My father has a 99 L. He has used it mostly as a display truck for his business. He has decided instead of buying another truck he will convert the L to a commuter truck. I'm trying to figure out ways to get better gas mileage for him. We thought gears and tires would help a little. Are there other things that can help out?
What are the highest avail. gears for a 9.75 rear end, currently has 3.73? I was thinking a 285/60/16 tire, which is about an inch taller.

The most we could get as a trade for his perfect 99 with only 6000 miles was $20k. It would cost the same to get a new '01 standard cab 4.6L xlt on the x plan. This is why we want to make it a commuter.

 

99 Lightning has 3.55 gears unless you changed them. Keep you foot out of it and you can get decent mileage. I have seen 19 on the highway with the cruise on. Narrow and taller tires will help some. Bed cover will help.

 

A Lightning will never get great gas mileage. Instead of trying to improve fuel economy of a 4700 lb truck with a V-8 and poor aero-dynamics, why not just buy a car designed for commuting?

 

If you want to make a big difference in the rear gear ratio with tires, stay with the 18" and go with the Bridgstone 285/60/18.
The 16" tire will only be 1.01" taller. Wereas the 18" 285/60/18 will be 3.01" taller. Speedo will read 10.5% slow.

 

Remember that thread a while ago about moving the boost actuator down (?) a little to make the blower come on sooner? How about moving it the other way (up) to make it not come on at all?

Pardon my lack of technical terms, it's been a while and my brain's full of other things.

-Ollie

 

Try to get a hold of masterloggie--he has a 2000 L with a bed cover, Nitto tires(bigger, but d/k their size), stock wheels, and a 4-way flip chip with one 'side' set up for economy driving. He told me a few months ago that he got 20+ mpg on a trip to Ohio and back(to middle GA). He said he keeps meticulous mileage records. His email is masterloggie@hotmail.com.

Btw, the bigger tire 'killed' his 1/4 mile times.

Dan

 

I think that's a first for this Message Board. 'How do I make my Lightning slower?'

I agree with 351stang. Try swinging a commuter car or truck (Ranger?) instead.

 

https://www.f150online.com/forums/sh...threadid=51961
https://www.f150online.com/forums/sh...threadid=51954

Here are two threads in which I've asked this before an no one knew the answer then. I think there are several things that can be done to help the commuter L.

Tuners (correct me if I'm wrong) are firing all cylinders when shifting compared to 4 cyl stock. Shoot, I've seen advertised (no expertise at all) cars that when idle, shut down a few cyinders. Is this something to think about when set on cruise; shut down a few cylinders?

Isn't there a boost dump similar to that on Turbo chargers that can be computer controlled. Most of the time leave the boost open. At WOT close it down and give it everything its got.

Change the shift points. Don't change at the perfect, most preciese time to go faster through 1/4. Change when best suited, more like the Ranger or someother non-Speed focused vehical.

Is there such a dyno that shows what RPM is most efficient rather than most HP? (My idea is off but you get the pic.)

And for Heavens sake, put a brick under the petal. Don't be a lead foot.

Now. if you're one of the people that drives the Beamer to work for MPG and drive the L for thrills and excitement, then you won't be interested in makeing it more efficient. But they've priced it below the rolls royce level, so more people can afford it, but only it. Not some other vehical for fun. Now understood, this is no rice burner. If I really wanted MPG, I'd get some 1.6L POS. But I hope you get the idea. So I'll get off my soap box now and ask again; Is there anything to be done to increase MPG !?

 

Thanks for the help guys.
When my dad bought the 99 it had the 3.73 gears on it. I thought about moving the boost actuator up thanks for confirming that it may be a good idea. That is a good idea for the tire size that way he won't have to buy new wheels. I'm still looking for a 3.08 gears for the 9.75 rear end.

He uses this truck as advertisemet for his business, so he would rather drive it than another truck because it will get more attention. He also tows a trailer. It is usually only a couple thousand pounds maximum.

 

I think the range of advice has been pretty well covered. I use my truck as a daily driver, and range on mid to high 13's for MPG by just driving sensibly. Or perhaps you can say that my lowering the Lightning helps with highway mileage, but I don't do too many cruising highway miles each day.

Anyway, not to be a 'scavenger', but... if your father ends up removing his 3.73 gears, I would be interested in buying them. Or perhaps trade my stock 3.55 for his 3.73, if I can figure out how to schedule that. Thanks!

~rick