787 & 951 rave valve tuning

[Tweaked & Twisted cycles]

hi all
my question is this . on the 787 and 951 engines using rave valves i am looking for info reguarding the tuning of the spring rate adjustment on the rave valve and the common affects known . i am a tech and i am experianced in most all engine modifications and building however i have been intrested in playing with the spring rates but the opertunity hasnt presented it self. i have an xp 1999 coming in for a custrom compete build and would like to know a little more info on the casue and affect side of playing with the rave valve rates

any info is appreciated
thanks joe

[Bill O'Neal2]

Re: 787 & 951 rave valve tuning

Joe,
There is very little effect no matter where you set the spring rate by adjusting the red knob.

The adjuster affects when the valve opens, sooner or later as rpm rises. There are zero HP differences in any setting.

If you need more bottom end grunt, adjust them inward. That makes the exhaust port timing stay lower longer before the valve opens and raises the port timing.

If you play with the rave red knobs in conjunction with the red knob on the water regulator, you may see slight changes in the low to midrange power band.

A general rule is rave knobs in, water regulator knob out, or vise versa.

[Tweaked & Twisted cycles]

Re: 787 & 951 rave valve tuning

thank you for the info