23 mpg over 600 miles (1 Viewer)

[Muddy Bean]

I know some of you detest mpg threads, so feel free to go have a burger while I ramble on about my eco-driving yesterday. Wife and I had a good long day to drive 600 miles and we both decided to stray from my norm of 80mph and drive the entire way at a cool 55 mph. Most of the route was limited 65 or 60 with occasional runs of 70 mph limits so we felt safe and comfortable putting along at 55.

Since this thread merely rambles on about my mpg gains and what it took to get there, I'll ignore any remarks about safety, "don't buy a cruiser if you care about MPG's", and a sundry other snarky remarks here's what I did:

1. Before the trip, I cleaned the throttle plate and area with throttle body cleaner spray. I also thoroughly cleaned the MAF sensor with MAF sensor cleaner spray. Air filter is brand new. Ran two cans of SeaFoam through vacuum line on intake manifold. Also poured a can into fuel tank. Disconnected the battery for about an hour.

2. Next day, (day of the trip) I filled the tank with 93 octane, and topped it off (yes, I ruined my charcoal canister etc etc).

3. I proceeded to drive and never once allowed my RPM to climb over 2000 rpm on acceleration. I set the cruise at 55mph and RPM at that speed was approx 2000-2100 rpm.

4. I drove 600 miles on that tank of fuel (gps corrected and matched my odo) and then filled the tank once again to the brim for most accurate mpg numbers (fuel filled cup). If you don't believe me, map it yourself. We drove from Cicero Indiana to Rock Hill South Carolina and never stopped for fuel until we reached our hotel in Rock Hill (at the 600 mile mark). Put in 26.62 gallons. MPG comes out to 22.6 Here are snapshots of various odo/fuel gauge readings during the trip:

Couple of important facts to know:

1. We are running slightly smaller than stock tires.

2. I broke my front diff, so we are running in 2wd with machined flanges.

3. Our factory roof rack is currently removed. 4. Truck was loaded down for the trip. Heavy enough to sag the rear a little.

5. I'm running 51 psi in my tires. So yes, we did drive 600 miles on one tank of fuel. Flame away.


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[TXLX100]

On behalf of everyone. GTFO here!

I filled up today with 20 gallons after 260 miles, 13 MPG on 87 octane.

 

[Muddy Bean]

On behalf of everyone. GTFO here! I filled up today with 20 gallons after 260 miles, 13 MPG on 87 octane.

Can I get my money back for my gold star? It would purchase a decent amount of fuel.

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[OregonLC]

I've seen 22 on a stock 04 at 60-65. Myth busters says rare but possible.

 

[Lx470iH8Mud]

I can't get better than 10.4 combined and 13hwy

 

[re_guderian]

55 m.p.h.(and low RPM acceleration) is by far the biggest contributor. I'd bet at 51 psi you tires rolling diameter isn't too far off of stock? Might that affect mileage adjustment? Throttle body abs OEM roof rack are likely minor contributors, if any discernable impact at all in my experience. I've had a fill up, (only a qtr tank, though) at 20 mpg, also at ~55 m.p.h..

 

[Muddy Bean]

I've seen 22 on a stock 04 at 60-65. Myth busters says rare but possible.

It's sad that this truck is so wound up at 55 mph. It could do better with a larger overdrive gear...

55 m.p.h.(and low RPM acceleration) is by far the biggest contributor. I'd bet at 51 psi you tires rolling diameter isn't too far off of stock? Might that affect mileage adjustment? Throttle body abs OEM roof rack are likely minor contributors, if any discernable impact at all in my experience. I've had a fill up, (only a qtr tank, though) at 20 mpg, also at ~55 m.p.h..

I concur. Other data points: When we started the trip, ambient temp was 19 F. At trip end it was 42 F. In North Carolina and South Carolina we faced mild headwind and, of course, mildly mountainous terrain. With smaller diameter tires, you have to remove some of the miles your odo indicates, hence why you see 602.7 on the odo. 602.7 actually equaled exactly 600 miles. So if I made any mileage mistakes. It would actually be in my favor. That being said, I didn't. I actually calculated the actual distance before the trip even started.

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[Jordan345]

Ha! I get 220 miles per tank if taking it easy. I love hearing what is possible. Well done mate


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[ENGINE er]

this simply gives me hope i can improve on my 11 city/11 highway MPG.

 

[ntsaint]

I concur with the slow acceleration and eye on RPMs method for mileage. After 5 years of being in the 11/12 camp I changed my methods this summer.

Gradual acceleration, driving in ways that keep rpm under 2000, and never exceeding 69-70 on highways. Now I get 13 in city and normally between 15-16 on highway.

And my truck is fairly loaded. 33" tires, frontrunner rack, sliders, rear bumper, and drawer system. The only drawback is the obvious...driving like a little old lady.

 

[Elijah]

Absolutely possible, and in the realm of reality. It's very hard for me to 'ecodrive' the 100 series but my DD/commuter is a 1992 Geo Metro XFI. I regularly ecodrive (top speed 60, shift before 2k rpm, taller than stock tires, etc) the Metro and see a consistent 55-56 mpg. If I drive it hard the mpg comes all the way down to 45ish, that doesn't happen to very often though. For some weird reason, I absolutely despise buying gasoline for regular every day life, though I don't think twice about it for a trip to Moab, etc.

Great job on the killer mpg! It takes extreme discipline to accomplish what you did.

 

[KlausVanWinkle]

I believe you. I got 18.5mpg driving my first 100 6hrs home from the dealer in PA to VA. But it was mostly down hill. From mountains to the swamp that is Richmond.

My truck weighs about 5800lbs now with drawers and a rear bumper on the way and I still get 15-16mph on highway trips. I think the roof racks and antennas are what get people. I took my cross bars off and just run my HAM antenna now.

I wonder about the not accelerating over 2000rpm. The European driving style would tell you to get up to speed as fast as possible so you can cruise in overdrive.

 

[Sandroad]

The 2WD drive helped a lot! As did those pumped up tires. I can get 20 mpg in my LC if I hypermile at 55 mph, so 23 is certainly possible.

 

[stonepa]

I can believe it. It's amazing what you can achieve hypermiling a big vehicle. My current commuter is a Volvo XC70 and I consistently exceed the EPA highway estimates driving in town. I'll have to see what I can do with my Cruiser.

 

[OregonLC]

No one will believe this either, but in the 100 you can do better on the hills than on the flats. Reason: fuel cutoff on the downhill. This assumes you keep your foot completely off the gas and don't feather it. True more is spent going up but this is recaptured as potential energy on the way back down. I know the hypermile heads will say its better to coast in N but (a) that's illegal (at least in OR, not that anyone would know) and (b) it is rare to coast without using brakes before accelerating again (i.e. stoplight, corner). Transforming dead dinosaurs into brake heat is a big killer of MPG.

 

[Bismarck]

No one will believe this either, but in the 100 you can do better on the hills than on the flats. Reason: fuel cutoff on the downhill. This assumes you keep your foot completely off the gas and don't feather it. True more is spent going up but this is recaptured as potential energy on the way back down. I know the hypermile heads will say its better to coast in N but (a) that's illegal (at least in OR, not that anyone would know) and (b) it is rare to coast without using brakes before accelerating again (i.e. stoplight, corner). Transforming dead dinosaurs into brake heat is a big killer of MPG.

^^ what he said. Driving in the mountains and coasting downhill in gear on I70 always seems to average out to 18+ mpg round trip to/from Denver with no traffic.

 

[e9999]

it's a bit puzzling to hear you say that you have (slightly) smaller tires than average but your odo correction is only 0.5%. That's of the same order as a tread wear correction. So basically, if that is the only correction needed, your tires are the same size as OEM then. Or if they are significantly smaller then your odo calc is not right. What's their nominal size?

I wouldn't say it's not possible to get a 22mpg with a heavy load, but the only likely explanation aside from a tire correction error or pump autostop issue (interestingly, 26+ gallons seems like a lot to cram in there, you must have been running on fumes - not that if it were less in reality it would decrease the calculated mpg of course) would seem to be the 2WD bit that most of us have no experience with. And that would still be something like a 25% increase which seems rather high. (That is besides other reasons like losing a lot of altitude overall, backwind, magic gas, somebody put in a diesel engine in without you noticing etc). Maybe some day I will do away with the front flanges and see what happens, that's actually not a lot of work and may pay off quickly if you would get even 10% mpg increase.

 

[Elijah]

I don't think the 2wd is a likely explanation at all, actually. I think the much more likely explanation is the driving style, which also most don't have any experience with.

 

[2000UZJ]

I see 14 highway and 8-10 city here in Atlanta. When I was cruising on I-70 I was seeing 16MPG. When I got to Denver I was seeing a combined 18MPG.

I have seen 21MPG on my ScanGuage. It was going down the longest hill I could find

FYI- the 100 does ~50MPG's coming down pikes peak.

 

[Muddy Bean]

it's a bit puzzling to hear you say that you have (slightly) smaller tires than average but your odo correction is only 0.5%. That's of the same order as a tread wear correction. So basically, if that is the only correction needed, your tires are the same size as OEM then. Or if they are significantly smaller then your odo calc is not right. What's their nominal size? I wouldn't say it's not possible to get a 22mpg with a heavy load, but the only likely explanation aside from a tire correction error or pump autostop issue (interestingly, 26+ gallons seems like a lot to cram in there, you must have been running on fumes - not that if it were less in reality it would decrease the calculated mpg of course) would seem to be the 2WD bit that most of us have no experience with. And that would still be something like a 25% increase which seems rather high. (That is besides other reasons like losing a lot of altitude overall, backwind, magic gas, somebody put in a diesel engine in without you noticing etc). Maybe some day I will do away with the front flanges and see what happens, that's actually not a lot of work and may pay off quickly if you would get even 10% mpg increase.

Love all the interesting responses. One note on this one, can't vouch much for the odo correction but I do know that it's exactly 600 miles from my friends house in Cicero, IN to our Econolodge hotel in Rock Hill SC. This doesn't include a few rest stop runs for the bladders. Those add only a very nominal amount of distance. But assuming just 600 miles, it's still amazing MPG. Someone mentioned how much discipline it took. It was hard for me to do. I'm a lead foot and have always been one. Not proud of that fact, but it is how I've always been. My wife is pretty chill about it, but i commonly have the needle kicking around 90 without realizing it. Kinda silly, so I'm attempting to slow down. This was hard to do. We added literally 2.5 hours to our total trip driving time based on our GPS calc. So that was hard. Having people pass you like you're standing still was sometimes intimidating. But I wanted to see what the truck could do. I am not going to make it a habit to hypermile like the nutso guys on ecomodder forums, but I might try one more time to get even better numbers with a couple more aces up my sleeve.

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