Posted by moss6 on January 16, 03 at 17:54:02:
In Reply to: 4.10 rear to 3.73 or 3.42? would it greatly improve gas mileage with 8.1l? posted by Joe on January 14, 03 at 17:19:09:
Joe,
From reading enumerous posts on mileage claims from 8.1 owner's for nearly two years now I would say that the vehicals geared 4.10 are on a par mileage wise with the 3.73's and possibly even have a mileage advantage. You state that you are getting 10mpg in town, we are geared 3.73 with our 2001 8.1 and have always hovered around the 9 mpg mark in town until I had Wester's Garage reprogram the PCM. We now are always above the 10mpg mark in town but I wonder if it wouldn't be better with the 4.10's.
Now on the highway at 75mph the mileage was always in the 15mpg range if the wind wasn't a factor, sorry but I haven't had the opportunity to check highway mileage since Wester's did the reprograming, highway mileage is probably in the advantage of the 3.73 but not by a substantial amount.
A note for Bob:
If you use a competent PCM programer (not chip) there is no need to use fuel with an octane rating that is higher than 86.
Randy