scan gauge

pops91710 · Post by **pops91710** » Sat Jul 28, 2007 12:59 pm

Earlier this year I purchased a gauge (http://pureenergysystems.com/store/Scan_Gauge/) that plugs into my obd port. It monitors all the engine functions including rpm's, gallons per hour, miles per gallon, intake air temp, spark lead, throttle position, engine temp, mass air, batt. volts, etc, etc, etc,

I keep close watch on the engine temp and noticed that I never exceed 206 degrees in the hottest spot on the desert and it dropped back to 195 or less when the fan began its roar.

I compared my gauge readings to the factory in-dash temp gauge and noticed it never fluctuated in the least. This leads me to believe that factory gauges are nothing more than mock gauges and no better than the idiot lights they stand in for.

I also found that lower engine rpm's do not necessarily equal better fuel economy. I found with my V10 I can use less fuel while driving in a higher rpm band. For example: Cruising on the road at 65 in third gear overdriven (factory tranny plus gearvendor tranny) at 2300 rpms drops my economy according to this scan gauge. Putting it in third direct (factory tranny only), fuel economy improves 3 mpg or better. Only on slight down grades did I notice the fuel economy is better the slower the rpms are.

Of course, in steep grades i never use the tall gears. Try the Cajon Pass in upper gears and you'll be pushing up sagebrush along a ravine somewhere!

snuffy · Post by **snuffy** » Sat Jul 28, 2007 4:45 pm

My opinion is the best way to figure gas mileage is by hand.

Shields · Post by **Shields** » Sat Jul 28, 2007 6:13 pm

Interesting, but I have found my monitor and dash gauge on temp are very synchronized with each other.

campswithcritters · Post by **campswithcritters** » Sat Jul 28, 2007 6:39 pm

My gauges also seem to be in sync with whats happening, they all respond to terrain changes etc. I have added EGT and Boost because I'm in a diesel but all my factory stuff goes up & down as they should and the factory mileage guesser is within 0.1 mpg of hand figuring.

pops91710 · Post by **pops91710** » Sun Jul 29, 2007 6:26 am

snuffy wrote:My opinion is the best way to figure gas mileage is by hand.

True, and I always do. But the gauge gives me an idea at how much fuel is going into those cylinders under various speeds and conditions. Something that cannot be discerned mentally. This helps me to understand my engine dynamics and to drive accordingly.