Johnny5

iTrader: (2)

So are there any reasons why you couldn't / wouldn't want to hook up the Fuel to the first channel and the N20 to the second and have the second channel come on as a small time delay? Wouldn't this effectively give you the ability to tune it out of the equation or is it unsafe for any reason?

What type of delay would you set if to like a .1 seconds or so?

Is the lean spike even bad enough to worry about messing with any of this?

02Vortech

iTrader: (4)

lean spikes are usually associated with dry shots of like 150hp you sound like your running a wet shot+b/c the maf will have to catch up to the sudden rush of oxygen-


but i was thinking the same thing- any info would be appreciated

NXJeremy

Generally the lean spikes that everyone talks about are associated with wet systems. However, these issues are blown out of proportion in most cases. A spike is just that, a spike. The large majority of these spikes last less than a second and/or less than 1000rpm. This very small amount of duration is not going to damage an engine. If damage does occur during that small duration, I would put money on it that the engine was already hurt and was going to break something in the very near future regardless. People just see the peak of the spike at 18:1 or whatever and freak out. When in reality the entire spike only lasts a couple hundred rpm.

You could spend hours and hours on a chassis dyno trying to tune the spike out of the graph, but IMO you are wasting dyno time and money on something that isn't going to hurt a good motor. However, I strongly suggest that you don't just disregard the spikes. Keep an eye on it to make sure that is just a spike and not a larger issue that can lead to hurting a motor.

02Vortech

iTrader: (4)

my bad on which one it is more associated with (still gotta keep learning )- will the FJO controller make this less severe when starting it out @ like 10% of a 100shot then bringing the power up lineraly?

Johnny5

iTrader: (2)

Thanks for the info. That makes sense to me.

30thz

iTrader: (3)

That was good info, thanks Jeremy

Beer99C5

iTrader: (21)

Thank Jeremy, I was kinda of concerned with this.

My plan to minimize the spike is to put the Nitrous noid further away from the jets than the fuel noid (which will be as close to the jet as I can get it). I know 950-1000 psi will probably travel the length of a longer hose quicker than the 58 psi on the shorter hose, but it should reduce the duration of the spike.

Beer

NXJeremy

No problem guys, that's what I'm here for .

02Vortech- Yes, the lean spike won't be as big if you are starting the progression at a very low percentage of the total horsepower amount. However, keep in mind that even though you are starting a small percentage, you are still activating both the nitrous and the fuel solenoids at the same time which is part of the reason that lean spikes occur.

Beer99C5- That is another option in minimizing the lean spike. This seems to work fairly well, but two issues that can pop up are; 1.) Trying to find the right length for the nitrous line that will minimize the spike can get pretty costly if you are testing different length lines. 2.) While adding length to the nitrous lines will help minimize the spike that occurs at the initial activation of the system, it can also make the car run really rich on the top end. This is because you are adding more volume that has to be filled with nitrous, which will decrease the pressure quicker as you are using the nitrous.

Here is an option that you guys running the FJO progressive controllers might think about. Keep in mind, this will only work if you are running a single stage system.

Set the nitrous solenoid's progressive curve and window of operation to what ever you want it to be. Make this the 1st. stage in the FJO program. Then, set the parameters in the 2nd stage of the program to mirror the 1st. stage with the exeption of the activation point. Set the activation point of the 2nd. to be just a little bit sooner than the 1st. stage.

Now wire the fuel solenoid to be the 2nd stage. The result will be that the fuel solenoid will activate a split second before the nitrous solenoid. Both solenoids will still follow the same progressive curve.

With a little playing this should effectively be able to get completely rid of the lean spike without making the car go really rich on the top end. It would take some re-wiring, but shouldn't be too bad.

One last thing, the above idea is solely based on what I know about our nitrous systems and what I know about the FJO controllers. Although it should work, no one has tried as far as I know.