No. I never run above 70 mph, usually only 60-65. I never said anything about running 80 mph.

 

Something is weird here...

I've been doing some serious studying of fuelusage and EGT... Basically thefaster you travel the morefuel you use the higher theEGT will be. Give you an idea...

25 MPH is about0.8 GPH (Gallons per hour) and 400*F on EGT
45MPH is about 2.0 GPH (Gallons per hour) and 500*F on EGT
55 MPH is about3.0 GPH (Gallons per hour) and 600*F on EGT
65 MPH is about4.0 GPH (Gallons per hour) and 700*F on EGT
(Information from my ScanGauge II)

I don't know how your going faster and burning less fuel it doesn't make any sense.

65 MPH /4.0 GPH= 16.25 MPG
55 MPH /3.0 GPH =18.33 MPG
45 MPH / 2.0 GPH = 22.50 MPG
25 MPH / 0.8 GPH = 31.25 MPG
(Information from my ScanGauge II)

These are the MPG I see on my ScanGauge II as I drive...

 

Well this is what I've come up with. 65-70mph 15mpg. 55-60 16.2mpg. And this was run on a perfect day. No wind, 60 degrees. And beautiful. I think I'll stick with 65-70mph for the small difference that it makes.

 

Hey Mike, isn't your truck a standard tranny? If it is, then your RPMs at 55mph would be lower than 04QC's right? An auto would inherantly have slip in the TC Vs. a clutch which would lead to higher RPMs at equal speeds which would lead to higher EGTs and boost. Or am I bassackwards here?

 

Little difference... Hmmm... I'll prove differently...

16.2 MPG x 35 Gallons = 567
15.0 MPG x 35 Gallons = 525

567 - 525 = 42 Miles difference farther!

42 Miles / 15.0 = 2.8 Gallons more used

$4.00 x 2.8 = $11.20 Dollar savings per tank.

Well... Yes I got a 5 Speed. But the gear ratio between auto and manual are a bit different. But yes the auto tends to have slipage in the TQ where the energy is turned into heat (reason why trans temp gauge is required). But once it locks up the slip should be gone. This is why a lot of people put a mystery switch in. But I would figure a higher RPM's but not a rise in Pyro because the HP is being wasted in TQ (slippage) maybe a rise is boost. Just thinking in theory and logic...

 

How much of the difference that 04qc is seeing could be from the box that he is running, as compared to the box that you are running Mopar man or the box that I am running?

 

On manual transmissions, there s no difference between 5th on a 5 speed and 6th on a 6 speed. You top gear and low gears are exactly the same on both trannys. The only difference is that the 6 speed has an extragearin the middle to help with towing.

 

Inderstanding how the box works is a big part of it. The part of it is SPEED. There is no way anyone can prove to me that you can get better MPG's a a higher speed. Pyrometer is a dead clue of how much fuel you burning... Higher the pyro the more fuel, the lower the pyro the more fuel your saving...

You right abuot the above...

Actually there is a small difference in top gears... As shown below...