intake lengths.
There are other useful SAE papers that Paul posts on the other list periodically.
Cheers
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