BertP
Edmonton, Alberta, Canada
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Quote:You folks all need to understand that dyno runs are done at wide open throttle. Basically they start from idle and then slam the throttle to wide open. These numbers are then plotted into the graphs you see.
If you are cruising along at a quarter throttle at 1800 RPMS your truck is not producing max power at that rpm. The only way for that to happen is the truck has to be receiving maximum fuel as it goes through that RPM. The only way to be receiving maximum fuel is wide open throttle.
I don't agree with much of what bert has to say, but he is right on this one guys. Sorry ![[emoticon]](http://www.coastresorts.com/sharedcontent/cfb/images/frown.gif "frown")
Tom
I have to ask why you are sorry, Tom. I am not trying to criticize or insult anyone, just trying to get to the truth. There is a phenominal amount of misinformation floating around concerning gassers vs diesels and HP vs torque. I would just like to be sure that newbies visiting these forums go away with accurate information that they can use to make a purchase decision.
Bert
* This post was
edited 07/07/04 10:37pm by BertP *
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BertP
Edmonton, Alberta, Canada
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Joined: 11/07/2003
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Ag Teacher - Thanks for the support. It was beginning to get a little lonely here ![[emoticon]](http://www.coastresorts.com/sharedcontent/cfb/images/smile.gif "smile")
Joe - Sometimes I have towonder if the internet you access is on the same planet as the one I do. I really cannot understand how you derive some of your conclusions. Sorry.
Bert
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tgatch
Meridian, ID
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Joined: 08/13/2003
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Bert,
I was saying sorry to Joe for taking up sides with you about the dyno thing. You and I still don't agree on what gets you up the hill. We do agree that the 8.1 produces more HP. But oddly, I did show you the new LLY Duramax is now rated to tow more than an 8.1. You still don't have an answer for that one. Obviously GM feels that the torque advantage of the diesel at 590 vs 455 was enough of an advantage to over come the hp disadvantage of 310 vs 320. ![[emoticon]](http://www.coastresorts.com/sharedcontent/cfb/images/wink.gif "wink")
I still say I want the torque of my diesel, over the higher HP gassers. Having come back from a 2100+ mile round trip I really appreciated that diesel torque as I was driving through the Cascades.
I also appreciated the 380+ mile range on 33 gallons of diesel. I generally don't run it that far, but I was just testing it out to find the comfort spot for me. I'm feeling that about 350 is a good fueling distance for me now, gives me a pretty good margin of error that way.
On a side note, I almost had two deer run out in front of me, but they turned and bolted back into the woods as I came closer. Anybody else ever wonder if the whine of the turbo is a good deer scaring tool???? If it is, I just found a very good reason to own a TURBO diesel...
Tom
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BertP
Edmonton, Alberta, Canada
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Tom - I did answer your question about why GM rates the DMax as having a higher tow capacity than the 8.1 - I said I don't know why. I have said a number of times that I am not a mechanical engineer and that there are a number of things that have to be taken into consideration when deciding on the tow capacity of a particular truck/engine combo. I have to admit, though, that I find it odd that the DMax is rated higher than the 8.1 only in the 3500 and not the 2500HD. What's the difference between those two trucks?
I don't think anyone has argued a diesel's advantage in the fuel consumption area. I am getting much better mileage with my DMax than I got with my 6 liter.
Bert
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tgatch
Meridian, ID
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Ooops wrong thread
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PSDExcursion
Millstone NJ
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Quote:Joe - Sometimes I have towonder if the internet you access is on the same planet as the one I do. I really cannot understand how you derive some of your conclusions. Sorry.
Bert, here in NJ a 5.4 Excursion is a dog compared to a 7.3 PSD towing a 41 ft TT and I am sure it's the same way on any planet.You said the 5.4 would not be working as hard as the 7.3 PSD and I say that is total bs.
2002 Chevy Express 3500 8.1 155" WB passenger van
41 Ft 2003 Thor Citation 41-ZBSR TT w/ Hensley Arrow
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sack1
Kent, WA
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Tincan931,
Throwing rocks at gassers? My oh my, has it come to this? Are we a bunch of kids here? Wait, don't answer that.
Gosh, I can hear the chest beating already.
'03 Chevy 2500HD 4x4, LT, Ext. cab, LB
8.1/Allison, 4.10
'03 32' 2955 Montana 5er
XM Radio/OnStar
Valley Hitch
Honda EU1000i
1984 VF700F Interceptor
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PSDExcursion
Millstone NJ
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Quote:Tincan931,
Throwing rocks at gassers? My oh my, has it come to this? Are we a bunch of kids here? Wait, don't answer that.
Gosh, I can hear the chest beating already.
This is not about diesel vs gasser but HP vs torque. Bert thinks the Chevy 6.0 has more power than the 8.1 . But his first post on the diesel vs gas shows he still doesn't have a clue.
I have been looking at this whole area of towing capacity lately and I have to admit that it doesn't make a lot of sense to me. In particular, I was looking at the published numbers for GM's 2500 HD series. I understand the comments about brakes made in this thread, but GM says that, for two 2500HD trucks that are absolutely identical except for engine and transmission, there is a 50% increase in max trailer weight ratings. If you compare a 2500HD with a 6 liter gas engine with the same truck with a Duramax, GM says that you can pull 50% more with the Duramax than you can with the 6 liter. If you consider that the two trucks have exactly the same HP (300) (so they should accellerate at the same rate), the same suspension & tires (so they should both be able to carry the same weight) and the same brakes (so they should both be able to stop the same weight in the same distance), you have to wonder why is one rated so much higher than the other? Both vehicles do have the same GVW, the only difference seems to be in the allowable tow weight. After a fair amount of insistance on my part, GM finally said that it is because the Duramax has a more efficient cooling system than the gas, so it can pull more.
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BertP
Edmonton, Alberta, Canada
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Years ago, I used to live in Yellowknife in northern Canada. It gets quite cold there in the winter with -40 being fairly common and dropping to -50 occasionally. When it got that cold, stray dogs tended to pack. Some theorized that is was for the social interaction while other said it was to keep warm.
I had a dog at the time who would not join a pack, but if a pack came around our house while she was out, she would siddle up to it and work her way to the middle. Once there, she would bite one of the dogs in the rear and then back out again before it turned around. When it did turn around, it woul attack the nearest dog and the fur would start to fly. In the meantime, our dog would have climbed up on a rock to enjoy the fight. I swear to this day that she had a smile on her face.
You remind me of that dog, Joe. You enter a thread and add nothing of substance. You then bite someone and then sit back waiting for the fur to fly. I hate to disappoint you, but I don't bite back. I post what I post after researching the subject and I am quite willing to accept that I am wrong if someone can provide proof. If I am wrong, I am wrong. It has happened in the past and it will probably happen in the future.
Bert
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sack1
Kent, WA
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From my understanding on the torque vs. HP thing in practical terms is, provided all else is equal (seldom, but good for comparison) the engine with greater torque should pull away from a stop more quickly. In others words, initial accelleration depends on torque output. But remember, there are other factors before the power hits the road, such as gearing which can be a torque multiplier. HP development then enables an engine to accellerate beyond any given point on the rpm band. In other words HP development then takes over and is the major factor in acceleration. But torque is twisting force and dictates how much of a load the engine can spin against, again all things being equal.
Remember too that getting a big 5er down the road @ 60 mph does not take maximum torque. If it did you'd have to have the right pedal buried to the floor. Extra torque would come into play when traveling up steep grades. That's why smaller engines that produce less torque might need to kick down a gear or two to use the torque multiplication the lower gears provide and spin further into their rpm bands to maintain road speed.
But this isn't a gas vs. diesel issue. It's a factor of available torque to pull a load and HP to provide increased speed from any given point in the range.
Torque and HP are not two seperate entities. Torque is twisting force that can be measured even at zero rpm (but you aren't going to go camping at zero rpm) and HP is the calculated indicator of work that can be done over time which factors torque and rpm.
It's easy to go bench racing and declare the winner based solely on peak numbers. But there is a real world out there. Some care to live it practically while others take it as the sky's the limit. It does not take a diesel to move an RV down the road. For me there are other very suitable tools in the shed that can get the job done.
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