• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

Ultimate Mileage Thread!

Pillow

Pillow

Recruit
Messages
500
Reaction score
2
Location
Warrenton, VA
Please post your experiences with tips and tricks that increased your mileage for your 6.5TD rigs!

I will keep this updated with a list of known ways we can decrease fuel consumption.

These are open for debate, but here are some that I see:


  • High flow air intake/cleaner
    High flow exhaust system (especially the downpipe)
    Light Wheels - PYOs at 18 pounds is hard to beat
    LRR Tires with slender sizing 235/85 or 245/75
    Stock 195F GM/Delco thermostat(s)
    Stock air splitter below bumper
    Stock ECU
    Stock vacuum wastegate system
    Turbo conversions - ATT or HX40II (both proven to increase mileage)
    ??? Feed The Beast ???
    ??? Walbro fuel pump ???
    ??? Fuel Treatments ???

Keep 'em coming!
 
Cruise control
Staying right around 2000rpm
Heath CAI
4" exhaust
Tests with ATT did provide 18-19+ MPG at highway speeds around 2000rpm w/ cruise
GM-5 is showing consistent 17+ mixed city and back roads. 18s on the highway.
AC off
Tires properly inflated.

If I lowered the truck and returned to stock tires with highway tread....
 
How about synthetic oils they claim to give better mileage don't know if it really true. Fuel treatments are the same way all claim to give enough boost in MPG to pay for themselves. Using 3.42 gears. Best one is keeping your foot from being to heavy on pedal.
 
gearvendors OD unit.
bed cap/tonneau cover.
According to studies backed by the department of energy, the average car will be at its advertised MPG at 55 mph. But as the speed increases:
- 3% less efficient at 60 mph
- 8% less efficient at 65 mph
- 17% less efficient at 70 mph
- 23% less efficient at 75 mph
- 28% less efficient at 80 mph
http://www.mpgforspeed.com/
 
A Team Turbo towing full throttle full load on 7% plus grades got me into double digit MPG's. Slightly better than gas 7 MPG with the GM3 turbo to 10.4 MPG with the ATT. And this was with 6.2 precups limiting boost to 17 PSI.

~2100 RPM is peak torque and at full throttle towing flatter areas with the GM3 I was near 11 MPG. MPG falls off quick over this RPM with the GM3.
 
Good stuff! Keep 'em coming.

The only one here that I did not see a difference with was switching to Amsoil (synthetic) gear oils. Not a complaint, but no noticeable difference to me on mileage.

I do believe that fuel treatment does help mileage... But perhaps just enough to pay for itself. It does help on start up and IP lubrication though IMO.

The Michelins came in today, so give me a couple weeks and I should be able to tell you all if LRR tires make a difference at all. I hope so!
 
Moving somewhere flat would likely help me a ton. Uphill both ways around town, constant grades on the interstate keep boost at 4 to 6. Sucks the fuel.

I want a 1982! sounds great!
 
I just got 19.5mpg on winter diesel today. That is with an ATT, 1/4 turn on the DB2831-4911, a 3 inch downpipe to 4 inch exhaust, and 2300psi pop injectors doing 70mph the entire trip (2500rpm)
 
I got 22 MPG the other week. Straight piped and intake is all that's done. Pretty much did 55 for the 220 miles I did in those 3 days. Haven't gotten that since :/ mainly due to fuel leak.

C2500. 4.10's. RCLB.
 
When I run around on the backroads here I do 55 ish with the torque converter locked and I bet I get around 22 or a little better. When I pulled the tactor up from laporte IN I did the same pulling the tractor and probably got close to the same MPG.
 
Changed wheels and tires to PYOs with 235/85R16E Michelin MS2 tires (Low Rolling Resistance).

+2 MPG!!!

Pretty bad traffic and still ended up with 17.2 City/mixed. My best ever for in town traffic!

Also I just installed a Walbro lift pump... Not sure if that will help mileage or not, we will see in another week or so.
 
Pillow said:
Changed wheels and tires to PYOs with 235/85R16E Michelin MS2 tires (Low Rolling Resistance).

+2 MPG!!!

Pretty bad traffic and still ended up with 17.2 City/mixed. My best ever for in town traffic!

Also I just installed a Walbro lift pump... Not sure if that will help mileage or not, we will see in another week or so.
Click to expand...

Wouldnt a little taller tire give you less rolling resistance?
 
Previously I had 265/70R17E on Hummer H2 wheels with TreadRight recaps on Mich LTX AT casings with Bridgestone Revo tread pattern. Clocked perfectly at 60 MPH.

The new set I have only clocked at 40 MPH but the 235/85s were spot on at that speed.

From my experience either of the above sizes match up correctly with the speedo program... The 245/75 setup stock is -2-3 MPH indicated.

IMO the reason for the mileage bump is a couple factors:
1. Lighter wheels (18# each)
2. Lighter tires (43# each)
3. LRR tires
4. Street tread versus AT
5. Narrower contact patch

My commute in total is about 80 miles a day... And takes roughly 2-2.5 hours depending on traffic. So I am not moving very fast. Normally I am between 65-70 on the open stretches and below 40 in the stop and go stuff. Yah, I know a crappy commute. :(
 


55-62 mph checking fields, pulled my large round baler @50 MPH for 30 miles, and herded calves down a back road 3 miles (after they got out). NOT BAD!!! :hihi:
 
Everything about your wheel/tires were working against you before. Glad the change helped.

The 235/85/16 tires should be 31.7" tall, and the 265/75/17 tires should be about 32.6" tall (unless tread all worn and walls sagging). So your new tires should be spinning a little faster, your RPMs up a little. This is good for in town, because either tire is tall to be paired with 3.73 gears, and takes more engine power to get it going than it would an even shorter tire. That and its not good with an automatic transmission to cruise at the torque converter's stall speed around 1500-1600rpm because it slips and wont stay locked. Better to be at 1800-2000rpm while cruising which you can probably do with a downshift if going around town up to about 50mph. Thats part of the reason a manual can get better MPG, not having to worry about the stall speed and lock. With a 4L80E , and tall tires without really low gears if youre below 50mph I would make sure its in 3rd to get good converter lock up, and if stopping the engine uses less fuel if in neutral or park (another reason manuals do better with MPG).

Now with your tires being a little shorter shorter it also means the drive shaft will spin a few more times per mile, which to it seems as though it drove further. So a small amount of the gain may be that youve always gotten a little better MPG than odometer was representing.
 
You must log in or register to reply here.
Back
Top