"Chasing MPG in my 80 series Lx450" How I increased my gas mileage.

mudgudgeon

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You should build a spreadsheet. Enter your trip meter and have it correct for the tires. Use that mileage to hand calculate fuel. I bet that scan gauge is off. You can use the spreadsheet also to compare each tank to the scan gauge to give you a running tally of it's error.

I've done this in the past with oem dash meters. It's surprising.
Yeah, I was wondering about the accuracy of the scan gauge, and how it stacks up to long term tracking of fuel use.

My current work hack tells me fuel usage. I've run out out of fuel when it said I have 30+km of range left.
Apparently, that's 30 km of downhill only range
 
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Yeah, I was wondering about the accuracy of the scan gauge, and how it stacks up to long term tracking of fuel use.

My current work hack tells me fuel usage. I've run out out of fuel when it said I have 30+km of range left.
Apparently, that's 30 km of downhill only range

I've yet to even see my fuel light.
Highway driving I fill up at about 350-400 miles. Work commute I fill up about every 300-315

I think I've only put more than 19 gallons in it once.
 

mudgudgeon

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It takes me about 1.5 to 2 months to go through a tank off gas,

Who cares what your mileage is at that rate! :lol:

I usually go through main, and sub tank in about 5-10 days, but my work location varies.
 

GW Nugget

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As it's simply a gauge and an estimate, that's why I suggested you verify with hand calculations.

Claiming a gain based on a gauge that's estimating fuel consumption is a game with no verifiable results. You have no actual proof other than hoping your gauge hasn't faltered. I was simply trying to help you prove gains.


I do drive a lot. I can also afford to drive my adventure rig daily.

48 miles round trip for work plus all my other driving.

The price per mile is because I wanted to see how much the continued rising fuel costs were effecting me. It's a calculation that took 3 seconds to add to an existing spread sheet.
Thats cool, so if I go old school hand calculation per tank it will be once every 2 months.
So if I say that I had to fill up at 220 miles last tank & Im at 248 with just under 1/4 tank left gives a good indication that my mpg has gone up.
I will do hand calculations in the next 55 miles.
 
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mudgudgeon

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Thats cool, so if I go old school hand calculation per tank it will be once every 2 months.
So if I say that I had to fill up at 220 miles last tank & Im at 248 with just under 1/4 tank left gives a good indication that my mpg has gone up.
I does give an indication for sure, but usage on a single tank is not gonna give a definitive indication of the change being due to your tweaks, or was the ambient air temp and barometric pressure more optimal last month? Was there a change in driving style? Etc.

Not saying you're wrong, more that longer term result will tell a better story.
 
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Thats cool, so if I go old school hand calculation per tank it will be once every 2 months.
So if I say that I had to fill up at 220 miles last tank & Im at 248 with just under 1/4 tank left gives a good indication that my mpg has gone up.
I will do hand calculations in the next 55 miles.

You can fill it before it's empty.

Or go for a drive to test your changes.

While the gauge is a nice indicator hand calculations are the only way to even remotely track fuel.
 

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Here is a 13.6 mph well actually 13.5 if go out 3 decimals
Screenshot_20220725-020804.png
 

Broski

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I does give an indication for sure, but usage on a single tank is not gonna give a definitive indication of the change being due to your tweaks, or was the ambient air temp and barometric pressure more optimal last month? Was there a change in driving style? Etc.

Not saying you're wrong, more that longer term result will tell a better story.
^^^ This
 

Broski

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You can fill it before it's empty.

Or go for a drive to test your changes.

While the gauge is a nice indicator hand calculations are the only way to even remotely track fuel.
^^^^^ And this
 

Broski

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Hand calculations over a minimum of three tanks to get a true reading 🤷‍♂️
 
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Huh, just rolled 313 miles (503 km) on the main tank only, city plus highway.

Last reported 260 miles (418 km) back in post #59 of this topic.

That's 53 miles (85 km) more.

So that means, either:
  • I was running on fumes these last 53 extra miles (85 km); or
  • the fuel gauge hasn't read accurately since I bought the 80 in 2013.

Since the 80 was running strong the entire time I'm going with an inaccurate fuel gauge.
 
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Here's an example

Its the one i use. My km's and trip meter are corrected for my tires before calculating mpg's

I am a poor with a 91 and a diesel so I don't have a fancy scan gauge but adding the comparison is simple.

View attachment 3068227
My spreadsheet is nearly identical.

I also added "lifetime" average gas mileage at the bottom. I am at 11.5 for a 4 year average. That's across about 60K to 80K miles total. So, when I'm planning a trip, I base it on the 11.5 average.

Yes, I have actually run out of fuel as I coasted to the pump on at least three occasions. My tank, filled to the brim from empty is 25.0 gallons.

I keep track of my fuel cost per mile because I am reimbursed mileage, based on fuel cost levels.
 
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Huh, just rolled 313 miles (503 km) on the main tank only, city plus highway.

Last reported 260 miles (418 km) back in post #59 of this topic.

That's 53 miles (85 km) more.

So that means, either:
  • I was running on fumes these last 53 extra miles (85 km); or
  • the fuel gauge hasn't read accurately since I bought the 80 in 2013.

Since the 80 was running strong the entire time I'm going with an inaccurate fuel gauge.

I have broke the 300 mile per tank mark towing a small travel trailer (pictured below) before. Not hard to do, but most people panic when the light comes on. I daily drove the 93 I had for 6 months with a non functioning fuel gauge. Once the light came on I had to get gas sometime in the next 3 days.

IMG_20191203_185851749.JPG
 
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My spreadsheet is nearly identical.

I also added "lifetime" average gas mileage at the bottom. I am at 11.5 for a 4 year average. That's across about 60K to 80K miles total. So, when I'm planning a trip, I base it on the 11.5 average.

Yes, I have actually run out of fuel as I coasted to the pump on at least three occasions. My tank, filled to the brim from empty is 25.0 gallons.

I keep track of my fuel cost per mile because I am reimbursed mileage, based on fuel cost levels.


I have that off to the side.

Avg
Avg since 35s
And avg since my trans rebuild recently because my mileage has jumped.
 
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One overlooked component for fuel efficiency is oil filtration and oil selection. The efficiency benefits are very small, but they are there. Lots of studies out there in regards to fleet management.

A bypass oil filter can get you a 1-4% increase when its filtering in the 4 micron range.

If your really chasing efficiency- full synthetic, low viscosity oil can get you another 1-2% increase. Would I recommend this? No.
 
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Maybe.

Gotta be careful here. These engines have knock sensors for a reason. PING (Pre-Ignition, AKA Knock) is VERY detrimental to an engine. A little can cause huge damage if sustained. You will also lean out the engine a little which increases heat. Yes, you will most likely get slightly better mileage, but at what cost? These trucks run for LOTS of miles for a reason.
 
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What about modifying the airbox for better flow?

There is plenty of info around for mods upstream of the filter, but I think the outlet from the airbox is ripe for improvement. I haven't measured the throat area but it certainly looks like a choke point to me.
 

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