6.5TD MPG Hiway mileage Poll!

[Cowracer]

Here ya go 16gaSxS...


The DuraBux guys have a MPG poll so lets have one for us 6.5TD owners so we don't feel left out.
Driving on the Highway NOT Towing at 65-70mph what is the MPG (us) are you getting?

1. less than 12 MPG

2. 12-13 MPG

3. 14-15 MPG

4. 16-17 MPG

5. 18-19 MPG

6. 20-21 MPG

7. better than 21 MPG

8. Just looking

[Tough Guy]

Good Job Mr.Cowracer!! Who doesn't love polling!

Chris

[jeffscarstrucks]

I haven't been here for a while so I better get caught up! I just checked mine on an empty road trip last week and it was right at 18 mpg.
'93 crew cab dually 5speed un-touched with 150k on the clock. I did order some guages today as I had better pay a little closer with those miles....a little tune up is way over due. Thanks to all who have helped me out in the past , JEFF
I miss this place when I have been gone a while!

[GMC Hauler]

Can you include the rear gear size... That affects everything

[16gaSxS]

Can you include the rear gear size... That affects everything

GMC; It's true but also driving habits, truck size, 4x4 vs 4x2, tire size, tire inflation, & maintaince all effect your MPG. I'm open to idea's we can set up to 10 questions on a poll. How would a gearing & MPG poll be set up? Any ideas?

[GMC Hauler]

GMC; It's true but also driving habits, truck size, 4x4 vs 4x2, tire size, tire inflation, & maintaince all effect your MPG. I'm open to idea's we can set up to 10 questions on a poll. How would a gearing & MPG poll be set up? Any ideas?

We'll you hit many, but let's see:

1. SB Reg Cab truck, SB X cab truck, LB Reg CaB truck, LB X Cab Truck, Suburban, Tahoe, other
2. 1500 4x2, 1500 4x4, 2500 4x2, 2500 4x4, 3500 4x2, 3500 4x4, 3500 duals 4x2, 3500 duals 4x4(do all 3500's have duals? if so, delete that portion of the question)
3. Fuel Additive no or then selections which basically find out how many oz additive per gal of diesel (1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5
)
4. Condition of vehicle: Excellent, Very Good, Good, Fair, Poor
5. Driving habits: Conservative, moderate, Lead foot (and add city/highway to each one of these)
6. Thermostat 160, 180, 190, 195, 200, 205, 210, 215, none
7. Overall rear gearing (rear end gear calculated with tire size to give an effective rear gear) (Gear Vendor guys must calculate this into account to compensate for the gear they are usually in)
8. Stock Air Filter/Replacement upgrade air filter/Cone Air filter
9. Intercooler Large/Intercooler Small/None
10. Mechanical Boost control boost Level 6,8,10,11,12,13,14,15,16,17,18/ ECM Boost Control
11. Kennedy PCM (a option for each level he has), Heath PCM 1.0, 2.0, Westers (and any others I may have forgotten)
12. Exhaust stock/stock kitty removed/stock muffler removed/stock both removed/3.0", 3.5", 4.0", 5.0" (is anyone offering 5"?)

You could probably get rid of question 4, asuming everyone's vehicle is average, or make an individual poll for excellent, very goog, good, fair, and poll (or just make 2 or 3)

I know that still makes 11 left, but it's tough to get rid of any of those...

How many options can each question have for an answer?

[Parrish206]

My MPG averages 14.8

_________________________
95 3500 ext cab,K&N air filter
no other mods

[Kenneth]

I have a 94 with 152,000 miles on it with no motor work. The truck is an ext. cab long bed, 3/4 ton with 3.73 gears. Everything is stock except a Heath Diesel lift pump. On freeway I get an average of 22 mpg and in town/highway i get an average of 17-19 mpg.

[dually0185]

18 MPG. That's not bad for a tank.

[sjgarcia]

Freeway: 13 to 14 mpg cruising at 75 mph.

City: 12 to 13 I think my dear wife likes to hear the diesel roar as she leaves the stops. :-)

4.10 rear end
Automatic trans.

Steve

[7thdaypope]

This is a great post from some real folks driving real trucks for real miles.

I am interested to know from those of you who have 3:42's under your rig if you have issues with lack of power especially while towing.

The gearing is great for mileage as we can clearly see from the posts, but can you pull a trailer up a hill without leaning forward in your seat?!

I'm deciding how to get the RPM's down under 2,000 on the highway, whether to change the gearing, or go to taller tires, or a combination of both.

Give me your input, what you have done, what you have seen or heard.

[JohnC]

I am interested to know from those of you who have 3:42's under your rig if you have issues with lack of power especially while towing.

I had a standard in mine and pulled a 2 horse trailer, about 5000 lbs. You had to work the gears a lot. It would have been better with an auto, although I doubt the mileage would have been as good. We saw 17+ mpg towing on reasonably level ground.

If I had been any heavier, I would have stuck with the 3.73 gears.

[rustyk]

I only have ~1,000 miles on it, but the Suncoast tranny rebuild, and its TC and input shaft, have apparently increased fuel economy from 10.5 to ~11.5 mpg.

[Edahall]

This is a great post from some real folks driving real trucks for real miles.

I am interested to know from those of you who have 3:42's under your rig if you have issues with lack of power especially while towing.

The gearing is great for mileage as we can clearly see from the posts, but can you pull a trailer up a hill without leaning forward in your seat?!

I'm deciding how to get the RPM's down under 2,000 on the highway, whether to change the gearing, or go to taller tires, or a combination of both.

Give me your input, what you have done, what you have seen or heard.

My 1982 Suburban non turbocharged 6.2 has a 3:08 rear end and I tow a 26 ft airstream weighing close to 6k lbs. I'm using 30x9.50 15" tires. I tow in direct drive (3rd gear) and at 60 mph, the engine turns over at around 1900 rpms. It'll pull the smaller hills in direct drive but on steeper hills such as a 5% grade, once the speed goes under 45 mph, I shift to 2nd gear and then the engine puts out good power. I can pull as fast as 60 mph (3500 rpm) in 2nd gear if needed. I did some calculations and 3.08 gears with 15 in tires in direct drive is similar to 3.73's and 16 in tires in overdrive. Also, most transmission are the most efficient and can withstand the most torque while in direct drive.

[gerritk]

This is a great post from some real folks driving real trucks for real miles.

I am interested to know from those of you who have 3:42's under your rig if you have issues with lack of power especially while towing.

The gearing is great for mileage as we can clearly see from the posts, but can you pull a trailer up a hill without leaning forward in your seat?!

I'm deciding how to get the RPM's down under 2,000 on the highway, whether to change the gearing, or go to taller tires, or a combination of both.

Give me your input, what you have done, what you have seen or heard.

I don't tow heavy very much but I did last weekend. It was all flat roads in south Louisiana towing a fully-loaded 6 X 12 U-Haul plus rooftop carrier plus a cabin full of people, probably around 5K lbs or so. The vehicle ran well and we had to cross a couple of large bridges over the Mississippi and Atchafalaya rivers. I was able to maintain 55 mph with about 65% engine load showing on my Garmin EcoRoute and about 185 degrees intake temperature going uphill (that's about all that will show on this setup). I don't have a gauge pod installed yet. If I were towing heavy loads all the time I'd want 3:73's, but the mileage with the tall tires and 3:42's running free is around 22-23 at 65 mph and that is how I usually travel. I also installed a set of rear disc brakes since my last post. They definitely stop a lot better. I didn't notice any change in the highway mileage but I did gain about 1 to 1-1/2 mpg in town, due to the lighter weight, I suspect. All-in-all we now have about 175,000 miles on our Sub and we absolutely love it.

A few weeks ago I made a trip out to San Angelo with it (no trailer) and ran 70-75 mph the whole way. I got about 19 mpg in the Texas Hill country at that speed and was never lacking for any passing power.

[urcableguy]

To "dually0815".........Youre truck looks awesme,was wondering if i could get a few pics emailed?Just purchased exact truck and would like to do the exact lift and size tires..Good Looking Truck!!! Thanks, urcableguy@hotmail.com

[bassbone63]

1997 Suburban
1500 1/2 Ton (snicker snicker)
6.5L factory engine NO mods
3.42 gears
42 gallon tank
150,000 miles
highway 24mpg @ 65mph
city 15 - 18mpg depending on season

Not bad for something that weighs as much as a semi

[bbudus]

gets 16-18, doesnt matter if it is in the city, on the highway, pulling, towning, loaded, i hauled a 450 gallon water tank all summer, avg. 16.4, 4.10 gears, but I only drive the truck 63 mph, on the freeway i go 70.

[rustyk]

:
Originally Posted by rustyk
Well, I get about 9.3 mpg, but then my 6.5L TD is in an 18,000 lb. class A motorhome.

Things do change - with my replacement Peninsular Diesel AMG 230 HP (custom spec'ed) 6.5L TD, mileage is nearly 11 mpg...

Do a little here, do a little there...with the Suncoast HD tranny and TC, redoing the diffy (Someone had been in there previously and the pinion bearing clearance was way tight), and fixing a stuck caliper, consumption is now averaging 12.2 mpg over the last 5K miles.

[turbonator]

Our 6.5L in the ''Pugg'' is getting just under 14mpg......(C-5000 truck)...LOL.