Gas Mileage a tell of huh? (1 Viewer)

[rscoleman]

So Friday I took off from Austin to take Grandma home to Lake of Ozarks. 670 mile trip I35 to I35E to 75 to 69 to I44 to 5 to 54. Get this I got 17.2mpg according to LC no real wind to speak of and with temp temps in 50 to low 70. I was running from 75 to 85 using Cruise the entire way. The return trip on Sunday (minus grandma) I got 13.6 for exact same route basically same speeds. Just had bad head wind say 15mph for about 1/2 trip. 2016 LC200 stock except for tires Nitto Terra Grappler G2 stock size in XL rating.
Part that I find really cool is that 17.2mpg for trip going their. Wish I could replicate that most of time but usually I only see 16mpg at best.

 

[warm fuzzies]

What’s your tire psi?

 

[rscoleman]

What’s your tire psi?

So I was showing 39 and 40 on trip their and 38 and 39 on trip back. Temps little colder on Sunday. I think the inflated pressure was 36 or 37 before I left on Friday. I had just aired them back up as weather changed.

 

[Tex68w]

It's telling how much a head wind impacts fuel economy on these trucks. I see similar numbers in the same conditions with 33's.

 

[bloc]

Cross winds seem to impact my mileage more than headwinds.. in my experience.

 

[rscoleman]

Cross winds seem to impact my mileage more than headwinds.. in my experience.

I44 Return was a cross wind coming from 45degrees at driver side. The 69 to 75 was mostly head on but gradually got less and less. That first 100 miles was like 12.8mpg and then slowly got better till it hit 13.6.

 

[mep1811]

As long you do don't modify your truck the mileage will be OK

 

[bloc]

As long you do don't modify your truck the mileage will be OK

Some mods are fine. Like a moderate lift. Others that significantly impact the aero profile, like a steel front bumper, rack with a ton of crap on it, RTT.. cause a lot more drag at highway speeds and yes impact mileage a lot.

Ultimately it comes down to how much horsepower is needed to push the vehicle down the road, between drivetrain (doesn’t really change), tire (for instance LT-metric ATs, worse with MT), or aero (mentioned above) losses.

That is why I believe cross winds are worse in my case. My aero is mostly stock, and toyota has done a surprising number of things to optimize aero on these vehicles. The shape of the side view mirrors is a good example. Head winds do add drag, but in a predictable way. Cross winds upset a lot of this careful planning. Or at least that’s my theory.

 

[grinchy]

Grandma is aero.

 

[Tex68w]

This is why I constantly question my desire to fully build the 200 with bumpers, winch, drawers, 35's etc. when I know that it will only negatively impact the performance on road and for long distance travel, which is kind of ludicrous when you consider how awful it is in this department even in stock form lol. The more I contemplate the idea of going with a more modest build and keeping the Cruiser as a Overland (I hate using that word)/long distance tourer the more I like the idea. I can easily run 37's on my truck (RAM 3500) with little negative impact to it's performance and fuel economy and even on 39/40's it would still get better fuel economy and have more power than the Cruiser on 33's lol. This is certainly something to ponder, but in the same breath I consider the alternative, which is to build it big and fuel economy and sensibility be damned as life is too short to quibble over the details. Only time will tell which side wins out haha.

 

[bloc]

I can easily run 37's on my truck with little negative impact to it's performance and fuel economy and even on 39/40's it would still get better fuel economy and have more power than the Cruiser on 33's lol.

I can't imagine 37s not having a huge impact on mileage, even if everything else is stock.

 

[linuxgod]

I can't imagine 37s not having a huge impact on mileage, even if everything else is stock.

Just changing from OEM street tires to decent 13" A/T tires will cut your mileage by 10-15%. So yeah I'd expect 37's to have a huge impact on our rigs, even with stock aero

 

[Tex68w]

I can't imagine 37s not having a huge impact on mileage, even if everything else is stock.

Just changing from OEM street tires to decent 13" A/T tires will cut your mileage by 10-15%. So yeah I'd expect 37's to have a huge impact on our rigs, even with stock aero

37's on "my truck" aka my RAM 3500. I get 18-20 mpg with 37's both hand calculated and with a corrected speedo for tire size. I can only touch 18 mpg in the Cruiser under perfect highway conditions with 33's and no lift lol.

 

[linuxgod]

37's on "my truck" aka my RAM 3500. I get 18-20 mpg with 37's both hand calculated and with a corrected speedo for tire size. I can only touch 18 mpg in the Cruiser under perfect highway conditions with 33's and no lift lol.

Not sure what the factory tire size was on the 3500 but assuming it was in the 31-33" range I bet if you ran the same tire in a smaller size your (corrected) MPG would be pretty similar. I also bet if you could find a 37 that was a street tire, not an AT, that your MPG would go up (inversely to the amount of traction you get in crappy weather).

I've never seen 18mpg, even stock, unless I drove 55, though I've seen purportedly undoctored photos people have posted showing it's possible. I used to get about 17 when driving 65-70 when stock. As soon as I went to 34" A/T tires that dropped to ~15. Bumper took that down to about 14. If I drive 80 I get ~13mpg but I'm built and re-geared so my data points aren't really useful to others now. (All of the above mpg is corrected for tire size, btw).

Side note: I had a 3rd gen 4Runner that got 18.5mpg all day. Didn't matter if I was driving highway speeds or suburban traffic, summer or winter. When I replaced the OEM tires with identical size Bridgestone Dueler AT Revo's (which are a relatively mild AT tire IMO) it dropped to 17mpg all the time. Tire weight was very similar, and size was identical - I'm sure it was related to the tread compound and pattern. When I got a new set I (temporarily) switched to non-AT Geolanders... which sucked in the rain but my MPG went back up to 18.5. After a few weeks of hating them I switched back to Dueler AT Revo's and again my MPG dropped to 17 flat.

 

[bloc]

37's on "my truck" aka my RAM 3500.

Got it.

I do love the idea of a basic aev lift and 37s on a 5.9. But the build quality compared to the cruisers I’ve owned would drive me nuts.

 

[Tex68w]

Not sure what the factory tire size was on the 3500 but assuming it was in the 31-33" range I bet if you ran the same tire in a smaller size your (corrected) MPG would be pretty similar. I also bet if you could find a 37 that was a street tire, not an AT, that your MPG would go up (inversely to the amount of traction you get in crappy weather).

I've never seen 18mpg, even stock, unless I drove 55, though I've seen purportedly undoctored photos people have posted showing it's possible. I used to get about 17 when driving 65-70 when stock. As soon as I went to 34" A/T tires that dropped to ~15. Bumper took that down to about 14. If I drive 80 I get ~13mpg but I'm built and re-geared so my data points aren't really useful to others now. (All of the above mpg is corrected for tire size, btw).

Side note: I had a 3rd gen 4Runner that got 18.5mpg all day. Didn't matter if I was driving highway speeds or suburban traffic, summer or winter. When I replaced the OEM tires with identical size Bridgestone Dueler AT Revo's (which are a relatively mild AT tire IMO) it dropped to 17mpg all the time. Tire weight was very similar, and size was identical - I'm sure it was related to the tread compound and pattern. When I got a new set I (temporarily) switched to non-AT Geolanders... which sucked in the rain but my MPG went back up to 18.5. After a few weeks of hating them I switched back to Dueler AT Revo's and again my MPG dropped to 17 flat.

Stock tires on the RAM were 34"+ just like they were on all of the Super Duties I had prior to it. Tire size has been corrected down to the millimeter in the BCM and I verify with hand calculations every few tanks. I was getting 20-23 mpg when it was stock, you probably already know this but diesels are extremely efficient especially in comparison to a gasser equivalent. The 3.73 gears certainly help and I imagine I'd see lower numbers if I had the optional 4.10's instead.

I live on the coast in south Texas, it is very flat down here and in the region as a whole where I spend the majority of my time driving, this obviously lends itself to better fuel economy than someone who might see varying terrain and altitudes (lots of inclines/hills) on a regular basis. Bone stock the Cruiser would touch 21 mpg on the highway with low winds but 19 was standard on road trips. Now I see as low 15.5 mg in town at times and as high as 18.5-19 mpg on the highway depending on winds and payload. These are hand calculated numbers and I cross reference with numbers/percentages adjusted for tire size as well.

With our GX we had decent fuel economy when it was bone stock but those numbers plummeted with 285/70/17's (not even a true 33) to somewhere around 14-15 mpg and when towing a utility trailer full of dirt bikes out west I saw numbers as low 7.5 mpg, pretty abysmal for a relatively light load of 3,500 lbs (trailer, bikes, gear, occupants). Out of the three 5th Gen 4Runners we had I could never get decent fuel economy once modded and the 5-speed made it nearly impossible to hit 5th gear even when towing an empty utility trailer. I imagine I could see single digit numbers with the Cruiser if I were to throw a sizable load behind it but that's not really necessary with the 3500 sitting in the driveway.

 

[Tex68w]

Got it.

I do love the idea of a basic aev lift and 37s on a 5.9. But the build quality compared to the cruisers I’ve owned would drive me nuts.

It's certainly not a comparable build quality but it's a massive improvement over where they were just 10 years ago. Somedays I actually prefer the RAM over the Cruiser when on the highway, it's surprisingly a comfortable and decently quiet ride on the highway.

 

[stonepa]

My LC has been paid for since new so mileage to me is largely irrelevant. Even at $3/gallon it would take quite a while for me to spend more on fuel than the sales tax alone on a new electric or hybrid.

 

[MCtree]

I drove from Houston to Telluride two weeks ago. And then back to Houston.
Vehicle is stock except for 0.5” larger tires at 46psi.
And I had a 3 gallon rotopax strapped to the roof rack.

I found it interesting that I got 16.1mpg on the way out (both per the mpg on the cruiser and also measuring with an app on my phone).
On the way back to Houston, I got 17.3mpg.

I guessed this difference was because of the altitude change. 50’ to 9500’ and then back to 50’.
But now maybe I wonder if it was a cross-wind.

Also, you guys who can hit 18mpg impress me. I don’t think I’m heavy on the gas petal, but maybe I need to work on that.

 

[bloc]

Over dozens of trips from Texas to Colorado and many well beyond that, I consistently get better mileage at altitude than near sea level where I live. I assume it has to do with fuel and possibly spark adjustments by the ecu more than thinner air offering less wind resistance.