Dry lean spike Q...
Thread Starter
Registered User
Joined: Jun 2007
Posts: 22
Likes: 0
Dry lean spike Q... OK guys, I changed my nozzle location (to richen it up) and upped the shot. I get a major lean spike but then go dead rich afterwords. I have a WBO2 in the car and tried it on 800psi just to see what it would do. She spikes so hard the car falls on its face then swings the other way and goes way rich (off the gauge both ways). I have all the safety stuff in my system and upgraded pump and injectors. I would get a spike in the old set-up but not this bad and it would stay on the lean side (12.8-13.0) which is why I moved the nozzles. I am thinking to reduce the rich condition I should move the angle of the nozzles, but what about the lean spike?
Thread Starter
Registered User
Joined: Jun 2007
Posts: 22
Likes: 0
I have yet to adjust anything. Wanted to get some opinions first.
Todd, So you think moving the nozzles away from the MAF wires will reduce the lean spike? Does not make sense since this is what measures the additional O2. Please explain.
Joey, the idea of spray is to get it to the motor as soon as possible with no delay. It would make sense if I had a traction issue though. But I want nitrous at the noid and into the motor when I hit it.
Todd, So you think moving the nozzles away from the MAF wires will reduce the lean spike? Does not make sense since this is what measures the additional O2. Please explain.
Joey, the idea of spray is to get it to the motor as soon as possible with no delay. It would make sense if I had a traction issue though. But I want nitrous at the noid and into the motor when I hit it.
Since you've already moved them, let's not use the word "move". I said rotate. By rotating the nozzle a little, the spray may disperse across the wires more efficiently. The "cloud" burst effect. Also, look at the direction of the fan-out. I'd like to see a pic of your nozzle placement and the type of nozzle you're using. How far away is your nozzle?
Trending Topics
Thread Starter
Registered User
Joined: Jun 2007
Posts: 22
Likes: 0
I have to take some pics. They are straight shooters pointing at the MAF about 4" from the wire. I have them mounted on a steel bar pointing directly at the wire. Only adjustments I can make are the angle they enter the openning(up and down). I wonder what would happen if I rotated the MAF 90*.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
Originally Posted by NEVER ENOUGH
"I have all the safety stuff in my system and upgraded pump and injectors."
i ran straight shooters with the nozzles from the NOS 5177 kit about 4-5 inches from the maf, spraying directly at the maf and it tried to kill my car. try bouncing the nitrous off of the lid right before the maf.
and you said "shooters"...does this mean 2...2 of the 5177 nozzles?
i also had 2 of the NOS straights angled at each other like this / \ but not so close as those lines...so that when they shot, the nitrous from both would collide and make a cloud right before the maf. worked ok but not the best. could try it.
and you said "shooters"...does this mean 2...2 of the 5177 nozzles?
i also had 2 of the NOS straights angled at each other like this / \ but not so close as those lines...so that when they shot, the nitrous from both would collide and make a cloud right before the maf. worked ok but not the best. could try it.
Sorry brain fart, thought you had a wet kit. Changing the angle should help the lean spike also it maybe cured with some temp/fuel enrichment tuning. Checkout the writeup Robert56 had on this.
Last edited by JoeyGC5; Aug 3, 2007 at 03:04 PM.
Thread Starter
Registered User
Joined: Jun 2007
Posts: 22
Likes: 0
Joe, thought you missed it. Did not think any more specifics were needed, but every bit helps in diagnostics eh.
42lb green tops and Racetronix pump with 390rwhp NA on a MD dyno through 9" and locker with 4.11s. Injectors are at 65% duty cycle at peak power NA from what I can remember.
I use dual 5177 nozzles, yes. I will try changing the angle to bounce off the lid more. Oh and this was hitting it on a pretty much ideal NA tune with timing pulled above the max NA load in the high octane spark table. I did not log it, but I could tell that once it went rich, it was not pre-igniting.
It is strange that a direct shot to the MAF wire would cause such a high lean spike. I will try it. Any other feedback from anyone?
42lb green tops and Racetronix pump with 390rwhp NA on a MD dyno through 9" and locker with 4.11s. Injectors are at 65% duty cycle at peak power NA from what I can remember.
I use dual 5177 nozzles, yes. I will try changing the angle to bounce off the lid more. Oh and this was hitting it on a pretty much ideal NA tune with timing pulled above the max NA load in the high octane spark table. I did not log it, but I could tell that once it went rich, it was not pre-igniting.
It is strange that a direct shot to the MAF wire would cause such a high lean spike. I will try it. Any other feedback from anyone?
Originally Posted by NEVER ENOUGH
It is strange that a direct shot to the MAF wire would cause such a high lean spike. I will try it. Any other feedback from anyone?
Well you have to remember the temperature difference from nitrous right out of the nozzle to the MAF. The MAF will typically freeze for a moment or two, then your lean spike. Thats where the fuel/temp tables help out, might try and search Robert56's old threads I think he originally had a simular issue.
Originally Posted by NEVER ENOUGH
Joe, thought you missed it. Did not think any more specifics were needed, but every bit helps in diagnostics eh.
42lb green tops and Racetronix pump with 390rwhp NA on a MD dyno through 9" and locker with 4.11s. Injectors are at 65% duty cycle at peak power NA from what I can remember.
I use dual 5177 nozzles, yes. I will try changing the angle to bounce off the lid more. Oh and this was hitting it on a pretty much ideal NA tune with timing pulled above the max NA load in the high octane spark table. I did not log it, but I could tell that once it went rich, it was not pre-igniting.
It is strange that a direct shot to the MAF wire would cause such a high lean spike. I will try it. Any other feedback from anyone?
42lb green tops and Racetronix pump with 390rwhp NA on a MD dyno through 9" and locker with 4.11s. Injectors are at 65% duty cycle at peak power NA from what I can remember.
I use dual 5177 nozzles, yes. I will try changing the angle to bounce off the lid more. Oh and this was hitting it on a pretty much ideal NA tune with timing pulled above the max NA load in the high octane spark table. I did not log it, but I could tell that once it went rich, it was not pre-igniting.
It is strange that a direct shot to the MAF wire would cause such a high lean spike. I will try it. Any other feedback from anyone?
Check my web sites for the pics of my nozzles in my Vararam, same neck and distance to MAF as the f-bods. I use one 90*, hitting MAF wires (index nozzle so you know exactly which way it's pointing) directly and one straight shooter, also in the neck 3 to 4inches away, which shoots directly back into the air box, and instant 11.5 area a/f and no, noda, zilch, none lean spike, goes instantly to dialed a/f in micro seconds. I have it on logs if ya want to see it.
One thing some miss. Depending on what rpm you spray, and what rpm your WOT power enrichment comes on, they may not be in sink. If out of sink, you'll get a lean spike no matter how it's set up. I have mine set a couple hundred rpm before spray starts, this way you have PE WOT multiplier in operation before the spray hits the MAF wire. Something to check to be sure.
Robert