ADJUSTING INTAKE CAM

[SC HYBRID]

when adjusting the intake cam,would it be best to have an advance or retarded setting ?
right now i have a +2 intake and +5 exhaust........

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SC HYBRID 94-GSR
JRSC @ 12 psi
12.7 @ 109

[Rboosted717]

I would try to keep the intake cam at 0. The reason you go to a R cam is to pull in more air, but advance it, it will pull too much in. I would do the TOO setting (intake 0 exhaust 5) I think...

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Mike Marsey
'98 ITR #0717
Supercharged w/220+whp @ 5psi
For all your JRSC type R questions, go to:
http://www.geocities.com/superchargedtyper/

[lundgren]

Remember by shortening the overlap, you BUILD MORE BOOST, but you REDUCE excavation.

You can really cause trouble, but advancing the exhaust, and retarding the intake.

[SC HYBRID]

Lund,lets say i have the following:
what would be the results more or less ?

+5 EX , 0 INTAKE (WOULD THIS BE MORE EXCAV ?
+5 EX ,+1 INTAKE
+5 EX ,+2 INTAKE
+5 EX ,+3 INTAKE
+5 EX ,+4 INTAKE (AND THIS BE MORE BOOST ?
+5 EX ,+5 INTAKE (IS THERE A CHANGE AT ALL WITH BOTH GEARS AT SAME LEVEL ?

+5 EX ,-5 INTAKE (WOULD THIS BE THE MOST EXTREME EXCAVATION ?

WHAT EXACTLY IS THE BEST ROUTE TO TAKE WHEN FORCED INDUCTION IS INVOLVED ?
MORE EXCAVATING OR MORE BOOST OR A MEDIUM ?

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SC HYBRID 94-GSR
JRSC @ 12 psi
12.7 @ 109

[SC HYBRID]

also 1 more thing,would my +2 intake,+5 exhaust be the same as a 0 intake,+3 exhaust ?
because both intake and exhaust are +,and there is a difference between both of +3 ?

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SC HYBRID 94-GSR
JRSC @ 12 psi
12.7 @ 109

[lundgren]

Well it's hard to say with your car, but this I know, reducing overlap increases cylinder pressures. So watch your boost gauge, listen for knock, and watch the numbers and the A/F on the dyno. You may have to reduce timing with less overlap, but with more cylinder pressure it might be better. Or more timing, and more overlap may work best.

There are many variables, but I was simply saying, you'll want to be careful.

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http://www.groupbuycenter.com/

[TrustGs-R]

hit the dynos sir...that's the best way to find your optimal cam timing setup.

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96 gsr hitting 12s
90 hybrid hatch hitting 14s

[1fstGSR]

There is a difference in +2, +5 versus +0, +3, it is the compression cycle timing. When you stop trying to fill the cylinder and when you start to evacuate it. If you start the fill sooner, the piston will be lower in the cylinder when you start compared to -3 intake which would have the piston farther towards the top of the first part of the cycle. Remember you have fill (1st) compress (2nd) combust (3rd) evacuate (4th). It is all about having more vacumm to help fill the cylinder and not having the exhaust open too soon as to waste fresh intake mixture. (i.e. overlap) positive cam timing is later in the cycle so if you have positive exhaust you are reducing overlap which helps on supercharged engines because we tend to blow mixture through on overlap events.
Will