Best ScanGauge Calibration Technique for accurate MPG

Hello all,

I have had my scanguage for a while and at one time thought I had it calibrated pretty well, but then started trying to "top off" the tank and compare actual gallons used against what the scan guage stated and it does not seem to be that accurate any more. I wonder if it's winter gas (oxygenated) causing me to not be able to fully fill the tank. Seems that sometimes I can get a lot in after the first "click" of the nozzle, other times only a half gallon or so. I wonder if it's best just to do a slow fill till it hits the first click, then not try to fill it any more. The only thing about that is, that there are always different flow rates at different pumps, and slopes, so I figured topping it off would be the best way to get a consistent figure.

Anyhow, I'm curious how other ScanGauge owners have been calibrating theirs, and the easiest way to keep it calibrated - in other words suppose I decide to put in $10.00 instead of a complete fill, what would be the best thing to do then ?

Thanks !

 

I've found that following the book has worked out very well for me. i.e. same gas station, same pump, no more fill after the first click "off". I still do not have a good technique for only putting $10 or so in and not filling it up so I just fill it up every time.

 

+1

Different pumps will stop at slightly different fill levels.

It's my understanding that on modern sealed fueling systems there is a return that's supposed to draw away the fumes from your tank as you fill to keep them from escaping into the atmosphere which is why you don't smell the gas when filling like we used to in the "good old days". The reason you're not supposed to top off the tank after the pump stops is that if you keep squeezing the handle the return system will end up sucking up fuel along with the fumes.

 

X2
Especially...do not over-fill after that click!

Adjust the gallons on the pump versus what the scangauge is telling you (what it thinks you used - fillup screen).

Don't top off so much. Sometimes I think the Scangauge can't get 'settled' (so to speak) if you're constantly resetting the information when topping off. Let it go for an entire tank....several tankfulls....

 

Hey what did everyone set their scan guage to for setup>speed 0% with 285s? Thanks in advance

 

Just get going at 60 mph on a the freeway according to the SG. Then at a mile marker, start a stop watch. stop the watch when you hit the next marker. The amount the number differs from 1 minute is your percentage.

 

I use +7% for figuring out Odometer diff mpg when gasing up does that sound right? Somebody must be using around this number right?

 

Bump - looking for speed adjustment % for 285s?

 

When I do a fillup I enter how many gallons I put In the tank on the SG, I.e. 17.1 or so. It has been pretty accurate. Don't fill anymore past the initial click when the pump stops. As for bigger tires I increased mine to 6%. If my speedo is at 60 I'm really going 64. I used my gps for this. This also changes how many miles you are actually getting out of a tank, my odo on the truck said 286, the SG said I had like 298.

 

Thanks Keason.. that is what I was looking for. I'm just getting used to my new Scangauge. At first I wasn't too impressed but its starting to grow on me. I'll leave 7% for now. Going into winter I want to experiment with a Hot air intake to improve MPG in this Frozen Tundra I live in 6 months out of the year

 

"hot air intake" ?
why?

 

To improve MPG, its a hypermiling thing. Basically I want to hack a stock intake (a spare of course) and make it pull air from right above the header, or close to the engine. The burn is more efficient, air temp is warmer and thus better mpg so they say..

 

I think it is because, Hot air is less dense and a result the computer will adjust the fuel at a particular throttle position down so that the air to fuel mix is still correct. Less power but less fuel used at the same RPM setting. It's is the reason why MPG drops in the winter, cold air is denser which equals more fuel required for the proper air fuel mix.

A few more details:
ideal air to fuel mix is 14.7 lbs air to 1 lb gas - I have no idea what they set the range around this ideal to be, in the engine's ECU.

Air at sea level 10 degree F is about .084 lb/ft3
Air at sea level 90 degree F is about .0781 lb/ft3
so this 80 degree change has about 15% decrease in actual air going into the cylinder. If the computer did not adjust the fuel being injected the engine would be way rich - resulting in some bad emissions.

There are other items also being monitored and adjusted for: pressure, humidity etc. all which feed into the proper amount of fuel to inject.

 

Hmmm thats interesting

 

Yep that's it. I'll post up how it goes...first thing is to understand the baselines on the Scanguage and go from there.

 

there are people on here selling stock intakes from time to time for pretty cheap that you could experiment with