Diesel gas argument

LandCruiserPhil

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Diesel gas argument -

I travel a lot with a guy that has a 1HDT with a 5sp
Me - 1FZJ with stock gears and 35's
Both rigs weight is with 100lbs

Highway test

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In our 188.3 mile highway test it was cheaper to drive gas. Combined off road/tarmac the diesel seems to get about 20% better mileage than the 12.5 MPG the gas gets. Factor in the 25% premium for diesel fuel and Im 100% good with gas going forward. I only carry 40gals (500+mile range)and my diesel partner carries 65gals (1300+mile range) making it make the diesel look on the surface. Now lets start factoring in repair and maintenance cost and gas looks better IMO.
 
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The more of the trip that is off-road or low speed, the bigger the fuel economy gap will get.

The diesel is a simpler engine, easier to increase the power of (if that's something you want), holds its value better, and will also last much longer between rebuilds. Which one is better depends entirely on how it's going to be used.
 
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This is evident even in the domestic market. Ford just introduced a pushrod 7.3 V8 and chevy is about to unveil a new 6.6, targeted at the full size market. Add in that diesel is supposed to spike in 2020 when the commercial ships switch over to ULSD and it really becomes a choice of running diesel if you just really like diesel. I weighed both very heavily for a recent purchase and ended up going gas - easier/cheaper to maintain, cheaper to operate, cheaper to buy.
 

george_tlc

 
 
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? You got 188/11.08 = 16.97 mpg in a petrol 80 with offroad and 35's etc?

Was the diesel towing the petrol 80 ?


Anyhow, the beauty of the diesel is the range and relative simplicity. Though modern diesels (common rail etc) are quite a nightmare and as complicated and more than a petrol equivalent. I have an old school diesel in my oz patrol and offroad and in the bush I wouldn't trade it for any petrol vehicle. The range is the key in places like oz, there are many places (especially western oz) where you MUST have a range in the 800+ miles for a lot of trips. Last trip fuel up to fuel up was 1400km (875 miles) and obviously you need to have some margin... Carrying that much fuel would be 'interesting' if it was petrol and averaging maybe 12mpg (US) :)

I have 1200km (to empty) range in the patrol's tank. Then add 1 to 5 20litre jerries to add more as needed. That gets me to about 2000km range. The western oz canning stock route would challenge that range (hence there's a fuel drop off - drums, that you can pre-order at the beginning of the 'season').

In the US, I'm happy enough with petrol. More available, rather cheap and with a subtank there's not many places that you would have range anxiety. There's just soooo many places to fuel up here with minimal/minor detours.

cheers,
george.
 

LandCruiserPhil

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The more of the trip that is off-road or low speed, the bigger the fuel economy gap will get.

The diesel is a simpler engine, easier to increase the power of (if that's something you want), holds its value better, and will also last much longer between rebuilds. Which one is better depends entirely on how it's going to be used.
I also own a LHD diesel 80 and the cost of entry it MUCH more than a gas 80 of the same condition something that needs to be factored in.
 

fjbj40

 
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Interesting.

When I converted my fj62 to a bj62 my km's per tank went from 550 for the 3fe/a440 to 850-900 km for the 3b/h55 with turbo. Not only better mileage but much more useable tq with the diesel and the low speed 4wd was much better with the diesel.

The smiles factor was better also:)
 

alia176

 
 
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This is a great argument and one that I have from time to time. Given the hwy speeds of this country, I don't think a 1HD-T or 1HZ gets good mpg doing 70+ on the hwy. The torque/hp of a 1HD-FT is less than 1FZ-FE, granted the diesel torque comes in earlier than the 1FZ. Meanwhile, the diesel folks are watching their EGT on the hills 🤣

I get the novelty and you like, what you like. But in this country, given the cost of petrol and the availability of it makes it difficult for anyone to convert to a diesel on that basis alone. My diesel brothers' favorite line to me is " I like to enjoy life in the right lane". Yeah, well you get 20+ mpg doing 62 mph but I gotta haul ass to the trailhead come Friday after work. Wheel all weekend, then haul ass home Sunday evening. Like I said, if you got a diesel itch, by all means scratch it.

I'll freely admit that the diesels sip fuel while wheeling in 4low while the petrols just suck the fuel down like it's going out of style.

1HD-FT (turbo'ed, flagship)
hp 168 hp@3600 rpm
torque 280 lb-ft @2500 rpm


1FZ-FE (non turbo) 212hp@4600 rpm
torque 275 lb-ft @3600
 
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Somebodyelse5

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Diesel gas argument -

I travel a lot with a guy that has a 1HDT with a 5sp
Me - 1FZJ with stock gears and 35's
Both rigs weight is with 100lbs

Highway test

View attachment 1924672

View attachment 1924674

View attachment 1924675

In our 188.3 mile highway test it was cheaper to drive gas. Combined off road/tarmac the diesel seems to get about 20% better mileage than the 12.5 MPG the gas gets. Factor in the 25% premium for diesel fuel and Im 100% good with gas going forward. I only carry 40gals (500+mile range)and my diesel partner carries 65gals (1300+mile range) making it make the diesel look on the surface. Now lets start factoring in repair and maintenance cost and gas looks better IMO.
I think the bit of the equation that's missing is how the diesel will continue to perform with a heavy loaded rig. There is a reason that semi trucks and the tow pigs are almost exclusively diesel... the torque they produce and how easily and reliably you can up performance with simple tuning. If you really want to see the diesel shine, go hit some mountain passed (or just drive up the i17 to flagstaff) and then compare the milage. There isn't much that will beat a turbo diesel when torque and efficiency is what you want.
 

LandCruiserPhil

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This is a great argument and one that I have from time to time. Given the hwy speeds of this country, I don't think a 1HD-T or 1HZ gets good mpg doing 70+ on the hwy. The torque/hp of a 1HD-FT is less than 1FZ-FE, granted the diesel torque comes in earlier than the 1FZ. Meanwhile, the diesel folks are watching their EGT on the hills 🤣

I get the novelty and you like, what you like. But in this country, given the cost of petrol and the availability of it makes it difficult for anyone to convert to a diesel on that basis alone. My diesel brothers' favorite line to me is " I like to enjoy life in the right lane". Yeah, well you get 20+ mpg doing 62 mph but I gotta haul ass to the trailhead come Friday after work. Wheel all weekend, then haul ass home Sunday evening. Like I said, if you got a diesel itch, by all means scratch it.

I'll freely admit that the diesels sip fuel while wheeling in 4low while the petrols just suck the fuel down like it's going out of style.

1HD-FT
hp 168 hp@3600 rpm
torque 280 lb-ft @2500 rpm


1FZ-FE 212hp@4600 rpm
torque 275 lb-ft @3600
FWIW the test was done without a lot of grades and at 62mph. That will change shortly as my travel partner with be upgrading the 5sp with a 20% higher gear in 5th. This will change our agreed cruising speed to 66MPH putting the gas RPM at ~2200 and the diesel at 2000.
 

LandCruiserPhil

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I think the bit of the equation that's missing is how the diesel will continue to perform with a heavy loaded rig. There is a reason that semi trucks and the tow pigs are almost exclusively diesel... the torque they produce and how easily and reliably you can up performance with simple tuning. If you really want to see the diesel shine, go hit some mountain passed (or just drive up the i17 to flagstaff) and then compare the milage. There isn't much that will beat a turbo diesel when torque and efficiency is what you want.
Correct one can factor all kind of variables both ways. I drop to 10-11 mpg going to Flagstaff but pick up the loss MPGs on the return trip. :meh:
 

alia176

 
 
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There isn't much that will beat a turbo diesel when torque and efficiency is what you want.
Alright, let's compare a Turbo'ed petrol with a turbo'ed diesel on the same hwy grade. I've included the specs of the two engines up above and as a NA petrol engine, it already has some higher numbers than a turboed diesel. Now, it'd be nice to compare apples to apples by having some turbo'ed petrol engine specs.

Or would you rather compare a 1HZ which is NA with a NA 1FZ-FE? I believe a NA 1HZ engine is considered to be a "fumigator" at altitude by laying a smoke screen on the hwy. 🤣

NA = normally aspirated
 
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This is all a bit silly. The diesel will always end up getting better gas mileage, and last longer. Back when I had my 3/4 ton you couldn't pay me to drive the same truck with either the 6.0 HO gas or 8.0L gas, the mpg were abysmal compared to the Duramax in the same frame. Couldn't even get me to look @ the new gas motors they're bringing out because they won't be anywhere near the TQ or MPG of the current Diesels.

Anywho, I average high 20s (with 35s) / low 30s mpg with my 1HDT on long trips here in the PNW. Around town in heavy traffic it's in the high teens (it is what it is).

These gas vs diesel arguments on here remind me a lot of my other forums where people buy the base model V6s and argue with the LS3/SRT8/Coyote crowds about how much more economical their V6s are because they chose the base models on price and perceived better gas mileage (it most certainly never is better) and defend it until the bitter end. 🤷‍♂️
 

LandCruiserPhil

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Alright, let's compare a Turbo'ed petrol with a turbo'ed diesel on the same hwy grade. I've included the specs of the two engines up above and as a NA petrol engine, it already has some higher numbers than a turboed diesel. Now, it'd be nice to compare apples to apples by having some turbo'ed petrol engine specs.

Or would you rather compare a 1HZ which is NA with a NA 1FZ-FE? I believe a NA 1HZ engine is considered to be a "fumigator" at altitude by laying a smoke screen on the hwy. 🤣

NA = normally aspirated
Having logged 1000's of miles in different diesel over the last year it boils down to what each individual wants to deal with IMO. They all have pluses and minuses. I will say the V8 twin turbo diesel is an awesome power plant. Should be a crime not being available in this country. My wife also loves power and calls it a jet fighter.
 
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