Diesel vs gas......................

[blt2ski]

OK folks, there have been a few to many diesel vs gas threads that have shall we say gone to "Hell and a hand basket"! So if all of you would put in you BEST, no flaming reasons for going gas vs diesel, pro and con, I will either leave your thread, or copy and paste pertinant info to the 4 posts of pro and con of diesel or gas. This can include the GM 8.1 vs Dmax or Ford V-8/10 vs PSD etc too.

Be real and honest in you answers, not hear say, flaming etc PLEASE!

If posts are good ones, I will leave, if inflamatory or trolling in nature, they will be deleted! I will get this stick'd to the top for future parusing for those that need this type of info.

Added 6-23-04

We are getting closer to answers I am looking for etc.

Stuff like Ken's - T-Bone posts are good. There are a few others of you that have not posted, some with a 9 point question and answer type to figure out how you went with one or the other. If you are one of those, PLEASE repost in this thread. I may have to look up whom has done this and PM you, but if you think this is you, you now know what to do.

Also, for those of you with $ per gallon for either fuel right now, I would prefer to see a post with ...."in my area, diesel is typically .10 less than unleaded" then explain your numbers. As currently in the Seattle area, diesel and unleaded are any where from 2.05 -2.30 per gallon, with mid test .10 more and premium about .20 more, with equal high low splits. Two weeks ago those prices were upwards of .30 -.40 per gallon more. people were posting $ per gallon that were for me. "I wish" If someone is reading your post a year from now, they may want to know where your paying 1.65, when the price of fuel is over $3 per gallon. Let's keep prices out of it if possible.

Bert and tin tipi, got into a good discusion on the pros and cons of RPM's, drive train etc. I would prefer to NOT see the quote of the other in responding threads, maybe just write a quick wording of re tranny gearing, instead of the whole 40 words or so in that paragragh, so the repsonse is shorter if possible quicker and easier to read etc.

I have deleted some 15+/- posts, that were off topic etc. Please note, I am trying to keep this at the top, as the ONLY gas/diesel thread in this area. So if one is trying to decide, we do not have to go thru this BS any more. As such, I will be deleting ANY future posts close to resembling this type of topic. I may have to change "this" title to a better one, if one has a better sounding title, to be more positive, better claification, let me know here, or in a PM/e-mail, what ever you feel most comfortible with.

Again thank you for all of you that are keeping responses positive, etc.

Also we could use a few more positive reasons to go gas, as many can see I have both gas and diesel, both have a place! Both have positive reasons to buy that fuel, lets keep the threads etc to that purpose only!

Marty

[Hannibal]

It's odd how in every one of these torque verses horsepower or gas verses diesel threads, it seems like we're seeing the same thing but we perceive and portray it in a different way. I've owned six diesels and plan to own another. After 21yrs of groaning diesels, the Hemi feels "alive" with it's ability and "necessity" to rev. Just the same, I'm looking forward to a new 6.7L Cummins whenever the Hemi starts getting tired or I simply run across the one I want. Will the 6.7L Cummins tow our new lighter 5th wheel any faster? No. I run with traffic now with no trouble. Due to the Cummins high torque at low rpm, it makes the necessary horsepower at a much lower rpm and will once again feel like it's hardly working to do the same job. A MDT with a Cat would be even more overkill. 300hp at 1800rpm with 200hp at a mere 1100rpm would really make easy work of towing our rv's. But it's still horsepower and it's still because of the diesel's high torque at low rpm that it makes the necessary hp at such a low rpm. Horsepower in our application is nothing more or less than "the rate at which we apply or torque". More torque mean you reach your necessary hp at a lower rpm.
Bert. That's a good thought that I've often wondered about. Aside from the love affair with Overdrive, if we could gear a diesel with a 3.07:1 (Dana) and use direct for towing and O/D for empty mpg, then we could see some of those 25-26mpg 70mph flat interstate runs with the HD diesel pickups lumbering along at 1500~rpm or less. Yes it may downshift to direct on the uphills (same torque but needs a little more hp to multiply axle torque a little more) but that's not as sacrilegious to the diesel Gods as it seems. The 6.7L Cummins makes as much hp at 1500rpm as my Hemi makes at 2800rpm and 5 more hp at 2900rpm than my Hemi makes at 5400rpm. All due to torque. But, without rpm, we're not going anywhere. With rpm, it's expressed as horsepower. Work over time. 70 miles in one hour...
If your engine made 14,000ft/lbs of torque but only ran 12rpm, you could pull a huge load really easily. But it would be painfully slow. Because it would only be 32hp. Extreme but an example of what I'm trying to say.

[BertP]

Madhatter1 wrote:
Oh yeah, one more thing. I dare anyone with our high HP pickup diesels to try to go nose to nose with a F650 with a 300HP CAT or Cummins and think they have more power. Those engines have much more HP down low and therefore much more torque. My own 350HP 6.7 could not move what those trucks can move. Not a knock on our Diesels, just trying to show the point to the Gas only crowd. No offense intended for gas guys that see both sides.

Just in case you incleude me in your "gas only" crowd - in spite of the fact that I own a diesel - I wanted to point out that this post is the closest to hitting the nail on the head. You stated

"Those engines have much more HP down low and therefore much more torque"

. Notice the "much more HP" phrase. THAT is what people like me have been saying. If you have the HP - regardless of what rpm it is made at - then you will move the load (assuming that your vehicle isn't hamstrung by bad gearing in the tranny). Notice that I didn't say anything about gas or diesel or which one is better. I am just referring to power. If you change the gearing in your Dodge, you will either blow the doors off those F650's or reduce your Dodge's towing ability to that of a VW Rabbit - depending on what gears you choose. Gearing makes a HUGE difference in towing ability.

Bert

[Madhatter1]

Oh yeah, one more thing. I dare anyone with our high HP pickup diesels to try to go nose to nose with a F650 with a 300HP CAT or Cummins and think they have more power. Those engines have much more HP down low and therefore much more torque. My own 350HP 6.7 could not move what those trucks can move. Not a knock on our Diesels, just trying to show the point to the Gas only crowd. No offense intended for gas guys that see both sides.

[Madhatter1]

I give up. I hand the argument over to GA camper since he seems most up to speed on this deal (sorry). The thread is gas vs Diesel so readers can figure out which will work best FOR THEIR APPLICATION. While there are many gas trucks capable of pulling heavy loades one must still decide how much, how often, how many $. The gas guys rather than explain why gas works for their applcation works better are trying to say there is no use for a high torque Diesel pulling a heavy load many times over a long distance. So heres my "BS" challenge. Take two similar trucks, hook them to 20K trailers, and see which one can get from NY to CA faster. Rules are do not exceed the speed limit by even 1 MPH. The diesel will win due to less fuel stops and less loss of speed through the mountains. Go ahead and say the gasser will maintain the same speed through the mountains. I will not disagree, but admit it will add 1 more fuel stop to do so.

[Hannibal]

Not the case at all. While my truck is a 3/4 ton, we hooked our 10,400 lb high profile 5th wheel to it and took many vacations all over the southeast. The little Hemi out tows my previous SO Cummins with 100ft/lbs less torque but 100 more horsepower. Folks tend to relate gas engines with horsepower and diesels with torque but, regardless of fuel, it's horsepower that determines at what speed you can move the load or accelerate the load. Horsepower is the result of torque and rpm in our application. As Madhatter said, the diesel's high torque simply means you make most of your horsepower at an rpm that's below peak torque rpm of most gas engines. The straying off to different applications was just as an example that you can move a heavy load up to speed with no torque at all. But, you won't move a load without horsepower be it steam, thrust, leverage, gravity, bear feet or torque X rpm. Horsepower is what determines how fast we go. Diesels, because of their higher torque, simply make more of it at a more palatable rpm. If they don't have enough torque to overcome their limited rpm, then the higher horsepower engine will outrun it loaded or not as is the case with my current and previous trucks. In the past 102k miles, I have yet to run into a stretch that I couldn't maintain speed, although it may require some higher rpm to reach the necessary horsepower to keep it rolling. If you do the math, you'll see that if you have 300hp to the transmission from the Hemi at 4200rpm and the Cummins at 2900rpm, gear reduction to bring them both to the same road speed will mean equal torque to the rear axle. Not talking about calculated flywheel torque on a chassis dyno but, actual rear axle torque.

A 350 horsepower weedeater? I've never seen one. How do you carry it?:B

[GACamper]

It take both HP & Torque depending on your needs. As you said the one with the most HP can win giving the GVW. High HP low Torque will work in a lets say a regular 1/2 ton pickup used for cruising around and hauling your trash off. But most people on this forum use our truck to pull with. So we are looking at more Torque then HP.
Yes the 1/2 ton Gas pickup may be able to go fast faster. But hook lets say a 10,000 pound camper behind it. It's going to struggle even to get moving. While the High Torque Diesel will pull away and cruise all day.
It all boils down to your needs. If you want to haul your trash off in a real big hurry get a high horse power gas engine truck to do so. If your needing to haul let say a 10,000 pound camper up Mount Eagle. Then get a High Torque Diesel.
Both HP & Torque both have there needs in one way or the other. You got to have one to have the other for some kind of motion to happen.

[dougsee3]

blt2ski wrote:


"IF" you want to even things out, now you have to "spec" what the "specs" are as to which is better. A rig with 150HP 600 lb ft of torque at 2000 RPMs say diesel, or what ever fuel you want, vs a rig with 200HP and 600 lb ft of torque at 2000 rpms. The 200 hp rig will win! or should anyway. assuming everything else equal. But when one starts messing with the different variables involved, it is any body's guess as to which will be better at times. Sometimes a hei as Steve has will do as well as a diesel, other times, the diesel will do better, and others, jet fuel!

marty

This is where some confusion is that you cannot have two different HP's at the same torque and the same RPM. As the Hp is calculated from the torque and RPM.

But I do agree that the one with the more Hp can win given the GVW is the same. This would need more torque at 2000 RPM, or the same torque at higher RPM to give the higher HP.

Look at any dyno chart diesel does not go that high, but the HP and Torque cross or are the same at 5250 RPM. Also note the Hp continues to climb even when torque is falling or until the motor runs out of fuel and air or its peak efficiency if you will.

[GACamper]

Never worked on a tank before. I just saw that it does have a Torque rating of 2,750-ft @ 3,000 rpm's and you said it had little to no Torque....We need to talk about trucks...Not Tanks! We're getting way off track...:S

[BertP]

GACamper wrote:
Here is the specs on the AGT1500 M1 Abrams tank. I guess it all depends on what you consider very little Torque....

MIL-SPEC
Designer: Chrysler Defense
Manufacturer: General Dynamics
Engine: Honeywell AGT1500 turboshaft
Horsepower: 1,500 @ 3,000 rpm
Torque: 2,750 lb-ft @ 3,000 rpm
Shaft Rotation: Counterclockwise
Exhaust Temperature: 930 degrees F
Total Dry Weight of Engine: 2,500 pounds
Fuel Types: Diesel, jet fuel, gasoline, and marine diesel
Oil type: Synthetic
Transmission: Allison DDA X-1100-3B four-speed
Crew: 4
Length: 387 inches
Width: 144 inches
Height: 93.5 inches
Curb weight: 69.54 tons
Ground clearance: 19 inches
Ground pressure: 15.4 psi

Think about what that is saying - When was the last time you heard of a turbine that runs at

3000 rpm

???????? The engine runs at either 22,500 rpm or 26,600 rpm (I forget now). The number they are quoting there is the output of the power pack that includes a reduction gear after the engine to get the rpm down to 3,000. If you accept the claim that that engine generates 2,750 lb-ft of torque, then I can claim that my DMax puts out 6770 lb-ft of torque (605 from the engine * 3 from 1st gear * 3.73 from the RE). So my little DMax STILL puts the Abrams engine to shame 🙂

Bert

[GACamper]

dubdub07 wrote:
Now this is a smart dude! You must drive a Dodge!

Really I drive a Cummins. It just happens to have a Dodge wrapped around it.....

[GACamper]

BertP wrote:
When it comes to trying to figure out the capabilities of an engine, torque never matters. Only HP can tell you what an engine is capable of - just like the AGT1500 mentioned earlier that is in the Abrams tank. It develops very little torque but lots of HP. That's why it can propell a 70 ton behemouth at 50+ mph. And it will do it in exactly the same manner as a high torque 1500 HP diesel.

Bert

Here is the specs on the AGT1500 M1 Abrams tank. I guess it all depends on what you consider very little Torque....

MIL-SPEC
Designer: Chrysler Defense
Manufacturer: General Dynamics
Engine: Honeywell AGT1500 turboshaft
Horsepower: 1,500 @ 3,000 rpm
Torque: 2,750 lb-ft @ 3,000 rpm
Shaft Rotation: Counterclockwise
Exhaust Temperature: 930 degrees F
Total Dry Weight of Engine: 2,500 pounds
Fuel Types: Diesel, jet fuel, gasoline, and marine diesel
Oil type: Synthetic
Transmission: Allison DDA X-1100-3B four-speed
Crew: 4
Length: 387 inches
Width: 144 inches
Height: 93.5 inches
Curb weight: 69.54 tons
Ground clearance: 19 inches
Ground pressure: 15.4 psi

[blt2ski]

BertP wrote:
Sorry, Marty, I didn't mean to start another one of these wars. I'll retire for another while to give you a break 🙂

Bert

Bert
Don't worry, I'm fine, some days it is what it is! I still feel there is NO BEST motor, be it gas, diesel, jet fuel, alcohol, _________. It will depend upon the "job" at hand! Transfer of power to the ground, water or air. Some motors, heck, why have a motor designed to go a million miles/hours, if all it is doing is propel and ICBM for 6-8 hrs to its target! Altho some I've heard have to survive those 8 hrs with no oil as we know a motor should have! makes for some interesting bearing materials and parts etc.

Off to work work, done with morning paperwork. along with trying to find some work! a little slow in construction these days!::M:M:M:M

marty

[Ace_]

The Perkins install in my F250 is almost complete. Thanks for the help guys!

[BertP]

Sorry, Marty, I didn't mean to start another one of these wars. I'll retire for another while to give you a break 🙂

Bert

[blt2ski]

mgratner wrote:
BertP,

What you said was silly. In 4+ years of fulltiming I have never been passed by a tank.

This thread has gotten so far afield it should be closed.

Cigar Mike

Then I'd have 5 or 6 or 7 threads with the same BS going on in them! Easier to sorta kind keep the one going in a straight line!

Reality is, yes, no one on here has been passed by a tank, no do I think we will be passed by a tank any time soon. "BUT", as he mentioned two motors, same HP, different torque, different RPM, moving the same item at the same speeds. Due to a different transfer of how the power is getting to the ground.

"IF" you want to even things out, now you have to "spec" what the "specs" are as to which is better. A rig with 150HP 600 lb ft of torque at 2000 RPMs say diesel, or what ever fuel you want, vs a rig with 200HP and 600 lb ft of torque at 2000 rpms. The 200 hp rig will win! or should anyway. assuming everything else equal. But when one starts messing with the different variables involved, it is any body's guess as to which will be better at times. Sometimes a hei as Steve has will do as well as a diesel, other times, the diesel will do better, and others, jet fuel!

marty