Quote:
Originally Posted by GoodOak
I'm really gland I found this thread.
I only recently joined Ecomodders after purchasing a gas guzzling small truck for my small business. I bought a ScanGauge and installed it this past Monday. I was surprised to see that my MPG is so low for so long when I accelerate very slowly, and when I accellerate at a more moderate pace my MPG increase much faster.
I am attributing this to the very low gearing a truck has in 1st and 2nd gear which gives you lots of power but not much efficiency. AFAICT from ~100 miles of driving, I seem to get 1-3mpg in 1st and then when it gets into second I get 6-8 mpg. Third gear brings the MPGs into the double digest. The increase in speed probably has something to do with this as well since it increase the miles in "miles per gallon".
I'm glad to see others are having similar results and that I am not crazy. My new strategy will be to accelerate more briskly to get out of 1st and 2nd quickly up to more efficient gears.
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I have noticed this as well with my jeep. Even though it is an automatic, how far I push the accelerator can vary the RPM's before it shifts. When I accelerate slowly, it will shift anywhere between 2000-2250 RPM. I find that this usually gives me a worse MPG in the long run because the longer the time it takes for the transmission to build up the RPMs, resulting in a long and drawn out rate of consumption of fuel. If I accelerate at a brisk pace, the RPM's will hit between 2500-3000 RPM, which gets me a better MPG in the long term because the time it takes to get up to those speeds is shorter, thus reducing the rate of consumption of fuel.
And that's always the thing about big trucks and SUV's, having terrible consumption in low gear. By having the smaller/shorter gearing, the torque is amazing, but it takes so much energy to get it up to speed. Something that helps though in those low gears is having a 4 WD truck with a limited slip or some type of actuating locker. By having power go to all 4 wheels when accelerating, the energy needed to get the transmission going in low gears is reduced, making accelerations quicker, much cleaner, and helps reduce the fuel consumption from a dead-stop acceleration.
Since I need to replace the front differential on my jeep (thank you lil' sis for engaging the true-locker and taking a turn and blowing the whole thing out), I have been researching a couple replacement options. The two I find best for on-road, and off road if that's your forte, are Auburn Gear brand lockers and Powertrax "no-slip traction system." What's nice about the Auburn Gear ones are they are electronically acuated. When in an off position, the locker acts like a limited slip, but when on acts as a full locker turning both wheels on your axle at the same rate. The Powertrax one is a cheaper alternative that I personally think is brilliant. Inspead of acting like a limited slip, whihc cuts power to the wheel that has grip to the one that has least amount of traction, it will cut power to the wheel with less traction and give it to the wheel that has more traction, thus keeping you moving forward. Rear differentials will end up giving your axle the feel and control like a posi-traction rear end, and the front end diffs will have the same effect.
Links if anybody wants to check these out are:
StylinTrucks.com
Lockers and Other Jeep Parts and Jeep Accessories by 4 Wheel Drive Hardware
The Powertrax locker is made by
Richmond Gear. What's cool about this one is they manufacture them for any type of accepting axle for cars, trucks, tractors, and UTV's.