I went to get my car tuned today and it went great on motor. But when we went to spay it on the dyno it was extremely lean, like off the chart. This was with .088N and .080F jetting in a 4150 plate with 7psi fuel coming from my stand alone tank and a -4 nitrous feed line. We then went down to a .073F jet and the A/F was still way to rich (10.3). That was the smallest jet I had on me so we lowered the fuel pressure and it literally did nothing so we just wrapped it up and called it a night. The others with me swore up and down that much nitrous just cant flow through that -4 feed. But the guy I got this kit from was the first one to get into the 8's with a stock cubed LS1 and everything is ran and hooked up exactly the way he had it with the exception of a "horsepower in a box" timing tuner. I've personally watched him run his car many many times with a bigger shot on a -4. But if what they are saying is true I'm thinking maybe its not getting enough nitrous for the fuel jet size causing it to go extremely rich. Tomorrow I am going to lower the nitrous jetting and see what happens. The previous owner of the nitrous kit told me to keep an 8-9 spread between the nitrous and fuel jets at 6.5-7 psi for fuel pressure, but it was just way to rich. If this does not work then what else do you guys think it could be? I'm beating my head against the wall and have no clue what else to try.

 

Anybody have any ideas? Really need some help to figure this out.

 

What brand and style of plate is it? Have you tried calling the manafacturer to get some baseline jetting? This will also depend if its a perimeter spray or center bar, etc. Sometimes a rich condition can be caused by a clogged nitrous filter. Have you checked your fittings also? I can give you better tech with a little more information, awaiting your reply!

-Garrett

 

Is it lean or is it rich?

 

Well I just got off the phone with them and didnt get any kind of baseline. I was told that their jet charts and baselines are for 6ft -6 lines only and he couldnt really help out or give a starting point. So I'm going to try to find some more jets locally or order them and try more of a spread. If that dont work I will start dissecting the solenoids to check for a clog anywhere since I dont run a filter.

 

Way to rich

 

I've got the same problem. Trying to figure it out this spring when the snow is gone but interested in what you find out. I'm running E-85 but seems like we've got a pretty similar set-up.

 

What nitrous solenoid are you running? How long is the -4AN main feed line you're running? Did you ever get a jet smaller than 73?