"Chasing MPG in my 80 series Lx450" How I increased my gas mileage. (1 Viewer)

GW Nugget

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Hello all since gas has gone to astronomical prices I thought I could make a game out of it called "Chasing MPG in my 80 series Lx450" How I increased my gas mileage.

My 80 for the last 2 years has basically just has been getting me to work & back, it did pull the 25' foot trailer 2 hours South two times last year. The gas mileage has dropped down to around 220 miles per tank fill up generally clicks @ 22 gallons after the light. So we are going to start with 10 MPG as my base.
Also lets get some facts out of the way:
4:88 gear & 37s come out to .5% over. Checked it many times with GPS trackers & the main one is Google maps it shows speed & distance. My speedo is off about 1 mile per 200 miles. I do have the 10% UD gears but it does not effect the speedo. I run 89 octane Chevron gas. I have a 97 Lx450 OBD2 with an Ultra gauge. My commute is about 5.2 miles to work 10.4 total commute. Have 3 stop signs through my small town & country road the rest the way to work.

Also to note the stuff I did below is what I did & by no means am I telling you legally what to go do to your vehicle.

So all that out of the way let's have some fun...

Like I wrote we are starting at 10 MPG. The 1st things I did is common knowledge for fuel economy like airing up the tires to full psi, using braking less, coasting & I took out about 200 pounds of stuff off/out of the rig. Also the Ultra gauge taught me that quicker accelerations to speed then hitting "cruiser" control ASAP got more efficiency. All that & only really got me about 11.5 mpg.
Now your say all that for 1.5 MPG? Yes we are building Rome brick by brick.
Another one of my issues is my rig gets to temperature about half way to work so the ECU is running in a limp/rich fuel mixture giving bad fuel mileage. If I drive the long way I get better MPG but use more gas.

2nd thing I did was reduce vacuum leaks from the manifold. I replaced a few hoses not holding vacuum, one was my brake booster (my brakes work much better now), the largest one was the PCV valve, so I plugged it off...yep plugged it off. I also added a inline oil catcher to the vent line since any blow-by will now go up that way then dump in front of the throttle body valve. This way the crankcase fumes will still be sucked through the manifold but wont cause a big vacuum leak in the manifold. Make since? The goal is the more vacuum the better chance fuel turns from liquid to vapor.
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This increased my fuel mileage by approx. 1 mpg. At this point I was getting a solid 12.5 mpg after 94 miles of daily driving.
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3rd thing was adding heat blankets on exhaust to send more heat to the front Cat o2 sensor A warmer o2 sensor will send less fuel through the engine if the cat is hot enough. This helps in my MPG in my short commutes because it gets the o2 sensor out of a rich fuel mixture mode sooner. They also have helped lower engine bay heat. I bought 3 of the 9" strait blankets plus a 3" 45 degree blanket. CXRACING HEAT WRAP / HEATSHIELD $35 each.
This got a solid 1 more MPG with 41 miles of daily driving.

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The 4th thing didn't necessarily help MPG but is one step to reducing heat under the hood & reducing the risk of blowing another head gasket.
HuddExpo sells a "EGR Test Plug Kit".
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The 5th thing I did was replace my 41K mile plugs for a set of hotter burning Pulstar Plasma Spark Plugs. (IBE1H10) fits 1FZ-FE 4.5L fzj80 $15 per. I was hoping for more than 1mpg, but was told that it sometimes takes up to a full tank of fuel to get better results. I have not done cap & rotor yet mine still looks good, I can do it later.
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1 step at a time & document...
At this point I am getting excited because there is more things I'm working on that hopefully will give even more results.
Stay tune & Happy Trails to you.

Edited later:
People wanted old school calcs..
Here is a 13.6 mph well actually 13.5 if go out 3 decimals
Screenshot_20220725-020804.png

 
Last edited:

GW Nugget

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This will be a on going thread with more to come...
 

1973Guppie

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The best way to get better gas mileage out of your 80 is to buy a commuter car s***box and keep the 80 for road trips. I have a 2005 echo I beat on daily.
 
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The best way to get better gas mileage out of your 80 is to buy a commuter car s***box and keep the 80 for road trips. I have a 2005 echo I beat on daily.

Even better is a motorcycle....

@GW Nugget are you planning on replacing any fuel parts, ie fuel filter, fuel pump, injectors, fuel pressure regulator etc.

I am very curious about your vacuum modifications, that sounds like an easy cheap way to get a small improvement.

I will be honest, I know nothing about the EGR system. My rig has aftermarket headers and I believe they block the egr somehow. To avoid the constant code I installed the same test plug from huddexpo.

So theoretically I could copy what you did with the pcv valve and catch can without any issues right?

I am looking forward to your updates.
 
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Are you tuned for 89octane? A higher octane fuel is inherently more difficult to ignite and unless the timing is advanced, requiring the octane to ward detonation you're not helping your cause.

Have you calculated cost to increase mileage vs cost saved per mile? I'm curious where the break over point will be in miles driven.
 
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Are you tuned for 89octane? A higher octane fuel is inherently more difficult to ignite and unless the timing is advanced, requiring the octane to ward detonation you're not helping your cause.

Have you calculated cost to increase mileage vs cost saved per mile? I'm curious where the break over point will be in miles driven.
Good points (above). Chevron gas around here is generally quite expensive. I've run 85 octane (at altitude), no problem.
Stock compression IS low, which makes for an octane friendly engine.
 

clx16

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I can't contribute yet but i replaced all the vacuum lines and put in new injectors that are more than two holes, and cleaned the throttle body. I tried to reuse the EGR gasket and it didn't work so hopefully as soon as that is in i can provide some better numbers. Right now though i am 13.2 mpg on average. I am hoping the new injectors improve that as the exhaust seems to be far less rich.

Current config is all stock including original cats and EGR. Front, rear and side armor with 2.5 in lift running 33" and speedo is corrected for those tires. No gearing changes at all. Have a slight miss at idle so probably need to fix the wiring harness near EGR since it def got hot before i insulated it. 286k miles or so.

Edit for more context info: timing is set to 6 degrees and i only run 87 ethanol free gas. Have been for a few years now.

Monitor via OBDII
 
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Fun thread, thanks for posting! Your improvements are actually really impressive. Those with a longer commute might not see such a big overall improvement from these steps, but they're probably starting out better than 10mpg too.
 
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Admirable work, Sir! I think we all have a fleeting interest in trying to get the best mileage we can. Most of the time, I just figure it gets what it gets, and like many others here, I just drive a more efficient vehicle unless I need the capabilities of the LandCruiser.

That said, here are a few comments to help you get statistically meaningful results that might be more repeatable by other members here;

1) after you make a change, drive the same course at the same times of day as best you can. Removing the variables of traffic density, air temperature changes, and stop-and-go rush hour will help with consistency of results measurement.

B) get fuel at the same pump at the service station every time, if possible - pumps are usually checked by weights and measure annually, but some pumps vary in flow rate and dispensed volume. Reduce variables of using different pumps at different stations, if that matters in your calculations. Looks like you're using a ScanGauge to define your mileage estimates.

III) double-check your ScanGauge with manual calculations - fill the tank up until the (same) pump shuts off, drive the course, then refuel, noting how much fuel was dispensed. Divide Miles driven by Fuel Gallons, and see if there's a measurement system error between this and your ScanGauge. At least you'll know if it's accurate.

You'll note that I'm not suggesting changes to your plan for efficiency, just thinking about ways that you can substantiate your gains toward helping other Mud members to get similar results. Thank you for your time and effort on this worthwhile cause, and looking forward to your findings,
 

ToyotaDon

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2nd thing I did was reduce vacuum leaks from the manifold. I replaced a few hoses not holding vacuum, one was my brake booster (my brakes work much better now), the largest one was the PCV valve, so I plugged it off...yep plugged it off. I also added a inline oil catcher to the vent line since any blow-by will now go up that way then dump in front of the throttle body valve. This way the crankcase fumes will still be sucked through the manifold but wont cause a big vacuum leak in the manifold. Make since? The goal is the more vacuum the better chance fuel turns from liquid to vapor.
View attachment 3060338View attachment 3060339
This increased my fuel mileage by approx. 1 mpg. At this point I was getting a solid 12.5 mpg after 94 miles of daily driving.
View attachment 3060340


In my opinion, you are asking for trouble in plugging the PCV valve. The valve is supposed to be calibrated to balance out the pressure differences between blowby gasses on the bottom with manifold vacuum on the top. Without that differential, you are going to have more pressure in the crankcase at times, leading to more oil leaks and a few other possible problems.

If the goal is more vacuum, then you should be looking at the largest source of vacuum loss; the throttle plate. Keeping the throttle plate closed will definitely increase fuel mileage. ;)
 
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I have a 2003 Honda insight , it gets 54 MPG if I pay attention, 48 if I drive like a maniac. It's tiny, and has lots of road noise inside due to poor sound insulation.

I also have a 2018 GX460, which I ABSOLUTELY LOVE driving, and gets 18 MPG.

My GX will never get the mileage my Honda Insight gets. I wish I could not care about gas prices, but if I average the two vehicles I am getting 36 MPG and get to drive a luxury SUV half the time.

36 MPG works for me, even if the price is driving an econobox half the time.
 
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If I buy a Honda Ruckus 49cc scooter that gets 100mpg, does that let me average out my mpg with the LandCruiser? Unsure where we're going with this analysis,
 
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@GW Nugget what is your base timing set at? Did you check to see if your tstat is stuck open? My 80 is at full temp in about 3/4 mile this time of year.

Last time I did mileage in my 80 I got 17.0mpg all highway between Flagstaff and Kanab cruising at about 70mph. That's a pretty light 80 loaded with 8 days of camping gear and me. Truck has a 3" lift, 35" mud terrains and part time 4wd. Motor is stock other than base timing set about 7 degrees, a 170 tstat (which hurts MPG's) and a 2.5" exhaust with a magnaflow cat and flowmaster. I run all synthetic fluids and 91 octane in low elevations or high temps, 87 is fine where I live (7000ft) all but a few weeks out of the summer.

One of the big culprits of poor fuel economy in 80's is fuel boiling off due a non functioning evap system. I just went through my evap system before the 17mpg trip, as well as a lot of the PM's you did already. Ethanol content is another killer, as it lowers the boiling point of gasoline - and it just sucks all around. You can test for ethanol content with a graduated cylinder or one of the test kits out there if you want to log that as well. I usually get shell gas, their premium is usually around 5% ethanol and 87 is around 8-10%. I get about 10% worse fuel economy with 10% ethanol VS ethanol free.
 
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If I buy a Honda Ruckus 49cc scooter that gets 100mpg, does that let me average out my mpg with the LandCruiser? Unsure where we're going with this analysis,


My triumph get 50 mpg's. If I use it to commute to work and run most of my errands than I am saving enough $$$ on gas to pay for the motorcycle and insurance!!!!! Plus it keeps the miles off the toyota and its also as fun to drive as the cruiser.

download (1).jpeg
 
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Last time I did mileage in my 80 I got 17.0mpg all highway between Flagstaff and Kanab cruising at about 70mph.

Did you correct for the oversize tires when you got 17 mpg's.

Those kinds of drives are where these rigs will see the very best mileage. When I drive highway 89 or any of the other state highways here in Utah I can get in the 16 mpg range but I have never seen 17. I also have 35's, 4:88's and a part time rig.

That being said my rig averages about 11.5 mpg's around town, climbing mountain grades, and offroading. Although I once got 18 mpg's on the AZ strip. Did about 190 miles on basically flat gravel roads that day and I only stopped twice. Average speed on that trip was 50 mph. I thought I had broke my fuel gauge lol.
 
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Did you correct for the oversize tires when you got 17 mpg's.

Those kinds of drives are where these rigs will see the very best mileage. When I drive highway 89 or any of the other state highways here in Utah I can get in the 16 mpg range but I have never seen 17. I also have 35's, 4:88's and a part time rig.

That being said my rig averages about 11.5 mpg's around town, climbing mountain grades, and offroading. Although I once got 18 mpg's on the AZ strip. Did about 190 miles on basically flat gravel roads that day and I only stopped twice. Average speed on that trip was 50 mph. I thought I had broke my fuel gauge lol.
Yep, figured the % difference via GPS speedo. With 4.88's and 35's the numbers look great before the correction :cool:

I forget what my truck weighs, but It was something like 5700 with me in it and all of the stuff I normally carry but no camping gear. No roof rack either.

Last time I went to Moab I got 12.3mpg towing a 16ft brick shaped travel trailer with a 30-35mph tailwind. On the way back I had the same wind from the same direction and got 5.5MPG, mostly in 2nd gear. Filled up in Kayenta and again in tuba city.

My 80 gets much worse MPG around town and on trails, usually between 10 and 12mpg. I had a trip that was like 6mpg before I went through the evap system.
 

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