What kind of mileage do you guys with 6.2 getting?

[Eric M.]

What are you guys with 6.2 diesel, T400 combos getting for milage? Give me truck size (Blazer, Burb, 1/2, 3/4 or 1 ton), gears, tire size and miles on engine.

Thanks,

Eric M.

 

[tRustyK5]

The TH400 rigs don't get astounding mileage...probably 17 or so. Any of the 700R-4 rigs get low to mid 20's all day long on the highway.

Anyways, more specifically I have two 6.2 rigs here.

#1 is an 83 1/2 ton. 6.2, 700R-4, 3.42's and 235-75-15's. dead stock.
In town, 17.5 mpg - 19 mpg. Freeway cruising at a steady 65 mph it gets 26 mpg.

#2 was my K5. 6.2 SM465/205, 4.56's with 40's. Heavy, horrible aerodynamics, big bias ply tires, no overdrive. In town it'd get 14-15 mpg. On the highway my best ever was 16.5 mpg at 65.

To get good mileage out of them you need to gear em so that cruise rpm on the highway is as near to 1800 rpm as you can get it. This is where the OD tranies really help...you can keep the kind of gearing that makes them move nicely, and still cruise economically. looking at the above examples, the '83 pick-up cruises at 1850 rpm, the K5 cruised at nearer to 2600 rpm.

Every 100 rpm over the magic 1800 loses near enough to one mpg...

Hope that helps.

Rene

 

[Eric M.]

Thanks,

That helps. I found an 84 K3500, dually, 6.2, T400 and the seller is claiming it gets 25 MPG. I'm now driving a 4 cyl. Mazda to the city (25 miles each way) and switching to my truck for work. If I can get a truck that gets 25 MPG, I'll drive that!

I'm thinking this guy is pushing it a bit.

I'm assuming 4.10 gears and 235 85 R 16 tires.

Thans,

Eric M.

 

[tRustyK5]

16-18 would surprise the hell out of me with that combo...unless he has some sort of gear vendors OD or something similar. With some sort of OD he might see low 20's, but the TH400 is a power eating monster that hurts economy. 25 mpg? Only if he was coasting without the engine running half the time.

I think he is hoping for someone to take his word for it in a market of steadily decreasing resale values for the bigger older stuff(diesel or not)

Rene

 

[Eric M.]

I think he is hoping for someone to take his word for it in a market of steadily decreasing resale values for the bigger older stuff(diesel or not)

Rene

I think you've got it. Kind of a risky move to put 25 MPG in the ad these days. It's a good way to end up in small claims court, especially if the EPA ratings for the rig new weren't that good.

I wasn't really looking to buy, but was surprised when I saw the ad.


Eric M.

 

[tRustyK5]

I agree, risky move on his part.

Rene