Questions about fuel trim and AFR

I will be installing a volant intake soon and I want to make sure it isn't doing anything bad to my engine so I'm trying to keep track of the engine management numbers as well as I can. Using the Torque app I've been keeping track of the MAF, AFR, and short term fuel trim and plan to compare the numbers before and after the volant. The only issue is I really don't know what the numbers mean, so I'm hoping somebody here can explain them a little so I know what is "good" and what is "bad".

Current numbers with stock everything and new spark plugs:
AFR = 17.89:1
short term fuel trim = ranges from 0.0 to -0.8
MAF = 0.8 g/s

Like I said, I'd like to know what these numbers mean and what kind of change after the intake would be acceptable. Also, what else should I look at? Torque has more settings than I could ever use so if there's anything else I should be keeping track of let me know.

 

AFR is the main one you should be concerned about, it's the ratio of air to fuel inside the combustion chamber. 14.7 to 1 is perfect mixture if memory serves me right. When you accelerate it should go rich (10-12) and when you decel or let off the gas it goes lean (20-22). At normal cruising/throttle it should read about 14.6-14.8.

According to your reading you're running lean already (too much air coming in) and adding an intake would increase the lean mixture if the computer can't compensate by adding more fuel to the mixture. Do you have a check engine light on? Do you have any air leaks that you're aware of? Also I'm not sure how accurate that app you're using is. I personally have an AFR gauge that's mounted on my dash with the sensor mounted on my exhaust manifold

 

Your AFR seems high for stock setup. Is this at idle? Long term is more important than short term trims. As long as they are under +/- 10 (closest to zero being optimal) you are ok. There is tons of info on fuel trims so just google it.

MAF will change with throttle response and don't recall what it reads at idle.

Are you doing the volant with ram air scoop?

 

I'm not installing the ram scoop, at least not yet. Those numbers where the last readings when I pulled into the driveway after a short 5 mile trip, I just started keeping track so I may not have enough info for the long term readings yet. No engine codes and the only change is new spark plugs with less than 50 miles on them so far. I really don't know how accurate my torque app is so take the numbers with a grain of salt, but I'll go on a few more trips and do some highway driving and record the results.

Here are some updated numbers after taking it on the interstate, I don't know where that 17 reading came from but now it looks more like it should (I think)

AFR = ranged from 12 to 18, but mostly around 14.6 to 14.8

long term fuel trim = 3%

MAF = between 4 to 50

 

Everything looks good there. I know Gadget from URD did claim that the Volant intake did have some issues with with MAF readings, but that was a couple years ago - and I think it was more an issue for supercharged trucks. If your planning to supercharge later I recommend you go with a TRD gen I intake (if you can find one) or an AFE stage II intake. Also, if you don't mind cutting a little sheet metal and soldering wires you could get the URD true cold air intake.