I installed my nitrous system (NX GM EFI wet kit 50-150 adj.) and put the 50 jets in to test it out. However, instead of running 40-45 psi of fp as recomended, I was running 50 psi. I had someone follow me and he said after I hit the nitrous, all he could smell was fuel. I know I am overly rich, but how much power do you think I'm losing as a consequence?

Tomorrow, I will get plugs 2 heat ranges colder, lower the fp and try the 100hp jets at the racetrack - i'm tempted to try the 150hp jets, but NX rates their kits at the wheels and I'm not sure if I should run octane boost or a combination of 93 octane and race gas in order to pull it off; I'm not sure if the bottom end could take it anyway. What do you guys think?

Wish me luck at the racetrack

Kyle

 

93 octane is fine for the 150 shot on a L98.


get plugs 2 ranges colder, and when change them.. look at how your old plugs were... if they are white, you're lean..

 

Thanks for the tips, 12secgta.

Can anyone estimate how much power I was losing by running the fuel jet too rich?

Any other suggestions?

 

depends on how much too rich. my bet is that if you are following the recomendations on which jets, none. but if you are WAY fat then maybe a little. If the pressure you are running works for the motor when you are NA, then dont mess with it. put smaller fuel jets in (or larger N2O jets) & tune it that way. if you are good on fuel NA & you turn it down to fix the fat condition when you are on the bottle, it could run lean when you are NA.

let me amend this by saying, the only way you are going to know what is going on in the motor is by looking in the motor. Pull some plugs & see what is going on. let them do the talking for you.

BW

 

Thanks for all your help! I will go down to the parts store and pick up a few jets based on NX's recomendations for 50 psi.

 

I have a 1990 formula 350 with pretty much the same mods and the same NX kit....where did you put the nozzle...or do u have the stock air box?

 

I have a custom CAI setup..

I drilled a hole, and installed the nozzle about 4" in front of the TB.

 

Because of how fast the engine will eat parts if you go slightly lean, commercial N2O systems are jetted very rich for safety. Not just a little rich, but if you're running the recommended jet sizes 50-100% rich. What comes out of the tailpipe will be about the same as if you had your car setup to run at about 8:1 at WOT.

Yes, you will gain a little power by running it leaner (usually you can get away with going at least on step down in the fuel jet, ie, run the 100hp fuel jet with the 150 hp N2O jet. On a dyno this usually adds up to 20-30 extra hp) without any problems, but it's not really worth it for the safety margin you loose if for some reason your fuel supply hickups. If you really need the extra power, just run a bigger shot of N2O. It's not like you're trying to get the best gas mileage going down the 1/4 mile...

 

He's absolutely right about the manufacturer's jetting the setup pig rich to begin with.. Ever wonder why you see a puff of black smoke when most cars spray?

That's the reason I used the recommended jets to start with, then tuned the fuel jet accordingly...


But.. Use their jetting unless you know what you're doing..

 

I'm dyno tuning my car on the 21st with a wideband 02, so I will bring some extra jets and tune my car to a reasonable a/f ratio - I'm looking for 30 more hp - May find it, may not.