This is a test, right?
A question for a question.
Here is a little story about two people, we'll call them Ruth and Sumner and they live in Utah.
Well it seems that they must journey to Southern California in the winter time for some reason and being Mac sailors they bring along da boat.
Sometime during their adventure Sumner buys a dodad to calculate fuel mileage and stuff at a auto swap meet. After installing it he now has the abillity to read average and instant fuel mileage.
Sumner, after doing some expirementing, has discovered that by driving 60 mph at 2,000 rpm in 5th gear on his manual transmission he gets 18 milles per gallon on the highway. This is the sweet spot while towing the Mac.
On the way home they stop in Baker, Ca to fill up and streach their legs and all the time Sumner is saying,"how cool the new dodad is and that it really helped him find the sweet spot for towing".
Ruth says,"that nice."
Accending Baker Grade Sumner keeps the engine in the sweet spot (2,000 rpm) and notices in horor that the instant fuel mileage on the dodad is droping from 18 to 15 to 12 to 9 all the way to 6 mpg! What can be wrong, a fuel leak or some thing??
About the time they reach the summit Ruth asks," Sumner, where are your sun glasses?".
Oops, gotta turn around and go back to the gas station in Baker and get the sun glasses.
Holy Moly! Now look at the dodad, 18, 25, 50 mpg. It must be broken. We still have the boat back there and the motor is still at 2,000 rpm, no tail wind.
After retreving the sun glasses and starting back up the grade Sumner shakes his head and says, I just don't understand it,
the mileage changed from 6 to 50 mpg and I kept the rpm at 2,000 and we had the same load.
Ruth in her infinite wisdom lowers her reading glasses and says, do you think it might have something to do with the throttle position?:dance:
Did I pass
Quote:
Fuel usage and RPM really don't really equate.
Rick why then do we use overdrive transmissions in our cars to achieve better gas mileage? Now saying that there still is an rpm that an engine is going to be most efficient at gas mileage wise. Most cars now seem to be in that range somewhere between 1800 and 2100 rpm even though their peak torque might be between 3000 and 3500.
Ok I got to get out in the shop and get something done
,
Sum