08-20-2002, 08:02:00 PM
I just installed a 2 stage cheater kit on my bb. I am new to this nos game so I have alot of questions. The first one is does a holley red pump have to be regulated to run the nos? it would be dedicated just for the nos. someone told me that nos is supposed to be at about 4 psi and so the holley red would put too much fuel in and run rich. I am going to TRY and keep it simple and run 100 for the first stage and 150 for the second stage, at least until i learn my way around. any other suggestions would be helpful also. thanks
[This message has been edited by JONSBBC (edited August 20, 2002).]
08-21-2002, 09:09:00 AM
Look at fuel pressure as a tuning tool for your nitrous system. You have no way other than bottle pressure/temp to regulate the flow of N2o, so fuel is your primary tuning tool. I always used the assumption that the jet combination in the kit was intended for 6psi. Any time the fuel pressure droped below 5psi I got worried. I never got in trouble or melted parts with those assumptions.
The Red pump is only like 70gph or so isn't it? Maybe for the first stage but I don't see that being NEAR enough for anything over 100-150 horse shot.
Some very general rules,,, reduce timing 2 degrees for every 50 HP of boost, increase octane 5 points for every 75 horse of boost. It's a starting point. Watch your plugs close!!! 0.005 seconds of detonation under boost = disaster
08-21-2002, 02:54:00 PM
I am sure that you know alot more than i do about it because all i know is what i read about it. the way that i understand the directions, you need .1 gallon per hour per hp. or 1 gph per 10 hp. that formula is supposed to be for the engine and nos together but this pump would only be for the nos. i have a holley blue for the motor. have you heard anything like that before?
08-21-2002, 09:55:00 PM
Best suggestion I can make here is to pick up the S A Designs book "Nitrous Oxide Injection" (from Summit, Jeggie, local speed shop, or even the local library might have it) and read it cover to cover before you ever flip the arm switch on the N20 system. Looking in your profile you have a monster there and to risk that investiment over the cost of a well thought out fuel delivery system just doesn't budget out to me.
Start by looking at century Performance's page Fuelish tendancies (http://www.centuryperformance.com/fuel.asp#Fuel). Sam has put together a nice overview of pump size, line size, regulator type and most important ,,, WHY and WHAT FOR. It will help you size the pump and line.
IMO you almost can't go overkill on a nitrous fuel system.
[This message has been edited by Marv Davis (edited August 22, 2002).]
08-22-2002, 01:20:00 AM
On a stock pontiac 400 i just put a T fitting in the fuel line from the stock fuel line and plumbed it the solenoid. Using the cheater system, we put a 180 shot through that motor. Held up for an entire bottle.. and we havent refilled it yet.
08-23-2002, 01:56:00 PM
Try this url for nitrous tuning.
it has to do with supplying the correct in weight of fuel to a certain weight amount of nitrous. For a 10% rich mixture it is 1lb of fuel for every 8.77lbs of nitrous.
This is a per minute calibration. So for 120hp gain you need 6lbs of nitrous and .684lbs of fuel in one minute.
Go figure the pump size you need. I can tell you that you dont need a crazy big pump to run nitrous. Using a 140gph pump should do just fine as you can get 2.33gpm which would be good for up to 400 hp. I wouldnt push it that high as the pump gets older it pushes less fuel but I think you could use a 140 safely to 250hp of nitrous power.
Now I have a pro fogger setup and can gop up to 600hp so I need somewheres in the range of a 300gph pump to run that.
1970 Pro Street Camaro
540 BBC 1400hp W/Nitrous
08-23-2002, 02:27:00 PM
I am going to make sure that i get that book and go from there. it should be up and going in a couple of weeks and i will let you know what happens. i would rather play it safe than blow my stuff up. thanks
[This message has been edited by JONSBBC (edited August 23, 2002).]
08-23-2002, 02:42:00 PM
billbeau I definately agree. JON surely doesn't need a 250gph pump for the Cheater plate. I guess I was more trying to emphasize that the self regulated Holley red pump is surely less than adaquite for reliable delivery jetted to 225 horse. I ran a cheater plate for a number of years with a Mallory 140 and a dead head regulator (yeah,, some scarey crap!) and at launch I could watch the fuel pressure go 6.5,,3....4,,,5,,6. Volume was apparently there as it never toasted parts,, but sure was scarey. Myself I would want to see a seperate pump and seperate return style regulator for each stage,, and another for the motor, low fuel pressure safety switch on each stage. I guess my whole point is overkill on a notrous system is much better than the alternative.
08-23-2002, 05:01:00 PM
Marv, I agree! I was comming from the standpoint that alot of racers dont have deep pockets and cant afford to run seperate pumps for both stages. Unfortunately for me I have no choice. Runing a 600hp fogger setup requires me to run a single pump and if or when I go to a 2nd stage i'll need another pump. Right now im going to be running two BG400's regulated by 1 Mallory 5 port return style for the motor and a mallory 2 port return style for the fogger system.
Fuel pressure safety switches are a must!!!