Quote:
Originally Posted by gaorenst
what i need to know is what made the biggest difference for him. I've put a flowmaster exaust in my truck, superchipped my truck, and put cold air intact but nothing near his results.
|
Those mods might help, but I suspect the Superchips on 91 would be the real difference maker. I got another 1-2 mpg with that, depending upon my right foot. CAI won't really help MPG, but will help hammer down HP. A Flowmaster exhaust I am not sure. I've not hit Big Dave's numbers yet, but I have hit 25 mpg a couple times. I suggest you focus more on aerodynamics. Our trucks are about as aerodynamic as a full sheet of plywood going into the wind... I am prototyping a kit right now, and if I can get some kinks ironed out, I'll be able to market it... Work keeps getting in the way though.
I also suggest following some of the 100 tips here at Ecomodder. I do not recommend engine off coasting...very bad for the auto tranny. Our trucks do have a Decel Fuel Cutoff (DFCO), but it is meant for braking, not fuel savings. It doesn't engage until the truck shifts up to 4th, and locks the TQ, and that is going downhill...
max_frontal_area, no, I did not consider the return fuel flow. I did notice when the engine settles down it will drop to 0.4 gal/hr, but at 60 mph on the highway, I am doing very good to get below 2.5 gal/hr (that's 24 mpg). No, my 4.7 does not have MDS...5.7s only.
Now I've added a topper, pushing my drag coeff a little higher, I think. :doh:
I have a trip this weekend up I-44, where I'll be rechecking the mpg to see how the truck does with some aero tweaks.