bluenote
Michigan
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Quote:As far as the Italian with no Face (must have lost it shaving), engine power is measured in a term called Horsepower. The 8.1 G.M. engine has more horsepower than any diesel engine offered in a pickup.
You are correct in saying that the vortec 8100 has more horsepower in stock form than any of the 3 diesels available in the US light duty truck market. Now, please explain why that engine is rated to tow less than the (by your standards of engine power) lower powered diesel engines? The reason, of course, is that horsepower is only one measurement of engine power. It is also a measurement that is derived from a formula applied to another form of engine power measurement called torque....AND....Regardless what you say, think, or feel about horsepower versus torque, the diesels have more available torque. It must be that the torque output of these engines has just a tiny bit to do with the irrefutable fact that they are rated to tow more, with all other things being equal.
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wkdelsol
sun city,ca. usa
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Joined: 06/29/2004
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My German friend tells me no one drives a diesel car on the Autobon freeway,the can't keep up.
(Just my two cents)
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bluenote
Michigan
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Quote:My German friend tells me no one drives a diesel car on the Autobon freeway,the can't keep up.
(Just my two cents)
That's very interesting. We hosted a foreign exhange student from Germany 3 years ago. His father owned a taxi firm, and most of their taxi's were diesel powered Mercedes Benz. He never mentioned any problem with driving them on the autobahn and I know for a fact that they used them out there regularly. In fact, he said that they can move right along with the fast traffic, pulling over only for the sports cars that are really hauling. Maybe a little VW diesel would run into problems, but there's no reason that any engine, regardless of engine type, couldn't maintain autobahn-type speeds when equipped with the proper gearing.
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BertP
Edmonton, Alberta, Canada
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Jeff - No, I am not 105 ![[emoticon]](http://www.coastresorts.com/sharedcontent/cfb/images/smile.gif "smile") .
I agree that the overwhelming choice of engine for heavy duty work is the diesel. My point has been that a claim that a gas engine cannot do the same amount of work as a diesel is incorrect. Yes, it will rev higher and burn more fuel than a diesel, but it will work the same. In spite of what seems intuitive, 500 HP at 1000 rpm is exactly the same as 500 HP at 5000 rpm or 10,000 rpm or .... you get the point. 500 HP is 500 HP regardless of what rpm it is generated at. Certainly, you will have to change the gearing to accomodate the different rpm, but as long as the engine is permitted to produce the 500 HP, you will get the same results.
Chris - I agree with most of your point, but HP is the only measurement of engine power. Torque is not power. HP can be derived from torque if we know the rpm, but torque itself is not power. It is true that, for a given set of tranny and RE ratios, a higher torque engine will get a larger load moving than a lower torque engine of the same HP, but that is because the higher torque engine can develop more HP at low rpm than the lower torque engine to get the load moving. With the exception of the 3500 DRW (and then only with the allison), the 8.1 is rated the same as the DMax. Part of the reason, I believe, that the DMax is rated higher in that one case is because it develops more HP than the 8.1 at low rpm.
Bert
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bluenote
Michigan
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Quote:With the exception of the 3500 DRW (and then only with the allison), the 8.1 is rated the same as the DMax. Part of the reason, I believe, that the DMax is rated higher in that one case is because it develops more HP than the 8.1 at low rpm.
This part of your argument is flawed.
It does not matter which truck/cab configuration you get the Duramax in, all current DMax's are the LLY with 310HP and 605TQ. In addition, all current trucks with the Duramax have the same 3.73 rear gears and all of them with automatic transmissions have an Allison. Therefore, the Duramax will develop that same higher HP at the lower RPMs than the vortec 8100 in all 2500HD and 3500 configurations. The 2500HD and 3500srw trucks both have the same 22K GCVWR that has been available since 2001 with Duramax/Allison and 8.lL/Allison trucks (only when the big block is paired with the 4.10 rear gears). Since it would be nearly impossible to max out the GCVWR on 2500HD and 3500srw trucks without exceeding payload capacity through 5er or gooseneck pin weight, it does not make sense to up the GCVWR's of those trucks with the newest version of the Duramax. With the 3500drw however, it is more likely that one could get to the GCVWR, while still remaining under payload capacity. Therefore, those trucks are rated for 23,500 pounds of GCVWR with the diesel. So, you have a diesel engine with a 3.73 rear end that is rated for 1,500 pounds more towing capacity than a big block with a 4.10 rear end.
I agree that torque is a different type of measurement than HP, but when you are considering the application of torque and HP in the case of light duty trucks when towing, the low end torque advantages of the diesel overcome the high end HP advantages of the big block.
I was merely pointing out that with ALL OTHER THINGS BEING EQUAL the higher torque diesels have an advantage when towing, even though they have less horsepower.
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BertP
Edmonton, Alberta, Canada
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Quote:
This part of your argument is flawed.
It does not matter which truck/cab configuration you get the Duramax in, all current DMax's are the LLY with 310HP and 605TQ. In addition, all current trucks with the Duramax have the same 3.73 rear gears and all of them with automatic transmissions have an Allison. Therefore, the Duramax will develop that same higher HP at the lower RPMs than the vortec 8100 in all 2500HD and 3500 configurations. The 2500HD and 3500srw trucks both have the same 22K GCVWR that has been available since 2001 with Duramax/Allison and 8.lL/Allison trucks (only when the big block is paired with the 4.10 rear gears). Since it would be nearly impossible to max out the GCVWR on 2500HD and 3500srw trucks without exceeding payload capacity through 5er or gooseneck pin weight, it does not make sense to up the GCVWR's of those trucks with the newest version of the Duramax.
I agree with the first part, but not necessarily the second. Since these trucks are used not only to pull RV's, but also commercial trailers (with a pintle hitch, for example), it would not be unreasonable to assume that the GCVW can be exceeded before the GVW of he truck is exceeded. You may run into difficulties with the max tounge weight, but the GVW sould be fine.
Quote:With the 3500drw however, it is more likely that one could get to the GCVWR, while still remaining under payload capacity. Therefore, those trucks are rated for 23,500 pounds of GCVWR with the diesel. So, you have a diesel engine with a 3.73 rear end that is rated for 1,500 pounds more towing capacity than a big block with a 4.10 rear end.
Unless you get the DMax with a manual tranny. In that case, the truck will have the same 22K GCVW as the 8.1.
Quote:I agree that torque is a different type of measurement than HP, but when you are considering the application of torque and HP in the case of light duty trucks when towing, the low end torque advantages of the diesel overcome the high end HP advantages of the big block.
Yes, there are advantages. I now have a DMax because of some of them. However, geared correctly the 8.1 will still outpull a DMax because of its higher HP. That may require a 4.56 RE - and the higher rpm that goes along with it - but it can get more torque and HP to the ground than the DMax because of its higher HP with the caveat that it has the proper gearing.
Quote:I was merely pointing out that with ALL OTHER THINGS BEING EQUAL the higher torque diesels have an advantage when towing, even though they have less horsepower.
And that is where we generally run into trouble. If everything else is equal (especially the gears), then the DMax will have an advantage over the 8.1, no question. If you look at the power curves for both engines, the 8.1 is developing around 250 HP at 3000 rpm (IIRC) while the DMax is developing 310 at the same rpm. That's quite a difference. So, from a dead stop until the 8.1 gets up to around 4000 rpm (or whatever rpm the 8.1 crosses the 310 HP mark), the DMax is developing more power than the 8.1. Any way you dice it, the DMax will walk away from the 8.1 up to that point. Now you may say that it doesn't take the 8.1 long to get up to 4000 rpm. But, if it is pulling a large load, that could take quite a while (relatively speaking).
Bert
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bluenote
Michigan
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Bert, sometimes I swear you argue just to re-read your arguments...
Say what you want about the GCVWR and GVWR of the different configurations, the fact remains....ALL current GM trucks with the Duramax/Allison have the exact same drivetrain, and the same frames, brakes, rear gears and axles for that matter. Therefore, the 1,500 pound higher GCVWR of the dually must be related to something besides the drivetrain capacities. The dually has a higher payload capacity, and therefore, is more likely to be able to max out the GCVWR. I don't believe that's just a coincidence...it's very likely that's the reason the dually has a 23,500 pound GCVWR.
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xmack
california
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Joined: 10/05/2004
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Simply put diesel good, gas bad
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BertP
Edmonton, Alberta, Canada
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Quote:Bert, sometimes I swear you argue just to re-read your arguments...
Then you should try rereading what I posted.
Quote:Say what you want about the GCVWR and GVWR of the different configurations, the fact remains....ALL current GM trucks with the Duramax/Allison have the exact same drivetrain, and the same frames, brakes, rear gears and axles for that matter. Therefore, the 1,500 pound higher GCVWR of the dually must be related to something besides the drivetrain capacities. The dually has a higher payload capacity, and therefore, is more likely to be able to max out the GCVWR. I don't believe that's just a coincidence...it's very likely that's the reason the dually has a 23,500 pound GCVWR.
Again, the fact that the same DRW truck with a DMax but the manual tranny has a 22K GCVW instead of the 23.5K you refer to implies that there is more to it than the GVW rating of the truck. Whether you have the Allison or the manual tranny, the GVW is the same, but the GCVW is different.
Bert
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justJeff
Ocean Shores, Washington
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Joined: 09/05/2004
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Sure, it will burn more fuel, probably break more often, and not last as long..but hey a gas engine COULD be manufactured that would keep up with the diesel. Just kidding a bit Bert. Face it, if there was a realistic way that a gas engine could be developed that made some type of sense for heavy equipment or heavy hauling, we'd have it. Some heavy equipment/trucks costs hundreds of thousands or even millions of dollars, and they all have some form of diesel engine in them. Almost anything is possible, it just doesn't always make sense.
I've owned quite a few aircraft, all powered by gas engines. Certainly for light weight in a piston powered aircraft it only makes the most sense. A six cylinder Cat in a two place aircraft makes as much sense as a 8.1 in a D8.
Our smallest piece of equipment is an ASV RC50, it has a 50hp Cat diesel in it. It is a wonderful piece of machinery for it's inteded purposes. The older, similarly sized pieces of equipment that were gas powered are considered antiques and are almost impossible to sell. Same with some types of boats, if they don't have a diesel or two they just aren't considered as desireable, largely due to safety considerations.
People that make a living with machinery demand the best tools for the job. For years now that has overwhelmingly been accomplished with diesel powerplants. It's not due to slick marketing or misinformed consumers. Why would someone want to burn more fuel and be less safe for goodness sake?
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