That's one way to *brick* a turbocharger.
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Obviously, those specific regions/dialects are wrong
Careful there. Most people have no clue about the way they speak. Your specific region/dialect might also be wrong (whatever that means).
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Duly Noded.
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If we had a
:rimshot:
badge for bad jokes… I'd probably have 30
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I think that, like spellar/gramming, would be an "[a]warded when admins can be bothered doing it since it happens so frequently" badge.
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Every home improvement project takes much longer than planned.
I hope that in spite of the setbacks, you're still making concrete progress towards the goal!
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Paging @Groa...
Never mind...
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Damn straight. Suck my exhaust pipe, you Prius driving tree hugger.
The car salesman said that if I were concerned about fuel efficiency, I should buy a car with a V8 instead of an I4. A V8 burns fuel twice as efficiently.
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I did take a picture of the concrete, FWIW.
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The car salesman said that if I were concerned about fuel efficiency, I should buy a car with a V8 instead of an I4. A V8 burns fuel twice as efficiently.
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That one went the other way
Suck it, Brits! We Americans aren't the only ones who can mess up English!
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Suck it, Brits! We Americans aren't the only ones who can mess up English!
Trust me: we know.
You've seen half our place names, yes?
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You've seen half our place names, yes?
For example, Perranzabuloe…
Fuck you, Discourse, for fucking up that onebox! Fuck you, fuck you, fuck you, fuck you!
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My friend's tongue-in-cheek fuel economy argument: if you accelerate to freeway speed in a V8, the engine only has to go full-bore for like 10 seconds. If you do it in a hybrid, you're engine's going full-bore for like 30-40 seconds. Therefore, the V8 will save gas over time.
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Nothing competes with Head-Smashed-In Buffalo Jump in Canada: http://en.wikipedia.org/wiki/Head-Smashed-In_Buffalo_Jump
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My friend's tongue-in-cheek fuel economy argument: if you accelerate to freeway speed in a V8, the engine only has to go full-bore for like 10 seconds. If you do it in a hybrid, you're engine's going full-bore for like 30-40 seconds. Therefore, the V8 will save gas over time.
That is not as far from the truth as you might think. It is preposterous in that no one should be regularly going full throttle if you care about fuel economy. But, it has been shown several times that it matters more how you drive than what you drive.
Top Gear did a demo a few years ago where they pitted a Prius against a BMW M5. The Prius went around the track as fast as it could, the M5 just had to keep up. The M5 got twice the mpg that the Prius did.
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Top Gear did a demo a few years ago where they pitted a Prius against a BMW M5. The Prius went around the track as fast as it could, the M5 just had to keep up. The M5 got twice the mpg that the Prius did.
Ok that's a stupid test that means nothing and you're ruining my joke so please fuck off and die, thank you.
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Ok that's a stupid test that means nothing
No, it does mean something. It means:
it matters more how you drive than what you drive.
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Exactly. I had a friend in high school who had a 4-cylinder Ford Ranger and got shitty mileage (10mpg?), because he drove it like a 16 year old male.
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How do you drive a 16 year old male?
He drove the vehicle in the manner that 16 year old males stereotypically drive.
But, if you want to get all pendantic on my phrasing, when I was 16 I was mostly driven by titties and beer and the elusive promise of sex. Also, you are a pervert for asking.
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when I was 16 I was mostly driven by titties and beer
@RaceProUK said:Beer and porn
See? I was right!
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My friend's tongue-in-cheek fuel economy argument: if you accelerate to freeway speed in a V8, the engine only has to go full-bore for like 10 seconds. If you do it in a hybrid, you're engine's going full-bore for like 30-40 seconds. Therefore, the V8 will save gas over time.
I'm a Prius owner, and even I can appreciate that one!
...it matters more how you drive than what you drive.
QFT.
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The Prius went around the track as fast as it could, the M5 just had to keep up. The M5 got twice the mpg that the Prius did.
They both did 70mph.
edit: No, wrong, Prius went as fast as possible, M3 kept up. Nothing to see here.
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Pedantry denied.
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They both did 70mph.
edit: No, wrong, Prius went as fast as possible, M3 kept up. Nothing to see here.
I know you corrected yourself, but I phrased it poorly. To clarify:
It was a road track, so it encompassed acceleration, braking and cornering. The Prius was driven as quickly as it could be around the track, spending a lot of time at full throttle. The M3 only had to keep up with the Prius, so it never broke a sweat.
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Top Gear did a demo a few years ago where they pitted a Prius against a BMW M5. The Prius went around the track as fast as it could, the M5 just had to keep up. The M5 got twice the mpg that the Prius did.
That result only came because they ran they Prius way outside of its ideal conditions. As a general rule, internal combustion engines are most fuel efficient at full throttle. Here is a chart:
This shows that small engines working harder get much better fuel economy than large engines at part throttle. The biggest reason for this is that at part throttle, much of the engine power is being used to suck the intake air past a mostly-closed throttle plate. The term for the energy used to do this is "pumping losses". At full throttle, pumping losses go down to almost zero.
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Here is a chart
...that has one fatal flaw as it pertains to this discussion. I will let you see if you can find that flaw before I point it out to you...
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I think I see two, but I'll let @Jaime respond to your challenge before I post my answers.
BTW, not asking this to be jeffed, but wouldn't it be more appropriate if we agreed to continue this in the car talk thread?
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The flaw is that the proud was at full throttle and the M3 was just keeping pace.
So the chart is not an accurate model of what happened.
Still @Jaime is right. The reason the M3 whom that one is that the M3 was operating in its optimum power band and the Prius was well outside its optimum power band.... Almost redlining really.
And as fun as that show is, they do have a documented history of deliberately making hybrid and electric cars look bad.... On purpose....
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So the chart is not an accurate model of what happened.
Still @Jaime is right. The reason the M3 whom that one is that the M3 was operating in its optimum power band and the Prius was well outside its optimum power band.... Almost redlining really.
Thank you, that's what I meant.
My first statement was explaining why the Prius lost. The chart has nothing to do with the Top Gear experiment, but is a general statement about why bigger engines get poorer fuel economy.
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My first statement was explaining why the Prius lost. The chart has nothing to do with the Top Gear experiment, but is a general statement about why bigger engines get poorer fuel economy.
No, your interpretation of the chart and first post would seem to say the Prius should have won as it was at red line the whole time. But your chart has a big flaw, as it pertains to this discussion. It would work for generators though.
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No, your interpretation of the chart and first post would seem to say the Prius should have won as it was at red line the whole time. But your chart has a big flaw, as it pertains to this discussion. It would work for generators though.
I am not interpreting the chart to say that. The chart specifically says that redline is where you get nearly the worst fuel economy. The chart was never intended to refute the Top Gear test. @accalia got it, and I even pointed out that she was right to prevent anyone from thinking I was posting a BSFC chart for that purpose. Here is where I did that:
My first statement was explaining why the Prius lost. The chart has nothing to do with the Top Gear experiment, but is a general statement about why bigger engines get poorer fuel economy.
The chart does say that given a specific vehicle and a specific driving task, the smallest engine that can perform the task (without forcing a downshift) is the most efficient choice. The chart was meant mostly to refute this:
The car salesman said that if I were concerned about fuel efficiency, I should buy a car with a V8 instead of an I4. A V8 burns fuel twice as efficiently.
But, since @Groaner didn't actually believe it, I didn't want to post in response to him. It seemed more appropriate to respond to the Top Gear test mention.
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I feel like I am getting @lucas'd or @blakeyrat'd? Have you been drinking?
I am not interpreting the chart to say that. The chart specifically says that redline is where you get nearly the worst fuel economy.
...but you said earlier...
As a general rule, internal combustion engines are most fuel efficient at full throttle. Here is a chart:
Also:
This shows that small engines working harder get much better fuel economy than large engines at part throttle.
And, by your interpretation of the chart:
This shows that small engines working harder get much better fuel economy than large engines at part throttle.
Because:
The biggest reason for this is that at part throttle, much of the engine power is being used to suck the intake air past a mostly-closed throttle plate.
And:
At full throttle, pumping losses go down to almost zero.
Now, to clarify, I am not:
But, since @Groaner didn't actually believe it, I didn't want to post in response to him. It seemed more appropriate to respond to the Top Gear test mention.
...saying that the Top Gear test was unbiased and scientifically accurate. But, it does illustrate a very good point that I put forth earlier when I said:
it has been shown several times that it matters more how you drive than what you drive.
If you drive a Prius, or any car that is capable of high mpg really hard, it will get shitty fuel mileage. If you don't drive them slowly and cautiously, they will get just as shitty of fuel mileage as much larger cars do.
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Oh, and besides all of that, the chart is rubbish as it pertains to this discussion...but it would work if we were talking about generators...as I said.
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This shows that small engines working harder get much better fuel economy than large engines at part throttle. The biggest reason for this is that at part throttle, much of the engine power is being used to suck the intake air past a mostly-closed throttle plate. The term for the energy used to do this is "pumping losses". At full throttle, pumping losses go down to almost zero.
This is actually a much bigger deal on forced-induction (turbocharged and/or supercharged) engines than it is on atmospheric-induction engines, but atmospheric-induction engines still benefit some from this technique -- low (to mid in your chart) RPMs at WOT give much better SFC than any RPM at almost no throttle. @Jaime -- I'd love to see a 3D version of that chart for a Lycoming or Continental that shows you the impact of mixture control, from full rich to full lean...because I'm sure the automixture on the engine your chart is for is having some impact on SFC vs RPM for a given throttle setting.
Sadly, there aren't any good sources for this handy, but this is the best distillation of the idea I could find:
Theoretically the most efficient rpm will be some composite value between torque peak where VE is highest and a somewhat lower rpm where frictional losses are lowest. Pumping losses are more a function of throttle angle than rpm. Since Lycoming engines have a very flat torque curve, it is probably safe to assume that VE does not vary much over the range of say 1800 to 2400 rpm. Logically this confirms the theory that very low rpm at WOT will give the best SFC on these engines (assuming even mixture distribution).
Lindberg was the one teaching low rpm/ high MAP for best range in WW2 on
P38s. We have to remember that these were turbocharged engines where we
have more control of MAP than with atmo engines. It has been shown that
energy is recovered from the exhaust in the form of boost which reduces
pumping losses on the intake stroke. This is where a fair proportion of
extra hp comes from in turbo/supercharged engines. In effect, the
compressor's work is forcing the piston down rather than having the
crank pull it down as in an atmo engine. By using high MAP and low rpm
we get the best composite of high VE and low frictional losses.We do have to figure prop efficiency in here though. Your prop may not
be well optimized for this flight condition so that adds another
variable.OTOH -- the problem with the Top Gear test is that the Prius isn't designed to sit there and cruise down a highway at relatively constant engine settings to begin with; like all hybrids, it's a stop-and-go car, and gets much better fuel mileage puttering around city traffic than it ever will out on the highway. I'd like to see their test replicated with the Prius replaced by a standard (i.e. non-hybrid) small car -- the results should be much different in that case.
(Sidenote: if you go "turbos are for ricers" and dismiss me that way, I'll have to drop a large pile of WWII era aircraft engines on your head.)
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It wasn't on the highway. It was a road course. Like stop and go on meth. ;-)
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OTOH -- the problem with the Top Gear test is that the Prius isn't designed to sit there and cruise down a highway at relatively constant engine settings to begin with; like all hybrids, it's a stop-and-go car, and gets much better fuel mileage puttering around city traffic than it ever will out on the highway. I'd like to see their test replicated with the Prius replaced by a standard (i.e. non-hybrid) small car -- the results should be much different in that case.
They could always do a “‘cruise’ round central London at 4pm” test. :D
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deliberately making hybrid and electric cars look bad.... On purpose....
This statement was brought to you by the Redundant Department of Redundancy Department.
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well sonetimes you gotta beat that dead horse...
I'm not saying that their result was wrong mind you, just that they deliberately arranged the test so that the M3 was in its element and the Prius wasn't.
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I'm not saying that their result was wrong mind you, just that they deliberately arranged the test so that the M3 was in its element and the Prius wasn't.
Did I disagree with you and not notice it?