BertP
Edmonton, Alberta, Canada
Senior Member
Joined: 11/07/2003
View Profile
|
Quote:alaska511 Has a good point. everyones situation IS different. Howeve if you are in the market for a vehicle then the compairson opens up.
A: Diesel Pro
1. Diesels are more fuel efficent than gas 100:1 air fuel ratio compaired to 14.7:1 for gas. Diesels are no meant to be cheap (other than fuel cost) they are mean't to be more durable.
I think that the 100:1 mixture ratio is a little generous. Around 35:1 would be more realistic, I believe. Also, the diesels are not necessarily more durable. The CTD is listed as a medium duty engine, so it has greater durability, but both the PSD and DMax are light duty just like the gassers.
Quote:2. To get equal in torque (what really counts) you have to go to a huge gas engine which consumes even more fuel.
First, torque is not what really counts, but higher torque does usually mean greater efficiency because you don't have to waste power spinning the engine to get higher HP.
Second, while you can increase the torque output of a gasser by increasing its displacement, you can also increase its torque the same way it is done on the diesels: add a turbo. Just try removing the turbo from a CTD, PSD or DMax and see how much power you are left with. They will run (basically none of them have a turbo at idle) but they will be less than anemic.
Quote:B: Gas Pro
1. Gas is more readily available, I know you may not have trouble finding diesel, but fact is not every station has Diesel.
2. parts for gas engines on the whole are more economical.
3. Gas engines are in lighter vehicles. You won't get a Diesel in a 1/2 ton.
True. The biggest problem with a diesel - and why there are very few diesel engines in aircraft - is their weight. I whent from a 1500HD with a 6 L gasser to a 2500 HD Dmax and lost payload because of the additional weight of the engine and tranny. A half ton will not take the weight of a DMax, for example. Even if you were to beef up the front end enough to take the weight, the percentage of the entire weight of the truck that would end up on the front end would make it dangerous to drive.
Quote:c:Neutral
1. Noise and smell. Diesels do make more noise and some don't like the exhaust and fuel odor. I happen to like it better than gas, but thats a personal thing.
Yup, diesels stink ![[emoticon]](http://www.coastresorts.com/sharedcontent/cfb/images/biggrin.gif "biggrin")
Quote:One might conclude I drive a Diesel, when in fact I drive gas. If the Cummings had been available in 1/2 ton I would have a diesel. For those who love 3/4 an 1 ton thats great but those beat my back to death. If I drive one of Emergency Managements trucks it kills my back. My truck is an authorized emergency vehicle and I prefer to us it. The ride is like compairing a Cadallac to a dump truck to me. Yes it does limit my choices in trailers. A 1/2 ton will limit you to about 7500 GTW. I don't have any trouble towing as long as I keep my CGVW under the trucks limit. If one desires a 3/4 or ton truck then it becomes a choice factor. The Diesel will cost more initally but you will get better fuel mileage. If you trade every year or two you probably won't recover the cost. If you keep it long term it will save you money. If your like me and going light you don't have the option and will be stuck with gas. ASE Master automotive, Master HD truck, Paint & collision repair. Since 1976
And one might conclude that I own a gasser, but I have a DMax. You are 100% correct that it is a personal choice. Get what you need and like and enjoy it.
Bert
|
PSDExcursion
Millstone NJ
Senior Member
Joined: 08/17/2001
View Profile
 Offline
|
Quote:In fact, I think Ford gives higher tow ratings (by 500 lbs) in the Super Duty pickups (F250/350) to thier V10 over the PSD despite lower peak torque AND peak horsepower.
Ok, it's time to cut the BS. The 2005 Ford 325HP 6.0 PSD has up to a 7,000 lb higher GCWR than the new 355HP V10 in the same truck with the same trans and with the same axle ratio or even when the V10 has a higher axle ratio because of much more torque.
The 2005 320HP 8.1 Suburban has a 3,000 lb higher tow capacity than the 335HP 6.0 Suburban because of much more torque.
This forum needs a bs protector big time.
2002 Chevy Express 3500 8.1 155" WB passenger van
41 Ft 2003 Thor Citation 41-ZBSR TT w/ Hensley Arrow
|
Aquaduct
Winchester, VA USA
Full Member
Joined: 05/30/2004
View Profile
|
Quote:Quote:In fact, I think Ford gives higher tow ratings (by 500 lbs) in the Super Duty pickups (F250/350) to thier V10 over the PSD despite lower peak torque AND peak horsepower.
Ok, it's time to cut the BS. The 2005 Ford 325HP 6.0 PSD has up to a 7,000 lb higher GCWR than the new 355HP V10 in the same truck with the same trans and with the same axle ratio or even when the V10 has a higher axle ratio because of much more torque.
The 2005 320HP 8.1 Suburban has a 3,000 lb higher tow capacity than the 335HP 6.0 Suburban because of much more torque.
This forum needs a bs protector big time.
Good Lord, Joe, don't you ever tire of being a jerk?
What I said is absolutely true. On the Ford website, comparable 2004 F250/350 trucks with automatic transmissions have equal maximum GCWRs and the diesel has 500 lbs less tow ratings probably due to the extra wieght of the diesel. And the V10 only has 310 hp. And less torque than the PSD.
So what that they have different rear ends? That's the point. If you've got horsepower, you can gear for torque. Duh.
Looking further, this holds true through F550 with one exception that requires some special differential.
And as near as I can tell (I haven't made Ford specifications my obsession like you appear to have since I worked there 6 years ago and I've never cared about GM specs), the V10 and the PSD have different transmissions, 4-speed vs. 5-speed automatics and 5-speed vs. 6-speed manuals.
Now manual transmissions are another story, where the diesel has significantly more maximum GCWR than the gasser. That difference isn't really about engine torque (although I suspect it is at the root of it), it's about a manual vs. automatic transmission. And before you read something stupid into the above statement, I suspect that an automatic's relative inability to handle torque is at the root of this apparent anamoly. A manual transimission lets the vehicle take advantage of the horsepower and torque of the diesel. Basically, they have to derate the vehicle to keep the automatic transmission alive.
And in the end, so what? The point is that it is a system. Anyone who buys a tow vehicle based on either maximum torque or maximum horsepower is stupid. My example simply shows that it is possible to buy a vehicle (and a wildly popular RV TV) with better tow capacity and lower hp AND lower torque.
For someone who needs help understanding tow capacity and the differences in vehicle capabilities, that's an important point to make. I certainly don't need to prove anything to you.
So, what Ford Superduty pickup will tow best? It all depends.
|
PSDExcursion
Millstone NJ
Senior Member
Joined: 08/17/2001
View Profile
Offline
|
Quote:That difference isn't really about engine torque (although I suspect it is at the root of it), it's about a manual vs. automatic transmission. And before you read something stupid into the above statement, I suspect that an automatic's relative inability to handle torque is at the root of this apparent anamoly. A manual transimission lets the vehicle take advantage of the horsepower and torque of the diesel. Basically, they have to derate the vehicle to keep the automatic transmission alive.
BS, in both the Ford and GM diesels the automatic trans has a higher rating than the manual trans.So who is the real jerk ? ![[emoticon]](http://www.coastresorts.com/sharedcontent/cfb/images/rolleyes.gif "rolleyes")
|
rotbaron
Hendersonville TN.
Senior Member
Joined: 08/12/2004
View Profile
Offline
|
[quoteA:I think that the 100:1 mixture ratio is a little generous. Around 35:1 would be more realistic, I believe.
[quote]2. To get equal in torque (what really counts) you have to go to a huge gas engine which consumes even more fuel.[/quote]
3. Gas engines are in lighter vehicles. You won't get a Diesel in a 1/2 ton.[/quote]
[quote]c:Neutral
1. Noise and smell. Diesels do make more noise and some don't like the exhaust and fuel odor. I happen to like it better than gas, but thats a personal thing.[/quote]
Yup, diesels stink :B
[quote]One might conclude I drive a Diesel, when in fact I drive gas. If the Cummings had been available in 1/2 ton I would have a diesel. For those who love 3/4 an 1 ton thats great but those beat my back to death. If I drive one of Emergency Managements trucks it kills my back. My truck is an authorized emergency vehicle and I prefer to us it. The ride is like compairing a Cadallac to a dump truck to me. Yes it does limit my choices in trailers. A 1/2 ton will limit you to about 7500 GTW. I don't have any trouble towing as long as I keep my CGVW under the trucks limit. If one desires a 3/4 or ton truck then it becomes a choice factor. The Diesel will cost more initally but you will get better fuel mileage. If you trade every year or two you probably won't recover the cost. If you keep it long term it will save you money. If your like me and going light you don't have the option and will be stuck with gas. ASE Master automotive, Master HD truck, Paint & collision repair. Since 1976[/quote]
And one might conclude that I own a gasser, but I have a DMax. You are 100% correct that it is a personal choice. Get what you need and like and enjoy it.
Gee I guess I must be a dumb&**, 35 years as a professional mechanic, owned two transmission shops. Taught Nashville Auto Diesel College 5 years, taught mechanics another 21 years, Get to go to factory schools at no cost to me and do every year. Have been consulting and expert witness since 88, billing at $200 per hour and $400 per hour for depositions. Held ASE certifications since 76, back when it was NIASE. My guess is that unlike me some have never rebuilt a diesel fuel injection pump, rebuilt diesel engines, rebuilt automatic transmissions, or even own the diagnostic equipment. I have my own Sun Interrogator with 4 gas, lab scopes, OBDII equipment and a garage full of Snap-on tools. I have former students doing R&D for NASCAR teams, and in 77 I built engined for a Can-Am Lola the clocked 216.3mph Oh and BTW I am in the Automotive Service Assn. Hall of Fame, but then I don't have a clue about what I am writing and you know everything.
Note: Due to invalid formatting, all formatting has been ignored.
|
|
|
tgatch
Meridian, ID
Senior Member
Joined: 08/13/2003
View Profile
|
Aquaduct,
The numbers for the Ford Superduty trucks have changed for the 05's. The V10 is no longer 310HP, and they can now be equiped with the Torqshift.
Nobody still seems willing to answer the question Joe posted though...
Quote:he 2005 320HP 8.1 Suburban has a 3,000 lb higher tow capacity than the 335HP 6.0 Suburban
Why???
I know we could change the rear end gearing in the 6.0 and ultimately it will be able to out run the 8.1 towing the same weight. Our problem will be how long that engine lasts. Bert likes to point out that his 6.0 was rated to last as long as his Duramax. This is true as long as it is used within the specs of the 6.0 geared the way it came from the manufacturer. If you gear that 6.0 to do the same job as the Duramax I would suspect a significantly shortened engine life.
So, the ultimate answer is not so much diesel vs gas. It's more where your torque is produced. More low end torque, means more low end HP. I am sure that an 8.1 towing 12,000lbs day in and day out will last as long as the Duramax. That is within its design specs. Try that with a regeared 6.0 and you will cut its life drastically.
Gas vs diesel? Answer, preference.
High torque @ low RPM vs High HP @ high RPM? Answer, once you do both my guess is you will tow with the high torque motor. Again preference.
Personally I like getting about 12 mpg towing my 11,000+lbs Hitchhiker. Sure my truck cost me a little more up front, but I keep vehicles for a long time so I will see the break even point and beyond. Even then I will recoup my intial investment at trade in or sale, as long as the current trade in value trend stays where it is now.
|
BertP
Edmonton, Alberta, Canada
Senior Member
Joined: 11/07/2003
View Profile
|
Quote:Gee I guess I must be a dumb&**, 35 years as a professional mechanic, owned two transmission shops. Taught Nashville Auto Diesel College 5 years, taught mechanics another 21 years, Get to go to factory schools at no cost to me and do every year. Have been consulting and expert witness since 88, billing at $200 per hour and $400 per hour for depositions. Held ASE certifications since 76, back when it was NIASE. My guess is that unlike me some have never rebuilt a diesel fuel injection pump, rebuilt diesel engines, rebuilt automatic transmissions, or even own the diagnostic equipment. I have my own Sun Interrogator with 4 gas, lab scopes, OBDII equipment and a garage full of Snap-on tools. I have former students doing R&D for NASCAR teams, and in 77 I built engined for a Can-Am Lola the clocked 216.3mph Oh and BTW I am in the Automotive Service Assn. Hall of Fame, but then I don't have a clue about what I am writing and you know everything.
Wow, Dan, did I hit a nerve or something? For the record, I did not call you, nor did I imply that you are a "dumb&**" or use any other derogatory term to describe you or anyone in your lineage. I simply questioned your statement that diesels run at a 100:1 mixture ratio. Think about it: If diesels ran at 100:1 and gassers ran at (let's round up for easier math) 20:1, that means that for each combustion cycle, the gasser burns 5 times the amount of fuel that the diesel burns. Since the diesels and gassers cruise at almost the same rpm (around 2000 rpm@ 60 mph), that means that a diesel engined truck would get 5 times the fuel mileage that a gasser gets. I have never seen numbers like that.
Basically, we were both wrong. While a gasser runs at 14.7:1 and will tolerate very little deviation from that ratio, a diesel has a variable mixture ratio - which is one of the reasons that diesels tend to smoke when they are under heavy load. So, is 100:1 a ratio that a diesel will run at? You bet. In some cases, when negative torque is detected, the fuel to a diesel is actually shut off resulting in an infinity:1 mixture ratio. It is more of a philosophical discussion as to whether the engine is "running" at that point or not. But, the mixture ratio that a diesel spends most of its time at is decidedly less than 100:1 or even 35:1. I have done a couple of google searches trying to find information on exactly what the "normal" ratio is but have not been successful. If you have any additional information, I would love to hear it.
Bert
|
BertP
Edmonton, Alberta, Canada
Senior Member
Joined: 11/07/2003
View Profile
|
[quote]he 2005 320HP 8.1 Suburban has a 3,000 lb higher tow capacity than the 335HP 6.0 Suburban [/quote]
Why???
I know we could change the rear end gearing in the 6.0 and ultimately it will be able to out run the 8.1 towing the same weight. Our problem will be how long that engine lasts. Bert likes to point out that his 6.0 was rated to last as long as his Duramax. This is true as long as it is used within the specs of the 6.0 geared the way it came from the manufacturer. If you gear that 6.0 to do the same job as the Duramax I would suspect a significantly shortened engine life.[/quote]
The operative word in the above is "suspect". I tend to agree with you but, since we do not know exactly how GM arrives at the tow numbers, I can no more completely agree with you as I can completely disagee with you. We simply don't know. There have been many posts on this forum and eslewhere by very knowledgable people who have also not been able to difinitively state why a particular vehicle has a specific set of ratings. Lots of speculation, but few hard facts.
[quote]So, the ultimate answer is not so much diesel vs gas. It's more where your torque is produced. More low end torque, means more low end HP. I am sure that an 8.1 towing 12,000lbs day in and day out will last as long as the Duramax. That is within its design specs. Try that with a regeared 6.0 and you will cut its life drastically.[/quote]
Again, I can neither agree nor disagree with you. I am inclined to agree, but I have no hard facts to back up what is basically a gut feeling.
[quote]Gas vs diesel? Answer, preference.[/quote]
Now [b][i]that[/b][/i] I can agree with :B
[quote]High torque @ low RPM vs High HP @ high RPM? Answer, once you do both my guess is you will tow with the high torque motor. Again preference.[/quote]
Again, I agree.
[quote]Personally I like getting about 12 mpg towing my 11,000+lbs Hitchhiker. Sure my truck cost me a little more up front, but I keep vehicles for a long time so I will see the break even point and beyond. Even then I will recoup my intial investment at trade in or sale, as long as the current trade in value trend stays where it is now.[/quote]
I like the higher mileage and the fact that aux tanks for diesels are [i]much[/i] easier to come by than ones for gassers, at least in my experience. Even Transfer Flow has a much more restricted product line up for gassers than for diesels.
As you mentioned above, get what you like and enjoy it. Don't buy one type over another just because someone said that his brother's friend's girfriend's uncle's sister-in-law has one and says that it is the best. Try them out and see for yourself.
Bert
Note: Due to invalid formatting, all formatting has been ignored.
|
Aquaduct
Winchester, VA USA
Full Member
Joined: 05/30/2004
View Profile
|
Quote:Aquaduct,
The numbers for the Ford Superduty trucks have changed for the 05's. The V10 is no longer 310HP, and they can now be equiped with the Torqshift.
Nobody still seems willing to answer the question Joe posted though...
Quote:he 2005 320HP 8.1 Suburban has a 3,000 lb higher tow capacity than the 335HP 6.0 Suburban
You'll notice that Joe never bothered to answer my question. In 2004, the V10 automatic has the same GCWR and a higher tow rating with lower horsepower and torque.
At least I'm saying that there are many other factors to consider. Really, I'm even bolstering a side of his argument by pointing out that it ain't all about horses either. Joe just makes grandiose claims that "every manufacturer" bases tow ratings and GCWR on torque and then just dismisses everyone who disagrees as profoundly stupid. Then he changes model years. And then he misquotes you and makes fun of you in every thread he's got an opportunity to.
Frankly, I don't know anything about the 2005's. Don't keep up on the magazine reviews. I can only work with what's published at the moment.
If you want to buy Joe's arguments, feel free. In the long run it won't matter. Gas or diesel, similar vehicles with similar engines will give relatively similar towing performance.
Personally, he bores me.
|
johnandlaurie
Everett, WA, USA
Full Member
Joined: 03/23/2004
View Profile
|
I love my new (used '99) PSD, but get only 13 MPG, not much less tho when towing. Is this in the ball park? also fuel prices here are $2.09 gal, abour 10-15 cents more than gas. John (Wash. state)
|
|
|
|
