So I went to the dyno today and went 18+:1, thank God the guy doing the run knows his $hit and got out of it right away. Anyway, I'm about done with N2O unless someone can help me. I have no idea what could be wrong. I know my fuel solenoid is working, I have a racetronix pump, TR6's, I've taken timing out (running a 150 shot) and I'm even running a bigger fuel jet. Anyone else got any ideas? Oh, and I've put about 7 bottles through it and I've never blown the motor orbviously so I don't get it. It can't just be coincedence that both times I've gone to the dyno it's gone lean. What do you guys think my next step should be? If you need more info, post up and I'll answer the best I can.

Thanks.

 

I would ensure the Schrader valve was removed from the fuel rail.Confirm correct jetting, then ensure bottle pressure where its supposed to be.

Then I would check and ensure the Fuel noid is firing with the nitrous noid.

 

yeah did you take the center pin out the schrader valve on the fuel rail? If you didnt do that there is no fuel going through your nozzle.

 

Yeah I got the schrader valve. Pressure was at 900 and I forget the jetting but I'm pretty sure it was 62 nitrous and 35 fuel.

 

are you sure the fuel noid is working? just because it clicks doesn't mean its working. i usually put the fuel line from the noid into a bottle, arm the system, and bypass the tps/window switch to make sure the fuel is flowing. i have had three fuel noid pistions swell on me.

 

I've done it similiar to that way and I've also armed the system without the bottle open and when it gets past 3k rpm where the window switch kicks it, it goes pig rich so I'm sure it's working.

 

When your afr go's that high did you guys pull the plugs to see what they looked like?Are you sure his wideband is accerate.

 

Is this just upon activation, or through out the pull?
Robert

 

I didn't because it was a dyno event where I didn't have a lot of time to do stuff like that, not a tuning session. Then I came home and the car's been in the garage since then cuz I'm scared to drive it lol. I plan on pulling them tomorrow and see how it goes from there.

 

It was at the very beginning where I know a lean spike is going to happen but it was off the chart lean. The guy doing the run has dynoed plenty of LSX's and said it wasn't normal so I went with what he said, and everyone there could hear the detonation too.

 

Generally a lean spike upon activation is accepatable as long as it last less than a second. With that said, 18.1 is kinda steep.

Might try a line lenght change, longer nitrous shorter fuel. Check your fuel filter for being partially clogged. Try another fuel noid. Another cure can be adding a reg and return at the rails. In your tune is a PE multiplier rpm activator, make sure it's set to add fuel a couple hundred rpm before spray comes on (may be a contributing factor). A stand alone fuel system can also cure this ill. just a matter of figuring what is slowing the fuel supply down upon activation.
Robert

 

Post up the graph. I was having the same problem before.

 

What was your problem? Did you get it fixed?

 

It starts out lean and then I get a huge lean spike at around 4k. It doesn't smooth out until 5k. I'm running a 150 shot fuel jet and a 100 shot nitrous jet. I didn't get it fixed yet. I'm waiting til spring so I can get the jet swapped to a 150 shot and get the A/F under control. I believe it's just a tuning issue that can be fixed with a dyno tune.

My advice would be try running a smaller shot to see if you can get the A/F at 11.8. Then work your way up from there. Check the duty cycle too.

 

I had the same problem with mine when i was on the dyno ! i had 150 jets in and it spiked on inital hit of spray to 17.1. I went up on the fuel jet and my tuner fattened it up in that rpm range where it was leaning out and it fixed all of it back down to 12.3 .1 ! Of course your going to want to do a na pull to make sure everything with NA will be ok with the fattened rpm range but it solved my problem and lost no power on NA ! By the way i had a racetronix kit with the hotwire kit so fuel delivery wasnt the problem!

 

I agree with that completely.


Yesterday when I was having my car tuned -- I put in the recommended 100 shot jets (NX) and it ended up a lot leaner than I would have liked (12.5-12.8). I put the fuel jet for the 150 in so the jetting ended up being 52N and 41F, put my A/F right at 11.8 with a slightly leaner spike with the initial hit. It is a little different for my car because I've got an LT1 but its still something to keep in mind.

 

To me it looks like a over all fuel supply problem, rather than a typical lean spike upon activation. Here's why, you don't see it going lean on intial hit (however stays at stioc), but when hitting your higher demand area, like a delayed lean spike. Do you have an upgraded fuel pump? and/or do you have a falling fuel pressure. You have enough fuel supply to go commanded richer when n/a, but not enough on spray?
Robert

 

I have a stock fuel pump. I can't remember what my duty cycle is. What would you recommend? A LPE B-A-P?

 

A Racetronics fuel pump should do the trick, talk to Matt at HSW. DC is only a concern spraying dry.
Robert

 

Okay. I am spraying a wet shot...