500 miles to a tank?? Yes! (1 Viewer)

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From Denver, up over Loveland Pass to Keystone and back today netted 16.9 mpg today...
0B362EF5-4B0C-48F4-A80C-28D20FA6A4B5.jpeg
 
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There's a guy on here that got 600 Miles on a tank once. He used low rolling resistance tires, and drove all flat at the most efficient speed. 23MPG is what he got from what I remember. This was year ago, but is posted on this forum somewhere - probably buried. I remember seeing it I couldn't believe it.
 
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There's a guy on here that got 600 Miles on a tank once. He used low rolling resistance tires, and drove all flat at the most efficient speed. 23MPG is what he got from what I remember. This was year ago, but is posted on this forum somewhere - probably buried. I remember seeing it I couldn't believe it.

 
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Are you sure the trip was “0.0” when you started?
Haha yes I'm sure. I actually did two tanks is in a row and zero's the trip after each one. OKC to Tucson on two tanks of fuel. Nearly a thousand miles. Could be an anomaly ... got twenty mpg yesterday over a 130 mile trip up from Mexico back to AZ. I thought maybe it was going from 31" to 33" tires. I did the calcs, and there would be 22,044 more tire revolutions in a 501 mile trip on stock tires than the 33's. That's equal to 33.87 miles so if you adjust for this you get 467.13 miles to the tank. HOWEVER I haven't yet calculated the efficiency loss of turning the larger tires ... odds are it will be more than 1.7 gallons of fuel to make up the 33.87 miles. Either way, with a decrease in fuel mileage with larger tires, still nicking 467 miles to a tank is pretty good I think.
 
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suprarx7nut

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Haha yes I'm sure. I actually did two tanks is in a row and zero's the trip after each one. OKC to Tucson on two tanks of fuel. Nearly a thousand miles. Could be an anomaly ... got twenty mpg yesterday over a 130 mile trip up from Mexico back to AZ. I thought maybe it was going from 31" to 33" tires. I did the calcs, and there would be 22,044 more tire revolutions in a 501 mile trip on stock tires than the 33's. That's equal to 33.87 miles so if you adjust for this you get 467.13 miles to the tank. HOWEVER I haven't yet calculated the efficiency loss of turning the larger tires ... odds are it will be more than 1.7 gallons of fuel to make up the 33.87 miles. Either way, with a decrease in fuel mileage with larger tires, still nicking 467 miles to a tank is pretty good I think.
You're going to have to let us know if you get a negative fuel trim error check engine code or something. That's so crazy.

Did you already mention what type of tire and pressure you're running?
 
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@suprarx7nut I'm in the process of getting Torque Pro set up so I can monitor a few things, look at trim banks etc. The tires are 275/70/18 K02 so 33 ish but they are old, I think the second set the trucks ever had and have about half or less tred depth left. On that trip I think I had 35 psi ... maybe 40. I did baby foot it, 60-65 but no drafting or anything. Was running the AC. I kind of wanna do one more long trip. I have a feeling I need to change the timing belt soon ... it's the original from 06. Truck has almost 80k miles now.
 

suprarx7nut

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@suprarx7nut I'm in the process of getting Torque Pro set up so I can monitor a few things, look at trim banks etc. The tires are 275/70/18 K02 so 33 ish but they are old, I think the second set the trucks ever had and have about half or less tred depth left. On that trip I think I had 35 psi ... maybe 40. I did baby foot it, 60-65 but no drafting or anything. Was running the AC. I kind of wanna do one more long trip. I have a feeling I need to change the timing belt soon ... it's the original from 06. Truck has almost 80k miles now.
It would be really neat to compare and contrast some data logs once you have that setup. If you'd be willing to share, I'd love to see a data log with fuel trims, fuel flow, air flow, rpms, speed, etc...

I've put a lot of concentration into driving my 06LX wtih the same tires at the same pressures as "hyper-miley" as possible in the last couple weeks and I can barely maintain a corrected 14mpg (so around 13MPG by the odo). I've got a little extra weight with the sliders and winch, but most my driving is by myself or just my wife so I think we're in the same ballpark. Elevation difference might explain some difference, but I wouldn't expect nearly that much.

Interesting stuff!
 

ramangain

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It would be really neat to compare and contrast some data logs once you have that setup. If you'd be willing to share, I'd love to see a data log with fuel trims, fuel flow, air flow, rpms, speed, etc...

I've put a lot of concentration into driving my 06LX wtih the same tires at the same pressures as "hyper-miley" as possible in the last couple weeks and I can barely maintain a corrected 14mpg (so around 13MPG by the odo). I've got a little extra weight with the sliders and winch, but most my driving is by myself or just my wife so I think we're in the same ballpark. Elevation difference might explain some difference, but I wouldn't expect nearly that much.

Interesting stuff!
Post a recent pic of the front cross-sectional area of your rig. If you aren't using the stock front bumper, you're blowing right through the 0.4cd (literally).
 

suprarx7nut

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Post a recent pic of the front cross-sectional area of your rig. If you aren't using the stock front bumper, you're blowing right through the 0.4cd (literally).
Dissent front with full bull bar.

While I know it's not doing any favors, I think the aero impact of that bumper has an impact on the order of <1% MPG. We're looking at a ~30% difference in this case, so I consider it negligible.


Excerpt: “Typically, interfering with the airflow on a vehicle can impact fuel economy significantly,” said Bear. “However, Ex-Guard products minimize their effect on aerodynamic drag because they are mounted several inches away from the front of the vehicle and are designed with round tubing, allowing air to continue flowing."

I've also got no lift and actually have AHC set just below factory standard heights by ~0.25-0.5". Overall area should be very close to OEM, maybe even less.

Full skids are installed as well. Not helping on weight, but creates a nice big flat area where OEM has large gaps.
 

ramangain

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Dissent front with full bull bar.

While I know it's not doing any favors, I think the aero impact of that bumper has an impact on the order of <1% MPG. We're looking at a ~30% difference in this case, so I consider it negligible.


Excerpt: “Typically, interfering with the airflow on a vehicle can impact fuel economy significantly,” said Bear. “However, Ex-Guard products minimize their effect on aerodynamic drag because they are mounted several inches away from the front of the vehicle and are designed with round tubing, allowing air to continue flowing."

I've also got no lift and actually have AHC set just below factory standard heights by ~0.25-0.5". Overall area should be very close to OEM, maybe even less.

Full skids are installed as well. Not helping on weight, but creates a nice big flat area where OEM has large gaps.
How on earth did you get to <1% MPG from that bumper? My BS radar just went through the roof, so I'd love to see the calculations.
 

suprarx7nut

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How on earth did you get to <1% MPG from that bumper? My BS radar just went through the roof, so I'd love to see the calculations.
In that link they tested a bull bar setup on a semi tractor with trailer. Net results were -0.51% in mpg.

Not my test, nor data, but seems reasonable to me. The dissent bumper doesn't add much area (does it?) and the oem bumper isn't exactly shaped like a Bugatti. 🤷
 

ramangain

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Lemme give an example for my skepticism. I have the Clearview towing mirrors on my rig. Big ol' Dumbo ears. I ran with them in FL and OR for a few months and never saw above 15mpg, and I drive like a granny in my rig. Always Costco gas. Fair amount of highway driving.

After my tow to OR, I put the stock mirrors back on for a few tanks of gas. Immediate 10% MPG improvement. I have no other aftermarket appendages (except a 7 pin tow socket) on my rig.
 

ramangain

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In that link they tested a bull bar setup on a semi tractor with trailer. Net results were -0.51% in mpg.

Not my test, nor data, but seems reasonable to me. The dissent bumper doesn't add much area (does it?) and the oem bumper isn't exactly shaped like a Bugatti. 🤷
I don't doubt the bull bar stuff one bit - plus that's for a full semi tractor which has the OEM frontal area of the Vatican to start.

I do believe the cd changes non-insignificantly with the high clearance, angular front bumpers on the Hundys. Your gut doesn't think so when you park your rig next to an OEM rig and just pretend you're an air molecule looking to slide by?
 

suprarx7nut

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I don't doubt the bull bar stuff one bit - plus that's for a full semi tractor which has the OEM frontal area of the Vatican to start.

I do believe the cd changes non-insignificantly with the high clearance, angular front bumpers on the Hundys. Your gut doesn't think so when you park your rig next to an OEM rig and just pretend you're an air molecule looking to slide by?
I think it makes a difference, but I think it's real small. I can't imagine the Dissent is twice as impactful on a 100 as this thing is on a semi:
1609818564536.png


Hard to say from my data since I didn't add just the front bumper. I added the front bumper, winch, sliders, rear bumper, compressor, 2nd battery, skids, recovery gear, larger tires, etc...

Here's my data along the LX journey so far:

Pre-bumper on 32" Cooper AT: 14.75 MPG st dev .99
Post-everything mostly on 33.2 KO2: 13.89 MPG std dev 1.05
Total Difference: -5.8%

OP is getting 18.8-20.0 MPG.
OP difference from my initial LX mileage: 28% to 36%

All my mods and a summer's worth of trail driving lost me 5.8% MPG. @Escape Artist is over here escaping physics at five to six times that difference in the positive direction. That's impressive as hell and I can' see how the bumper explains more than a couple percent or so of that difference.

Also worth noting EPA estimate for highway MPG on a 100 with stock tires is only 17 MPG. To beat the EPA estimate in an unmodified car by nearly 20% is pretty crazy, IMO. On Fuelly, there's no other 06/07 LX470 above 16.4 MPG. 18-20 is an anomaly worth learning about for me.

I wonder if @Escape Artist 's rig has a fuel mod from the PO or something that's leaning out cruise. Or an over-correcting speedo box (though the map seems to confirm distance).

Consider me thoroughly puzzled and intrigued.
 

MJK

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I have a 17-mile suburban commute where I drive 45-55 and probably stop for somewhere between a half dozen and a dozen lights. As a byproduct of attempting to 'zen' my commute lately, I have noticed what does and does not seem to impact my MPG.

Primary drivers: speed, how hard I accelerate, some coasting before hitting the brakes
Seems to help some: cooler weather, fresh synthetic driveline fluids, keeping tires at 35psi
Seems to make no difference: what octane of fuel I use, how much stuff I have in the truck at the time

In full zen mode, I get 16.5-17 MPG a tank all stock on 87 octane. I have no idea how you guys get 10-12 unless that is a product of road warrior driving and with full armor. I get that towing a 4000lb trailer to the dump.

About the only thing I still want to do (that might impact MPG) are some DT headers and new O2 sensors. It smells rich at idle.
 
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I am planning on getting Torque set up on a tablet and sharing data with @suprarx7nut so we can identify the mechanism. The previous owner was the original and i'll ask if they did anything to modify it. With the exception of this set of tires the rig is completely original as far as I can tell. I'm pretty sure I can get the same results again on the next road trip I take. I am also planning on bumpers, winch, armor, 2nd battery n fridge which will be 750 lbs or so. I will be interested in the mileage decrease at that time ... rolling resistance becomes a moderate factor unless you run 80psi. But your truck wasn't even getting the 17 mpg highway (an 06 epa mileage) when it was bone stock? Looking forward to seeing if there is something interesting in the datum. Aero can play a rather significant factor though ... with small aircraft just waxing the plane makes a detectable difference in fuel burn. Installing little pieces to cover up the gap between the flaps and wing makes significant differences ... I mean all these things add up to 3 to 5 knots on the same power setting - effectively if you reduced throttle to keep the same true air speed fuel burn goes down quite a bit.

I rode my BMW motorcycle on a 26,000 mi trip from Argentina to North America (hence the name Escape Artist as it's the YouTube Channel) and my mileage was around 28 mpg wit my the big panniers and gear. The same GS empty but with the side cases and top box gets only 35 mpg but without the cases nearly 50 mpg. Certainly on a small vehicle like a Motorcycle or a faster vehicle like a plane these things are amplified.

A lift, a bull bar, a roof rack ... even without weight makes some measurable parasitic drag. Not a huge amount, but maybe more than we might first think. To calculate it, requires a wind tunnel ... Or several laps around a test track. I suspect just three psi in the tires and an aftermarket bumper and it's additional weight and drag are worth maybe 2 mpg alone in the red.
 
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MJK

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I don't think any of us bought an MPG queen, but it is an interesting topic. I look forward to seeing what the data shows.
 

suprarx7nut

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But your truck wasn't even getting the 17 mpg highway (an 06 epa mileage) when it was bone stock? Looking forward to seeing if there is something interesting in the datum.
No, closest I got was 15 MPG. I live north of Denver and almost all my driving is highway (either I-25 or the many 55-65MPH two lane county roads in my semi-rural area). Also got in some road trips this year.

Here's the distribution from Fuelly for all LX470s. These stats are totally user generated so could be wildly error-prone, but I think the overall distribution is accurate enough to be meaningful. Note that at least one of the high outliers is a mislabeled Lexus ES sedan. I suspect the others above 17 or 18 are also mislabeled or the user skipped an entry resulting in one or more fuel up's with a doubled MPG value. If you click into any high MPG user you can normally see weird trends where the fill ups go 12, 14, 15, 13, 24, 12, 14, 13, etc...

Mode MPG is 13 over nearly 2 million miles.

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