Diesel vs Gasoline

[billiebob]

I don't know as I have ever flooded an EFI engine before...

Below 10*F my F-150's PS pump groans for awhile but it never misses a beat starting, we have been down to -20*F and it has been faultless.

Park it unplugged overnight at -40 and see what happens.
Most cars with the digital outside thermometers won't register below -35..... tells you what the engineers design for.
Flooding a car with EFI which pumps at 85psi or higher also washes the cylinders and contaminates the oil requiring an oil change every time you flood an EFI car. With a carbureted engine the mechanical pump pumps at less than 10psi which does not wash the cylinder nor contaminate the oil. And if you know yer car, you'll never flood a carbureted engine.

Ten years in the arctic, I kept a pickle jar of gas behind the brake booster, every morning, lift the hood, pull the air cleaner cover, dump in some raw gas, pump the pedal, turn the key, it fired up everytime, NEVER left me stranded even at -60F. But an EFI engine HAD to be plugged in to start.

By the time the air cleaner was on and the hood down and I was in the cab,,, the tappets would quit clattering as oil finally got to them. Three blocks later the flat spots on the tires were flexing and the ride was smooth. Another 5 minutes and the heat was coming thru the defroster.

We did a lot of sledding up north and in the morning the guys with the 2 stroke sleds were prime, 2 pulls and running. The guys with the new EFI 4 strokes were pulling out the genset so they could plug in the block heaters for an hour.... Modern technology only works if you stay within the parameters the computers were designed to operate in. And nothing you do will overcome those short comings. Good old carburetors and analogue technology would let you work around the problems.

EFI is all about convenience.... and compliance with CARB, EPA, CAFE .... etc. It does fabulous things for the environment and makes driving a thoughtless process for everyone but once you step beyond the conditions EFI and computers were designed for......

 

[85_Ranger4x4]

Park it unplugged overnight at -40 and see what happens.

I don't have anything with an engine heater. According to my calculations -20F is about -30C so I am not far off on temp.

 

[charlieaarons]

My 906LA in the 05 Unimog started at -25F with 15W40 with no preheating at all. I have no doubt that it would do the same at -30F with the 5W40 that’s in it now.

 

[JaSAn]

And broke down 5x more often. And burned 50% more fuel. Oh, and needed adjusted when changing altitude, and needed 3x more routine maintenance, and still needed a valve job every 60k.

1970 Dodge D-100, 2WD, 225 slant 6, 3 in the tree, 1 bbl. with auto choke.
- averaged ~22 MPG (got 35 once with a tail wind).
- Never adjusted the carb, drove up to 10,000 ft. (Beartooth pass).
- Drove it for 380,000 miles (body rusted away).
- All repairs and maintenance done myself (valve job at 250,000 miles).

If I didn't THINK about touching the gas pedal, it would start up to -20ºF; below that it needed starter fluid.
Drove it for a winter without a starter (lived on 22 Ave W in Duluth, Minn).

I could have packed 3 suitcases in the engine compartment.

jim

 

[lucilius]

1970 Dodge D-100, 2WD, 225 slant 6, 3 in the tree, 1 bbl. with auto choke.
- averaged ~22 MPG (got 35 once with a tail wind).
- Never adjusted the carb, drove up to 10,000 ft. (Beartooth pass).
- Drove it for 380,000 miles (body rusted away).
- All repairs and maintenance done myself (valve job at 250,000 miles).

If I didn't THINK about touching the gas pedal, it would start up to -20ºF; below that it needed starter fluid.
Drove it for a winter without a starter (lived on 22 Ave W in Duluth, Minn).

I could have packed 3 suitcases in the engine compartment.

jim

...always good but not really surprising to hear that sort of experience. Older vehicles, e.g. diesel and gas pickups, have their pros and cons but (in my opinion, not a groupthink advocation) I'd prefer to deal with the cons of older vehicles versus the cons of newer vehicles. I'd rather maintain my own vehicles when possible and have found that new ones have too many points of failure which tend to be electronic/"smart" and costly+difficult to impossible to fix on your own. I don't see the gains in mileage, performance, and reliability in new trucks, esp. once they're a couple of years old and start having problems because they are very precisely engineered to make the corporations as much profit in the short, medium and long term (which is fine, no one is being forced to buy a truck) more than to exceed minimum acceptable performance/longevity/etc. standards for the buyer. I don't need to drive further or faster or "more" this or that criteria than I did twenty years ago when I started driving. Disregarding crowding, highway speeds and conditions haven't really changed in the last few decades and neither has offroading: I always wonder if people are doing that much more with all the "new stuff" versus in the past with less. Maybe so, but when I read about Yvonne Chouinard et al. driving the old funhog VW camper from AK to Patagonia, the "Turtle", my grandfather and his old 60's gas Ford P/U driving across Canada, and other journeys, they didn't really seem to be at a loss for getting the most out of the experience because of reliability, fuel efficiency, top speed hp/ft lbs, wifi connectivity, heated/cooled seats, etc. Most of the features that seem to sell new cars and especially trucks (i don't need 400hp and 900 ft lbs) seem unnecessary, again IMO, unless you need it for your work. I'm personally looking forward to a glorious future of maintenance-free, alternative energy-powered vehicles with unlimited range, million mile tires, etc. but I think we're decades or more away. A twenty+ year old diesel pickup or gas land cruiser will do everything I need it to and [again, IMO] is preferable to the new rigs. I also try to spend more hrs per year self-powered on my mtn bike, running/climbing/hiking/skiing than i do sitting in the old, unheated/uncooled in-sore-need-of-new-foam seat in my easy to maintain, reliable, 18mpg, full-size and generally unmodified diesel pickup. Suum ciuque.

 

[nickw]

...always good but not really surprising to hear that sort of experience. Older vehicles, e.g. diesel and gas pickups, have their pros and cons but (in my opinion, not a groupthink advocation) I'd prefer to deal with the cons of older vehicles versus the cons of newer vehicles. I'd rather maintain my own vehicles when possible and have found that new ones have too many points of failure which tend to be electronic/"smart" and costly+difficult to impossible to fix on your own. I don't see the gains in mileage, performance, and reliability in new trucks, esp. once they're a couple of years old and start having problems because they are very precisely engineered to make the corporations as much profit in the short, medium and long term (which is fine, no one is being forced to buy a truck) more than to exceed minimum acceptable performance/longevity/etc. standards for the buyer. I don't need to drive further or faster or "more" this or that criteria than I did twenty years ago when I started driving. Disregarding crowding, highway speeds and conditions haven't really changed in the last few decades and neither has offroading: I always wonder if people are doing that much more with all the "new stuff" versus in the past with less. Maybe so, but when I read about Yvonne Chouinard et al. driving the old funhog VW camper from AK to Patagonia, the "Turtle", my grandfather and his old 60's gas Ford P/U driving across Canada, and other journeys, they didn't really seem to be at a loss for getting the most out of the experience because of reliability, fuel efficiency, top speed hp/ft lbs, wifi connectivity, heated/cooled seats, etc. Most of the features that seem to sell new cars and especially trucks (i don't need 400hp and 900 ft lbs) seem unnecessary, again IMO, unless you need it for your work. I'm personally looking forward to a glorious future of maintenance-free, alternative energy-powered vehicles with unlimited range, million mile tires, etc. but I think we're decades or more away. A twenty+ year old diesel pickup or gas land cruiser will do everything I need it to and [again, IMO] is preferable to the new rigs. I also try to spend more hrs per year self-powered on my mtn bike, running/climbing/hiking/skiing than i do sitting in the old, unheated/uncooled in-sore-need-of-new-foam seat in my easy to maintain, reliable, 18mpg, full-size and generally unmodified diesel pickup. Suum ciuque.

Don't forget these two, traveling since 1984 in the FJ60, gas, of course...

Worldrecordtour, Indian Ocean, Sri Lanka, Yemen, Socotra, Mauritius, Rodrigues, Madagascar, Reunion, Guinness Book of World Records, Toyota, LandCruiser, Emil, Liliana, Schmid

What many of the older rigs are not good at is safety. I'm happy to forgo WiFi and touch screen and tech, but heated seats (a must) and a heated steering wheel (if I could have gotten it) are absolutely wonderful.

 

[billiebob]

Oh, and needed adjusted when changing altitude

My '79 F250 had a carb which automatically adjusted for elevation changes.
I never tried to fly it so I can't comment on changing altitude.

 

[Dalko43]

When you can get a 20mpg+ F-150 with a 36gal fuel tank (and roughly 700+mi range) off the showroom floor... who cares about extra fuel tanks? Especially in a country you have to really try to get more than 100 miles from a gas station.

The rest of the world doesn't really care about diesel emissions and in addition to the typical diesel drama (glow plugs, injectors, gelling...) the rube goldberg crap they have to stick on a diesel in the US for emissions is what kills my desire to be involved with one.

Except that when you're actually using your F-150 for work as opposed to empty highway cruising, you're not getting anything close to +20mpg. The F-150, and most 1/2 tons on the market, is designed for the average Joe who wants a truck but doesn't truly need one. Everything, from ride comfort to gearing and engine tuning is optimized for daily driver practicality and comfort.

The truly dedicated trucks, especially the 3/4 tons, don't use turbo gasolines because they realize the efficiency advantage is negligible, arguably non-existent, in working applications.

So for the the purposes of expo/overland builds, I don't see the F-150 turbo offering a big range advantage, at least not in line with the advertised mpg #'s.

I think a couple main reasons overseas, fuel prices have promoted fuel efficiency over performance and they don't or didn't have the requirements for higher powered vehicles due to speed limitations. I work with a bunch of folks from the UK, Scotland, Ireland, etc. and they all grew up driving N/A 1.X diesel cars. The lusted after the turbo gas versions. Same can be said for some of the older diesel trucks, N/A hiluxes and other midsize vehicles back in the day wouldn't have the power keep people happy with the higher speeds in the US. Larger displacement V8's worked well and we started to get the infrastructure to support it...just as overseas they had the infrastructure to support diesel so continued the development of them. Has very little to do with "range" as large tanks could easily be fitted or designed if that was required on gas engines, although folks naturally gravitated towards diesels because of it for expo use.

It really wasn't until the diesels started getting turbo-charged in light duty trucks that they really started to take off here...which was what, early 90's? Not that long ago. The old non-turbo GM 6.2s, Cummins 5.9's and the OLD SCHOOL Nissan 2.8 (I think it was) in the Scout.....were workable but hardly palatable to the majority of people when you could step up to a gas engine and get 2x+ the power.

We have this nostalgia for old diesels, fact was, back in the day, very few people wanted them. In speaking with some of the old timers, they all wanted the big gas V8's and seemed to get around and explore just fine without any of your worries.

In the far northern climates the Russian GAZ trucks were (and may still be) gas powered, which have seen more action and expo use than 99% of anything else out there. They may have to carry a 55-gal drum of extra fuel, sure, but certainly a workable solution....

Diesel never got popular in the states because most people, to include truck owners, don't really need heavy towing, low-end torque capability with decent range. Also, fuel has historically always been very cheap in the US, whereas is generally more expensive in other parts of the world (for regulatory reasons and other factors). Even today, many Americans with low-paying blue-collar jobs are willing to buy and own a gas-guzzling vehicle because fuel costs are manageable..though that may change going forward. The rest of the world is different in that regard: fuel costs a lot more and trucks and 4x4's are generally only bought by people who truly need them. Diesel is implicitly understood to be the preferred option for trucks and 4x4's in overseas markets because it offers better torque delivery and better range...both qualities are highly valued by overseas consumers.

I will point out that in most working applications for the US, diesel is still preferred. Arguably expo/overland use is subset of working applications; diesel has a lot of advantages to offer (as noted above). And arguably that is the reason why diesel has made a resurgence of sorts in market segments that previously had little to no diesel options (midsized and 1/2 ton trucks and SUV's).

GM is offering a 1/2 ton diesel that can get 29mpg on the highway...EPA-rated, not based on some forum-goer's big fish tales. There isn't any gasser within the segment that even comes close to that. So all this talk about why some might prefer to see more diesels in the US...that isn't just due to nostalgia.

 

[calicamper]

Except that when you're actually using your F-150 for work as opposed to empty highway cruising, you're not getting anything close to +20mpg. The F-150, and most 1/2 tons on the market, is designed for the average Joe who wants a truck but doesn't truly need one. Everything, from ride comfort to gearing and engine tuning is optimized for daily driver practicality and comfort.

The truly dedicated trucks, especially the 3/4 tons, don't use turbo gasolines because they realize the efficiency advantage is negligible, arguably non-existent, in working applications.

So for the the purposes of expo/overland builds, I don't see the F-150 turbo offering a big range advantage, at least not in line with the advertised mpg #'s.




Diesel never got popular in the states because most people, to include truck owners, don't really need heavy towing, low-end torque capability with decent range. Also, fuel has historically always been very cheap in the US, whereas is generally more expensive in other parts of the world (for regulatory reasons and other factors). Even today, many Americans with low-paying blue-collar jobs are willing to buy and own a gas-guzzling vehicle because fuel costs are manageable..though that may change going forward. The rest of the world is different in that regard: fuel costs a lot more and trucks and 4x4's are generally only bought by people who truly need them. Diesel is implicitly understood to be the preferred option for trucks and 4x4's in overseas markets because it offers better torque delivery and better range...both qualities are highly valued by overseas consumers.

I will point out that in most working applications for the US, diesel is still preferred. Arguably expo/overland use is subset of working applications; diesel has a lot of advantages to offer (as noted above). And arguably that is the reason why diesel has made a resurgence of sorts in market segments that previously had little to no diesel options (midsized and 1/2 ton trucks and SUV's).

GM is offering a 1/2 ton diesel that can get 29mpg on the highway...EPA-rated, not based on some forum-goer's big fish tales. There isn't any gasser within the segment that even comes close to that. So all this talk about why some might prefer to see more diesels in the US...that isn't just due to nostalgia.

Mileage at a cost. Everything comes down to cost per mile. I’m pretty happy with my 3.5 Ecoboost and I really like diesels. My use pattern would wreck a modern diesel in 6months. Err diesel emissions system... I rarely see more than 8 min of highway during the week. The 400hp and crazy ftlb at diesel like rpm in the 3.5 is a great alternative. Last weekend we did 4 days in the Sierras hauled 8 plus dog Sat Sun then came home all on 1 tank of gas. 21mpg trip average. My 2.5L Subaru same trip minus 4 more passengers typically did 27-28mpg. I’m betting the 3.5 gets nearly identical mileage as the Subaru towing my 4x6. Subaru ran 21mpg towing the trailer no bikes on the roof 18mpg with bikes. The 3.5 will probably do 20-21mpg with trailer no bikes.

 

[85_Ranger4x4]

Except that when you're actually using your F-150 for work as opposed to empty highway cruising, you're not getting anything close to +20mpg. The F-150, and most 1/2 tons on the market, is designed for the average Joe who wants a truck but doesn't truly need one. Everything, from ride comfort to gearing and engine tuning is optimized for daily driver practicality and comfort.

The truly dedicated trucks, especially the 3/4 tons, don't use turbo gasolines because they realize the efficiency advantage is negligible, arguably non-existent, in working applications.

So for the the purposes of expo/overland builds, I don't see the F-150 turbo offering a big range advantage, at least not in line with the advertised mpg #'s.

My father in law trailed me on my last trip in his ‘13 F-150, Supercrew 6.5’ bed with a 5.0. Bed was loaded with gear including two good sized coolers and a Matco top box. Not super heavy but far from empty, for volume he was full. He ran from Ottumwa Iowa to Streetsboro Ohio on one tank. Roughly 600 miles. All two lane running just shy of 60mph which is pretty close to what you tubers report for cruising speeds on decent going while overlanding in places like Australia (80-100km/hr seems fairly normal) I was very impressed.

Diesels were never popular in the states in because they went from underpowered, cold blooded, unreliable, loud smoking piles of crap to over complex expensive piles of crap with only a brief ray of sunshine that ended about 15 years ago when they could outrun their own smoke and not need Rube Goldberg junk to meet emissions (which diesels overseas dont have to worry about near as much).

And the 3.0 Duramax you speak of has a lower tow rating than either Ram or F150 diesels. But the F150 is for wannabes anyway so who cares...

 

[Charles R]

While Id agree with the statement, your now comparing two rigs that have very different performance baselines and I can't think of any two similar class modern vehicles where this comparison can be done, aka same torque, drastically different HP, it's an apples to oranges comparison. You could probably look at one of the old cummins 5.9's with 160 hp and 400 tq relative to something like the modern Ford 6.2 which is close tq wise but has ~2.5x the power. I'm sure the Cummins would get much better MPG, but would have significantly less performance at speeds higher than a crawl...

I can provide an apples-to-apples comparison. But I will acknowledge both vehicles feature an older generation of engines. (My diesel is pre-DEF, and I know newer HEMI's have much better fuel economy.

So here's some totally non-scientific anecdotal information.

I own two Jeep Grand Cherokees of the same generation.
My 2005 Hemi, makes 330hp/375tq.
my 2007 CRD makes 215hp/376tq.
Both have a 5000lbs. curb weight. Both were identically equipped, including tires and suspension. (as noted in my sig, I took the parts from one and put it on the other)

I bought the CRD after my Hemi got 4.3 mpg on one particular off-road trip. (I let the engine idle a lot on that trip)
The CRD got 11.2 mpg when I copied that trip, including the idle time.
Because of emissions venting needs in the fuel tanks, the CRD has a 22 gal. tank vs 21gals. for the HEMI

Simple math now shows a total range of 90.3 miles for that tankful of gas...
And 246.4 miles for that tank of diesel.
For that specific situation I would have needed an extra 36.3 gallons of gasoline, or 7 very full jerrycans. That's also, by the math shown above, 145 lbs of diesel vs. 378 lbs of gas for the same distance.

Some more numbers. With my city heavy driving, the HEMI averages 10-12mpg., the CRD averages 17-18mpg. At a level ground freeway speed of 70mph, my HEMI got 16, and my CRD gets 20 when the lifted suspensions are matched. When I bought my CRD, and it was still 100% stock, I drove it back from Colorado. Through Utah/Nevada I was seeing 20mpg @ 85mph, but my HEMI currently max's out at 18 @65mph. Since I've figured out the HEMI really just seems to suck the gas when it's idling, I minimize doing that. Even still, it will only average high single digit mileage at best while off-road. By comparison, while on a recent trip across the Mohave Road, I averaged 16mpg across the dirt.

So while I know the new diesels are rife with emissions muck, and the newer gassers are VERY impressive. I still feel there's some validity to a diesel overlander. I fully agree that the manufacturers have been putting WAY too much engine in most of these things though. I've long believed a smaller turbo 6 cylinder was perfect for a 1/2 ton pickup, or any SUV. One thing to keep in mind is that diesels are VERY miserly with fuel at idle and part throttle conditions. And when it comes to actually doing WORK, the gassers will always start inhaling fuel like there's no tomorrow.

But for the most part, I do agree that the most modern diesels are making it harder to choose them over the most modern gas engines.

 

[billiebob]

Me, I love the simplicity of gas, I'll love the simplicity of an electric overlander even more someday but for me, today, gas rules. I drive a 14L diesel for work and yes diesel hauls when you need that but right now most diesels are way over rated/powered for what we do as overlanders. A complete waste of power and fuel and payload and $$$. Thankfully North America is coming alive with 2L and 3L diesels far better suited to overlanding. I still think I prefer gas but if the elusive cost to own and operate and buy a diesel becomes less than gas, I'll likely jump on the bandwagon.

 

[billiebob]

I own two Jeep Grand Cherokees of the same generation.
My 2005 Hemi, makes 330hp/375tq.
my 2007 CRD makes 215hp/376tq.
Both have a 5000lbs. curb weight. Both were identically equipped

the HEMI averages 10-12mpg., the CRD averages 17-18mpg.

Out of curiousity, are the 0-60 acceleration times comparable ?
The Hemi was built to make power, not economy.
The CRD was built to get high mpg, not accelaration.

I know you think you are comparing apples to apples but what would the results be with
a 3.6L gasser in one Cherokee and
a 5.9L diesel in the other.

But I agree small diesels, 3.0L and smaller are all we should see in modern 4 wheelers.

 

[Charles R]

I've never timed them myself, but Magazine articles put out when they each first came out put the CRD only about 0.5 seconds behind the hemi, in the 1/4 mile. Probably the biggest reason for that, is that these CRD's do not have a drivetrain that was matched to the engine as well as it could have been.

My HEMI actually cruises at a lower RPM (1800 @ 65) than the CRD does. (2400 @ 65). Everyone who owns one of these recognizes the CRD should have featured the lower axle ratios available in the 3.7L versions, but the premium ELSD was not available for that ratio, because it's a completely different axle/housing. The HEMI's 5 speed also features a transmission with two overdrive ratios, with a lower final ratio than the CRD's 5 speed.

So in this case, it's the HEMI that was tuned better for mileage.

 

[calicamper]

I've never timed them myself, but Magazine articles put out when they each first came out put the CRD only about 0.5 seconds behind the hemi, in the 1/4 mile. Probably the biggest reason for that, is that these CRD's do not have a drivetrain that was matched to the engine as well as it could have been.

My HEMI actually cruises at a lower RPM (1800 @ 65) than the CRD does. (2400 @ 65). Everyone who owns one of these recognizes the CRD should have featured the lower axle ratios available in the 3.7L versions, but the premium ELSD was not available for that ratio, because it's a completely different axle/housing. The HEMI's 5 speed also features a transmission with two overdrive ratios, with a lower final ratio than the CRD's 5 speed.

So in this case, it's the HEMI that was tuned better for mileage.

My heavy tow package 3.73 ratio 2019 Expedition with the 10spd runs between 1600-1900rpm on typical highway trips. 75mph its in the 1900ish range.