DragStuff

Hi ! i just buy the 71900 Nitrous Controller for my Cuda with 750 hp on motor and 250 of shot ... i had installed the crossplate 1 years ago with good success... my last setting with best time was 250 hp from launch .. and best ET 9.32.. i would install this controller for make a ramp like 200 hp spray on launch and 350 total hp spray after 4 second ... will be ok ? good idea ?some advice ? eventually thia controller is possible disactive for regular activation with switch.. ?? for street use ?

anyone have some idea also for timing retard ? i have 7 al digital and 71900 Eddy nitrous controller .. thanks

You won't likely get the results you're looking for attempting to use a 4 second ramp. There are numerous issues with that in addition to it being slow. I would think you would be able to get your ramp in by two seconds, the issue is even though you are pulsing the nitrous and fuel, you will start to build up backpressure at the jet and even though you're still pulsing it, it'll be at 100% anyway - on the nitrous, but maybe not the fuel... So don't try to use that long of a ramp. Start at a launch percentage that will let you get it off the line, say 20% - 30% then get it all in as soon as you can without spin.

You timing retard needs to activate when the progressive / nitrous activates. With the limited ignition controls you have, you don't have options to do any ramping of timing. It'll need to retard when nitrous starts.

hi John , i don't understand this problem of backpressure , you think is better a short ramp in 1-2 sec ?? from 200 to 350 hp ?? before shifting ?? i would use my crossair blue plate and two solenoid for fuel and two for nitrous , but i don't want use two stages ,

this is my combo now : i have blue plate with single solenoid bigger 1/4 fitting and tee with dual jet , maximum shot that i have tried is 56-56 fuel jet , and 61-61 nitrous jet , around 250 HP with zero delay activated immediately at launch with 9 degree retard , i start in 2nd and shift at around 100 mph in 3 nd , best result with this setting is 9.32 , finish line at very high RPM 7450 , im looking for 30.5 tires instead 29


Wait for your info ..

Thank you very much

Your quickest ET's will typically be when you get to 100% as fast as the track can handle it. Since you don't race on a really well prepped track, how quick that will be will have to be something you experiment with.

therefore.. not improving with more hp ?? if track is not very good ??

Not sure what you're saying there - All I'm saying is you want to try and get the nitrous ramp to 100% as quick as you can and not spin.

Sure ! I came make a ramp very quickly!! no problem.. I hope the engine will support this shock ! .. you can explaine me the problem of backpressure on the solenoids ??

Imagine that you're at the sink in your house, when you turn the water on just barely, the water flows right down the drain with no buildup in the sink. Now put something that partially clogs the drain, let's call it a "JET". Turn the water on again where it's slowing flowing out, again, the water goes down the sink without building up in the sink, now slowly start increasing the volume of water.

What happens in the sink? It starts to fill with water, but the amount of water flowing out of the drain is the same - it's flow rate is determined by the restriction (JET).

On your car, the solenoid is the water valve, the line going to the plate is the "sink", the jets are the restriction in the drain.

The small the jet and/or the bigger the solenoid opening, the quicker this happens.

Does that paint a picture that makes sense?

yes , understand !! but which problem i can found on the car ?? under 50% ?? is better start at 50% or more ?

read this :

Trash Cans (non specific models) start to work around 20%, and reach full open at around 70% at 15 Hertz settings. Back to our calculator, that is a pulse width of .0133s at those settings. Technically they might be able to open at 16% if you drop down to 12 Hertz, that is the same pulse width. If we go up in Hertz, let's say 20Hz, 27% Duty Cycle will generate an equivalent pulse width. Hopefully these correlations will make sense as to how Frequency and Duty Cycle affect where large solenoids can operate at. Fuel solenoids respond much better than nitrous, so realize that if you attempt to use a 20% launch Duty Cycle, it's possible your fuel solenoids will be pulsing but your nitrous may not be at that point.

On the other end of the spectrum, if we're at 15Hz, and the solenoid quits pulsing at 70% and goes full open, the on pulse width is .0467s but the off pulse width is only .020s, which is really short amount of time. Increasing the frequency at the same percentage to 20Hz shortens our off pulse time to .015s, so whichever way you slice it, it starts getting difficult to achieve total control over these solenoids.

In general, the higher the frequency (Hertz) the narrower the working range of Duty Cycle you can control with the solenoids. However the higher frequency also tends to deliver a smoother output when it does work repeatedly.

this is the wire that will be with the controller ! , let me know !

It's unlikely you'll be able to make the car hook on a non-prepped track at 50% or higher. I'm not sure how much you were using before you got the controller and this plate, or what HP level you were spraying before. My guess is you'll want to start at somewhere between 20-30%.

You cut and pasted some text from my Progressive Controller article, not too sure why...

Regarding the wiring diagram, I'm not up to date on the wiring for an edelbrock controller, never used one. But in general that diagram looks like it would function. There are a couple issues, #1 that relay that powers the positive side of the solenoids needs to be a high current relay. Not sure what the safety switch is, if that's a fuel pressure switch, pitch it. Those cause all kinds of problems.

Missing is a transbrake interrupt circuit - does the car have a transbrake? If so, you need something to prevent the nitrous from coming on while you're on the transbrake. If you're foot braking the car, realize that throttle switch shouldn't be coming on when you're stalling against the converter.

raffaplymouth wrote:yes , understand !! but which problem i can found on the car ?? under 50% ?? is better start at 50% or more ?

Hi John .. no transbrake !!! yes i have copy your link for asking minimal percentual of start .... my last setting with 250 hp sprayed from launch with zero delay saw very good traction and no spin with 29 tires 9.32@148 1.42 60 ft 3800 lb with my ass , now i have 30.5 tires