Cam design limitations

moper said

Bill - Is there a reason why you can't run more duration? I think even if Comp was to grind of of thier MM series lobes you're still looking at 15° more at .050. That's assuming that A) the cam could be ground to that lobe and B) you do not have a lot of idle time, and/or can run a lobe-oiling lifter.

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Look... I have no experience in building and tuning turbo motors, so I have to listen and pay attention to those with experience in this.

Those voices tell me that 210-215 degrees @.050" is what works best, because when you start getting over 220 degrees, the overlap allows too much of the pressurized, incoming mixture to be blown out the exhaust valve.

THAT is why we run 115 degrees of lobe separation and short duration; with 25 pounds of air pressire blowing the mixture into the cylinder, a lot of duration is neither necessary nor desirable... it just reduces cylinder pressure.

That's what they tell me..