6.5 MPG

[Marty Lau]

After doing a couple of upgrades and a bunch of maintance I took a 4,000 mile trip. I calculated the MPG when I took the time to fill right to the top of the neck. Most of the driving was at 72-75mph from Montana, Wyoming, Colorado, Kansas, New Mexico, Arizona, Utah, and back to Montana. So there was lots of hills and flat. My cruise was not working .
16.9, 16.5, 18.1, 19.45, 17.0, 19.89, 19.34

All except the 17.0 was highway, the 17.0 inlcuded a bunch of mixed driving. I had more fill ups but did not take the time to fill to the top of the neck and the tank could have held 2-4 gallons more so I didn't calculate MPG. I think part of the lower first 3 was related to Winter Blend #2 or could be took some time for new gears and water pump and things to "break in". Truck now has 160,000 miles not too shabby at 75 mph.

[Tough Guy]

Thats an average of approx. 18.2 MPG for the trip.

Thats really good, last year I went to Arizona and back (2400 miles) and averaged 19 but I was only driving 70 or so.

Cheers

[MTTwister]

My last tank - around town - 50% blend - a lot of 4wd (bad roads) = 11mpg. [img]redface.gif[/img] Definitely Need upgrades!

edit - btw the Header title blew me away - thank goodness you forgot the leading 1..

[chickenhunterbob]

Very good,

MPG appears a little better on the way home too, well, I suspect you may have had a ligher load coming home.

A load of quail probably weighs less than a load of shells and dogfood.

[Marty Lau]

I found out over lunch today that the first tank was 60/40 blend. It also included some mixed driving (70 miles apx. Yes I had less 16 gauge and 28 gauge shotshells and dog food coming home and a cooler full of frozen quail!!
The last tank was from Brigham City Utah to Boulder Montana. Plenty of up hill.

[vernj4]

16ga...........what is the auto transmixer you have installed? Of the chip, exhaust and boost controller, which items do you feel contribute to the fantastic mileage? when running 75 mph, how many rpm's are you turning? what size tires do you have?

[MikeC]

Geesh

To get that kind of mileage in mine three things have to happen.

1) Tailwind
2) Downhill
3) Kenworth pushing

Congrats, hope the good fortune continues.

Mike

[Marty Lau]

Originally posted by vernj4:
16ga...........what is the auto transmixer you have installed? Of the chip, exhaust and boost controller, which items do you feel contribute to the fantastic mileage? when running 75 mph, how many rpm's are you turning? what size tires do you have?

I have the 4L80E GM auto that came with the truck.
I have gotten that kind of MPG since I went to new down pipe and 3.42 ratio (@ 37,000 miles now have 160,000 miles), it's a 4X2 so I have less weight than a 4x4. I run the 245-75-16E tires and brand doesn't seem to make much change. at 75 mph it's turning about 2100-2050 rpm. If I slow up to 65 I pick up almost 2 MPG.
My MPG was suffering, but I found out I had no boost so I installed the TurboMaster boost controller and new injectors help bring things back to "normal". I figure I picked up 12% increase in MPG going from 3.73 to 3.42 and getting rid of that factory down crunched pipe.

[ 02-16-2004, 02:26 PM: Message edited by: 16ga SxS ]

[TurboDiverArt]

Originally posted by MikeC:
Geesh

To get that kind of mileage in mine three things have to happen.

1) Tailwind
2) Downhill
3) Kenworth pushing

Congrats, hope the good fortune continues.

Mike

How about drafting that Kenworth?

[TurboDiverArt]

That's great MPG. I just picked up MPG too and I will agree with you that unrestricting the exhaust or slowing down makes a lot of difference.

I have a Suburban K2500 with 3:73's, 8600 GVW. I drive highway almost the whole way to work each morning. Drive about 350 miles each week. I fill up at the same Hess station once a week so the tank doesn't drop below half a tank in the winter.

The truck has the stock factory exhaust (yes still has the crunched DP) and new stock size Bridgestone

[Dieselboy]

I know I'm no 6.5L, but I do have some good mileage to share! Lately, with all the Banks boost leaks fixed, and dual 195F thermostats, I've been averaging 17 mpg with an all time high of 18.5. That with 15psi of peak boost, DB2-4878, T prechambers, MHI TE06H, and my 700R4. The same setup with 180s yielded about 15 mpg, and 160s gave about 14.

[Marty Lau]

Art;
Glad the clean up helped, you will see an improvment when you change that @#%&* down pipe.
I did the gear change first then about a month later the down pipe and exhaust. By seat of the pants I gain back most of power lose from gearing.
Your truck will run cooler and pull better and use less fuel all for a no maintaince item. I figured pay back on exhaust and gear change was like 60,000 miles and that was at $1.15 per gallon. So I really ahead of the game at $1.60 and 120,000 miles later. I also found out when I had the 3:73 gears that I did pretty well at 63 mph turning about 1950 rpm.