Emergency situations occur regardless of what kind of engine you have or how you normally drive. When they *do* occur -- say, a truck doesn't see the red light at the intersection you've just entered -- you'd better hope you're in the 200hp minivan and not the 83hp item.
-Stern
Yes.
Yes.
Why?
Apparently.
Reason why is because I thought the slant 6 was a taller engine, thus with bigger connecting rods. I was incorrect.
If memory serves, you're an engineer, right? Mechanical engineer? The extent of my technical background is made up of a couple of Physics/Chemistry background classes with some Calculus and some C++ classes and such. So I am always glad to learn new stuff from people. I've heard it said that the first step to knowledge is to admit you know nothing. Memorable quote from a computer science book I read about 5 years ago: "with the internet, we are quickly becoming a global village filled with village idiots."
No paper necessary - I see it in my mind's eye from your excellent verbal description. Thanks for the education.
Bill Putney (to reply by e-mail, replace the last letter of the alphabet in my address with "x")
The 2.2/2.5 shares *many* design aspects with the slant-6, which is not surprising since they had the same daddy.
Naw, I just play one on the radio ;-)
Also: "It has been said that a million monkeys with keyboards would eventually reproduce the world's great works. The internet has proven this is incorrect."
-Stern
My point is that the gearing doesn't cause an increase in power. The engine running faster is what changes the power output. Gearing can ONLY affect torque intrinsically, it can't affect power. Power is constant through any set of gears, neglecting that which is lost through friction in the gears.
Matt
Actually, longer connecting rods for a given stroke does have a beneficial affect, but it isn't huge typically. You are wasting less effort pushing against the cylinder wall and more pushing against the crank.
Matt
That is the underlying premise behind genetic evolution. It is as flawed there as it is with respect to the internet. :-)
Matt
Well ... ... actually longer rods actually reduce torque by changing (reducing)the rod angle to crankshaft(relative to the piston travel)just after TDC .... what they do is move peak torque further up the rpm range ( usually increasing horsepower), however that peak torque is reduced... shorter rods produce more torque at a lower rpm as the rod angle is greater as the piston move down from TDC..
Ted
Sorry, none of the above is correct. Go back to some basic engineering texts and let us know when you're ready for a quiz.
-Stern
Sorry,, I cede... should study first then put foot in mouth..... only quoting what I remember from school a *long* time ago,, probably wasn't any research to back it up then,, just some body's explanation at the time...don't remember
So after reading the text's I could find quickly online (stuff that didn't seem like it had an agenda anyway) It seems,, ( first look anyway) there really hasn't been a lot of research done on this..
Thought this article was pretty good..
But I do appreciate the education.. I will let this rest now,, Thank you.
Why do you get such poor mileage out of your vans? I average 19-20 "mixed", 25 "highway" and 17 "city". I've never gotten below 16MPG on a tank...ever that I can remember (and I check mileage at every fillup). Ironically the very best was 28 on a 470 mile trip to Myrtle Beach doing 70-75 most of the way...got there on one tank with gas to spare.
| > > If I were to purchase a used 2002 or 2003 town and country or caravan, | which | > > engine is the most reliable? 3.3? 3.8? any others? | >
| > I have been amazed that my 97 3.8 Caravan gets 27-28 miles per gallon | > and my 3.3 '92 Caravan got only 23-25 on the highway. In fact I | > (three peple plus luggage) just completed a 5000 mle round trip to | > Alaska in the '97 and got over 30 mpg average because we were obliged | > to drive at less than 62 mph. | |
If the road to the bakery was on a 15%-20% grade I bet they'd mind.
Once again, that is true *IF* you are looking at the HP at a given ENGINE RPM (NOT vehicle speed). *BUT* my point was that if you look at the HP at any given VEHICLE SPEED (NOT engine rpm) (as the vehicle is accelerating from, say, 0 to 60), at that given vehicle speed, there is more HP being produced than at the same VEHICLE SPEED, as evidenced by the higher rate of acceleration at any given speed.
Stated another way, at a given vehicle speed at WOT, if you freeze it in a moment of time, with the lower gearing, there is more HP being produced by the engine at that vehicle speed than with the higher gearing at that vehicle speed (which you say in your next line below).
Remember HP is a product of torque and rpm. With the lower gearing, you're at the higher HP part of the curve at a given vehicle speed precisely *because* rpm is higher at essentially the same torque (once again, until you get into the higher rpms where things start tailing off).
AHA! So if you have lower gearing, for a given vehicle speed, you *DO* have more power (until super high rpm). That's all I'm saying. I think that once you think it thru you'll see that we're in violent agreement.
Lower gearing will mean more power at a given vehicle speed (at the low and mid part of the curve) because of the truth of your immediately preceding statement ("The engine running faster is what changes the power output").
You haven't said anything wrong. You're only limiting your vision to looking at HP in relation to engine rpm. Expand your vision to look at it in relation to vehicle speed, and you'll see what I mean.
I challenge you to plot out a typical power curve: HP vs. engine rpm. STEP 2: *NOW* replace the horizontal scale labeling with *vehicle speed* instead of engine rpm for some arbitrary real-world reasonable gearing. STEP 3: *NOW* duplicate that plot, but divide all the numbers on the horizontal scale (vehicle speed) by 1.2 to represent 20% lower gearing.
You should immediately see that for a given vehicle speed, HP will be greater (remembering to ignore the top end of the scale where the curve drops off).
But again, do not take this to mean that I disgree with you when you say that, relative to engine rpm, HP output will be the same regardless of gearing (for a given engine rpm) - basically, a naked engine dynamometer test. That will always be correct. You, so far, are refusing to look at vehicle speed. I am looking at HP in relation to engine rpm (which you are also doing), *AND* in relation to vehicle speed (which so far you are not doing) and simply stating what is true for *both* relationships (the two graphs I talked about).
Bill Putney (to reply by e-mail, replace the last letter of the alphabet in my address with "x")
Haha! Bravo, Matt! 8^)
Bill Putney (to reply by e-mail, replace the last letter of the alphabet in my address with "x")
Are you a radio host? Or SW user? I listen to SW on my Sangean SW receivers (ATS505 that receives SSB and a 602) but I don't have a transmitting SW radio.
Because in a family of five, we owned 2 K-cars, therefore we were bound to use one for our family trips. That car got us where we wanted to go, for a number of years, didn't see a need to buy a beefier vehicle, although we DID opt for the 2.5L and not the 2.2L engine.
Have you ever come across those asshole drivers that you want to get past, but they make it difficult? Normally we would drive at a mire mild 105-110 km/h speed.
Meh, that car's transmission never "skipped a beat"
I understand what you are saying, but the point is that the power increase doesn't come from the gears themselves, which is what you said originally. The gears themselves can't MAKE power. They can MULTIPLY torque, however. This is a very common missunderstanding and I was simply correcting it. Read any good text on gearing or mechanical engineering and you will see this principle.
I know what you are saying about the gearing allowing the engine to run faster at a given road speed which allows the ENGINE to produce more power at a given road speed, but the GEARS aren't producing the power. That is the fundamental point. If you look at the power going into the differential and look at the power coming out of the differential (or transmission, same thing), the power coming out equals the power going in (minus losses due to friction), no matter what the gear ratio between output and input. However, if you look at the torque going in and coming out of a gearbox, it is proportional to the reduction ratio.
Matt
Please provide quote(s). If I really said that, then I failed to include the full context in a particular sentence because it was the
20th time or so that the context of vehicle speed vs. engine speed had been stated, and was, by then, understood (either that, or I didn't state what I intended because *never* would I say or imply that gears produce power taken in full context).If I contradict that *anywhere*, please quote, with context.
As an engineer, I certainly understand the law of the conservation of energy. Gears cannot produce power. However, they can and do cause better effect (acceleration) by moving the speed of the engine up higher into its power band where - yes - more horsepower is being produced (by the engine - not by the gears themselves). Did the engine produce more power? Yes. Did the gears produce more/any power? No. But they put the engine at an operating point where it can produce more power. That is not the same as saying that gears produce power. They can result in more power (from the engine), but they cannot produce it. Again - on that, we are in violent agreement.
I never said that gears produce power (unless I *really* screwed up in which case you will show me where that occurred). I was careful to qualify my statements (how many times did I say "relative to vehicle speed not engine speed" or the equivalent? If I failed to do that at some particular point, please show me where.
Consistent with everything I think I said (unless I plain screwed up somewhere and did not properly convey what I intended - again - show me where, and I will honestly assess what I said).
Bill Putney (to reply by e-mail, replace the last letter of the alphabet in my address with "x")
A theory is not proven - for sure. It is only "not" disproved. Hence we keep reading statements couched with phrases such as "suggests..." and "apparently indicates...." Not exactly "for sure 100% true" statements. So far, the "works" written by the aforementioned simians has not happened. That does not mean it will not happen in the future.
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