DragStuff

a friend told me people use higher than rated (6 lbs) fuel pressure on a plate system. trying to better atomize the shearing abilitys perhaps as high as 8 or 9 lbs and run smaller pills. whats the truth behind this theory?

I don't think you'll find much if any difference in atomization in the small differences in pressure you're talking about. The biggest benefit from a higher pressure tune up is that small variations in fuel pressure affect the tune up less. For example at 5.5 psi a drop of 1 psi has far more effect on fuel volumes than a 1 psi drop on a 12 psi tune up, so from that point of view the higher pressure tuneups are a little more consistent because pressure variations don't effect fuel volume change as much.

We were working with a combined plate and fogger system for a friend. The car would not run a pass just on the motor without stumbling. We found that our friend had upped the fuel pressure like you were talking about. As soon as we put the fuel pressure down to 6, the motor ran great. There were no differences for the NOS. The only outcome is that the car ran better overall with the fuel set at 6 (588 BBC) I think your friend needs a new theory is what I really think

thx debroah for your input,what i wasnt clear was to run the normal 6-7 lbs of pressure to carb,then run more (on a seperate regulator)to the plate...i think perhaps you might of interpeted that i was talking about motor and nitrous being ran on one regulator?let me know any thoughts,thx russ

I ran a system with 10.5 lbs. pressure and staggered down the fuel pill accordingly to keep the tune right. We could then tune it in large pressure increments without a lot of danger, plus it provided better resolution. Pressure and jet area are directly related. Believe it or not, there was a 18 jet spread in some holes (48/30). This may not have been the absolute fastest way to skin the cat, but it didn't hurt parts, and a blind man could tune it.

I am running 8.5 psi on my plate and a smaller fuel jet and my truck is far less tempermental to pressure fluctuations. I don't plan on going back to the 6psi tune up. I believe it is exactly like John described it. A half pound or a pound is far more of a change as a percentage when you only have 5.5 or 6 psi v/s 8.5 psi or even more. But it's a nobrainer you have to jet down with more pressure.