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Ok, lets talk LSA

November 20 2011 at 7:34 PM

Danford1  (Login danford1)
from IP address

Response to Thanks and email sent. n/m

Ok, lets use the above mentioned cam (263/274 advertised, 212/222 @ 0.050, .610/.562, 112LSA with 44.5 degrees overlap).
Using my DD2K I input the cam specs then started to change ONLY the LSA.
That is 112 LSA , 44.5 overlap (valve events 23.5, 59.5, 73.0, 21.0)
I tried 110 LSA and got 48.5 overlap (valve events 25.5, 57.5, 71.0, 23.0)
I tried 109 LSA and got 50.5 overlap (valve events 26.5, 56.5, 70.0, 24.0)
I tried 108 LSA and got 52.5 overlap 9valve events 27.5, 55.5, 69.0, 25.0)

The hp/torque graphs were on top of each other up to about 4000 rpm, a slight pull ahead over 5000 rpm for the tighter LSA's. Only about 5 hp difference up top and 3 ft lb difference at 4000 rpm. Not enough to write home about...

So here is my question.
Concerning idle quality.
Given the above cam lobes and only changing LSA, would the 108 LSA cam have more of a lope to the idle over the 112LSA cam? It is 52.5 overlap vs 44.5 overlap.
I do want a bit of lope to the idle... yes I know this is a fuel miser engine build. I might sacrifice a mpg here or there to have a better sounding engine. I really don't want to balance a nickle on the air cleaner while it is running... A steady hum or purr from the tail pipes will just put me to sleep...


This message has been edited by danford1 from IP address on Dec 30, 2011 10:24 AM

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