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Re: Sports Mufflers
Posted: Mon Sep 26, 2011 9:44 pm
by r90s
Re: Sports Mufflers
Posted: Mon Sep 26, 2011 10:43 pm
by Major Softie
How exactly does that work without paying any attention to displacement, valve size, or valve count? Without even getting into the difference in flow between a 50cc cylinder and a 900cc one, a 4 valve head is going to behave very differently than a 2 valve head at the same lift.
Re:I'll give it a try.
Posted: Tue Sep 27, 2011 10:28 pm
by Chuey
Major Softie wrote:
How exactly does that work without paying any attention to displacement, valve size, or valve count? Without even getting into the difference in flow between a 50cc cylinder and a 900cc one, a 4 valve head is going to behave very differently than a 2 valve head at the same lift.
I don't know that much about engines but they don't ask about the actual lift. I think it may work because they are dealing with pulses and they may be a constant. How'd I do?
Chuey
Re: Sports Mufflers
Posted: Wed Sep 28, 2011 1:42 am
by Major Softie
I don't think so, but I did miss that it DOES ask displacement.
crunching numbers
Posted: Wed Sep 28, 2011 9:38 am
by vanzen
There are a number of
FREE exhaust system calculators on the web.
The link that Jon Lars has provided
may provide some good
basic information to begin a design.
Displacement as well as valve timing, lift, duration, and overlap are considered (re: Major and Chuey)
Valve size, however, is not part of the criteria ... and to my simple way of thinking
primary I.D. will be a function of valve size in order to correctly establish a torque peak RPM.
Intake runner size (esp. cross-sectional area), length, and port shape should also be contributing factors ...
I suppose that this may explain why there will be "free" exhaust system calculators
and / or $600.00 software –
and the value of expertise from the likes of Craig Hanson !