CLASS RACER FORUM - View Single Post

Adger Smith · 07-08-2011, 12:01 AM

Kevin,
I see you have fallen victim of the old story of increasing pressure to maximize flow. It will increase flow, but not nearly as much as is generally thought. Yes, I have done the math. I have a real nice spread sheet I use at the dyno for determining the fuel flow of different size jets at various pressures. When you are dealing with NOS these pressures & flows become very critical.
There is a limit to the amount of fuel pressure that a float can see & hold the N/S closed. That pressure goes down as the seat area is increased.
There is another issue with fuel that is often overlooked. "Air in the fuel". High pressure is your enemy when putting fuel in the float bowl without being air entrained. I think everyone has put a garden hose in a bucket. What happens when you put the high pressure nozzle vs the open hose in the bucket?
If you really want a solid slug of fuel to the N/S put about a .060-.070 bypass jet in front of the regulator and about a .040 jet as close to the out side of the regulator as you can.

07-08-2011, 12:01 AM	#6
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,446 Likes: 575 Liked 880 Times in 311 Posts	Re: Fuel volume drop after regulator? Kevin, I see you have fallen victim of the old story of increasing pressure to maximize flow. It will increase flow, but not nearly as much as is generally thought. Yes, I have done the math. I have a real nice spread sheet I use at the dyno for determining the fuel flow of different size jets at various pressures. When you are dealing with NOS these pressures & flows become very critical. There is a limit to the amount of fuel pressure that a float can see & hold the N/S closed. That pressure goes down as the seat area is increased. There is another issue with fuel that is often overlooked. "Air in the fuel". High pressure is your enemy when putting fuel in the float bowl without being air entrained. I think everyone has put a garden hose in a bucket. What happens when you put the high pressure nozzle vs the open hose in the bucket? If you really want a solid slug of fuel to the N/S put about a .060-.070 bypass jet in front of the regulator and about a .040 jet as close to the out side of the regulator as you can. __________________ Adger Smith (Former SS)