Ok so Ive been reading all your post about checking plugs and using A/F gauges. The other day I did a dyno pull (first one) with my nitrous. I have a 46 n20 pill and a 26 fuel pill right now with a nitrous outlet 92mm plate. I was using an AFR gauge and it said the a/f went to 14.0. We stopped the dyno pull early but I didnt check the plugs.

Is my fuel jet too small? Should I check the plugs anyway and disregard the A/F gauge if the plugs look good? And are the plugs going to get a good soot ring on them after just one pull on the dyno if there is little to no idling?

 

Yes Fuel jet too small...looks like your shooting for just under 90 shot. Since you know your lean, I would consider the trying the 33 next time.

What was the bottle pressure? Should have been 950-1000; if it was higher that too may be contributing to being lean. If first time spraying it is the schrader valve out of the fuel rail?

Next thing to check is whether the WB reading is accurate (Cars WB compare to Dyno's WB or compare WB to plugs...)

 

Thanks for the jet chart. I needed that. I couldnt find one for some reason.

The bottle pressure was 1000 or just under. I ran the heater until it hit 1k then killed it and purged.

I will check the plugs against the wideband next time. As much as I can tell it was accurate because it read 12.3 when I ran it N/A which is at least close to what it was the last time it was tuned.

 

12.3 N/A is a bit rich. Leaving some pawr on the table. I shoot for 12.8-12.9

 

Thats what it was the first time it was tuned. Im curious to know if the a/f gauge is accurate or not.

 

The wideband is tending in the right direction (PE richens) correctly based on the NA run, so I would say the lean nitrous reading is real. Maybe the fuel noid is not firing, that is pretty lean for a under 100 shot that was 12.3 NA. I don't think your getting fuel from the Fuel noid.

 

I test fired it into a bucket before putting it on the motor but it is possible. It is the ZEX NMU thing. It says it needs to be programmed but there is no way to program it on my car. I cannot activate my system unless the car is running and it says the car has to be off to program it because the pedal has to go all the way to the floor for 30 seconds or some crap. I bought a new fuel noid off a member here though so hopefully that will correct my issue along with the proper jetting.

 

well 46/26 was lean with the zex thing so i wouldnt jet the fuel solenoid at 26 again. it is amazing how a jet chart can help!

 

Were you tuned on ethanol'd fuel and then fueled up with non-ethanol'd fuel? 0.5AFR is a common swing with the differing pump gas ethanol contents. If you tuned your Ve and MAF tables to one ethanol content and then fuel up with a different, your WOT AFR will be affected, trims will take care of the cruising AFR.

Keep this in mind when nitrous tuning by jet size.

 

Good info. Ill try and keep an eye on what type of fuel I put in. Most places dont tell you if they have ethanol or not anymore so its hard to keep track of.