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Telly
04-12-2013, 08:55 AM
I burned my first full tank of gas in the new 100. Thought I'd share my mgp experience. 2003 with 135,000, full tank of Costco 85 octane, drove conservative (soft accelleration & at or below the speed limit), 60/40 highway/city driving. The fuel light came on at 335 miles and I filled with 359 miles. MPG = 15.9. Not too bad. With better fuel with mostly highway and ideal weather, I think the rig could reach 17 mpg but I doubt I'll ever see it. My 07 Tacoma used to get 19-20 so this is not too big of a hit in MPG.
Doug

MDH33
04-12-2013, 09:04 AM
I haven't tested very accurately, but it seems like our Tundra gets pretty similar mileage to our old Tacoma as well. Definitely doesn't work as hard climbing the hills. :cool:

Corbet
04-12-2013, 09:05 AM
When I was researching 100's on MUD years ago most reported that premium fuel provided enough MPG to offset the additional cost.

Now that many in the club have them someone is sure to post up.

spectre6000
04-12-2013, 09:44 AM
Unless the 100 has a high compression engine (which I feel pretty safe saying it doesn't) high octane fuel isn't going to help. Higher octane fuel in a higher compression engine CAN yield better fuel economy because the ECU (modern engines only here) will retard timing (producing less output) in the presence of low octane fuel. All octane does is prevent ping (like the tetraethyl lead used to do).

What might help (depends on who supplies the fuel at your Costco) is getting better quality gasoline. Murphy Oil tends to be the go-to supplier for most of the really cheap off-brand fuel stations, and the low quality fuel can absolutely have an effect on how your engine runs and the resulting fuel economy. For instance, in my air cooled cars (more sensitive to tune and such than water cooled cars), I stick with Exxon or Chevron (the "up to 10% ethanol" blend) because it's consistent enough to tune for and it's good quality. After running for several months on Exxon, I was once forced to fill up at a station in the sticks that was definitely not the good stuff. The engine ran noticeably hotter, slower, and got 2-3 mpg worse. The next fill up was with quality fuel and was like a free tune up. The cost difference between name brand quality gas and the cheap crap you find at discount pumps is absolutely worth it and can yield positive MPG results; additional octane is only worth it in modern high compression scenarios...

RicardoJM
04-12-2013, 10:22 AM
I compute MPG with every fill up. Pretty solidly 16.something MPG mean value. Occassionally, I'll see something in the 15.something - 14.something area and less often I get 17.something. I put in premium. My LX470 is a stock 99 that I've been driving for 10 years.

farnhamstj
04-13-2013, 08:14 AM
I have always run 91. I believe there was a software update that makes is acceptable to run 85.???

15.9 is about the best you will ever see. But you didn't but a 100 for the gas milage.

corsair23
04-14-2013, 08:11 PM
Am I wrong in my thinking that most non-carbureated, EFI vehicles anymore typically require 87 or higher?

Once in awhile I'll put 91 in the LX but typically I run 87...I don't think I've ever put 85 in there...The 40 yes, but not the LX. Am I wasting $$ :confused:

subzali
04-15-2013, 08:04 AM
My 2000 Tundra manual calls for I think 86 or 87 or higher...I'll have to double check that though.

My 22RE red truck would ping on 85 so I always used 87.

coax
04-15-2013, 11:32 AM
Am I wrong in my thinking that most non-carbureated, EFI vehicles anymore typically require 87 or higher?

Once in awhile I'll put 91 in the LX but typically I run 87...I don't think I've ever put 85 in there...The 40 yes, but not the LX. Am I wasting $$ :confused:

I'm definitely not an expert, but I would imagine those octane requirements have to apply for sea level, where you'll need more octane. Up here at 5k+ I don't imagine that 85 would pose any problems (and why our low grade starts at 85 compared to other lower elevation places where it starts at 87). Of course other factors like heat, carbon buildup, RPM, timing setting, throttle will also affect octane requirements. FWIW

I run 85 in the cruiser with the timing at about 4 degrees, but at 8k feet and high RPMs detonation shouldn't ever be an issue. Granted I had the head all cleaned when Robbie did the HG so no carbon build up in there.

coax
04-15-2013, 11:36 AM
When I was researching 100's on MUD years ago most reported that premium fuel provided enough MPG to offset the additional cost.

Now that many in the club have them someone is sure to post up.

Does anyone know if the 100's fuel management will actively advance timing if the octane supports it? I was under the impression that most (if not all) cars will run on a standard timing map, and reduce timing in large increments if knock is detected. I was not aware that any engines would advance the timing past the map until it gets close to pinging, and then dial it back a bit? Seems pretty risky from an engine live standpoint? And hence really no mileage gain from higher octane? (Since octane rating is not a measurement of energy content in the fuel, but the resistance of the fuel to detonate?

Mostly just curious as I did a bunch of reading about knock/detonation/timing/octane/etc recently. Interesting stuff. :cheers:

Corbet
04-15-2013, 12:21 PM
I can't answer but from memory Toyota calls for premium in the 100 series where us 80 series owners just need to strain out the big chunks from what ever crap petro we want to use. Mine sees nothing but 85. And at 13MPG a lot of it.

MTSN
04-15-2013, 12:54 PM
I can't answer but from memory Toyota calls for premium in the 100 series where us 80 series owners just need to strain out the big chunks from what ever crap petro we want to use. Mine sees nothing but 85. And at 13MPG a lot of it.

True the 100 does call for premium. I have filled up about 20 times in my 100 and have used 87 on all but two tanks and have averaged between 13.5mpg with heavy rush hour traffic and as high as 16.4mpg on all flat interstate traveling. The two tanks of premium fell right within the typical average, so I went back to the cheap(er) stuff since ~$.20x23ish gallons adds up quickly over time at those mpgs.

Telly
04-17-2013, 10:38 AM
Just as a follow-up, I filled again with 87 in lieu of 85 octane. Same driving habits and got the same 15.9 mpg as I did with 85 octane. I did not feel like there was any difference between 85 and 87 regarding power nor did not hear any detonation. I think its good practice to use 87 but I don't see the benefit of using 91. Doug

corsair23
04-17-2013, 12:05 PM
All these years spending money on 87 when I didn't have to? Dang...

Sort of ingrained into my brain now though...