That's seems to be where you should be. My friend's 90 G20 got 16-17mpg going to Colorado at 70-80mph. 5.7L/350cu in. TBI injection, cat delete and true dials, fresh tune-up, hotter coil. We weren't racing to get to speed but not holding up traffic either.
When Chris Farley talked about living in a van down by the river, did anybody else think that wasn't such a bad idea?
Vans are not made for economic fuel efficiency, so that is why I also have a car. The ideas stated above are a good start, but one thing that was left out is, changing the rear gear ratio to a lower number if possible. Many years ago I installed a Dodge 340 in my van, from a 318 and the mileage went from 12-14 per gal. to 8. The extra power was a lot of fun, but my pocket suffered. I ended up changing the gear in the rear from a 4.10 to a 3.55 and I went back up to 10 mpg. I may not seem like much, but that is about a 25% increase and that would pay for it's self in one year of driving.
My E350 with 460 and C6 gets about 8 MPG. Empty. I just got it though, so I'll be getting a tune-up done, and tires. I do see an RV cam in my future.
Before I went through the trouble of a cam swap, I would start with a full tuneup and checking for timing chain stretch, vacuum leaks, proper operation of the timing advance system, and changing the rear axle gear to something like 3.2 or a numerically lower ratio. That 460 has enough torque to be happy with something in the 2s, so there is no need to spin extra RPMs on the highway.
Tires really won't make a whle heck of a ot of difference, but if you need tires anyway, get some with low rolling resistance, if you can find them in the size you need.
My 1991 Dodge B-250 with a tbi 5.2 V8 and do trans gets a mix city/highway of 13.5mpg, and 16mpg highway. I am having a intermittent idle issue, and once fixed, I might see a addition mpg on each measurement. The city/highway mpg is at speed limit, the highway one is at a average speed of 75mph, so not too bad for a rolling cinder block ! LOL
My van : 1989 Ford E-150 Econoline, currently named “WOLF-DEN IIâ€
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