Nitrous cutting out, surging? Help please.

todds95sn95 · 06-19-2005

O.K. I just installed a cold fusion nitrous kit on my 95GT, the problem is that when the n2o is activated it comes in strong then starts cutting out almost like you're flipping the switch off and on. I've tried my timing from 6 deg to 10 and didn't change the cutting out but helped power, I have tried Autolite 23's gapped from 32 to 42 and no change, so I tried NGK UR5's gapped from 35 to 42 and still cuts out, but the NGK's made more power. My bottle pressure has been no lower than 850 and no higher than 1000 during all of this, this was all done with a 100hp jetting, the cutting out starts around 4800rpm's, I put in the 125hp jets and the cutting out got alot worse, started cutting out around 3800, any suggestions?

NoSlow5oh · 06-19-2005

I'm not familiar with the cold fusion nitrous kit. If you don't hear any detonation, chances are you are running too rich. It would help to tell us about the kit, what all features you have, how the wiring is routed, wet or dry, how you mounted the bottle. All of these can affect the performance. I had problems with mine just because I mounted the bottle 90* of what it was supposed to be. Most nitrous kits come really rich so its harder for the dumb to blow up their engines. Try using it when the bottle pressure is around 1100 psi. That will lean out the fuel a little bit and its still within safe levels. Stay with the smallest shot untill you get this figured out. Don't get greedy.

todds95sn95 · 06-19-2005

Sorry, it's a wet kit, and the bottle is mounted with the bottom of the bottle at the back of the car and line is pointing down like the instructions showed was the best mounting position. As far as wiring, it's got a wot switch and a toggle switch to activate it. It did seem to do a little better with higher bottle pressure, and I haven't heard the slightest detonation. A friend of mine has a snap on scan tool and with it hooked up the car shows to be rich all the way through 5200 rpm's so I'm thinking that's the problem but I want to be sure before I try leaning it down any. Thanks for the quick response, have any more suggestions?

NoSlow5oh · 06-19-2005

Okay, I just remembered something. When I hooked up my fuel pressure safety switch, the car did the same thing as you described. It came on strong, then started bucking. If you have the fuel pressure safety switch, thats your problem. Once you open the fuel cylinoid (spelling?) the pressure drops below that of what you have the safety switch set for, for a split second, causing it to cut off the nitrous.

todds95sn95 · 06-19-2005

I don't have a fuel pressure safety switch, but I did some more testing today with it and found that when my bottle pressure hits 1100 the car runs great, no hesitation and no detonation so I must be running too rich. Thanks for the reply though, any more suggestions are appreciated, thanks.

NoSlow5oh · 06-20-2005

One more suggestion, don't get greedy! Respect it and it will provide years of trouble free performance.

todds95sn95 · 06-20-2005

I understand completely, I'm getting some smaller fuel jets to use with my 100 and 125 shot so I can fine tune it with them. I'm not going over 125 until I get a windows switch and an msd digital 6 with timing retard, then I'd like to try the 150. Thanks again for the replies, alot of this is new to me so I'm open for suggestions.:thumbup

mrbob909 · 08-11-2005

Just kinda as a side question, have you changed any of the rotating assembly?
I have a 95 gt, and i looked around and found after 92 ish they stopped putting forged internals in the gt's and was told anything above a 50 shot was unwise unless you had forged internals...

Thanks

NoSlow5oh · 08-12-2005

Ford quit installing forged pistons in the 5.0's in 92, but that doesn't mean the pistons aren't that great. The main thing with hyperutectic pistons is that they can take a lot of power, but if you start detonating your chances of messing something up are higher. When I had the 95 GT, I tried out the 150 shot. Well, my 155lph fuel pump wasn't large enough to handle the extra fuel and I ran lean for a split second before I realized what was happening. That split second of running lean completely melted the tip of the spark plug off. Luckily it did nothing to my piston. With that alone I would say the pistons are pretty durable. I will say a 150 shot is pushing the limits of the motor and not just the pistons, but if you are carefull (which you can never be fail-proof) you should be able to use it and have no adverse effects on the motor. Plus, its a real kick in the pants when you hit the button. Oh, FYI - only the pistons were forged in the fox 5.0's. The crank and rods were cast and exactly the same as in the sn95 5.0's.