How part is part throttle though? I've only seen closed loop when my foot was off the gas pedal pretty much

I'm not sure where the switchover point is on the Z. For cruising on the freeway you'd definitely be in closed loop to maintain speed. Passing would probably jump into open loop.

DepointfiveO is in closed loop.:roflpuke2:

(NA)
G37 models with the manual gearbox are actually the least fuel-efficient, at 17/25; models with the automatic get up to 19 mpg city, 27 highway.

So how much MPG LOST should be expected with a SC setup compared to NA?

Wow that's really bad for a stock N/A G37. I have gotten 33mpg driving on the highway after I installed my intakes, but that was literally me driving 65mph the whole way and i reset my gauge on the highway, but I digress.

You should only really lose about 3-5mpg, assuming you drive the same. But let's be realistic here, you're probably going to step on it more, who wouldnt? XD.

I was getting 18-19mpg, but recently got a re-tune and on the first full tank I have gone farther total for same fuel. Will be filling up tomorrow and will report back.

is that mostly highway cruising?

THIS

A tune can make a difference with MPG, especially in closed loop driving.

*700th post*

Ok, had a chance to go through some old notes.
Average about 18.2 most of the time but was usually in the 17.5-18.5 range, after tune I was at 19.9MPG on the first tank. This was city and highway combined style, I sit through about 1.5 hours of traffic twice a week and in the morning no traffic.

I haven't finished my tank of gas yet ,I'm at half and I went 210 miles so far.

That sounds about what I got, my issue was once I hit half a tank my dots went from half to zero in a day and half (where the first half is like 2-3 days) with no real driving changes. My last 5 dots are basically worthless, once it hits those I need to be going to a station.

From my understanding the gauge is not 100% (especially range) because the injector size changes and the computer which outputs that info is not able to change. So your range and dots will not be 100% accurate right?

Ur right. once you switch injectors n fuel pump the computer is no longer accurate. Have to check your mileage manually.

MPG isn't accurate, but Dreamer is saying the gas level gauge also becomes inaccurate. Can others confirm this? When I am lower than half tank, the dots go away quicker even NA, is this what Dreamer is referring to or is it significantly more so supercharged?

No, that is what I am referring to, seems the dots are not the most accurate below half a tank. That gauge is basing all its assumptions off your range, injector size, etc. And once you start messing with tuning, injectors, and such it throws it off.
MPG you just do manually, I think mine reports out I get 30MPG now which is not close at all. Range will usually over estimate at first but after the first 30 miles it comes close to what I usually get per tank but I never have it on that screen. I keep it on outside temp.

I like when it says I have 60 miles left till empty,that mean I need gas right now.:roflpuke2: