Uncorfortable with nitrous tune

**RealLiveMD** · 08-30-2009, 04:34 PM

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I took my car in for a nitrous tune yesterday. I'm running a 125 shot. The NA tune was at 11.5 to 1 and 25 degrees timing. The tuner changed the A/F to 12.8/1 and this was the best we got. I'm uncomfortable with how the a/f is so rich until its below the computers ability to read. I'm runnig 116 in a standalone and 125 nitrous pill with 100 fuel pill. The tuner said that if I went with a small fuel pill that the car would be too lean. So this is the best we got. I'm uncomfortable because the power is low and my graph doesn't look like anyone elses. Chime in. Give me comfort or complaints

**bluehawk2000** · 08-30-2009, 05:41 PM

what do you have done to the car? and what kind of kit are you running dry wet or direct?

**RealLiveMD** · 08-30-2009, 06:22 PM

Originally Posted by bluehawk2000

what do you have done to the car? and what kind of kit are you running dry wet or direct?

214/230 .601/.575 117 , ported 243's and all boltons on M6, running wet HSW plate kit with C16 in a standalone.

**Nick@HSW** · 08-31-2009, 07:23 AM

What was your bottle pressure at? Full bottle? Looks like pressure was dropping way off up top. What about timing?

Nick

**RealLiveMD** · 08-31-2009, 10:12 AM

Originally Posted by Nick@HSW

What was your bottle pressure at? Full bottle? Looks like pressure was dropping way off up top. What about timing?

Nick

pressure 1000-1050, timing 25

**Nick@HSW** · 08-31-2009, 11:36 AM

What about weight?

**RealLiveMD** · 08-31-2009, 02:36 PM

Originally Posted by Nick@HSW

What about weight?

at the end of the run the bottle was 17 pounds with the opener bracket. I'm getting that you are suggesting that if i had more pressure, the curve would have stayed up throughout instead of falling off. I hope that thats the case. If so though, I'm still abit lean with the 100 fuel pill and the 125 nitrous pill becaust the a/f seems to be about 12.9 then it dives off at the same time that the torque dives off. I used 100 fuel pill because the 125 had me way too rich with the C16.

**Nick@HSW** · 09-01-2009, 07:14 AM

Originally Posted by RealLiveMD

at the end of the run the bottle was 17 pounds with the opener bracket. I'm getting that you are suggesting that if i had more pressure, the curve would have stayed up throughout instead of falling off. I hope that thats the case. If so though, I'm still abit lean with the 100 fuel pill and the 125 nitrous pill becaust the a/f seems to be about 12.9 then it dives off at the same time that the torque dives off. I used 100 fuel pill because the 125 had me way too rich with the C16.

17lbs. = empty. Fill the bottle and make sure you get right around 25-26lbs. in there w/ the bracket on (bracket weighs around a lb.). You cannot go by pressure to determine how much nitrous is in the bottle. As seen above in the dyno graph you simply do not have any liquid left in the bottle to vaporize and stabilize pressure through the run.

Here's the bad news...since this was done on an empty bottle we really don't know where your true a/f is gonna hit. So changing jetting etc. really is a guess.

Nick

**jakesz28** · 09-26-2009, 06:33 AM

12.9 afr on nitrous may not be that lean. In all honesty a rich nitrous kit is what kills pistons. I would say you want close to the same afr on nitrous as you do N/A. I know of some guys that run leaner on nitrous and they are healthy. The thing with nitrous is it builds heat and burns faster. I will take a leaner (but clean looking plug) any day with timing being pulled as opposed to others that want a rich afr and have to run lots of timing trying to get heat in the motor.

Also 17 pounds the bottle was low. I would also tune the nitrous for about 900-950 pounds of bottle pressure. You will find that the pressure is more stable there and doesn't fall off as much during the run.

**RealLiveMD** · 09-26-2009, 03:06 PM

thanks man.

***Ed Blown Vert*** · 09-26-2009, 03:46 PM

Lean is mean to a point. But I have to disagree. I would rather be richer than leaner.
Leaner can make your engine detonate.

My last engine I went way lean on a run, blew my engine.

**jakesz28** · 09-26-2009, 05:10 PM

If you’re talking about your blown combo in the sig that is a completely different engine with different needs. A rich nitrous motor will lift ring lands. This damage usually will happen with the thought of rich is safe mentality. What is usually happening with a nitrous motor is it is over timed and rich. Then when people pull fuel out the timing will cause the detonation. I sprayed 350hp on this LT1 without burning a plug tip or piston. I have been leaner then 13.1 AFR