exhaust valves float under boost....

[Anonymous]

Exhaust valve float under boost. I think that was why I was hitting "the wall" at 5500 rpms and not accelerating more.

http://forums.modulardepot.com/showthre ... genumber=1

I was using stock explorer 302 springs on the exhaust side. That and my little 1-bbl was only 1.125" venturi!

 

[Anonymous]

is it an easy fix?

 

[wallaka]

Yep. Stiffer springs

 

[Anonymous]

The pressure in the exhaust manifold is often times three times as much as the intake side. All that pressure pushing on the backside of the exhasut valves makes the springs work harder.

"Valve float" doesn't mean they hang wide open....just a sliver off the seat is all you need to lose big power!

 

[xctasy]

The pressure in the exhaust manifold is often times three times as much as the intake side....

Your a freekin animal, President Linc. And we like it!

 

[fast64ranchero]

Linc, I can say I know about valve float, I have a dyno sheet here somewhere of my old 289 360WHP @ 6800rpm and get this @ a tad over 7K rmp less then 190WHP thats a loss off 170 WHP in 200 rpm all due to valve float, my new 269Cu IN 250 will be set up with 135LBS on the seat maybe that will help....