Mpg?

[Artemis Entreri]

What kind of Mileage are you diesel guys getting out of your diesel blazers? Need something with good(better) mileage then my k5, figured diesel might be the way to go and id love another toy, if the mpg was worth it.

Thanks

 

[tRustyK5]

My daily driver '83 1/2 ton pick-up gets 24.3 mpg week in and week out. This is 70% highway and 30% city. 100% highway it'll near 26 mpg. 100% city it still manages 18 mpg.

6.2, 700R-4, 3.42's and 235/75 R15's.

My old 81 K5 before I had overdrive used to get 16.5 mpg highway with the 6.2. That was 5" of lift, 39.5's, 4.56's and the poor 6.2 spinning at 2600 rpm. I figure 20 mpg was more than possible with overdrive...

Rene

 

[AJMBLAZER]

Rene's numbers are typical. Some of the guys with 4x4 Blazers and the 700R4 have reported up to 25mpg on the freeway but that's with highway gears and small(ish) tires. However even getting anywhere over 13mpg with one of these around town is awesome when you compare it to a similar gas powered truck.

 

[thedrip]

I'm only getting about 10ish around town... but theres a few things contributing to that
6.2, fuel turned up
th350
4.56 gears and 42" tires
ALL my driving is in heavy traffic, during rush hour, and I drive the truck like I stole it. It's WOT more often than not

It also does a number of drive 1/2 mile, sit and idle for 30+ minutes, drive 1/2 mile type runs during the day.

 

[tRustyK5]

The really rough rule of thumb is 1800 rpm cruise rpm on the highway (~65 mph) will net you the max fuel economy. This is typically 25 mpg for our trucks, with lower lift and smaller radials.

Every extra 100 rpm at 65 mph loses you approx 1 mpg.

If you start crunching numbers using the online gear calculators you'll soon see how valuable an OD tranny is for these engines. It takes aggressive gearing to get them to where they feel like they make good power, and then OD to keep them in the mpg sweet spot on the highway.

I only drive my '83 to work and back...so the variables are well defined and don't change much if at all. I've been playing with things like tire pressure to see what if any effect it has on my fuel economy. Went from 32 to 37 psi and saw no appreciable difference in economy. Next up is an oil change which it needs anyways, new air filter, and new fuel filters. Exhaust is soon, likely 2.5" or larger duals.

Beyond that the only other stuff i could do is get rid of the huge camper mirrors (95% for sure that's gonna happen) and lower it 2"/4" (95% sure that's not gonna happen )

It's my rolling 'experiment'...

my guesses before hand. Fuel filters...no gain. Air filter, .5 mpg gain if it's as dirty as I think it is. Camper mirror delete...maybe .5 mpg (they do have a pretty large flat surface area). Oil and filter, no appreciable gain. Lowering it...no gain. Exhaust...possibly a .5 mpg gain. I think this one really depends on how poorly the currect 2.25" duals with turbo mufflers flows.

So I might squeak up to a tick over 25 mpg on my regular drive.

Right now I get 420 miles from one tank, and it takes just over 17 gallons to fill. That's two weeks of driving for me.

Rene

 

[AJMBLAZER]

So I might squeak up to a tick over 25 mpg on my regular drive.

Right now I get 420 miles from one tank, and it takes just over 17 gallons to fill. That's two weeks of driving for me.

Rene

I hate you and your pristine diesel pickup...

 

[tRustyK5]

Rene

 

[6.2Blazer]

Back in the mid to late '90's when my '90 was stock except for tires (6.2/700r4/3.73/32" mud radials) it consistently got 17-18 mpg and most of that driving was city or backroads (very little constant speed driving) and was driven by a teenager (let's just say I got a couple of speeding tickets in it). In other words, pretty bad driving habits for mileage.

Never checked it on highway trips.

 

[Drey]

I drive my 86 2wd hard. Never get much below 17 Ive broke 21 once although I think my truck has to high of gears, at 55 it almost seems like the motor is bogging down. I think If I got it out on the interstate and ran 65-70 with it I would do alot better.

I havnt check my mileage in the last 2 tanks but I turned my pump up 1/4 turn and it doesnt downshift out of OD hardly at all anymore when its pulling hills. I havnt noticed anymore smoke then before either.