heres fte and a few others
1HDT maximum efficiency? (1 Viewer)
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heres fte and a few others
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Thanks!
This post includes a line showing fuel consumption as RPM's increase (see the bottom line on the graph):
3b twin scroll turbo
There is always going to be that trade off between speed/time and fuel economy. For economy I try to keep RPM's at or just under 2000 which looking at the graph in the other post would be about right.
3b twin scroll turbo
There is always going to be that trade off between speed/time and fuel economy. For economy I try to keep RPM's at or just under 2000 which looking at the graph in the other post would be about right.
This post includes a line showing fuel consumption as RPM's increase (see the bottom line on the graph):
3b twin scroll turbo
There is always going to be that trade off between speed/time and fuel economy. For economy I try to keep RPM's at or just under 2000 which looking at the graph in the other post would be about right.
Is the lowest line on the above 1HD-T dyno chart also fuel consumption?
I got my best mileage to date on the weekend, travelling about 95km/h on relatively flat highway, no AC, cruise control on, 2.5" lift, 33" tires, stock gearing (4.11 I believe), auto. Worked out to 20.8mpg (US). I usually would travel about 113km/h on a 100km/h speed limit highway, but I was part of a convoy.
for 5 spd owners short shifting each gear and keeping rpm range between 2500 on upper side and where the tach drops for each shift should result in best fuel economy for around town driving. (should be damn slow.....but hey u got a Landcruiser to "cruise" not a Landracer. )
Dropping hwy rpms by going to larger tires will help somewhat.....but will likely impact overall speed around town if you keep between the 1400-2500 rpm shortshifting range with bigger tires,
)Dropping hwy rpms by going to larger tires will help somewhat.....but will likely impact overall speed around town if you keep between the 1400-2500 rpm shortshifting range with bigger tires,
what i like to see in those red/black graphs above is how broad the area under the curves is for the 1hz. It looks real similar in area to the 4.7-v8... and highlights why adding the right turbo to the hz really wakes it up and produces a bit nicer/broader area under curve than the hdt. Im guessing this is mainly due to camming choices by Mr. T for each which would make sense as the Hz is likely a more Mine-oriented duty design vs hdt which likely designed for higher speed/higher power hauling duties.
Yes, I believe so. It shows how the consumption really starts to climb just over 2000 RPM. Best economy I've observed was 22.5 MPG (US). This was without adjusting the odometer reading for oversize tires. Here's my detailed documentation of fuel economy since 2011 with my truck:
1994 Land Cruiser (Toyota Land Cruiser) | Fuelly
As you know, my specs are similar to yours @IanB, but I'll post for everyone's reference:
1994 HDJ81 (250,000 kms)
Auto
~3" lift
Presently running 285/75R16 Duratracs (changed from 285/75R16 BFG TA/KO at ~200,000 kms)
Stock gears
Marks 4x4 part time kit installed at approx. 230,000 kms (no observed change to fuel economy)
Stock CT26 at 16 psi
Power rod mod
FMIC installed
From my observations I can get 22 MPG (US) running at or just under 2k rpms (just over 90km/hr on my speedo) for extended highway drives through the mountains. I'm sure flat drives could give better results. Running at 105km/hr (I think this was about 2200 RPM) my consumption jumps (MPG drop) and I get only about 17 MPG. That's actually worse than I see on a daily basis with 100% city driving! Of course, this is likely a result of the way I drive around town. I'm not gunning it from one light to the next.
*Edit: forgot some of the deets on my truck, added...
Last edited:
GTSSportCoupe
2LTE abuser
Anyone know what sort of economy the 1HDT in the 70 series gets? I would expect it to better than in the 80 series because of the option to run 2wd? Also lighter vehicles?
I wonder what effect increasing boost has on fuel consumption? My observations once I got my gauges installed were as follows:
Stock
100km/h = 10psi, to go faster means to add fuel, EGT's increase quickly, 120km/h = about 1050F on flat roads
MBC set to 16psi
100km/h = 10-12psi
120km/h = 14-16psi, EGT's around 950F on flat roads
MBC set to 22psi, ATEB's "power rod mod" tuning
120km/h = 16psi, EGT's around 875F on flat roads
Speed limit on the #1hwy is 110km/h on the prairies, traffic flows at 120km/h. The truck is MUCH happier at these speeds with the increased boost, and still pulls down 17-18mpg for me.
My running average since I got the truck is 17.1mpg, and if anything it seems to have maybe gotten slightly better since upping the boost this summer. Over my last 10 tanks I'm averaging 18mpg.
Stock
100km/h = 10psi, to go faster means to add fuel, EGT's increase quickly, 120km/h = about 1050F on flat roads
MBC set to 16psi
100km/h = 10-12psi
120km/h = 14-16psi, EGT's around 950F on flat roads
MBC set to 22psi, ATEB's "power rod mod" tuning
120km/h = 16psi, EGT's around 875F on flat roads
Speed limit on the #1hwy is 110km/h on the prairies, traffic flows at 120km/h. The truck is MUCH happier at these speeds with the increased boost, and still pulls down 17-18mpg for me.
My running average since I got the truck is 17.1mpg, and if anything it seems to have maybe gotten slightly better since upping the boost this summer. Over my last 10 tanks I'm averaging 18mpg.
If it's better I suspect it would have more to do with the vehicle weight than 2wd vs 4wd. I didn't see any difference in converting to 2wd on my 80. I've read other threads where people have reported something like 5% better economy. However, I think the part time conversion may have better results on fuel economy on the gas engines than the diesel.
The reason for the 1HZ extra power with a turbo maybe in the higher compressions ratio 18:1 vs 16:1
I think the improved economy from less weight would be eaten out by less aerodynamics of the 7* vs the 80 series,at least on the old boxy shaped models.
AussieHJCruza
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Isn't the 1HZ really high, like 21:1 or something?
The 1HZ has more down low but I reckon a 1HD-T makes up for it higher up, a especially so if it gets tickled a bit
AussieHJCruza
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Yeah, that makes sense. I wouldn't want to blow 25psi into a 1HZ though. I guess you can't have your cake and eat it too.
mudgudgeon
Resident galah
Agreed. Its all about compression.
1hz pulls like a fourteen year old with a Victoria's Secret catalogue from basically idle.
1hd-t in standard tune doesn't really get cracking until 1800rpm-ish.
serenity
SILVER Star
Probably the other reason the 1hz pulls well down low is because it's mated to the lower geared h150 gearbox. I would love to try the h151 box behind a 1hz to see the difference.
FWIW, I have a "stock" set up (was never actually stock in this part of the world). Newish factory-spec tires, no lift, a bit of armour, maybe less than 400 lbs total (bumpers and sliders). 1HD-T has somewhere around 380,000 kms on the clock. Original turbo with a rebuild kit about 100,000 kms ago. Rebuilt injectors and pump. Factory boost (max is about 10.5 psi). H151 manual transmission, part-time transfer, 3.70 diff gears. Basically my economy should be about as good as possible.
My odometer is calibrated by GPS with a Yellr Box. I have been keeping detailed fuel records since I put the truck together. The very best tank I got was 9.15 L/100 km. That may have been a mis-calibrated pump at a gas station. Other than that, my 2 year average (over 38,000 kms) is 11.17 L/100 km.
I would estimate my driving is about 60% highway, 35% city, and 5% gravel roads. I typically cruise at 90-110 km/h on the highway, which works out to around 2000-2500 rpm on the tach.
I am interested to hopefully find out one day if a GTurbo and/or intercooler could improve my mileage.
My odometer is calibrated by GPS with a Yellr Box. I have been keeping detailed fuel records since I put the truck together. The very best tank I got was 9.15 L/100 km. That may have been a mis-calibrated pump at a gas station. Other than that, my 2 year average (over 38,000 kms) is 11.17 L/100 km.
I would estimate my driving is about 60% highway, 35% city, and 5% gravel roads. I typically cruise at 90-110 km/h on the highway, which works out to around 2000-2500 rpm on the tach.
I am interested to hopefully find out one day if a GTurbo and/or intercooler could improve my mileage.
AussieHJCruza
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My on highway economy is improved with a GTurbo, intercooler and all that. Around town is about a litre per 100 worse, but that's probably my driving.
mudgudgeon
Resident galah
Yes gturbo and intercooler would definitely give you an opportunity for improved economy IF you can resist sticking more right boot in to it
