need nos help.

[HICKL]

Ok guys, getting close, found a deal on a Victor jr 2999 (the one with the built in 1" spacer) and got a holley cheater plate (Thanks John Scott!). Have everything plumbed in and am getting close to trying this stuff out.

 

Here is my question, I understand to choose my jet size on the fuel side, I have to work off my fuel pressure. I was playing with the plate last night and with the car running, I have 6 lbs to the fuel solonoid. If I open the solonoid and let it spray fuel, It drops to around 4 lbs. When I choose my jet size, will I base it on 6 lbs or 4lbs? Also, won't the 4lbs reading change which each jet size due to more or less backpressure?

 

Will be starting with a 100 or 150 shot and prob won't go past that....ya right..

[grumpyvette]

base it on the 4 lbs you see spraying fuel,(for now) and don,t forget to retard the ignition total advance and work up to the point in the ignition advance just before you get detonation indicators, but the truth is if your seeing any drop in pressure the fuel system needs to be upgraded, you probably need bigger lines and a better fuel pump and better fuel pressure regulators

 

 

http://www.centuryperformance.com/fuelish-tendencies-understanding-fuel-pressure-and-volume-spg-140.html

 

http://forum.grumpysperformance.com/viewtopic.php?f=55&t=211

 

 

 

in this diagram the dead head regulators are some what optional, but the rest of the diagram holds true, damn I wish you were local, we could have a real good time

Edited September 30, 2009 by grumpyvette

[HICKL]

I know my fuel system as far as the plumbing goes could use improvement. I have a holley red fuel pump in the back. Can anyone tell me if that pump is enough to feed my system with a nos plate? I can re-plumb the piping, just wondering if I need to start from scratch.

 

thanks

[grumpyvette]

http://www.holley.com/12-801-1.asp

 

at 97 GPH at no resistance flow, and only 71 GPH at 4 psi for FEEDING BOTH NITROUS, and a carb on a high performance application its MARGINAL UNDER THE BEST CONDITIONS in fact without NITROUS its MARGINAL on a high performance application

 

Features

 

* Tumble Polished Billet Look

* New Lower Housing Casting for Enhanced Fuel Flow and Quieter Operation

* Maximum Pressure Is 7 PSI

* Motor Draws 2 Amps Current

* 7 1/2 Amp fuse recommended

* Constant Fuel Flow with No Pulsation

* Improved design for street/strip applications

* Distinctive “RED” logo

* Flows 97 GPH (free flow)

* Flows 71 GPH at 4 PSI

* Regulator is not required

* Has externally accessible pressure relief valve (max 7 PSI)

* Rotor/Vane pump design is more tolerant of contaminated fuels

* Weighs only 2.88 lbs

* Includes mounting bracket

* Repair kits are readily available

* Can be serviced from the pump end

* NOT compatible with alcohol or methanol fuels

* Use of safety shut-off switch, P/N 12-810, strongly recommended

* Not designed or recommended for use with fuel injection systems

Edited October 1, 2009 by grumpyvette

[HICKL]

So can i get away with a better pump or do I need 2 pumps?

[dr_hunt]

IMO the holley pumps are pretty much junk. I went through countless holley black pumps before buying an aeromotive to which I have to say, you get what you pay for. IMO a mechanical pump is ideal as the pump output increases with engine rpm whereas an electric pump flows pretty much the same all the time unless you have voltage drop somewhere along the time it's running which happens when guys don't run alternators for racing.

 

IMO a good quality mechanical race pump will feed your needs and a belt driven pump will carry you until you break the 2000hp mark.

[jnjdragracing]

We use two holley pumps on the Nitrous motor, one for the carb which is bypassed and one for the NOS which is dead headed. One is the black holley which is rated at 14psi and the other is a blue pump. If one dies then we can do some re-routing and ony use one.

 

We also caryy a holley pump rebuild kit just in case.....

 

The Aeromotive pump is nice but expensive, but you do get your moneys worth. Same with Barry Grant. If you go with one of these pumps then you only need one then you and tee off to carb and NOS but you will have to run at least a 10AN feed and 10AN return line....

 

 

John

[rytherwr]

Grumpy's diagrams are center target! I am a fan of two complete fuel systems from the tank forward and return-type pressure regulators. When set up properly with the correct size lines,, filters, pumps, and regulators, there is never a doubt as to whether you are going to get the right amount of fuel when you need it.

 

For my main fuel system, I use an Aeromotive Eliminator fuel pump with an Aeromotive fuel pump speed controller with -12 lines to the pump, -10 lines to the fuel rails, then to the return-type regulator and -10 return lines. I use the speed controller to keep the pump at a low ebb as I drive my car on the street as well as the track. You won't need anything with this much flow and pressure, but the setup can be the same configuration.

 

For my nitrous system, I use a Walbro in-line with -6 lines to the return-type regulator and -4 from regulator to the solenoid.

 

Although I have an abundance of potential fuel flow and pressure with just the Eliminator system, I run two systems because my main pressure regulator is controlled by engine vacuum or boost, therefore, the fuel pressure varies and I need steady state 55-60 lbs of fuel pressure under all conditions, which I can set up with the secondary system. It is critical that you set your fuel pressures while flowing as opposed to static, otherwise, you won't know if you have a pressure drop when you kick the solenoid and can't compensate for it. Most nitrous systems I am familiar with are jetted for a certain fuel pressure, so the correct steady state pressure saves a lot of aggravation and broken engine parts.

 

All the fuel pressure and flow numbers will depend on what kind of a nitrous system you are using...for instance, I use a couple of NX Shark nozzles in a two-stage set-up so I need between 55 and 60 lbs of fuel pressure at the solenoids. You don't need anywhere near that if I understand what your system is, however, I find the configuration I use is conducive to safe nitrous use under all conditions.

 

Hope this helps the cause.

 

Wayne