30 is probably not obtainable, but its a nice round number to attempt. My goal is not to achieve an excessively high FE, rather just improve what it is without negatively affecting the performance and capability of the vehicle.
The additional 100lbs numerically makes a difference, but realisticly haven't changed my FE at all. The 4.0 can be best described as a tractor motor, an additional 100lbs payload makes little difference to it. If any Metro driver wants to achieve an infinite mpg value I could tow you with little if any negative side effects
Ideal tread width to weight ratio is a 9.5"-10.5" wide tire without airing down. I currently have 30"x9.5" which meets that requirement fine. Running a skinnier tire runs the risk of slicing a sidewall when aired down off road. As this is my one and only vehicle, blowing a sidewall or two isn't an option.
Larger tires will be added down the road once this set wears out. However, that is so far away, it is not really a factor.
Its a 5 spd. The 3 spd AT is even worse in the realm of FE than the 5 spd is. 3000ish rpm @65 Auto vs 2100 rpm@ 65 manual.
AC has an electrostatic clutch, removing it isn't going to do much.
Alignment is good. Been meaning to check out the brakes but haven't had time.
I'm running full synthetic, and just tuned it up.
My front bumper extends approximately 10 inches in front of the grille in a flat plane, rather than the conventional rad block where you just fill in the grille slats, I thought about putting a piece of lexan I have lying around, angling from the front of the bumper to the top of the grille to circumvent the flat grille.
Yep, it is a literal barn on 4 wheels. Is there much hope for it? Beats me, but it would be different then most.
Originally Posted by theclencher
I don't think 30 is attainable without an engine swap at anything approaching normal highway speeds. I'm sure Toecutter will disagree!
At 3800 lbs it weighs more than two Metros! It has over 100 lbs of extras; usually we figure 100 lbs off is good for- what was it- 2% increase in FE? But perhaps it doesn't matter on something this heavy.
Electric fan might help some.
I wouldn't predict an airdam to help much as the sides and top of this vehicle are just as bad as the undercarriage.
If it was me I'd look at skinnier wheels and tires and pump them up high, perhaps that wouldn't degrade the off-road function that much if at all if the pressure is lowered for off-road duty. If it can stand to be geared up a bit via taller tires that might help. I'd take the spare off and leave it at home except for off-roading that goes way deep in the boonies. Put in an electric fan. Take off the passenger side mirror. If it has an A/T converting to a stick would almost certainly help but it would cost more than the FE payback. I'd take the 100 lbs of stuff off and look for other stuff besides to take off and see if it makes any difference. Does it have A/C? Take it off or at least take the belt off? Make sure the brakes aren't dragging and the alignment is good. Put light synthetic lube in all the gearboxes and diffs and run the lightest recommended oil in the engine. Tune that engine up but good. If I was feeling adventurous I'd look at lowering the seats and chopping the windshield; best bet for aero on this thing is to reduce frontal area (and the skinny tires would help some here too). Perhaps some sort of semi-pointy aero nose could be fashioned as a regular grille block probably would have minimal aero effect here, but even if we achieve attached airflow over the nose and hood it hits those awful fender flares on the sides and that flat windshield with square edges up above so it'd probably be for naught. My expectations for aero improvements are low so the best bet would be a low speed cruising approach, set the cruise at 50 mph and let all the hurrieds go around you.