Nx gemini kit, went to SpeedInc for a tune, Larry and Jim are great guys, First pull on N20, 150jet 975 psi on the bottle, pulls like crazy till it gets way up top, then it surges like hell, A/F 11.5-11.7 through the hole pull perfect straight line, then it leans out to about 12.1-12.2 and the surging on the graph begins.

Ok now we lowered the bottle pressure to 850psi and the pull was a bit cleaner very less surge A/F got to about 11.9, lost 6hp on this pull but picked up 15ft lbs of torque. WTF is going on here, I am tired of calling NX tech, and having them tell me to search this and that. I am about to toss the kit and get a HSW as I have on our 99 that works flawless.

N20 filter is perfect, has a wlbro 255 pump w/hot wire kit. Have not changed the fuel filter since I got it a year ago but I put about 100 miles on the car in a year, everything on motor is perfect, No window switch, and at this point NO FPSS.

 

i had something similar and found it to b a ground problem cutting out voltage up top fixed that up and all she wrote.

 

Just because you changed the fuel pump doesn't meen you have good pressure. Put a good gauge on it and see if you are maintaining fuel pressure. My bet is your dropping below 40 which is scary

 

No need to throw away the NX system. They make a good product..

Things to check.

1. Fuel pressure

2. How the bottle is mounted. ( make sure the valve is down so that the bend in the pick up tube is picking up liquid nitrous.

3. Kinks in the main feed line.

4. Flappers in the hoses. (This is a slither of teflon hanging down from when the hose was built.)

5. Spark Plugs. Make sure they are the right plug and gaped correctly.

6. Timming. Where is the timming at.

7. Bottle pressure needs to be at 1050

8. Grounds. (make sure all grounds are good.)

9. Wire. make sure the pwer wire to the relays is atleast 12 gauge

10. Voltage. (Check the voltage on the car and make sure you are not have a voltage issue.)

Let me know if you have any issues...
Dave

 

F/P was at 58 psi, I will check all the grounds, and go through your list. Dave what is wierd is the situation got better when I lowerd the bottle pressure from 1000 to 850

 

What was the exact problem? Maybe I will check mine.

 

Is the kit new? If it's used you may need to rebuild the solenoids.

 

also, are you using the supplied lines or did you hardline the kit.

Although it appears your issue is from the bottle not maintaining constant pressure... you have a heater on it? Have you checked the selenoids off the car while spraying thru the plate on a workbench?

 

i bet the lines that come with the kit could be an issue. i flowed it, and they dont work. could be not distributing the stuff right and cauzing an issue.
not sure, but its a starting point.

 

Had a problem JUST like this on the dyno with a customer's car the other day. Would you believe 2 degrees of timing fixed it and added 30 HP? I would have never guessed it.

 

Yes the kit is used, but was told used very little, came with the car, I am using the supplied lines, and we have 9* timming out for the 150 shot, and I actually have 2-15lb bottles on this set up both have the NX heaters on them.

 

+2 degrees of timming? I never tried the spray without retarding the timming you may have something there.

 

Could it be a MAF issue, I have been reading that the stock MAF is only good to 500HP?

 

Looking at your other post about having the wrong spring in the dedicated that could have been your issue..
Dave

 

Dave, that was a totaly different car, I have 2 LS1's, actually that car has HSW kit on it that works perfect. The dedicated was just add for extra saftey to run the BIG shots. The way it looks the NX kit is going to be in the BIG trash can by the end of the week. I have been over everything 10 times that you have stated in your list, Called NX again they are NO HELP at all, I just get the same....HUM got me!

 

i ran 9.0 148 with my stock maf 2 years ago with my ls2 402 2 stage

not to say the maf isnt bad, but you can run more then 500.

id rip it off tho, and run Speed dens and replace the stock lines with a "Y" style set up, and -9* on a stock tune? if its an f-body, that is way way to much timming pulled.
150 shot with 93 octain id say you want to be around 20-24* depending on the set up

 

Since its used, I'd rebuild the solenoids just to be safe. I bought a kit that had about 5lbs through it, but was 2 years old. It surged like you're saying so I rebuilt the noids and it fixed the surging. Just an idea.

 

I understand your fustration and I am trying to help you. However I am not there to look at the car and pin point the problem. Until you answer the list of questions I have asked I can not do anything to help you because I do not have the information needed to pin point the problem.. There is a process we can work through together and I will find your problem if its in the nitrous system. Forget NX talk to me. Ill guide you down the right path but you have to follow my lead. Give me a call and I will help you over the phone..

Dave

 

1. How is the bottle mounted in the car?

2. Do you have a fuel pressure gauge on the car where you can watch the pressure through the intire run?

3.What spark plugs and what are they gaped at?

4. What is the timming at?

5.How are your grounds ran?

6. What size wire are you feeding the relays hot with?

7.Check your wot switch and make sure that it is making good full contact through the intire pass. I have seen them make contact and then the blade goes just enough to cause the wot switch to click off and on.

8. Get a volt meter and what is the voltage at the battery with it running?

This is a start. Work with me here and we will pin point the problem.

Dave

 

Dave, I will check all those items when the car comes home, we are in the middle of a MAJOR FLOOD the levy is about to give way and we are all going to be 3' in water, so I moved the 2 F-bodys and all my toys till this ends, but I let you know, Thanx so much for the help. But I did air up my tire TUBE to float around...lol