So, got the wideband gauge hooked up. With the nitrous tune from Dave, at WOT without nitrous, my numbers in 1st-3rd stay at around 12.2-12.6 on the gauge. Is that good?? I'm not too sure where they should be at. I'm filling my tank as we speak, so I havent logged with the spray yet. What should my numbers with spray be? Also should I do runs in every gear to monitor the a/f?? Thanks in advance guys. More newb questions soon. I promise. lol
On motor, those are good A/F ratios to be at. Any leaner and the motor may start getting a little knock and the computer will start pulling timing. Also, keep in mind, if your computer picks up knock, it will start dumping fuel on it's own making your tune pig rich. It's best to stay out of knock for that reason alone. Too much fuel can hurt you worse than not enough timing.
Just so you can compare to something, my numbers on a N20 tune without the N20 are 11.7 thru all rpms. Make sure your jets are on the fat side when you spray, also let out if a/f ratios are in the 12s(IMHO) ARI- The numbers lower the number is that means you have more fuel, the higher the number is that means less fuel. Lean is mean but rich increases your odds of racing another day John
My numbers are the same as BTLFED right now. I see about 11.6-11.7 without juice. I wish my AF looked as good as yours. I am still working with Dave to get into the low 12s without juice. That will hopefully put me mid to high 11s with juice which should be plenty conservative. BTW, the lower the number the fatter the tune......higher number = leaner. I'm still not quite sure what the optimal AF should be on nitrous with these motors but after reading a lot of tech articles it seems that your AF should be about the same as NA maybe a tad richer.
Seems like JMatt should know these things Ari. He's got one of the biggest shots and is the quickest on the spray. PM him and I sure he'll help out anyway you can.
....my opinions......... on motor N/A you want about 12.2. FYI on A/F ratios .....10 is way fat ............. 13 is getting way lean. On nitrous a good safe ratio is around 11.5-12.0. Again, always use race gas at track above 100+ shot, to add extra safety net, and combat knock retard, detonation, etc. Don't forget about the better, colder plugs too. Good luck. You will love tweaking with the wide/band once you get the hang of it.
I agree 12.2-12.6 NA is great, 11.5-12.0 on nitrous is good as more fuel added with nitrous keeps knock down plus the more fuel to burn with nitrous should give you more power which oddly enough is the exact opposite NA. 10.0:novote:.......................12.0:good:.................14.0:no:............15.0..:blowup::rip: RICH.............................AVERAGE..............LEAN................TOO LATE.
Thanks guys. BIG help. :clap: So if I'm running lean with the Nitrous, should I try upping the fuel jet before adding fuel with the predator?? And if I'm running rich should I use a smaller fuel jet??
There is more than 1 way to skin the cat Ari, if your A/F ratio is a solid number thru the entire rpm range and you want to make a change, I would use the fuel jets to make the change. If you need adjustments only in certain rpms, then I would use the predator. If you need to lean it out, take it in small steps. Chris, on the tune I consider my best N20 tune I lean it out about 3% in all RPM ranges and I end up at about 12.5. On my Jeep leaning it out anything more and I lose slight power and tq falls.
Well this is the way I see it. Your AF ratio without nitrous is awesome right now in the low 12s. Once you spray it and notice it is lean, you could step the fuel jet up a little to compensate. If its too rich then drop the fuel jet a little. Think about it this way. You want as much fuel going through the injectors as possible so you can be assured it is being evenly distributed into each cylinder. Tuning the fuel delivery through the predator is safer than tuning it through a fuel jet.
Chris, if I spray and notice it is lean, then adjust the fuel, isnt that gonna fuck up my a/f without nitrous??? Do I have to keep tuning with nitrous and without to find the perfect mix??
Yep, you need a good NA tune seperate from your nitrous tune. I think you can now force multiple CMR tunes onto the Diablo now
So I have to change tunes back and forth everytime I have to spray. That kinda sucks. :cry2: Better than f'in up the motor though.
You wouldnt HAVE to switch tunes but in order to have the best of both worlds you would. Personally I just leave my nitrous tune in the jeep all the time. It would pick up some hp with the NA tune but its not a big deal to me. Sometimes the nitrous tunes will run better than the NA tunes in the 1/4 since there is no KR with the timing pulled for nitrous.
Best quote of the thread. Keeping the timing lower for nitrous since it won't lose you very much power NA anyway. Tune for ideal A/F ratio on motor with the predator and tune your nitrous A/F with your fuel jets. Typically, nitrous jetting comes in around 10.5-11.0:1 from the manufacturers. They set it conservatively 'cause they don't want you blowing your stuff up. Better nitrous power at 11.5:1.
I was in meetings all day and hadn't seen this thread. My opinion (FWIW): the 6.1L motor has proven time after time that 12.8:1 is the strongest NA AFR. I'm not sure why the Jeeps would be any different than the LX's. In theory, you could use the same wideband AFR of 12.8:1. In reality, the biggest pros ocnsider richening up the AFR by .5, suggesting a target of 12.3:1 for the maximum power/safety trade-off. In reality - we are street driven daily drivers, and want to be even more conservative. My goal is 11.5:1 - 12.0:1 throughout the run, and I don't have a cow if I see blips up in the 12.8:1 range. By "blip" I mean one half second out of a 12 second run.
