65fury

So i took a trip to Utah towing around 4-5k pounds and did between 70-90mph the whole way, except on the really steep hills i kept it around 55mph, anyways during the trip i averaged 13.5mpgs the whole way with a few 14.5mpg runs. My timing was at 15* and i had stock dvs, when i got home i still averaged about 14mpgs everywhere i went, i then installed my laser cut dvs for a lil more power, and still..... no better than 14mpgs. So i upped the timing( a bit to much probably) to 21* and still...... 14mpgs. Except on the highway i can get about 16ish mpgs........ so whats up with my mileage? no matter the timing or amount of fueling i mess with... my mpgs suck!... any ideas? thanks


jason

Mike D

My uneducated guess is the 6" lift and tire combo.

65fury

hahahahaha...... ya... thats a good possibility.... its just that i know some guys with the same combo and they were running 38's and got 20-21mpg towing i guess unless i got bored and threw stock suspension on my truck... i wont know for sure

jason

trksrfun

im sure your speed played a big role in that, what are your speeds now on the highway without towing.... towing at 70-90 will kill mpg while 65 and not towing will help get you more...

65fury

Well, when im not towing i do the speed limit 65mph, only reason for the speeding before is i was following people and i wasnt paying for fuel, but no matter the speed or style of driving...... i never get better than 15ish mpgs.


jason

DodgenIt

My brothers 96 12v was the same. No matter if towing or driving, he always got 15 mpg. Highway would bump up to 17, but around town no matter what he always got 15. He had that truck for 5 years, Had us stumped.

Lil Dog

You built the tranny, what torque converter are you using??

65fury

Well i had a custom one built in Idaho at a tranny shop that a friend built, since he knew how my truck ran and the hp i was pushing, but someone screwed up on shipping and i had to have my truck running that weekend for my trip to Utah cause i was towing a trailer... and i had to go with a no name triple disk convertor... from a local shop instead, still cost me $1100 for it too, but its held 500hp, until it started slipping and i just replaced it under warranty, but i had to use another convertor by the same company..... so i still dont like the way it locks up or holds. the company is Recon. Definantly not a performance company in any way... they mostly manufacture stock TC for all makes and models.


jason

matthais

I would say speed as well 90mph is dumping the fuel.

YOUNG GUNS15

i would say your 435's are killin it also, when i had those on my truck i always got between 13-16mpg and no higher...

Lil Dog

Just wondering if that TC is just not working properly. A slipping/loose TC is good for a couple MPG. Do you feel the lock up? IE the RPM drops hard and fast..

65fury

Well i wont disagree about the injectors.... although... a while back when i had this same motor setup, and a 3 speed auto transmission and 3.07 gears.. i got 21mpg once... As for the convertor... around town and highway before i lock up... it just sounds like im turning rpms and not going anywhere. Once it locks up it seems to hold and the rpms do drop. Under WOT and locked up.... well i think it kinda slips, but i dont know for sure.

Jason