In a message dated 12/11/98 12:12:59 PM, you wrote:
<<Hi,
I am interested in your comments about "high lift cam &
supercharger." Normally, you would not use both in a daily driver. What are
your specs on your cam and what kind of Vacuum reading do you get at idle?
Allen>>
Allen,
I think you might have high lift confused with high duration. It's the
duration figure you need to watch, as you dont want alot of valve overlap to
bleed off cylinder pressure.. more valve overlap also hurts idle quality and
will create less vacuum at low speeds like you said.
The amount of lift at the valve doesn't really hurt any drivability, and more
valve lift also means more available airflow..
My cam specs are .512"/.512" lift on the intake/exhaust side, w/ 210/220 deg.
intake/exhaust duration at .050" lift. I believe the advertised duration is
264/274, or somewhere inbetween. This is on a 112 degree lobe sep.
I get around 9-10" of vacuum w/ the air on at idle... the air uses around 1"
of vacuum, so it's still very streetable. Idle is choppy, enough to shake the
truck and make it sound very agressive through the dual 2 1/2"s that dump
under the truck, which might not be a good thing for someone else's daily
driver... but I wouldn't have it any other way.. :)
My truck is also OBD-II controlled, and the computer doesn't like the misfires
it detects at idle, but that's life... I'll have a custom one made up very
soon, but I'm still looking for someone to rework the cylinder heads.
ttyl
Patrick
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