Efficiency

[AutoDestruct]

The dictionary,   "The ratio of the effective or useful output to the total input of any system."

Was just wondering, since this is a much used topic, what the Efficiency of an engine is and how exactly this fits in with the idea of a motor vehicle.

I know the imports are better off than domestics but by how much?
If you have an efficient motor is it high in Hp and Torque, or just one versus the other?
What about fuel efficiencies?
Can you tune in one of these attributes(HP,torque,Gas) even more?  purpose building for efficiency in one area.
What is the mathematical equation for efficiency?

I wan't to get some insight into the arguments that go on covering these subjects.  V-8 rx-7, Corvettes, Ka-Sr, and such.  Anyone got some info?
<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/huh.gif" border="0" valign="absmiddle" alt=':huh:'>

[Jeff240sx]

Efficiency, in it's most broad sense, means total power in equals total power out.
Now, a gallon of gasoline has 1.8 x 10^24 Joules of energy, or something close and huge like that. &nbsp;But, since internal combustion engines are 18% efficient at the most, we don't see near that power. &nbsp;If the engine was 100% efficient, we would get 5 times the gas mileage and 5 times the power output. &nbsp;But much of that power gets converted into heat, taken up in friction, and generally sucked away.
You can't do much to increase the efficiency of the motor, running methanol would help since it doesn't burn as hot, ceramic engines would reduce friction...
Efficiency doesn't have anything more to do with gas mileage, power and torque than what I have mentioned. &nbsp;
Anyway... that is the fairly broad topic of engine efficiency. &nbsp;I'm sure someone will come in with finer details later.
-Jeff

[Natty]

Wankels.

I don't know much about them, but them seem good in theory. The rotor only rotates one way, where pistons go up and down. While one piston goes up it is taking energy right?

The ICE is really old and sadly, it may be fading away soon. It has changed alot, but it is still old technology.

Jeff

[AKADriver]

If you measure fuel in versus power out, import engines are NOT more efficient. &nbsp;The Corvette Z06 is rated at 19mpg city/28mpg highway... that's better than the much slower NSX (17/24). &nbsp;Remember... the 'Vette's engine is twice as large but spins half as fast. &nbsp;It's also a lot more cost efficient...

There are other measures of efficiency - the older generations of rotary engine are very space- and heat-efficient but yet they blow most of their fuel right out the exhaust and return dismal fuel economy. &nbsp;The modern Renesis rotary in the RX-8 is supposed to compare favorably to similar piston engines (such as the S2000's F20C) in that respect though.

[Jeff240sx]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (James @ Dec. 09 2002,8:37)</td></tr><tr><td id="QUOTE">--Does anyone know why turbo-diesels seem to be very efficient?--</td></tr></table><span id='postcolor'>
If I could talk to my friend right now, he could answer this.. but I can't, so I'll take a stab at it.
Diesel engines use heat plugs and compression to explode the fuel mixture, as opposed to electronics, low compression, and highly flamable gasoline. &nbsp;The rotating assembly on most turbo engines would astound you with their weight. &nbsp;They have a lot of rotational inertia and momentum to keep things moving. &nbsp;Also, turbochargers usually increase the efficiency of just about everything that they go on. &nbsp;A turbo uses heat to expand exhaust gasses that do nothing else but exit the tailpipe, to spin a compressor wheel and force more air into the cylinders than previosly possible. &nbsp;The turbo also draws air through the filter and feeds it to the engine, making life a little easier on the engine.
-Jeff

[Phlip]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (Jeff240sx @ Dec. 09 2002,8:07)</td></tr><tr><td id="QUOTE"></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (James @ Dec. 09 2002,8:37)</td></tr><tr><td id="QUOTE">--Does anyone know why turbo-diesels seem to be very efficient?--</td></tr></table><span id='postcolor'>
If I could talk to my friend right now, he could answer this.. but I can't, so I'll take a stab at it.
Diesel engines use heat plugs and compression to explode the fuel mixture, as opposed to electronics, low compression, and highly flamable gasoline. The rotating assembly on most turbo engines would astound you with their weight. They have a lot of rotational inertia and momentum to keep things moving. Also, turbochargers usually increase the efficiency of just about everything that they go on. A turbo uses heat to expand exhaust gasses that do nothing else but exit the tailpipe, to spin a compressor wheel and force more air into the cylinders than previosly possible. The turbo also draws air through the filter and feeds it to the engine, making life a little easier on the engine.
-Jeff</td></tr></table><span id='postcolor'>
Close, you also need to draw attention to the fact that a diesel uses ungoly compression ratios, like 15:1 and direct injection... When air is compressed that far, it is already damn close to combustion on it own, so you use direct injection of a SMALL amount of fuel and bang, there you have it. The engine does most of the work and needs only a little fuel to sustain combustion. The weight of the assemblies in a diesel engine are always much higher, but due to the fact that it all pretty much sustains itself, it can afford that tradeoff...

[Ni5mo180SX]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (AKADriver @ Dec. 08 2002,8:56)</td></tr><tr><td id="QUOTE">There are other measures of efficiency - the older generations of rotary engine are very space- and heat-efficient but yet they blow most of their fuel right out the exhaust and return dismal fuel economy. </td></tr></table><span id='postcolor'>
Rotarys are not heat efficient.

[AutoDestruct]

So the LS-1 is more efficent than the the v-6 in a NSX? &nbsp;That seems a little weird. &nbsp;So domestics are better than some imports. &nbsp;Everybody is always ragging on the V-8's as inefficent engines( v-8 Rx, Rb vs. Jz). &nbsp; So if bought a vette you guys couldnt talk efficiency smack on me. &nbsp; What about the B18C? &nbsp;something like 104 hp per liter. &nbsp;I know this is better than the vette, so how is the Ls-1 more efficient. &nbsp;Would'nt it be making 600 or something hp(104*5.7liters displacment) &nbsp;if comparable in Efficiency.

I am so confused <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/notify.gif" border="0" valign="absmiddle" alt=':notify:'>

[240racer]

I think the main thing that you guys are trying to get at is Brake Specific Fuel Comsumption. &nbsp;Usually just bsfc, it says how many gallons of fuel per hour are used to make a certain amount of brake horsepower for an hour. &nbsp;It's funny, most engines are pretty close to the same in this respect. &nbsp;Turbo engines actually tend to be higher, since they tend to run richer at peak power. &nbsp;However, the turbo engine that makes the same power as a non-turbo engine probably has a better BSFC at lets say half or full power, which is more relelvent to cruising anyway.
The other thing to look at is the power to weight of the engine itself. &nbsp;This is important for racing, airplanes and fuel economy. &nbsp;Remember it takes less power to accelerate less weight at the same rate. &nbsp;Airplanes have gone to gas turbine engines now because they are vastly superior in power to weight. &nbsp;One aspect of weight is just the size of the engine itself, Volume wise. &nbsp;Since most engines are made out of similar density materials, the smaller it is, the lighter it is. &nbsp;If you can make more power per displacement (specific HP) then you are more efficient.
As far as diesel engines go, the fuel itself has more energy per lb then gasoline, that's a big reason why it has higher efficiency. &nbsp;The other reason is that they aren't worried about the weight of the engine, just it's BSFC, so everything is tailored toward that. &nbsp;The main drawback of diesel engines is they are not able to run at high RPMs due to the difficulty of getting all the necessary fuel in at the correct time. &nbsp;The current high-tech diesels use direct fuel injection and they use the timing of the fuel to control the timing of the combustion since they don't have spark plugs. &nbsp;The cylinder pressures are very high when the piston is at TDC (if the C/R is 15:1, which is low, then the pressure is 220psi absolute) The fuel pressure has to be considerably higher then that for the fuel to even flow into the cylinder. &nbsp;Fuel pressures of over 1000psi are not uncommon. &nbsp;As they are able to reliably increase fuel pressure, they will be able to increase RPM, and then make more power.
BSFC examples can be found on the web
here are a couple examples:

0.26-0.34 Large industrial four-stroke diesel engines (very small hp/weight ratios)

0.28-0.36 Other four-stroke diesel engines

0.32-0.38 Two-stroke diesel engines

0.37-0.44 Fuel injected four-stroke gasoline aircraft engines

0.40-0.48 Fuel injected four-stroke gasoline automobile engines

0.43-0.48 Carburetted four-stroke gasoline aircraft engines

0.48-0.60 Carburetted four-stroke automobile engines

0.55+ Two stroke gasoline engines

0.55-0.70 Four-stroke aircraft engine takeoff fuel flows

the units are lbs/hr/HP

[adey]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (AKADriver @ Dec. 09 2002,5:56)</td></tr><tr><td id="QUOTE">If you measure fuel in versus power out, import engines are NOT more efficient. The Corvette Z06 is rated at 19mpg city/28mpg highway... that's better than the much slower NSX (17/24). Remember... the 'Vette's engine is twice as large but spins half as fast. It's also a lot more cost efficient...</td></tr></table><span id='postcolor'>
<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/sarcasm.gif" border="0" valign="absmiddle" alt=':sarcasm:'> &nbsp;yeaaah, because we all know that the NSX's V6 is representative of all import engines, right? &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/withstupid.gif" border="0" valign="absmiddle" alt=':withstupid:'> &nbsp;Sort of like how the Z06 is representative of all american cars.

That said, I don't care if the Z06 is faster or gets better fuel mileage; since I value quality and craftsmanship, I can't picture ever buying an american car.

[ca18guy]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (adey @ Dec. 11 2002,6:18)</td></tr><tr><td id="QUOTE">That said, I don't care if the Z06 is faster or gets better fuel mileage; since I value quality and craftsmanship, I can't picture ever buying an american car.</td></tr></table><span id='postcolor'>
Have you ever been in a corvette? If you would'nt like that car I think you just wouldn't like cars period. Why don't you leave this thread to people who have something constructive to add instead of bringing your insecurities about other cars in here.

[HippoSleek]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (adey @ Dec. 11 2002,12:18)</td></tr><tr><td id="QUOTE"></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (AKADriver @ Dec. 09 2002,5:56)</td></tr><tr><td id="QUOTE">If you measure fuel in versus power out, import engines are NOT more efficient. The Corvette Z06 is rated at 19mpg city/28mpg highway... that's better than the much slower NSX (17/24). Remember... the 'Vette's engine is twice as large but spins half as fast. It's also a lot more cost efficient...</td></tr></table><span id='postcolor'>
<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/sarcasm.gif" border="0" valign="absmiddle" alt=':sarcasm:'> yeaaah, because we all know that the NSX's V6 is representative of all import engines, right? <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/withstupid.gif" border="0" valign="absmiddle" alt=':withstupid:'> Sort of like how the Z06 is representative of all american cars.

That said, I don't care if the Z06 is faster or gets better fuel mileage; since I value quality and craftsmanship, I can't picture ever buying an american car.</td></tr></table><span id='postcolor'>
<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/baaa.gif" border="0" valign="absmiddle" alt=':baaa:'>

Japan is not the center of the automotive universe. I don't know why people on the internet don't realize that. It is a point - just like any other. Beyond that, it is a far cry from making the "best" car in any field. Just like Japan doesn't make the "best" of much of anything. Cheap and mass-marketed, yes. "Best" - NO. And "craftsmanship"? &nbsp;The NSX is THE most vanilla of the performance cars. &nbsp;Blandness does not equal craftsmanship.

If you want efficiency, I imagine a European diesel is on your list, as far as passanger cars go.

240racer - &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/thumbs-up.gif" border="0" valign="absmiddle" alt=':thumbsup:'> &nbsp;... I never realized when I rode motorcycles that I was on the least efficient machine possible~

[240racer]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">
I never realized when I rode motorcycles that I was on the least efficient machine possible
</td></tr></table><span id='postcolor'>
maybe they should make diesel motorcycles, that would be wierd

[adey]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (ca18guy @ Dec. 11 2002,05:35)</td></tr><tr><td id="QUOTE">Have you ever been in a corvette? If you would'nt like that car I think you just wouldn't like cars period.</td></tr></table><span id='postcolor'>
No, I have not been in a corvette, but I've seen them up close and can compare it with a '91 NSX that I've been in. All i can say about the Z06is "plastic abound"... the switches, buttons and dials look like they came out of my '93 240sx, not a new, top-of-the-line sports car like the z06 is supposed to be.
They may indeed have a "dual zone climate control" and fancy shmancy stuff like that, but where's the design or the craftsmanship?? This looks just like the JDM 180sx automatic climate control!
http://www.chevrolet.com/corvette/images/popup/conv_dualzone_h.jpg
Seriously, my volkswagen's analog/manual climate control looks better than that.
...and the plastic! I'm not saying plastic shouldn't be used, but at least use a plastic that doesn't look so brittle and cheap! this is reminiscent of the plastic chairs that I sat in in highschool.
http://www.chevrolet.com/corvette/images/popup/conv_active_s.jpg

Don't get me wrong, I haven't DRIVEN a corvette (yet) so I can't compare anything in that department, but I feel like the Americans in general need to take a big hint from European styling and finish departments.

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE"> I don't know why people on the internet don't realize that. It is a point - just like any other. Beyond that,it is a far cry from making the "best" car in any field. Just like Japan doesn't make the "best" of much of anything. Cheap and mass-marketed, yes. </td></tr></table><span id='postcolor'>

Hippo- I did not imply that Japanese made the best automobiles and nor do I pretend to feel that way. They do however, happen to make a car that looks the way I like, that fits my budget, and that I can toss around without too many maintanance issues. I wholeheartedly believe that the Europeans make the best cars, to which I don't think many would contend.

What I do mean to say though, was that American cars are, by a far cry, not the best at anything, either. They come off to me as even cheapER (fit and finish) than their japanese counterparts, and are even more "mass marketed" than most Japanese car companies.
I mean seriously, when was the last major chassis upgrade of the Grand Am? or the firebird or the Camaro for that matter... If the Japanese don't make the best cars, at least they're innovative!

[BadMoJo]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (adey @ Dec. 11 2002,2:23)</td></tr><tr><td id="QUOTE">I mean seriously, when was the last major chassis upgrade of the Grand Am? or the firebird or the Camaro for that matter... If the Japanese don't make the best cars, at least they're innovative!</td></tr></table><span id='postcolor'>
uhh yeah..... You can say the same thing about the S13 chassis as well, it ran from what 89-98. And as for the Z06, its by far the best car out there for the money these days. Yet I have not driven one, I have driven a standard C5 tho, and it was very nice.

Just don't put off all American cars as being crap just cuz they are american. At least it aint no shitty Jap econo box! <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/sigh.gif" border="0" valign="absmiddle" alt=':rolleyes:'>

[Ni5mo180SX]

Complaining about the plastic material used in the center console of a Z06 &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/sigh.gif" border="0" valign="absmiddle" alt=':rolleyes:'> Why are you driving a 240 again?


NSX being referred to as bland. I cant take that being anything other then a joke or sarcasm. Well there is a third but might not be suitable to mention right now...............

[adey]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (Ni5mo180SX @ Dec. 11 2002,10:54)</td></tr><tr><td id="QUOTE">Complaining about the plastic material used in the center console of a Z06 <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/sigh.gif" border="0" valign="absmiddle" alt=':rolleyes:'> Why are you driving a 240 again?</td></tr></table><span id='postcolor'>
Actually, even our plastic doesn't look as cheap or cheesy as the center console in the Z06... that said, my car is virtually stripped, so what's left of the interior of my car means nothing to me...

[HippoSleek]

Having been in a few C5's (not z06's), I didn't have any problems with the plastic. &nbsp;But if I were a stickler for plastics, I'd own a Honda... that stuff really is that much nicer than any other I've seen &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/hehe.gif" border="0" valign="absmiddle" alt=':hehe:'> &nbsp; I'll say that I've yet to see too many sports cars (Vettes, Vipers, Porsches, Ferraris) with decent looking switch gear. &nbsp;The exception was a Jag XJ220R (retail price $1M US) that was loaded w/ toggle switches, internal monocoque, harnesses, FIA seats, etc. from the factory. &nbsp;Not comfy - but durable and different &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/inlove.gif" border="0" valign="absmiddle" alt=':love:'>

I think the US is the best at one thing - hp/$. &nbsp;You can't touch the power of a Vette, Camaro (RIP), Moosetang, Maurader for anywhere near their price. &nbsp;For US cars as a whole, I certainly agree that they don't match up w/ their Japanese counterparts on MANY levels. &nbsp;I also would retract my earlier statement that Japanese cars aren't the best at anything on the grounds that I was thinking utility/classes - not manufacturing components. &nbsp;On those grounds, I think Japanese cars have the best initial quality for fit and finish in their respective classes.

And for those that haven't read the last decade of reviews calling the NSX bland, sterile, etc. perhaps you should rethink that Acura shrine you've been working on. &nbsp;But of course some people always seem to know better than the likes of Ceasar Csabre (sp?) and others that review cars for a living. &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/sarcasm.gif" border="0" valign="absmiddle" alt=':sarcasm:'>

[SilviaDriver]

i would have to agree with Hipposleek about domestics being hp/$, you just cant beat that. i mean as MUCH as i love the NSX [i can guarentee u i love it so much ill give my right nut] its only 290hp for 90gz?? [talkin new] whereas the vette is well over 300+ for watever price around 50gz? i dotn know. but we also must remember that acura put a lot of money in designing a good body for aero affect.

i always thought imports wanted to have small high hp NA engines. that were very advanced. like the s2000. 2.0L with 250hp [F20C] thats pretty impressive dont u say for a 2.0L. i always picked up domestics were known for big engines creating hp with low tech, so i guess they kept with it, rather than imports, small disp. with high hp per Litre

oh yea and the NSX is lovely! <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/inlove.gif" border="0" valign="absmiddle" alt=':love:'>

[AKADriver]

The thing is the LS1/LS6 engines are far from low tech... if those engines were built with 1960's technology they wouldn't be able to beat the NSX in power and economy. &nbsp;Stuffing more valves into a cylinder doesn't make an engine more high tech; in the 1920s it was possible to buy aftermarket DOHC 4 valve/cyl heads for Model T Ford engines. &nbsp;High tech is in modern alloys, composites, and electronics. &nbsp;Some of the hottest development in automotive engines right now is going on with diesels in Europe, most of which are 2 valve/cyl engines...

I've always thought the sterility was part of the NSX's appeal.. below 5000rpm it's like sitting in a lowered Accord. &nbsp;Maybe Volkswagen will build the Nardo W12 and give the dashboard nitpickers something to aspire to. &nbsp;Man, can VW make a sexy dashboard. <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/inlove.gif" border="0" valign="absmiddle" alt=':love:'> <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/sarcasm.gif" border="0" valign="absmiddle" alt=':sarcasm:'> &nbsp;Yeah, I do think the 'Vette has an ugly interior (a lot of the stuff inside is the same crap as a Tahoe or Impala) but spanking cars that cost five times as much comes with some sacrifices.

[adey]

yes... and (even) I must agree that you can't beat hp/$ on a muscle car...
It's a pity I'm (and in fac 'most' of us, according to my poll) not AT ALL into drag racing. It's just... not much fun when compared to road racing. <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/thumbs-up.gif" border="0" valign="absmiddle" alt=':thumbsup:'>

[HippoSleek]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (adey @ Dec. 12 2002,09:22)</td></tr><tr><td id="QUOTE">yes... and (even) I must agree that you can't beat hp/$ on a muscle car...
It's a pity I'm (and in fac 'most' of us, according to my poll) not AT ALL into drag racing. It's just... not much fun when compared to road racing. <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/thumbs-up.gif" border="0" valign="absmiddle" alt=':thumbsup:'></td></tr></table><span id='postcolor'>
Uh - I've been ROLLED by Camaros and Moosetangs at track events, personally. &nbsp;They beat most car's asses in 0-60 and 1/4 mi. &nbsp;But a z28 (non-SS) has as good of roadholding as an s13 - and aren't we always bragging about taking them in the twisties? &nbsp;(BTW: a Mustang has better roadholding than an s13. &nbsp;Check out last week's "sports car" post for more info (http://www.zilvia.net/f/cgi-bin/ikonboard.cgi?act=ST;f=1;t=20041)

I know this is off topic, but a Camaro SS will beat any 240 in EVERY category. &nbsp;A plain old z28 or Moosetang will beat an s13 in every performance category and the s14 only wins roadholding by a slim margin.

I'll raise my answer from HP/$ to all out bang for the buck... and now I know they are reasonably efficient as well.

[AKADriver]

The scary part is to consider that the pony cars are all severely compromised, suspension-wise, for comfort, drag launches, and production costs. &nbsp;The drawback with cars like this is that those compromises affect the stability and controllability more than the outright cornering performance. &nbsp;They can be a real handful to drive.

[AutoDestruct]

They lose in some category, &nbsp;or this would be pony.net or Zette06.net or some crap. &nbsp;Who gives a F*ck about the plastic for the buttons for the climate control. &nbsp;If you buy a car cause you like the dashboard you have got to be a f*cking idiot. &nbsp; This thread just lost control and plummeted to the ground blew up and turned into a inferno from hell. &nbsp;

R.I.P. Efficiency
<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/confused.gif" border="0" valign="absmiddle" alt='???'>

[Phlip]

Funny thing, this started as a smartly presented thread with good information, and turned into a "Japan is the center of the universe," "domestics suck" pissing contest, full of useless banter and subjective opinion... Personally,i drive an import with comparitively low output and mediocre gas mielage compared to the corvette people take to bashing... Personally, when you tell me I can walk off the lot with 405 legal horses for what a Z06 runs, I fall off the middle of the fewnce, where I have chosen to plant myself...