Diesel and gas
#31
07-19-2006, 01:59 AM
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The, "thought this was interesting" link got messed up, supposed to be this...
http://www.kuro5hin.org/story/2006/6/20/212325/307
The Audi diesel also won the american le mans race on Saturday.
http://www.kuro5hin.org/story/2006/6/20/212325/307
The Audi diesel also won the american le mans race on Saturday.
#32
07-19-2006, 02:04 AM
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Originally Posted by furball69
sure, make me work... 
I saw them on TV, I'll try to find links to some 6 seconders. I'll post them if I do. Oddly, the latest stat I could find is the 7.98 second run from 2004
http://www.cumminsracing.com/
If this one does 200 mph, it should be in the 6's
http://www.scheiddieselmotorsports.com/ScheiddieselMotorsports/drag.html
Thought this was interesting...
http://www.gizmag.com/go/5746/
I saw them on TV, I'll try to find links to some 6 seconders. I'll post them if I do. Oddly, the latest stat I could find is the 7.98 second run from 2004http://www.cumminsracing.com/
If this one does 200 mph, it should be in the 6's
http://www.scheiddieselmotorsports.com/ScheiddieselMotorsports/drag.html
Thought this was interesting...
http://www.gizmag.com/go/5746/
Real cool stuff...........Those Cummins can take some incredible abuse!!
#33
07-19-2006, 02:06 AM
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Originally Posted by furball69
The, "thought this was interesting" link got messed up, supposed to be this...
http://www.kuro5hin.org/story/2006/6/20/212325/307
The Audi diesel also won the american le mans race on Saturday.
http://www.kuro5hin.org/story/2006/6/20/212325/307
The Audi diesel also won the american le mans race on Saturday.
Taken from the above link;
The concessions afforded diesel-powered cars at Le Mans this year are numerous. Compared with a turbocharged gasoline-fueled car, the diesels enjoy a 50-percent larger displacement limit, a 52-percent larger intake restrictor, and an absolute boost pressure limit nearly twice as high. Additionally, the diesels are allowed variable nozzle turbines in their turbochargers. It is also rumored that Audi successfully lobbied to raise the minimum weight to accommodate the R10's massive powerplant.
Ladies and gentleman...........I rest my case.
#34
07-19-2006, 02:24 AM
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Originally Posted by tmyers
What a stupid debate. You are comparing apples to oranges. Don't bring top fuel into this they run nitro methane, not gas or diesel.
Look it is very simple. Gas has a limit of how high the compression can be. That is about 16:1. ANything higher than that and you can no longer control igintion. In addition because gas burns much faster that diesel you you have much short stroke engines. This allows for more rpms and more hp.
Because diesel takes that much longer to burn for the most part longer stroke motors are the norm. This means limited RPM's. In addtion the compression ratio for a diesel starts at 14:1 and goes as high as 25:1 in production vehicles today. to handle these compression ratios the engine are heavy, 100's of pounds heavier. Wiegh my 6 liter small block against the 6 liter PSD.
In almost all cases the gas engine will be quicker and faster until you reach the limitations of gas, i.e. to high of compression, stroke gets to long for an effecient burn. This is true in all cases if you don't want to put reliability into the equation. I mean have you ever seen a gas engine that is 3 storys tall. I have seen a diesel this tall though.
But within our normal everday limitation gas will always make more power. An example of this is my LS2 6 liter engine against the 6.0 PSD. Stock I have 400/400 at the engine where the PSD is if I remember right 315/575? But it has a turbo charger. Well I am think of turbo charging my Vette. This is a bolt on kit, no internal changes made to the motor. Expected RWHP/Tq 570/570. In otherwords about 680/680 at the crank.
Would I ever want to tow with this setup, NO!!!!! I'm making this torque past the redline of the PSD. I hope I never have to tow anything and spin a motor at 4500rpms. Could it, yes with ease, the power is there. BUt how long will the engine last if for every 6% grade I have to climb I have the engine at 4500 rpms. ..
And that is why we have diesel, it is fantastic because it can make big numbers at much less rpms than gas given the same CI. But you give up performance, i.e. quickness and speed in return for reliability.
Anyway now look what you made me do. Each has its application and those applications really don't cross.
Look it is very simple. Gas has a limit of how high the compression can be. That is about 16:1. ANything higher than that and you can no longer control igintion. In addition because gas burns much faster that diesel you you have much short stroke engines. This allows for more rpms and more hp.
Because diesel takes that much longer to burn for the most part longer stroke motors are the norm. This means limited RPM's. In addtion the compression ratio for a diesel starts at 14:1 and goes as high as 25:1 in production vehicles today. to handle these compression ratios the engine are heavy, 100's of pounds heavier. Wiegh my 6 liter small block against the 6 liter PSD.
In almost all cases the gas engine will be quicker and faster until you reach the limitations of gas, i.e. to high of compression, stroke gets to long for an effecient burn. This is true in all cases if you don't want to put reliability into the equation. I mean have you ever seen a gas engine that is 3 storys tall. I have seen a diesel this tall though.
But within our normal everday limitation gas will always make more power. An example of this is my LS2 6 liter engine against the 6.0 PSD. Stock I have 400/400 at the engine where the PSD is if I remember right 315/575? But it has a turbo charger. Well I am think of turbo charging my Vette. This is a bolt on kit, no internal changes made to the motor. Expected RWHP/Tq 570/570. In otherwords about 680/680 at the crank.
Would I ever want to tow with this setup, NO!!!!! I'm making this torque past the redline of the PSD. I hope I never have to tow anything and spin a motor at 4500rpms. Could it, yes with ease, the power is there. BUt how long will the engine last if for every 6% grade I have to climb I have the engine at 4500 rpms. ..
And that is why we have diesel, it is fantastic because it can make big numbers at much less rpms than gas given the same CI. But you give up performance, i.e. quickness and speed in return for reliability.
Anyway now look what you made me do. Each has its application and those applications really don't cross.
Kinda rehashed a lot of what I've been saying......
Top fuel was brought up simply because it's a spark ignition motor.....the compression(or boost) limitations have been brought up numerous times by me.
Given the right fuel, a blown spark ignition motor will always make more power. The fact that diesel will do the task much simpler, cheaper and more economically is the reason it is the obvious choice for bombing.
The original question (I think ???) was why diesels make so much more power than gassers............the answer is; all things being equal, they don't!!!
#35
07-19-2006, 03:16 AM
#36
07-19-2006, 03:17 AM
#37
07-19-2006, 07:25 AM
Originally Posted by DOHCmarauder
Maybe Top Fuel will also start using compression ignition also.. 
Wellllllllllllll.........
That's not entirely untrue.
"Spark plug electrodes are totally consumed during a pass. After halfway, the engine is dieseling from compression, plus the glow of exhaust valves at 1,400 degrees F. The engine can only be shut down by cutting the fuel flow."
http://www.cyclespot.com/forums/arch...php/t-142.html
Actually, this might be closer to glow ignition than compression ignition or dieseling. Engine powered modelers (airplane, boat, car etc) have been using glow ignition with nitromethan for many years.
Last edited by 76supercab2; 07-19-2006 at 07:58 AM.
#38
07-19-2006, 11:23 AM
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Originally Posted by 76supercab2
Wellllllllllllll.........
That's not entirely untrue.
"Spark plug electrodes are totally consumed during a pass. After halfway, the engine is dieseling from compression, plus the glow of exhaust valves at 1,400 degrees F. The engine can only be shut down by cutting the fuel flow."
http://www.cyclespot.com/forums/arch...php/t-142.html
Actually, this might be closer to glow ignition than compression ignition or dieseling. Engine powered modelers (airplane, boat, car etc) have been using glow ignition with nitromethan for many years.
That's not entirely untrue.
"Spark plug electrodes are totally consumed during a pass. After halfway, the engine is dieseling from compression, plus the glow of exhaust valves at 1,400 degrees F. The engine can only be shut down by cutting the fuel flow."
http://www.cyclespot.com/forums/arch...php/t-142.html
Actually, this might be closer to glow ignition than compression ignition or dieseling. Engine powered modelers (airplane, boat, car etc) have been using glow ignition with nitromethan for many years.
Dang it!!!!............I was hoping nobody would bring that up!!!!
You're 100% correct.....for 2 seconds, a T/F motor is a diesel!!!!
Right on about the model motors also.....but they are 2 strokes which may open up a whole new can of worms!!!
#39
07-19-2006, 11:27 AM
#40
07-19-2006, 11:36 AM
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Originally Posted by MJEmerson
somthing tells me the case has not been rested....we minds well move this to the politics forum...this is like the democrat / republican debate....or the ford / chevy debate.
The problem with the WWW. is that it's difficult to decipher one's tone or especially to get a point across in less than a novel type presentation.
I have for years touted diesels to be more better in certain situations....(I've also said the MAJORITY of light truck owners don't use their trucks in those situations)
I also realize when comparing available, over the counter, powertrains, the diesel stomps the gassers.....both in power and efficiency......but not JUST because it's a diesel. (Even though a gasser could never match an oil burner in efficiency ,this thread was about power)
But that darned Audi story said it better in a couple paragraphs than I could have in my 100's of rambling posts.....
Maybe that's why they get paid to write????.......LOL!!!
Last edited by Beast12; 07-19-2006 at 07:33 PM. Reason: fixed quote
#41
07-19-2006, 02:10 PM
Ahhh...but here's another twist: power and efficiency aren't unrelated. The last 25 years have seen great advances in power, largely through gains in efficiency. With vehicles running about 30% efficiency (meaning 30% of the available energy in a unit of fuel is turned into forward motion of the vehicle), any increase in efficiency while keeping the fuel delivery constant is a proportional gain in horsepower.
If you take two engines of equal displacement hooked to trannies of identical gearing and do whatever you want to them for air intake and get them to identical efficiencies (someone said "all else being equal..."), the diesel will outperform the gasser (we're talking pump fuel here). Bottom line is that a gallon of pump diesel has more available energy per gallon than gas. So a gasser will never "make more power" than a diesel--all else being equal.
Jason
If you take two engines of equal displacement hooked to trannies of identical gearing and do whatever you want to them for air intake and get them to identical efficiencies (someone said "all else being equal..."), the diesel will outperform the gasser (we're talking pump fuel here). Bottom line is that a gallon of pump diesel has more available energy per gallon than gas. So a gasser will never "make more power" than a diesel--all else being equal.
Jason
#42
07-19-2006, 03:33 PM
wow....a gas vs diesel but more technical!
i don't have any technical aspects to add to this discuassion, but i really feel, except for a few circumstances, the diesel vs gas thing is not comparable.
different engine designs for different uses, i can't see how they could make a gas engine work in heavy mining operations or long term use such as industrial generators.
but i can't see diesels being used for racecars, weedeaters, chainsaws and such.
i think they can be compared on the less extreme area such as light duty truck applications and small cars and even generators, but that is a personal choice. if costs of fuel was the same and costs of the diesel option was the same and noise wasn't a factor, i think you would see more poeple opt for the diesel due to the power and and fuel economy. of course it is my opinion.
i don't have any technical aspects to add to this discuassion, but i really feel, except for a few circumstances, the diesel vs gas thing is not comparable.
different engine designs for different uses, i can't see how they could make a gas engine work in heavy mining operations or long term use such as industrial generators.
but i can't see diesels being used for racecars, weedeaters, chainsaws and such.
i think they can be compared on the less extreme area such as light duty truck applications and small cars and even generators, but that is a personal choice. if costs of fuel was the same and costs of the diesel option was the same and noise wasn't a factor, i think you would see more poeple opt for the diesel due to the power and and fuel economy. of course it is my opinion.
#43
07-19-2006, 04:24 PM
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Originally Posted by jroehl
Ahhh...but here's another twist: power and efficiency aren't unrelated. The last 25 years have seen great advances in power, largely through gains in efficiency. With vehicles running about 30% efficiency (meaning 30% of the available energy in a unit of fuel is turned into forward motion of the vehicle), any increase in efficiency while keeping the fuel delivery constant is a proportional gain in horsepower.
If you take two engines of equal displacement hooked to trannies of identical gearing and do whatever you want to them for air intake and get them to identical efficiencies (someone said "all else being equal..."), the diesel will outperform the gasser (we're talking pump fuel here). Bottom line is that a gallon of pump diesel has more available energy per gallon than gas. So a gasser will never "make more power" than a diesel--all else being equal.
Jason
If you take two engines of equal displacement hooked to trannies of identical gearing and do whatever you want to them for air intake and get them to identical efficiencies (someone said "all else being equal..."), the diesel will outperform the gasser (we're talking pump fuel here). Bottom line is that a gallon of pump diesel has more available energy per gallon than gas. So a gasser will never "make more power" than a diesel--all else being equal.
Jason
I'll agree that on pump fuel it would be mighty close.....(read tmyers post on what an LS2 turbo can do)and I hope I've made that statement in one form or another during this diatribe ( using the compression statements as the example)
But even then, the diesel would burn less fuel.....
Last edited by DOHCmarauder; 07-19-2006 at 04:33 PM.
#44
07-19-2006, 04:27 PM
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Originally Posted by bf250
wow....a gas vs diesel but more technical!
i don't have any technical aspects to add to this discuassion, but i really feel, except for a few circumstances, the diesel vs gas thing is not comparable.
different engine designs for different uses, i can't see how they could make a gas engine work in heavy mining operations or long term use such as industrial generators.
but i can't see diesels being used for racecars, weedeaters, chainsaws and such.
i think they can be compared on the less extreme area such as light duty truck applications and small cars and even generators, but that is a personal choice. if costs of fuel was the same and costs of the diesel option was the same and noise wasn't a factor, i think you would see more poeple opt for the diesel due to the power and and fuel economy. of course it is my opinion.
i don't have any technical aspects to add to this discuassion, but i really feel, except for a few circumstances, the diesel vs gas thing is not comparable.
different engine designs for different uses, i can't see how they could make a gas engine work in heavy mining operations or long term use such as industrial generators.
but i can't see diesels being used for racecars, weedeaters, chainsaws and such.
i think they can be compared on the less extreme area such as light duty truck applications and small cars and even generators, but that is a personal choice. if costs of fuel was the same and costs of the diesel option was the same and noise wasn't a factor, i think you would see more poeple opt for the diesel due to the power and and fuel economy. of course it is my opinion.
Believe it or not, there are a whole line of Ford engines, INCLUDING the V10, used for powering pumps etc.....But I 100% agree that in that application the diesel is a no brainer.
http://www.powertechengines.com/100.html
Last edited by DOHCmarauder; 07-19-2006 at 04:31 PM.
#45
07-20-2006, 05:09 AM
