Has anyone went on a dyno to retard Intake and advance Exhaust cams? Did you notice any gain in high-end power.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fox297 &raquo;</TD></TR><TR><TD CLASS="quote">Has anyone went on a dyno to retard Intake and advance Exhaust cams? Did you notice any gain in high-end power.</TD></TR></TABLE>

For high end:
Advance Intake
Retard Exhaust

 

I know it seems dumb to retard Intake and advance Exhaust, but I've heard of some people making high-end power with this setup. Just wonder if anyone actually tried it on a dyno.

 

i advanced the exhaust and made 7 hp just from that on the crower stage 2's. the h22's are wierd though.

 

The theory behind retarding intake is that air/fuel mixture has mass and lag behind piston speed. So when the piston is at BDC, the mixture still has momentum and is still moving in while the piston is traveling up the cylinder.

When you advance the exhaust, you are opening the exhaust valve earlier on the power stroke. During this time, the hot gas is still expanding. It's this expanding gas that pushes itself out of the cylinder. So by the time the piston is at BDC and is traveling back up, it doesn't have to work as hard to push out the remaining gas.

However, to fully take advantages of these phenomenons, your cam profile should be wild enough so that your timing is at zero degree. Most of the all-motor race cars that I've seen has zero timing on their camshafts.

Note: I got these info from MotoMan!