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

effjay80

SILVER Star
Joined
Feb 7, 2017
Messages
282
Location
Northern Colorado
10 around town and 13-15 on trips. Not much more blood to squeeze out of the stone beyond keeping tuned up and airing up tires.
 
Joined
Jan 13, 2011
Messages
1,244
Location
Corrales, NM / Las Vegas, NV
I am usually at 15 to 16 on the hwy. Usually cruising around 65 to 70. But like others have said, I don't drive it daily.
 
Joined
Apr 14, 2016
Messages
2,282
Location
Oregon
I've wondered about the effects of some kind of air dam up front and possibly some skirts down the sides. Someone once posted here that turbulent air going under the vehicle creates a surprising amount of resistance.

Since the vast majority of my driving is short trips around town, where I get 10 - 11.5mpg, I'm intrigued by those exhaust sweaters...
 
Joined
Dec 10, 2007
Messages
9,003
Our 80 series are bricks on wheels, a lot of wind resistance, so IMHO there's not a lot we can do to increase MPG.

IME the obvious things that may make a small improvement (but not much) would be correct timing (or advanced a few degrees), fresh spark plugs/air filter/distributor cap/rotor, and clean fuel injectors.

The item that has made the largest difference IME in MPG was a tire (carcass/belts/tread) that was designed for lower rolling resistance along with keeping the inflation pressure near the high end of that tire's range.

I routinely get ~14.5 MPG on the highway (@ 75mph) running Michelin Defender LTX tires. I used to get 15.7 MPG when I was running a lower rolling resistance tire (Michelin Cross Terrain SUV) that unfortunately isn't manufactured any more.

FWIW
 

GW Nugget

Do the best you can with what you have...
GOLD Star
Joined
Jul 25, 2014
Messages
3,658
Location
Coalinga, CA
Website
forum.ih8mud.com
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.
Your right...
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.
All that got looked at about 5 years back when I did the head gasket.
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.
Yes kind of... I did put in full tank of 89 oct. then advanced the timing till it pinged, then rolled it back till it didn't ping. Result was better bottom end response. It will now pull my trailer up hills better with 91 oct.
I am willing to put in 87 octane for daily duty status to see if the is any improvement. I will try the mashing throttle trick to check for pinging with 87 oct.

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.
I agree, but use Chevron locally, because the other fuel in my town has more Ethanol in it. I try to stay away from Ethanol...
Awesome work! Watching And link for heat wrap goes to a blogging thing
Ooops. Now fixed. CXRACING HEAT WRAP / HEATSHIELD
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. ;)
I'm open to suggestion.
I can route the PCV hose in front of the throttle body (throttle plate). I would need to Tee into the same hose as the current air vent which in my mind is sucking gases out of the crankcase when the engine is running. I just want to keep a OE factory look on the PCV hose to keep the smog guy happy.
As far as Don being a good friend I don't know if you are messing with me on the throttle plate statement???
@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.
I think the Ultra Gauge has a timing feature. I will look into that since I have been asked here twice.
Edited later: My Ultra gauge reads 3-4* degrees @1000 RPM & 25* at 2000 RPM (I remember now last smog check read 3* degrees)
What is FSM OE stock timing suppose to be?

A thermostat is cheap, I can look into that also I put in a new one in 2015. Mine I can hear gargling through the heater core on cold mornings when open & closer while on warm up around 180*
I could get better mileage if I went longer distances, with the improvements my guess is 16 because before my instant mpg was 13-16 now is 18-21 mpg at 55 mph.
I have a new Delco charcoal canister on my rig so I hope the evap system works???
I will look for % of Ethanol next time at the pump.
 
Last edited:
Joined
Nov 17, 2021
Messages
1,909
Location
Arlington, Wa
Your right...

All that got looked at about 5 years back when I did the head gasket.

Yes kind of... I did put in full tank of 89 oct. then advanced the timing till it pinged, then rolled it back till it didn't ping. Result was better bottom end response. It will now pull my trailer up hills better with 91 oct.
I am willing to put in 87 octane for daily duty status to see if the is any improvement. I will try the mashing throttle trick to check for pinging with 87 oct.


I agree, but use Chevron locally, because the other fuel in my town has Ethanol in it. I try to stay away from Ethanol...

Ooops. Now fixed. CXRACING HEAT WRAP / HEATSHIELD

I'm open to suggestion.
I can route the PCV hose in front of the throttle body (throttle plate). I would need to Tee into the same hose as the current air vent which in my mind is sucking gases out of the crankcase when the engine is running.
As far as Don being a good friend I don't know if you are messing with me on the throttle plate statement???

I think the Ultra Gauge has a timing feature. I will look into that since I have been asked here twice.
A thermostat is cheap, I can look into that also I put in a new one in 2015. Mine I can hear on cold mornings open & closer while on warm up around 180*
I could get better mileage if I went longer distances, with the improvements my guess is 16 because before my instant mpg was 13-16 now is 18-21 mpg at 55 mph.
I have a new Delco charcoal canister on my rig so I hope the evap system works???
As far as Ethanol I will look next time at the pump.


If you've advanced timing you likely need higher octane. But at what cost of power?
You're spending more money for what, 10hp? Maybe.
 

baldilocks

Battle Ground, WA
GOLD Star
Joined
Jan 29, 2014
Messages
8,274
Location
Battle Ground
@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.
If you are going by the factory coolant temp gauge then your actual temp is only about 145-150 when the gauge reaches the normal hot indication.
 

GW Nugget

Do the best you can with what you have...
GOLD Star
Joined
Jul 25, 2014
Messages
3,658
Location
Coalinga, CA
Website
forum.ih8mud.com
If you've advanced timing you likely need higher octane. But at what cost of power?
You're spending more money for what, 10hp? Maybe.
In my town from 87 to 89 octane, there is 10 cent difference per gallon, that's $2.20 per tank. (To me that's not a big deal.)
I will put in 87 octane next fill up to test for pinging, but will leave the timing were it is no matter because it works good where it is for towing my trailer.
Edited later: My Ultra Gauge reads 3-4* what is stock timing?
 
Last edited:
Joined
Nov 17, 2021
Messages
1,909
Location
Arlington, Wa
In my town 87 to 89 octane is 10 cents per gallon, thats $2.20 per tank.
I will put in 87 octane next fill up to test for pinging, but will leave the timing were it is no matter because it works good where it is for towing my trailer.
Another way to look at it is that at 12.5 mpg the $.10 difference in cost is $.01 for every mile you drive
To offset that the 89 octane needs to average .22 mpg better than 87
 
Joined
Nov 17, 2021
Messages
1,909
Location
Arlington, Wa
I've wondered about the effects of some kind of air dam up front and possibly some skirts down the sides. Someone once posted here that turbulent air going under the vehicle creates a surprising amount of resistance.

Since the vast majority of my driving is short trips around town, where I get 10 - 11.5mpg, I'm intrigued by those exhaust sweaters...

ford did this on the super duties to help with mpg's

This is a 2008 F350
2008-Ford-F350 Super Duty Crew Cab-FrontSide_FTFSDC081_505x375.jpg



This is a 2009
hqdefault.jpg
 

mudgudgeon

SILVER Star
Joined
Dec 17, 2007
Messages
6,318
Location
Across the pond, and upside down
I was having a discussion with my 20 year old a couple of days ago about octane ratings. His mechanic told him he should be using premium, but his justification for why didn't stand up to logic.

Found this from the Federal Trade Commission, among loads of other articles

 

Broski

I love Wheelin my 80
SILVER Star
Joined
Dec 3, 2015
Messages
4,549
Location
Morro Bay, At the edge of the Pacific ocean
Joined
Mar 6, 2014
Messages
976
If you are going by the factory coolant temp gauge then your actual temp is only about 145-150 when the gauge reaches the normal hot indication.
I use the torque app on an old android phone, the stock gauge shows the same temp from about 160 until 230 then starts to climb. That’s about 95% more deadband than I am comfortable with
 
Joined
Jan 19, 2005
Messages
3,667
Location
South west utah
What octane does the toyota owners manual call for?
 
Joined
Mar 6, 2014
Messages
976
I was having a discussion with my 20 year old a couple of days ago about octane ratings. His mechanic told him he should be using premium, but his justification for why didn't stand up to logic.

Found this from the Federal Trade Commission, among loads of other articles

What was the mechanics justification and what is the car?

I am a mechanic and I have done a crazy amount of experimenting on Toyota and Lexus vehicles that call for premium.

On an 80 the ecu does not react fast enough to pull timing when transitioning from idle to acceleration to avoid pinging. It is also very hard to hear pinging from a 1fz, especially if you are in the truck with the ac on (which is when it is going to happen the most). This only really matters if you have base timing beyond the 3 degrees Toyota calls for.

On later vehicles like a 100 series they pull timing so fast you would have to run paint thinner to get them to ping, but they will lose power with every degree of timing pulled. Reduced power will almost always mean reduced fuel economy.

Where you run into problems is if you have a knock sensor fail while running 85 or 87 in a motor that calls for 91, but decide to keep driving with the check engine light on. Then you can burn holes in pistons pretty quick - especially when it’s 100+ degrees out and you have the windows up and ac on.

The only other benefit to premium is that it often times (but not always) has less ethanol content than 87.

If your motor is all stock, do what the owners manual says. If you want to turn timing up, octane, IAT’s, coolant temp, AFR, load and elevation all matter and can cook your motor quick if you don’t know what you are doing.
 
Joined
Jan 19, 2005
Messages
3,667
Location
South west utah
For the 80 series, 87 octane.

If I recall correctly the 87 octane rating was a "minimum requirement" rating.

Usually here in Utah we can get 87, 89, or 91 octane at the pimps so I run 89.
 

Users who are viewing this thread

Top Bottom