Hi guys ...I may be looking to drive 80 miles each way to my business ... not every day ...I 'll pick up a VW diesel for that ...LOL
I was wondering if any of you guys are running a under drive units on a 2wd trucks ...I'm getting 26 mpg right now , which is not to shabee ...I would like to get into the 30 mpg .
Thanks

Greg

 

Bump your timing up to 16*, that's good for a couple MPG's

 

An under/overdrive will not increase your mpgs.
Speed kills mpgs, not rpms.

 

Less RPMs dose not equal less fuel consumpion ...?
I would figure right now I'm 2000 rpms around 70 mph ...I would figure if I got the rpms around 1500 rpms I would be using less fuel .
Greg

 

Ask anyone who has lost 5th gear and had to drive an extended distance, even though they have it revved up they usually see the best mpgs ever, mainly because they are going slower.
The question about better mpgs with a gear splitter has been asked many times, I don't recall anyone ever saying they got better fuel economy. In fact one manufacturer, US Gear I think, is honest and states it's unit won't improve your mpgs.

 

think about it. Your at 1500 rpms but that means the engine is spinning slower and less power is avaliable, so u would have to give it more throttle to keep the same speed up therefore using up more fuel...

 

That I understand ...
I'm learning not to try and re-envent the wheel ...LOL

Greg

 

At a given speed, wouldn't it be more efficient to run 1600 RPM than 2000? You have to produce the same amount of power to keep the truck moving at the same speed, so wouldn't it be better to run near peak efficiency? (Isn't peak efficiency of an engine at peak torque, which is at peak volumetric efficiency, or am I way off?)

 

The way it was explained to me is that it takes xxx amount of energy (fuel) to move xxx amount of weight at xxx amount of speed. The rpm makes little difference.