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09-24-2003, 01:02 PM

Are you sure your bottle isn't getting close to empty? Sometimes when the nitrous is getting low, that can cause the system to not work as well...and function intermittently. I don't think your solenoids were "locked up"...and no that is not normal for your system to work and not work. I really don't think I have a allen screw on the back of my Hobbs switch. There's is an allen screw in the middle of my adjustable fuel pressure regulator though...you don't mean that do you? The reason why there was no pressure in your lines is because the solenoids hold the nitrous back from entering the motor through that last couple feet of braided hose. When you were loosening the hoses the other day which connections were you messing with? Because there really shouldn't be any pressure in the short line from the solenoids to the TB. If you mean why there is no pressure before the solenoids...then it most likely dissipated during the two days your car sat. Not sure where it goes...but you don't need to worry about tightening up anything. Was your bottle on during the two days your car sat? If not...then that would be another reason why you would have no pressure in the lines. You probably know this already...but make sure you don't ever accidentally inject nitrous into your motor without it running. If so...you'd have to remove all the spark plugs and turn the motor over several times with a remote starter switch to get all of the laughing gas out. Otherwise when you start your car with the nitrous in there...KABOOM!! And that would suck. So now that the system is working...is the Hobbs switch correctly hooked up? I hope so. Running the system without it is NOT GOOD and could easily damage your motor. Testing the nitrous with the motor off does work, say...if you just wanted to check to see if your fuel pressure boosts up to the appropriate 80-85psi., or you wanted to make sure you solenoids are working properly, or even to see if the nitrous itself will work (with the line disconnected from the motor of course). But yes with the motor off the system will eventually lose pressure and will stop squirting nitrous out of the disconnected line. With the motor started though, and the line disconnected I believe you can test the system. But the motor will still be boosting the fuel pressure to about double the norm so that would make for a rich condition for as long as you are hitting the buttom. I guess that is ok on the motor...but I'm not a 100% sure. It's been a while since I've done those tests. But I do know there are several ways to test the system with the motor both on and off. If I were you I'd refer to your NOS #5115 owners manual to make sure before doing any more test. Or call the NOS techline and talk to them. And while you have the tech line on the phone ask them which # of nitrous jets are for the 125 shot. Make sure they specify which # goes in the vacuum T and which one goes in the nozzle plumbed into the TB. I can't remember the exact jet #s off the top of my head. But I run a 150 shot, anyway. You may need to get an additional inline fuel pump if you plan on going up over a 100hp shot. The Hobbs switch will let you know if you're not getting enough fuel, by shutting off the flow of nitrous. Call your local speed shop or look on JEGS or Summit's websites and you'll find the jets that you'll need to upgrade your system. Sorry this is so long. Hopefully you can answer all of my questions...to help me get a better understanding of your system. Although it sounds like you have it figured out.

09-24-2003, 01:02 PM	#5
Simi Stang Guest Posts: n/a	5115 Are you sure your bottle isn't getting close to empty? Sometimes when the nitrous is getting low, that can cause the system to not work as well...and function intermittently. I don't think your solenoids were "locked up"...and no that is not normal for your system to work and not work. I really don't think I have a allen screw on the back of my Hobbs switch. There's is an allen screw in the middle of my adjustable fuel pressure regulator though...you don't mean that do you? The reason why there was no pressure in your lines is because the solenoids hold the nitrous back from entering the motor through that last couple feet of braided hose. When you were loosening the hoses the other day which connections were you messing with? Because there really shouldn't be any pressure in the short line from the solenoids to the TB. If you mean why there is no pressure before the solenoids...then it most likely dissipated during the two days your car sat. Not sure where it goes...but you don't need to worry about tightening up anything. Was your bottle on during the two days your car sat? If not...then that would be another reason why you would have no pressure in the lines. You probably know this already...but make sure you don't ever accidentally inject nitrous into your motor without it running. If so...you'd have to remove all the spark plugs and turn the motor over several times with a remote starter switch to get all of the laughing gas out. Otherwise when you start your car with the nitrous in there...KABOOM!! And that would suck. So now that the system is working...is the Hobbs switch correctly hooked up? I hope so. Running the system without it is NOT GOOD and could easily damage your motor. Testing the nitrous with the motor off does work, say...if you just wanted to check to see if your fuel pressure boosts up to the appropriate 80-85psi., or you wanted to make sure you solenoids are working properly, or even to see if the nitrous itself will work (with the line disconnected from the motor of course). But yes with the motor off the system will eventually lose pressure and will stop squirting nitrous out of the disconnected line. With the motor started though, and the line disconnected I believe you can test the system. But the motor will still be boosting the fuel pressure to about double the norm so that would make for a rich condition for as long as you are hitting the buttom. I guess that is ok on the motor...but I'm not a 100% sure. It's been a while since I've done those tests. But I do know there are several ways to test the system with the motor both on and off. If I were you I'd refer to your NOS #5115 owners manual to make sure before doing any more test. Or call the NOS techline and talk to them. And while you have the tech line on the phone ask them which # of nitrous jets are for the 125 shot. Make sure they specify which # goes in the vacuum T and which one goes in the nozzle plumbed into the TB. I can't remember the exact jet #s off the top of my head. But I run a 150 shot, anyway. You may need to get an additional inline fuel pump if you plan on going up over a 100hp shot. The Hobbs switch will let you know if you're not getting enough fuel, by shutting off the flow of nitrous. Call your local speed shop or look on JEGS or Summit's websites and you'll find the jets that you'll need to upgrade your system. Sorry this is so long. Hopefully you can answer all of my questions...to help me get a better understanding of your system. Although it sounds like you have it figured out.