Av MPG Readout vs Calculated

[Jim Allen]

Great info, Jack. I will keep the mitts off the reset!

I'll now have to go back and retest my calculated MPG and compare it to the AVG mpg from the Gryphon to determine an error. Considering that if the unit holds only 100,000 samples, over a 360 mile tank of fuel, resetting at fillup would have skewed the initial reading bigtime but by the end of that tank, it should be pretty stable.

[Jackpine]

Originally Posted by Jim Allen

Great info, Jack. I will keep the mitts off the reset!

I'll now have to go back and retest my calculated MPG and compare it to the AVG mpg from the Gryphon to determine an error. Considering that if the unit holds only 100,000 samples, over a 360 mile tank of fuel, resetting at fillup would have skewed the initial reading bigtime but by the end of that tank, it should be pretty stable.

Once upon a time I suggested that probably the Gryphon Avg Econ would differ from the true Econ by a fairly "fixed" amount. I don't know if this is true, because I only monitor Inst Econ. However, if it does, then it's simple to just apply the correction mentally.

Inst Econ certainly gives you a feel for "excess" usage or economical usage. However, I find I just tend to drive the way it "feels right" to get me where I want to go and to hell with the mileage.

I've been monitoring mileage using a spreadsheet. Over 5671 mostly highway miles of non-towing, I averaged 15.1 mpg. Towing my 3600# trailer over 3559 miles, I got 12.6 mpg.

- Jack

[ticopowell]

Originally Posted by JackandJanet

Once upon a time I suggested that probably the Gryphon Avg Econ would differ from the true Econ by a fairly "fixed" amount. I don't know if this is true, because I only monitor Inst Econ. However, if it does, then it's simple to just apply the correction mentally. That is what I have noticed, I dont know the % but it seems to be about 2 mpg's difference

Inst Econ certainly gives you a feel for "excess" usage or economical usage. However, I find I just tend to drive the way it "feels right" to get me where I want to go and to hell with the mileage. HAHA I wish I could say that... getting 13 mpg's doesnt let me... well my wallet wont let me at 13 mpg's

I've been monitoring mileage using a spreadsheet. Over 5671 mostly highway miles of non-towing, I averaged 15.1 mpg. Towing my 3600# trailer over 3559 miles, I got 12.6 mpg.

- Jack

Just thought I would comment on your post

[Jim Allen]

I pretty much drive by the instant economy. Kinda like one of those vacuum "Econo-Mizer" gauges they used to sell It's not so important what the actual number is, I just try to keep it as high as possible. On my truck, it's amazing how much less fuel it uses at a steady 55 than above 60.

[Jackpine]

Originally Posted by Jim Allen

I pretty much drive by the instant economy. Kinda like one of those vacuum "Econo-Mizer" gauges they used to sell It's not so important what the actual number is, I just try to keep it as high as possible. On my truck, it's amazing how much less fuel it uses at a steady 55 than above 60.

YES! But - I've posted this before. When I added the Gotts Mod, I found I could get about the same gas mileage in the 70 MPH range that I used to only get at 55-60. (Of course that lower speed mileage went up too.) Why? I don't really know.

I also believe you can get better mileage if you don't use the speed control on the highway, because it will try to keep you at your set speed going downhill and then will use more gas going uphill rather than using the energy gained in the downhill "coast". But again, I'm lazy, so I tend to use the speed control.

- Jack

[Jim Allen]

I can't see how the Gotts do much for FE. Or most CAIs. I ran for several years with a CAI on my 5.4L and, while there were some apparent initial upticks, really nothing much improved over the long term. But a tuned CAI, which replaces everything with a more flow-freindly runner, would have a better chance of making a change (good or bad) than the Gotts, which only makes changes in one area. I also had a chance to do some limited steady-state fuel flow tests on an engine dyno (4.0L Jeep) and couldn't see any remarkable differences. Would love to get a Modular on an engine dyno for about a week!

My truck is the 8200GVW and has 4.10:1 ratios. At any level of modification, it always does better at lower speeds. I think the Modulars like low rpms the best