Hey I put the pills for the wet kit according to what the directions for NX says, but I'm running lean when I spray. I was hearing detonation occasionally when the car hits 210 when I've sprayed and also slightly below that mark. I would have to make sure the car is cool before I spray. Well I dynoed again today and I'm at 314rwhp on 1st run and 315rwhp 2nd run. 3rd run I sprayed and was lean @364rwhp & 392rwtq. I am going to go back to the dyno next weekend and experiment with the fuel pills. Has anyone had this problem? What fuel pill are you using if this is so?

 

I ran a 24 jet insted of the reccomended 22 on the fuel side on mine with the 75. It was a little on the lean side. That was on the stock pump.

 

Test your fuel solinoid and make sure its working.Take the line off the nozzle and spray it int a cup or can.

 

My NX kit came with three sets of jets
75 shot: 41 N20....26 fuel
100 shot: 52 N20...35 fuel
150 shot: 73 N20... 41 fuel

i am putting the car on the dyno sunday. We will see if the 75 shot i have with a 26 fuel is lean or rich.

 

How do you know it's lean when you spray? Are you doing anything to retard timing when spraying? What is your FP set at?

Rich Krause

 

I sprayed my 3rd run on the dyno and it was lean.

I think my directions said for 75 shot 22. Let me go look for it and confirm.

I just confirmed it...it says for a 75 shot 41/22. 50 shot is 35/18. Tell me what you other guys may show on an NX wet kit.

 

The proper fuel jet for a given nitrous jet will depend on fuel pressure and nitrous pressure. Assuming 1000psi nitrous, 42psi FP, and a 41 nitrous jet, I would start with a 24 fuel jet. This would give a calculated AF (for just the nitrous component) of 11.8:1.

What is your FP? Have you verified that it isn't dropping at WOT? How lean was it, IOW, what was the actual AF ratio? What is the WOT AF ratio off nitrous? What is your bottle pressure? The more info, the better the answers.

If everything else is right and it's lean with the fuel jet you are using, pop in a bigger jet. But a bigger jet is not the correct approach if there is a problem with the FP regulator, the pump, etc.

Rich Krause

 

bigger fuel jets. pull out a few degree's of timing. go with two ranges lower spark plugs. never use platinum plugs!

 

The post above is correct. Each kit comes with jets for a given Fuel Pressure. Some may use a 22 jet, some may use a 26. What fuel pressure do you run your car at, and I will tell you what fuel jet you should be running. I find it very common for people to buy a kit, and install it, and bitch that it is fat. Come to find out they jacked the fuel pressure all up, so they have the wrong fuel jet. Let me know your running fuel pressure, and I will tell you what fuel jet you should be using. If you are doing these tests on the dyno, then what is the A/F ratio when you say you are lean?

 

My base fuel pressure at idle with stock fuel pressure regulator is at 39lbs.

 

I will post up my dyno sheet later on today.

 

Went to the dyno today and came up with this
N/A: 264 hp, 293 tq with a A/F of 12.5:1 (to rich)

W/ 75 shot: 315 hp, 375 tq A/F of 11.0:1 (WAY to rich)
Need to put a fuel pressure reg on the weak and go one size down on the fuel jet.
This was with a 41 Nitrous jet and a 26 fuel jet.

 

it could be that you need a bigger pump. i had the nx 150 shot on my car with stock fuel system and when i hit the button my pressure would drop way down. my fp was set at 40 with vacum line off. i have a fp guage and an a/f guage as well as a scanmaster and it was all saying rich so thats why the pressure got turned down. im gonna try a 255 pump so maybe that will fix my problem

 

12.5:1 on nitorus may give up a few hp, but I wouldn't go too much leaner. Now, I do agree that 11.0:1 is WAY too rich.

Rich Krause

 

11.2 on motor & 13.4 on nitrous.