What's up guys. I've since gone to the darkside and sold the '02 SS for an '05 GTO, and am running a wet 150-shot on it with no other mods.

I just got the FJO Progressive controller installed and programmed it with a 3000rpm 50% to 4500rpm 100% ramp and shutoff at 6250rpm.

My question is (since I haven't made it up to the dyno yet for progressive control - the car IS tuned for the 150-shot): When the FJO is cycling the solenoids for the progressive part, will the car tend to run lean? Thinking about it, it just seems to me that if you cycle the opening and shutting of a small space with gas at 900psi, more will go through than a liquid (fuel) at 60psi... so more N2O than fuel and create a lean condition. But that's just my guess.

I'm just wondering if guys have similar setups that have been on the dyno and know if their a/f was lean during the progressive part. If yes, was it bad? If not, why wasn't it? (your guesstimation)

Thanks!

 

Not a 100% sure, but isn't that factored into how they determined correct jet sizing.

 

I have used my progressor on several occasions when track conditions wouldn't hold spraying out of the hole - my wideband showed no lean conditions during the progression. However, if I were you, I would use the time based ramps instead of the rpm based - reason being, if you lose traction, rpms go up adding more nitrous and compounding the problem. I vary my starting percentage and time ramp depending on what the track will hold. As far as why it doesn't go lean - my theory would be that it is really no different than the ratio of fuel to nitrous that you get with the solenoids open - they will cycle against the pressure without a problem and the jets are what regulates the ratio (i.e. the pressure difference doesn't matter any more with them cycling than when they are full open). Make sense?

 

No you should not see a lean condition. The noids are opening and closing. the gasoline is a liquid, and the nitrous will be gasious until the volume of flow increases to the point of re pressuizing that line. Now the noids are hit with the same volts, BUT the nitrous noid needs alot more energy to open then the fuel. So the lift of the piston in the fuel noid will lift higher then the nitrous noid will. Becuase of the pressure against that piston.

Ricky

 

If anything you will run rich. Since the fuel solenoid usually has a larger orifice and you are pulsing the solenoids at the same rate the fuel side can flow more. Some controlers like the NOS 15835B had a fuel offset switch to help if this became an issue on a paticular tune up.

 

Thanks fellas! I'll be putting her up on the dyno soon to make sure, but wanted some advice on whether to worry before then or not.

 

Im not sure on this but I dont think that the noid is actually closed and opened when its on the progressive controller i think its held 70% of the way open, not all the way open 70% of the time and all the way closed 30% of the time. I think its like an injector its held open a certain percentage of the way to regualte flow so there isnt a rapid opening and shutting.

 

No they open and close, the faster or slower they do this is how flow is regulated.
Robert

 

Well im glad some one corrected me i always was under the impresson it was held open thanks for clearing that up.

 

dont mean to hijack this thread ,but was just wondering with a progressive controller would the noids wear out quicker cuz its closing and opening(pulsing) is a safety kit a must with them?

 

Absolutely, that's why I stick with multi stage. Ask anyone who really has run progressive for a period of time (not the guys that'll say I have been doing it for three years, but have only sprayed a handfull of times) like racing every weekend, yes noids will faulter after a time. Any mech device has a failure rate, even non pulsing noids, but think about how many times that are slammed open and closed per run pulsing. I would suggest at a min annual rebuilds, or even semi annual rebuilds.
Robert

 

thanks robert
when i get my kit plan on using it as often as i can so that cleared alot of things up for me.

 

Like Robert said anything machanical or electrical has a chance of failure.

This is why I suggest using good solenoids. I have set up my pesonal cars and many many many customers cars that have been faithfully using controllers for years on the same solenoids. The key is to just check them every now and then to make sure everything is going ok.
Dave

 

I agree with Dave the material in the plungers has come along way since the early days of nitrous. In the past the controllers were much harder it seems on the solenoids but with newer plunger materials they can live a long life even in a day to day use. The key is keeping an eye on them.