Diesel vs. Gasoline

Brutus · May 1998

I'll have to check my info, but I'm about 98% sure you can get the F-350 DRW V-10 with the 4.30 limited slip. I can't imagine a DRW without an option for a 4.10 or 4.30 option. DRW is for carrying heavy loads. The combination of the DRW with the V-10 power is a prime candidate for the 4.30 in alot of applications.

ChrisLy · May 1998

Wow, I thought diesels got much more mileage. The VW diesel in the new Beetle gets 48mpg. But if diesels in trucks get only 2-4mpg more than V10s, then why bother since diesels don't have nearly as much HP as a v10 or v8 and polute the air? After reading this, I've now decided to buy the T150 with a v8 when it comes out.

Chris

nascar6 · May 1998

ChrisLy,

Scroll through other conferences for fuel mileage.
Most people I've seen are getting anywhere from 17
to 22 mpg with the Dodge/Cummins 24v, and from 9 to 12 with the Dodge 488cu in V-10. The torque readings are really close between the two.
I'm sure you know that gas engines pollute with hydrocarbons and carbon monoxide also.

Brutus · May 1998

The major advantage of the diesel is the torque for towing. For example, the 500 lb-ft of torque you get with the Ford Powerstroke is 50 lb-ft more than the Dodge V-10 and 90 more than the Ford V-10. Granted, the horsepower in the Powerstroke is equivalent to the Ford V-8, so the V-10 will beat you off the line, but the diesel will pull a trailer in tow a lot easier at highway speeds.

dkg · May 1998

The state emissions people here in Colorado say that the polution from gas engines is much greater than the diesel. And from what I have read the reason for the new V10 big blocks is the current big blocks (454 and 460) will not pass the stricter emissions of the future.

If you are in a hurry to get to speed gasoline, if you want to tow and get better mileage then diesel might warrent another look.

For what it is worth, the state people thought the Ford and Dodge turbo diesels were the best available. And they really had no clear choice.

rite3 · May 1998

I talked to the dealer today about the 4.30's with the V10 being the only limited slip rear end availible in the F250 and he said they are just as cofused about it as we are. He told me that last year you could get the limited slip in 2 different gear ratios for guys who wanted lower or higher gears to tow with or for greater fuel mileage. Maybe the V10 is doing so well in MPG that people arent as interested in the deisel as they were when the 460 was the only option. Maybe those guys getting 16 highway with the V10 and the 3.73 non limited slip rear end are telling the truth. I have seen this three times posted at different sites.I just dont understand why Ford would offer it last year and not with the 99's. Oh well, I guess I will just have to upgrade and spend more money on the F350. Its an option on that model even though its more money I think its worth it. Hey, did I just type more money twice? HMMMMMMM??????.

mharde2 · May 1998

Good job Brutus, The thing that makes a diesel the best tow vehicle is that it gets its horsepower & torque at a very low rpm. Peak Hp at 2500 rpm with the diesel, 4000 rpm for the V10. Peak torque at 1600 rpm for the diesel, 2750 rpm for the V10. You can expect 50-60% better fuel mileage with the diesel.
The V10 can do the job just as well, just at a higher rpm...

bigfur · May 1998

Can sombody post why mechanics HATE diesels? I'm a body tech for GM and I love deisels. I hate to say it, but I reall like the new 99 powerstrokes

pworange · May 1998

Been reading about the advantages of diesels over gasoline engines. Torque and horsepower at low rpms etc. My question is how does a diesel do that. Isn't diesel fuel a lower grade than gas? Whats different about a diesel that allows it to develop low end torque and HP.

nascar6 · June 1998

pworange,

There are a few important factors.
Compression ratio: The higher the C.R. the more heat. A diesel engine is a 'heat' engine. It uses heat developed from the compression af air. A high C.R. equals a greater expansion of the gases following ignition and a higher percent of the fuel's energy is converted to power.

Injection system: Diesels are designed using the injection of fuel at the last moment to ignite the compressed air.

Fuel differences: A gas engine always uses about a 14:1 air to fuel ratio no matter at idle or full throttle. A diesel has fuel injected near the top of the piston's stroke in an amount corresponding to the load on the engine. At idle the ratio might be as high as 100:1 (very little fuel), however at full load it can be 25:1 or 30:1. This is still less fuel than a gas engine. Diesel=m.p.g. The fuel pump system and all the electronics decide how much fuel to use.

Fuel BTU's: Diesel fuel has a higher btu rating than gas (130,000btu for diesel to 117000btu for gas per gallon) hence diesel fuel has more 'power'.

BTW-The diesel was designed and patented in 1892 by Rudolf Diesel.

bigfur · June 1998

has anyone else heard anything about the new GMs are going to have a full CAT diesel in a few years

cdean · June 1998

The reason diesels develop low end torque is because diesel burns VERY VERY slow compared to gasoline. When gasoline ingintes it is like an explosion at top dead center, sending the piston downward. When diesel ignites, it burns slowly and is pushing the piston down for most of the stroke.

Think of those little toy pin-wheels, and you are holding it in front of a fan. the fan is blowing and spinning the pinwheel one direction and you will use your finger to turn it the other way.

a gas engine is analgous to you tapping the pinwheel with your fingers, pushing it in the opposite direction its being blown. after each time you tap it, it turns the other direction, but the fan blowing it the other way quickly turns it.

a diesel is analgous to you turning the pinwheel with your finger, never lifting your finger off of it. you cannot turn the pinwheel as fast, as tapping it, but no matter how much wind the fan is blowing, you can steadliy turn it the other way.

mharde2 · June 1998

powrange, Its the slow burning fuel, and high compression that gives the diesel its power. If you drive one you can feel it. Its a totally different feel than a gas engine. But I must caution you...You might fall in love.
Take one for a test drive...

cdean · June 1998

the higher compression ratio does improve the thermodynamic potential of an engine, but the main reason compression ratios are higher on diesels is to get enough heat generated from the compression to ignite the diesel once it is injected. cylinder temp must get up to 900 to 1000 deg F for diesel to combust. you don't get those temperatures with 9:1, 10:1, 12:1 ratios in gas motors.

queenms · June 1998

bigfur,

Below is a press release taken off the Gale Banks Site RE: diesels for light duty Ford vehicles.

"Navistar International Corp. said it is negotiating an extended term agreement with Ford motor Company to supply diesels for selected Ford trucks under 8500 lb. gvw, as well as for sport utilitiy vehicles. Navistar currently supplies 7.3L diesel to Ford for it's F-series and Econoline vans as part of a 1981 agreement that was recently extended through 2013"

Still nothing official on the Cat in the GM . . .

queenms · June 1998

bigfur,

Sorry the URL is:

http://www.dieselpage.com/articles.htm

rite3 · June 1998

I just cant believe that Cat and GM cant work this out. Cat is like Harley Davidson in american culture. That would get me looking at Chevy and GMC again in a second. Cat even sponsered a race team in NASCAR for chrissakes. If they dont manage to pull this deal off it will be a shame. I wouldnt be suprised if GM captured 20% of the deisel market back.

rite3 · June 1998

I meant to say: Cat is like Harley Davidson in American truck culture.

cdean · June 1998

Markus

the cat engine in the big ford's that your link went to is not that big a deal. cats are in practically every different brand of 2 ton and larger truck out there. The Cat 3116 has been in the 2 ton chevys for about 5 years now. those trucks are actually the best selling truck worldwide. ( a couple years ago, chevy sold over 1 million two tons alone, not counting GMCs, the majority of them with the cat engine.)

KCRam · June 1998

The diesel engines are now an "image" thing. Dodge had had a coup with Cummins, as everybody knows they are strictly an engine manufacturer, and one of the world's best in that field. The 6.9/7.3 Navistar is a good engine, but it has gasoline roots and is made by a truck-building competitor to Ford. The 6.2/6.5 was never a true Detroit Diesel engine; they "acquired" it in the mid-80s GM divisional reorganization.

Cat would give the new pickups the same heavy duty image as Dodge, and while the Isuzu is a decent midrange diesel engine, there's no "American TRUCK" image with it.

cdean · June 1998

i guarantee you the diesels are an image thing these days. how many powerstrokes and cummins do i see going down the road without even a ball on the bumper or a 5th wheel in the back---lots. i hear prospective truck buyers say the same thing all the time. " i want one of those diesels", or "man those cummins sure sound cool", or "those diesels will last forever, you know, so i'm smarter for getting one". what it comes down to is the economy is great and to the likes of the diesel manufacturers of this country, there seems to be a huge increase in the number of people with more money than common sense. i can't see how $4000 more for an engine that burns fuel that costs 20 cents more and gets only moderately better fuel mileage works out in the end. especially when you can buy 3 gas motors for what was paid for 1 diesel. might work out if gas motors only lasted 80,000 miles. not the ones I drive. last time i had a group debate (a face to face one), we sat down and ran the numbers between a powerstroke that got 16 mpg and a 454 that got 12 mpg. using invoice costs of the trucks and our areas fuel prices, the money-break-even mileage was 491,000 miles. not including towing of course, but you get the picture.

Rocles · June 1998

Keep in mind that Cummins makes the engine but can't really build a great one because of Dodge. Dodge has to build a better tranny if you really want the better diesel.

mharde2 · June 1998

No one builds an automatic that can stand up to a diesel engine. The new ford trans is only rated for 500 lbs of torque. The standard ISB 215 engine thats in the Dodge Ram is rated at 605 lbs of torque. Its just tuned down to 460 because of the transmission limitations.

mharde2 · June 1998

That would be 420 lbs of torque for the Dodge automatic. 460 with the stick. I think Dodge will come out with a new auto in the next year or two. Most likely in 2000. I would like to see them go with a Allison or something in that line.

Brutus · June 1998

I also think Dodge will come out with a 500 lb-ft torque diesel also once they get the tranny that can handle it. Dodge likes to have more hp and torque than Ford. Chevy V-8 engines like to do better than both Ford and Dodge. I suspect the GM V-10 will be no different. But generally, every additional hp or ft-lb of torque will require another sip of fuel.

By the way, if 10 cylinders provide more hp and torque than a V-8, while sucking up less gasoline, can the V-12 be very far off? Doesn't Ford have a V-12 in their experimental truck, the Powerforce?

KCRam · June 1998

cdean,
The operating costs are extremely variant depending on where in the country you are and how you drive. I'm getting an honest 50% better mileage with my Cummins than my gasoline Fords, and I pay 99 cents for diesel, same price as reg unleaded, so I make out in that regard. It's true, if the fuel costs neutralize the economy savings, then a diesel is probaably unnecessary.

mharde and Brutus,
The 6 speed stick is currently due for the first quarter of 1999 for the Dodge/Cummins. Cummins had made it clear they are prepared for an immediate power increase from the current 235/460 rating. I agree that Dodge needs a tougher automatic.

cdean · June 1998

kcram
don't tell too many people you can get diesel for that price, because folks around here would steal it from you.

regarding high torque auto trannies: parts in an automatic are much different than manual transimissions. manuals generally have solid steel gears throughout, which make them very tough. automatics have non metallic clutch packs, and those are what fail under the high heat and wear caused by high torque loads. they can make a trannies that absorb that kinda torque. but it would have to be very large and bulky, and hard to design a truck around. never fear. there are materials engineers making headways every day, and we are one breakthru away from some supermaterial that will make everyone's auto tranny last forever.

brutus

i don't think the powerforce had a v12 in it, but i think ford had some concept car that looked like an indy car that had a v12 in it. if you go to v12s in trucks, you can't drop your inches per cylinder too much, or you lose torque, that any amount of cylinders can't make up for, if they are not big enough. 10 briggs and strattons aren't going to put out 400 ftlb of torque. you reach a certain point where the tradeoff goes the other way.

a poke at the ford v10s from a chevy-- the 454 has the same torque and 25 more hp than fords new v10, while getting low to mid teen fuel mileage. not good for ford if their brand new motor is still outrun by a 30 year old block with 6 year old technology.

Brutus · June 1998

Then the new Chevy V-10 will probably get 20mpg. I had heard closer to 10-12 city and a couple mpg better on the hwy, which is sounding about the same as the Ford V-10.

Regardless, I'll take the Ford V-10 over a 454 anyday. The Ford V-10 is smoother running and more quiet. Like you said, the 454 technology is older. On the other hand, if GM makes their new V-10 like they make their V-8s, it should be one heck of an engine. The 350 and the 454 have done Chevy proud.

cdean · June 1998

i don't think an engine can get smoother or quieter than chevy's current vortecs. you can't tell the engines are running at idle unless you look at the oil pressure gauge. before they went to vortec, they were a little rougher and louder. but now they are smooth as silk, just like the fords are. it comes from precision computer control of ignition at low rpms, which was difficult in the past, along with greatly reduced internal friction. my only problem with fords is that they must cost more (?) to make seeing how they are using very high tech ignition with overhead cams, etc, and they don't have any performance advantage.

nascar6 · June 1998

Cummins won't have to make a bigger more powerful engine, they already do. Mharde2 is right about that. The 5.9L diesel is tuned-down. Cummins has made that engine for many years. They used to be (or may still be) used in Case construction equipment. 600 ft-lbs of torque is just an computer reprogram away in the 24 valve 'electronic' ISB engine.

mharde2 · June 1998

The B5.9 was not built for the Dodge truck. Dodge built the truck for the B5.9. This engine was in use long before they put it in a pickup. Other than Case its used in fire trucks, busses, marine applications, oil rig pumps, power generators, ect. The ISB is just the next generation of the B5.9. I hope it is as good as the B.

mharde2 · June 1998

These new gas engines are turning such high rpms, it nerve racking to me. The new Cheve Vortec 6000 is rated at 300hp at 4,800 rpm and 355 lbs of torque at 4,000 rpm. Thats too wound up for my taste.(Not that there is anything wrong with that.) I'll just chugg along in my old diesel thank you...

mharde2 · June 1998

This may not be the place for this, BUT.. All of you guys (and gals) out there that still have your dads. Show them how much you appreiciate them, and tell them you love them. Tomorrow they can be gone, and you will miss them more than you can immagine. And have a happy fathers day your own self...Mike

rite3 · June 1998

Amen.

kjbad · June 1998

"Dad, can I drive the truck today?"

"No."

"Happy Father's Day to you, too!!!"

Meanwhile, everybody in the free world seems to get their jollies talking about these trucks as if they are actually a member of the family, just like dear old dad but they use gas instead of belching it out. I understand the select few that have monumental loads to pull, but when is everyone going to wake up and stop feeding these companies our hard-earned money for nothing? Trucks are now about as yuppified as cafe latte and bagels. Instead of "working", you're supposed to be able to go to the golf course and carry your buddy's autographed clubs with you. I really need a four-by to do that!!! GM, Ford, and Chrysler are doing what any company should do...exploit a gimmick. Even Toyota will sell a few T150s because of a gimmick, and eventually the gimmick will fade and we'll all be stuck with goofy-looking trucks again. Wow...pass the keys, Dad...

Brutus · June 1998

Let's see, he's anti-truck, anti-father's day, anti-yuppie, anti-big three, and anti-Toyota. If you don't like trucks, you're in the wrong conference. The Internet is a big place, why not find somewhere else to play where you have more in common with the participants. Maybe whiner's anonymous?

Rocles · June 1998

Hey Brutus, is he like the mysterious dark matter of the universe?The Anti-Matter(s)!LOL!

nascar6 · June 1998

I'm sure he stops at all the 'yuppified' sites on his 'yuppified' computer. Of course he NEEDS his personal computer to make a living, or is that to get his jollies.

rite3 · June 1998

Read this guys bio, it says it all. The only (truck) he has ever owned is a KIA sportage, and he thought that was the ultimate. Oh, by the way kjbad the car you are currently in the market for (vw passat) is named after that sound you claimed your dad makes. That same man who supported you from birth, probably fought to keep this great nation free, and the good AMERICAN I am sure he is or was, he would respect your right to post your own opinion, and mine. It would be my recomendation not to return here posting crap of that nature as you will find the regulars enjoy a good fight, and you will lose. I see by your bio you have a son. I can only hope he dousnt treat you like you have treated your father. Happy dads day anyway.

nascar6 · June 1998

Has the smoke cleared yet!
Is it safe to come out and play?
Well said rite3.

queenms · July 1998

Brutus,
Heres the skinny on the PowerForce:

http://www.fordunleashed.com/Powerforce/Powerforce.htm

At the Chicago Auto Show, Ford Flexed its muscle with the new Ford Powerforce, a Triton V-10 powered four wheel drive Super Duty concept truck that literally towers over other pickups. Powerforce is longer, taller, wider, and has more interior space than any pickup on the road today.
The Powerforce, outfitted with Ford's high-performance Triton 6.8 liter V-10 over-head camshaft production engine, which delivers 265 horsepower at 4,250 rpm and 410 foot-pounds of torque at 2,750 rpm. It features an 8-foot cargo box and stands an impressive 81 inches tall on custom 19-inch two piece aluminum wheels and 35-inch off-road tires.
The monstrous Powerforce is planned to be Ford's 1999 heavy-duty F-350 workhorse pickup which will be on sale a year from now, minus a few of the innovative gadgets. The exhaust comes out through meaty chrome stacks behind the passenger cab, just like on a semi-truck. And the so called bull bars on the front look ready to knock down anything in the way. Power rotating running boards make entry and exit easy, even at Powerforce's height. Further more, a power lift tailgate aids in loading and unloading cargo. A remote key fob opens the tailgate and lowers it to ground level so large objects can be lifted to the bed.

cdean,
Not trying to make that particular Ford/Cat alliance a big deal just trying to keep another truck buyer from holding onto a false hope. Theres 2 great motors on the market currently and if your a diehard Chevy fan Chevy's got one. I too would love to see the Cat motor in a light truck, But who knows when and if that will be, or who the manufacturer will be. Only Cat knows...

Brutus · July 1998

thanks for the info Queenms. I've accessed the info on the Ford Unleashed site several times, but hadn't been there in quite a while. I was trying to recall what I had read, but was too lazy to go back and check it out myself.

mramsby · July 1998

Need advise on diesel fuel additives. Just got a 99' F350 diesel crew cab. I normally keep my trucks for ten years or more and would like to give it "the best" care I can. Are diesel fuel additives worthwhile and worth the money? Any negatives to fuel additives? Any brand/type better than others?

KCRam · July 1998

If I have had to buy diesel from an "unreliable" source, a bottle of STP Diesel Treatment ($2) makes sure everything is ok. In winter, a bottle of STP Anti-Gel (also $2) per tank keeps everything flowing, regardless of temperature. Make sure you use your engine block heater in winter if it's cold where you are - makes a world of difference in drivability.

stanford · July 1998

I've never used additives, either for oil or coolant, in my 7.3l. I've heard a lot of people saying that they really help, but I've got ~100K on my current motor with no problems. Use whatever diesel I come across (generally Texaco in city, truck stop on highway) but don't worry about it. The motor feels almost a strong as it did when I took it home, and still gets ~16 mpg city and highway combined. This is mainly in Texas, so I've never used my block heater.

Airwolf · August 1998

Kirkpama (or anyone):

A long time ago you said it would take 80,000 miles for the cost difference to be made up for the diesel. What was your calculation? I'd like to use it to determine if the diesel is better or not for my area (fuel price, etc).

Thanks,
Ryan

fredwood · August 1998

I too am considering a diesel. I just calculated that it would take about five years in gas savings to pay for the diesel (for my driving situation anyway). I think if you plan on keeping your truck for 10 years or more you may come out ahead of the game financially. I still just have a hard time spending an additional $4500 for just an engine upgrade.

fredwood · August 1998

You forgot to amortize the diesel engine, that's if your financing your purchase. At 8% for 60 months, a $4500 engine option actually costs you $5415.

stanford · August 1998

Assuming that you finance w/o a down payment.

Then again, if you put all your fuel on a card with 18% interest...

All kidding aside though, point well made. The diesel is not the economical choice you might originally percieve it to be. In fact, with the addition of some headers, etc (Gale Banks type) you could bring the torque of the gas engine up to diesel levels (which we already know the transmission can handle) and still save money.

Hmm.

richflynn · August 1998

Y'all have missed what I consider the most important points of diesel vs. gasoline.

The shear joy of the torque! The diesel is so much easier to drive because of this. I could start in Grapevine, CA at zero MPH and crest the Tejon Pass at 85 without even trying. This was with the '92 7.3L and no turbo. The only things that would ever pass me were god old detroit cubic inches or $50,000 so called luxury cars.

There's nothing to go wrong in a diesel. On my '92, an alternator and auto trans (under wty) in 130k miles. The engine is so simple. (I don't know about the computer controlled '99 7.3L.) The diesel did not, not start. I've had a lot more problems with my wife's '91 H with 100K LESS miles.

I think that the economy issue is almost a break even at 100k miles when the increased trade in value is considered. My dealer said that he can move a 100K mile diesel much quicker than gasoline.

Rich

Diesel vs. Gasoline

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