Why am I not going faster?

My bottle is lasting forever... I can close the bottle and still run nitrous for about 7 seconds. Those 7 seconds pull just as hard as if the bottle is wide open (can't be right)
My fuel pressure rises about 5-7psi at full throttle with 75 shot. This also doesn't sound right. Everything is hooked up correctly and I know I have good bottle pressure (full of nitrous and warm to the touch)
If anyone has anything to offer I would greatly appreciate it.

 

Did you check to see if there is anything stuck in the n20 filter? What is your bottle pressure? Low bottle pressure would result in less hp. Are you using non-platinum 1 heat range colder plugs?

 

Humm....FWIW, I have been running the Zex dry kit for over a year now and it has worked perfectly since day one. Now my motor, thats a different story. Anyhow, did you double check that you fuel jet is the right jet for the 75shot? I posted the jet sizes on a post a week so so ago. You should definently feel the 75shot when it hits(it would easliy light up the tires in first or 2nd when I was stock). As for what racin said on the other post about the fuel pump...that shouldnt be a worry for you since the zex kit comes with a 255lph inline fuel pump.

 

well I actually have a used zex kit and it didn't have the inline fuel pump, but I am pretty sure that not having that extra pump isn't effecting me with such a small shot (75hp). Bottle pressure isn't an issue. But I will check my nitrous filter. Is it difficult or risky to open the NMU?

 

are you the person I was talking to that doesnt have fuel side jets either?? If so...that is definently your problem. A 75shot with no fuel jet would be spraying TONS more fuel than the 75shot requires.

Also....I dont know what the NMU internals look like, I have not had to disassemble it yet. Also, I dont think zex gave us any filters in there....I could be wrong since I never checked for myself. I think zex would advertise it if there was one.

 

I have just taken apart my NMU and my filter looks clean as a whistle. Oh and to answer your question - I do have the correct jets on fuel and nitrous for the 75 shot. My next plan is to hook a volt meter up to one of my O2 sensors and see if I am close to correct air/fuel specs. I have one white wire, two brown wires, and one purple wire. Does anyone know which of these is the signal wire?

 

The 2 brown ones are the heaters. The white is the ground (I am relatively shure, I will look in the service manual when I get home). and the Purple is probably the signal. I can look on my car when I get home and see how I hooked mine up. One of the 2 wires will have continuity to ground, you could just check which one that is. The other one will be your signal.

 

Wow....Its nice to hear/know that our zex kit does have a N2O filter. Im going to take mine apart and see if its dirty or not cause I have run about 110bottles and never cleaned/checked the noid and filter(now that i know there is one).

Also, the purple wire is the signal wire. I know this for a fact becuse I used to have an electric air/fuel gauge that tapped into that wire. Good luck.

This is probably a dumb suggestion...but do you have the hoses going to the right ports(fuel pressure hose(right most hose on NMU) to FPR and the other Middle hose to the Intake vaccum port).

 

Also...I know you said you have pressure, but that doesnt mean there is enough in the bottle to really work. I know, when mine get to the last 3lbs(still tons of pressure 900+ heated)....it starts working like **** and thats when i consider it empty and get it refilled. Myabe your bottle is at that point. take it out and weigh it. Most are around 14lbs empty. Later

 

I'd get the bottle filled and get a guage for the bottle to see if you have the nedded 800-1050PSI...

www.nitrouskits.com has the coolest little digital pressure guage that takes about 5 minutes to install, costs like $130-150 i think, well worth it! I got the green version and reccomend it to everyone. Accurate to the pound verified by my mechanical guage

A 75 shot should be a decent kick in the pants but then it also depends how much power your car already makes. My 75 shot got me from 15.60's to a 14.20 so it was REALLY noticable.

 

Wow, thanx for all the replys! I will be hooking up my volt meter to the O2 sensor, now that I know it is the purple wire, over the weekend. I did double check to make sure by hoses were correct and they were. I'm looking forward to what I find out about my O2 readings and letting you all know what I find out. Thanx again for the awsome reply's.

 

Well my 02's read correctly...

It's like everything is working, but only at 50%... My next move is to purchase the 100 shot jets and see what happens. Anyone know where I could buy a bundle of nitrous jets?

 

Not sure where to get extras. Anytime I have ever emailed Zex Tek....I never get a response. Here is there number....maybe you can call and actually get some answers/prices. 1-888-817-1008

For a 100shot you want:

100shot: Nitrous jet=46, Fuel jet=78, 125shot: Nitrous jet 52, fuel jet 73.

Dont try to use other kit jets in the zex kit. You need Zex jets to work. Other kits would use a bigger hole for fuel, but a zex ket actually uses a smaller hole to crate more pressure coming through it to the FPR, instead of a bigger hole to flow more fuel like wet kits.

 

the bottle being warm to the touch doesnt mean it's got the right pressure.

i have had days where the bottle was warm,and still 200psi short of what i run.

only other thing is the solenoid in the "nmu" could be weak and not opening all the way.

 

Well I am still having problems I sure hope the NMU isn't weak...
Lately my car (off the bottle) feels like it has lost 15 to 20 horsepower. This is really odd considering the temperature has been dropping. I have been suspicious of spark plug wire problems, but I have inspected them quite a bit and not found any problems. They are brand new - less than 3k miles, along with NGK tr55's. I am totally stumped. The car will not bog or shake even it I floor it in 6th at like 1800 rpms. It just doesn't pull hard.
What is the best way (Cheapest) to detect "real" knock. I have ran octane boost through this last tank and next plan on buying a few gallons of race fuel. (100 octane). What should I expect?