*sigh*, Er, this is how you prove things Moron!. We have constantly PROVED over and over again that HP does not dictate acceleration. All you have done is written a whole lot of "hearsay", but no facts. What else can we do, but provide calculations and graphs, etc. to prove that torque dictates acceleration. We have done that, you have done nothing ... but constant prattle about how you are right and we are wrong. PROVE IT!!!, as we have proved all we need to prove. Owe well I am such a silly little boy, teak360 the great God of knowledge has said it is so ... so I must believe, even though he cannot prove anything, just supply verbal (er, typed) diarrhoea ... Sorry I do not live in that world, I listen to people who can back themselves up, not with silly childish bets, but with physics and mathematics or relevant references. Good bye teak360, prove with calculations or shut up! Pete
OK, so now you are resorting to name calling too. It's unfortunate you've stooped that low. Anyway, I challenged you to disprove any of my statements from my post before last. And you didn't disprove one, and that is because you can't. I have put my money where my mouth is and you haven't. What do these things say for your character?
The one things that's certain about this thread is that within 12 months someone will post a question about TQ vs HP...and this will start all over, albeit with a different cast, possibly. I am curious if ANYONE changed their opinion / understanding of the topic because of this discussion?
That you are all talk. I will do absolutely nothing, as money has nothing to do with this, and says nothing about your character. Prove your point or shut up. As for name calling, I appologise, but I have never talked to somebody with so much hot air before that refuses to prove his point. I have to conclude he cannot, thus as Mitch has stated over and over again, you are guessing and in this case wrong. Pete
Okay, guys... this is starting to just get ugly... I think teak360, Mitch, PSk, 4sfed4, and myself have all made our points on the topic at hand... if any of us were going to convince the other, it would have happened by now. I ask that we all let this thread return to the topic of the original poll... let's not embarass ourselves or Fchat by continuing down this rabbit hole. Thanks! Anyone with preferences on a higher-torque or higher-HP 360 replacement, feel free to take back over this thread...
Actually I am not sure if I have already made a comment on that Brian. I would actually vote for higher Hp, as I believe Ferraris are cars that you should have to work hard to drive, and thus be good at extracting the performance from the car (by using the gears well and carrying speed into the corner, etc.). There are many 4 door sedans that have the high torque, lazy driver situation covered, and are more comfortable and practical than a Ferrari thus why move into that competition. Pete
You must not have gone back and read "tell me about driving around at high RPMs". Your inability to learn when corrected multiple times leads one skilled in physics to acertain that you are not. Your inability to deal with equations, calculus, or describe your arguments with sufficient precision indicates that you, also, do not understand the mathematical basic for the physics involved in this physics problem. Yet you persist in stating that you are right and every one who is capable of doing physics problems and who do understand the math remains wrong; The sum total is that you are stupid with respect to physics, math, and how car accelerate. Now go back and read the thread. I'm still letting you go lightly. for now.... Whe I use equations, I don't end up with solutions that fail, yet when you use facts and formulas they do! do you know why? Its called physics, and it requires calculus to get useful results when several things are varried at once, like acceleration, velocity, distance, and the driving forces. Physics gives you a way to find solutions. Whatever you are doing fails miserably. But do you know why? By the way, I believe you when you say you believe what you ahve said to be meaningful and when yo say you think the solution works thusly. I believe that you believe. However, you remain incorrect. It also happens to be true! You see, since HP = TQ * RPMs / 5252, hp will reach a peak value when TQ * RPM = constant So, if TQ dropped by 1% when the RPMs rose 1%, power would be the same before and after the RPM rise. See: TQ * RPMs = TQ/(1.01) * RPMS*(1.01) When TQ drops faster than RPMs rise, then HP drops. My statement stands. If you don't believe me, I'll come back and do some differentiation for you tomarrow, perhaps you won't be so $^%$^ by then. Are you so incapable of learning that you must forever forbid the first granual of real physics to penetrate you thick skull? Look, physics is about practical applications of caclulus. Physics and calculus arguments are more easily explained with charts and graphs because many people only have the touchey feelie relationship with math and physics and charts and graphs give their mind something to latch one to so they can thinnk it through. At the very least, one skilled in the kind of problems can check the math and call me on the data--ever wonder why nobody did? But nowhere did you indicate that any of the math, equations, charts and graphs contain the slightest error. And you have the gall to claim I am unfairly manipulating the argument bu using <gasp> REAL DATA? So you admit that peak HP and car weight is not enough? The shapes of the curve is necessary--finally some progress. But which curve the power based one, or the TQ based one? I take a TQ curve multiply it by the transmission and differential ratios and divide by the rolling radius. You see, there is a relationship between the speed at which an engine turns over and the velocity of the car, tire smoke notwithstanding. This equations is: V = RPMs * tranny * diff / rolling radius * 2 * Pi / inches_per_mile This equations connects HP and acceleration in P/V = m * a; Causing HP to get divided by RPMs and thus turning it back into TQ * constant. Its the only way do do it correctly and accurately compute what happens to the car. I happen to use eXcel to perform the routine math and prevent arithmetic errors, and to make pretty charts. In other words, I simply apply the physical laws and run the equations. Presto--out pops an answer that is in line with how reality works! <gasp> When lots of things are varried simultaneously, I make eXcel compute the problem hundreds of time in tiny steps and integrate all the steps together. Look up numerical methods next time you are on a college campus. Thsi is a time honored way to comput things that do not have a closed form solution. Any Idea what I just said? No, here is you first misconception. Forces cause acceleration ( f = m*a ) not power, nor energy, not work, forces. Work gets done when movement through a distance happens ( w = f*d ). 2. yes 3. no, HP = TQ * RPMs/5252; however p = f * v = f * d / t 4. with the definitions in play here, forces cause acceleration, so you cannot apply a torque and not get acceleration. since f = m*a 4. just like above, see its all about TQ.
OK Pete. Here is a formula for you: tq x rpm/5252 = hp. This simple formula shows tq is simply a component of hp. Without rpm you have no hp, and the torque means nothing when it comes to accelrating hour car. Nondebatable physics. Here is another one: Force x distance per unit time is work. The more hp you make, the faster you do work (the greater the rate of acceleration of your car). Here's part of a paper on horsepower and torque written some time ago and referred to me by the author, Bob Palmer. He IS a physicist. I haven't communicated with Bob for some time, but the last time I did he was associated with NASA's Ames Research Center at the University of California. Why don't you be the one to tell him he's a moron? And Mitch, you can tell him he is stupid. To quote Bob verbatim: So, lets get this really clear; an engines potential for producing acceleration is directly related to horsepower, so you get maximum acceleration when your motor is putting out its maximum horsepower; period! Where it happens to put out its maximum torque has no relevance whatsoever relative to maximizing acceleration. The point of maximum torque might be an indication of the rpm range where the motor is most efficient, but thats another story. Regardless of whether you have a little tiny motor with small torque that can turn lots of rpms, or a great big motor with lots of torque, but limited rpm, if they both put out the same horsepower then they both produce exactly the same acceleration. In fact, little tiny motors have a distinct advantage in terms of weight which is why the highest performance cars like F1s use little motors turning 12-14,000 rpms and making great gobs of power. Thats not to say theres no drawbacks to this philosophy, but in F1 style racing the advantages outweigh the drawbacks. Lets press on a little further with the main point here. Ive tried to convince you by building logically from the fundamentals that its really horsepower, not torque that counts in measuring what a motor can do. Perhaps it is also important to point out what is not relevant in the foregoing discussion; e.g., the torque curve, the rear end ratio, the weight of the car, etc., etc. Of these, the most irrelevant is the torque curve. In fact, my advice to those of you who may have both torque and horsepower dyno data is to tear that torque curve sheet up and toss it in the trash. Failing the courage to take this bold step, perhaps you could at least tape it to the under side of a drawer or some similarly obscure place where, hopefully, over time you will learn to live without it. Remember, if you ever get really desperate for the torque data, you can just divide the horsepower curve by the rpms and multiply by our handy-dandy, easy-to-remember conversion factor (5252). To those of you who may remain unconvinced, but who are still with me, read on. I think I can anticipate at least one or two of your objections. Also, I may be able to add just a little more practical advice. Some of you may be thinking that, even if torque doesnt relate to acceleration, it must at least be an important characteristic of truck engines. At least thats what common wisdom seems to hold. But I could just as easily have made the same argument and come to the same conclusions by merely substituting work in terms of pulling a weight up an incline, just another form of force times distance, instead of work in terms of acceleration. It just so happens that the practical attributes of truck engines favor lower rpms. In particular, diesel engines have good efficiency and long life. They also have a limited rpm capability, so running at high rpms is simply not an option. A high rpm, high efficiency motor (e.g., a turbine) could easily be a good truck power plant. Although gearing might present some problems in the extreme case, fundamentally theres no advantage to a low rpm, high torque motor versus a high rpm, low torque motor if both make the same horsepower (although there may a valid issue comparing longevity). Certainly, Im not suggesting that it would be practical to replace a diesel truck motor with a F1 motor with the same horsepower. For one thing, the cost of a F1 motor would be prohibitive. But if we were to have a hill climb contest between two identically loaded trucks, the truck with the most horsepower between the shift points would win, regardless of the supposed torque advantage of a typical truck engine.
Almost all of the above is BS and your ability to obfuscate is impressive. By the way, I was allowed to take Calculus in college without the prerequisite algebra courses, so yes I know what calculus is. Please read my previous post quoting Bob Palmer, I would wager he could KO you in one round in a physics bout.
Cool teak360 now you are starting to talk with substance. Thankyou. Lets have a look at this statement of Bob's: Lets look at the hp calculation: P = 2*pi*rpm*T or the non metric version: P = T*rpm/5252 For both engines to have the same Hp but at different rpms then the T*rpm factor has to equal. Thus for the low torque engine (ie. the tiny motor with small torque) the rpm it revs is where it generates the Hp. Thus because it can rev so hard it can use much lower ratios in the gearbox and thus multiple the torque more and thus end up with a similar rear wheel torque value that causes the acceleration. If you like to think about that as Power causes acceleration that is fine with me, but in reality it is the force provided by the rear wheels that cause the F (for) > F (against) which makes the vehicle move. Most people simply use F = m*a to calculate that and get F from using F = T/d (which will be the radius of the driving wheel). T obviously will be the torque at the rear wheels. Thus if you like I can understand how Power hides the complication of Torque and rpm difference and gear ratios, BUT in the end it is still torque that accelerates the car, thus refering to another of Bob's comments: This is where I think we are having trouble. The original question that I remember was where will acceleration be maximum, at peak Torque or peak Hp. Now you cannot simply ignore the fact that at peak torque the rear wheels will have the most torque to accelerate the car, thus you will never have more accelerating G's applied to the car than at this point. BUT there is the other line of the acceleration debate which is where Bob's comments come in, and that is acceleration over time, and we have agreed over and over and over and over and over and over and over and over that with gears and time involved that peak power offers the most acceleration potential ... but you still will have the highest accelerating G's applied to the car at peak torque. Thus I again think we are discussing apples while you are discussing pears, and we are both right The comment I do not like that you make teak360, is that torque is not relevant, read Bob's comment: Thus remember Hp and you can always get back to Torque As I said above, Hp is a way of ignoring rpms and torque, but in the end Hp IS Torque applied at a certain rpm ... nothing else nothing more, it is calculated from the Torque the engine produces, which is the only force an engine produces. Pete
teak360, I am really disappointed you make these stupid statements. You were on the right track but again have hidden behind something you appear to not understand. Mitches comments and formula are not BS ... what a shame you cannot open your eyes. Remember this is not supposed to be a bullying process ... Pete
You're correct and I shouldn't have said his formulas were all BS. I should have just said he obfuscates with too many formulas and silly examples. By the way, do you think Bob Palmer is an idiot?
No I did not say that ... gee teak360 ... If you read my post, I clearly stated that we are not talking about the same thing. Bob even mentioned that!. Plus Power is a way of ignoring Torque and rpms, and thus gear ratios. But if somebody went to Bob and said I have a 1000 kg block and I want to accelerate it at x rate, he will use F = m*a. Now if that block was going to powered by a wheel then he would work out what torque he needed at that wheel, etc. One can see from reading Bob's comments that he was asked a different question (and he clearly states that). Thus in conclusion I will have to state this: 1. Acceleration will peak in first gear at peak torque. 2. You can compare 2 vehicles acceleration potential using Power (because the Power formula has all the necessary stuff in it already, ie: Torque and rpm). 3. You will not be able to calculate the acceleration at all times using just Power, without converting back to Torque at some stage ... but as I said above you could compare 2 vehicles. Thus going back to your original statements: To make a car change its velocity from x to x1, yes but the acceleration figure does not require any work to be done. Just a force to be applied at a mass. Thus the acceleration over time is not the same thing as the acceleration figures (G's) as they will change constantly, starting high and then reducing ... Yes, Torque is a force applied around an axis, thus a rotational force. No. If the car does not move, then there is an equal and opposite force stopping the car moving. Get rid of that force and the car will accelerate. Acceleration IMO has nothing to do with work and Hp. It is all Force balancing. Returning to your (er, one of your) original statements: I will agree with that simply because if you know Hp and weight you can calculate Torque and rpm ... ratios. But again accelerative potential is not the same as calculating actual acceleration in G's. All you will be able to calculate with Hp and weight is that car X should be faster than car Y over time. You will not be able to calculate exactly how fast at time Z the car will be going ... without converting to torque and rpms, and gear ratios and tyre size, etc. Pete
I didn't ask if you said it, I asked if you thought it. I'm not sure what you mean by ignoring torque and rpm's but my original intention back in the dark ages when we started this thread was simply to show that peak horsepower determines a cars maximum accelerative potential, not peak torque. I agree, acceleration in a car is determined by torque at the wheel. Remember that the maximum possible torque at the wheel at any GIVEN SPEED is determined by the engines maximum horsepower. It does not matter what the engines max tq is. Through gearboxes, and thus torque multipliers, we always get max tq at the wheel at max engine hp at any GIVEN SPEED. I'm not sure without reading back what you mean. This is true. It is also true that the max acceleration in ANY given gear will occur at peak tq. But don't forget that at any given SPEED, the maximum acceleration will be at max hp. (This is the place where most people get confused because it appears to be counterintuitve. Maybe you understand this Pete, I don't know. If you don't, simply do the math and you will see it is true). True, and it is the only way to do it. Torque alone won't do it. Ignoring all variables except horsepower and weight, which has been my conjecture all along, you CAN. I have only said that you can do it knowing max hp (implying it being applied continuously) and weight, but not knowing only max tq. I have only been trying to explain that you cannot increase a cars speed (velocity) from x to x1 without doing work to the car. And you cannot do work without hp. If you lift 550 lbs 1 ft you have done work. If you do it in 1 sec you are developing 1 hp. Or 550 ft lbs/sec. Work over time. I don't understand how you can say work over time is not hp. Of course Not true. This is very basic. Accelerating a car can not be done without adding kinetic energy to the car. You cannot add kinetic energy without doing work to the car. We can't do work without hp. Hp is the key like I have always said. You can;t do it knowing max tq alone. Using basic physics you can. I have never said other than max hp applied to a given weight allows the calculation of acceleration. This implies that you can determine speed at any given time, distance, etc. You cannot do this knowing max tq alone. THAT IS ALL I HAVE EVER SAID. Of course factoring in gear ratios, tire sizes, and any number of other variables will muddy the waters, and that is what Mitch has done. But these variable will never change the basic rule of physics that hp (which of course can be calculated as tq at the wheels) is what determines a cars performance. Tq is nothing more than a component of hp and, for example, the term low end tq is simply a way of saying an engine generates relatively more hp at low rpm. I think most people view torque and horsepower as two different things, when indeed tq is merely a component of hp. Let me once more state the point that I believe confuses most people. Max acceleration in any given gear is at max tq. Max acceleration at any given speed is at max hp. Only when an engine is developing its max hp can it (through gearing) develop maximum tq at the wheels at any given speed. To accelerate at the greatest rate you would have a CVT with the engine at peak hp. Do the math, calculate the max tq at the wheels at any speed and it will always be at max engine hp.
Brian, haven't you ever heard of OCD (obsessive compulsive disorder)? Like the guy that has to open and close his dresser drawer 35 times before he takes his socks out? I think a few of us have it on this thread. We have to post 35 time before we go to bed. Anyway, how else will we beat NNO in number of posts?
OK, so you took calculus in college. I happen to take calculus in high school, got accepted into sophmore calculus when I arrived at college, 4 semesters of differential equations, multivariate caclulus, abstract algebra, and several more advanced math courses; then later, while working for a living: I TAUGHT calculus in college as a night class, its been 20 years, but still..... My guess is that bob and I could come to an agreement, since we talk the same language, one that you don't seen to understand.
And thus, we come to the real reason you can't use TEAK360's rule of thumb. I've been waiting for over a week for someone to come up with the answer. Congrats to PSK: Power can be used to compute the ball park acceleration rate, 1/4 mile time,.... However, when COMPARING two vehicles that are 'close' in the rule of thumb calculation, the one with the bigger TQ will always win in the actual race. The Power under the curve argument is really a bigger TQ argument! (how do you think the power got under the curve?)
Finally; now if you'd just stop here, all would be well with the world, but no........... Have you ever differentiated the velocity vs. time charts found in magazines to determine acceleration? No, probably not....... However, if yo did you will find that peak acceleration in any gear occur at peak TQ. See! However, we have seen numerous examples where your function computed the wrong winner. Therefore, at best, you function is UNRELIABLE. We have not been saying that work is not done, what we are saying is that TQ causes the acceleration. You are saying that work caused the acceleration, this is incorrect, TQ caused the acceleration; work was expended during the acceleration, but forces caused the acceleration. Never in question. I claim you can't even with HP! Not accurately at least. And you remain wrong: for example, consider an engine that makes 100 lb-ft of TQ at all RPMs less than 8,000 RPMS, except at 6000 RPMs where this engine makes 300 lb-ft of TQ for the span of 10 RPMs or 342 HP. so, at 5994 RPMs the engine makes 114 HP and at 6006 RPMs the engine makes 115 HP. OK, you know the peak HP (342) and you know the average HP from 5000 through 8000 is 130 HP. Does this vehicle accelerate more like a car with 342 HP or more like a car with 130 HP? Take you time, and calculate carefully! And that is why it is so important that we educate you. You are simply incredulus. Except for that little fact that it doesn't. You keep claiming this, yet the reality is the opposite. HP is computed from TQ, not the other way around. TQ and HP are intimately related, not different, however forces cause acceleration and TQ is a force, HP is a rate of expending energy. Yourself as the prime example We are not denying that max acceleration at any given speed occurs at max HP, what we are denying is that this is meaningful in any sense of solutioins to physics problems. And only for the 1 MPH that corresponds to peak HP RPMs. We are not talking about vehicles with CVTs we are talking about manual transmissions with fixed ratios.
Mitch, out of curiousity what is it exactly that you think my "rule of thumb" is? Please state it to clear up any confusion. You're close, actually it can be used to compute the exact max potential acceleration rate and 1/4 mile time. Why do you keep talking about "rules of thumb" and things being "close". You aren't quantifying anything, so you're argument is merely specious and not indicative of a true teacher. Only if you know the rpm the TQ is made at can you determine which car will win. Again tq and rpm are horsepower. Read Bob Palmer's article again. Maybe you're talking about tq at a given speed at the drive wheels, in which case you are correct. But again that just means more horsepower at the engine. TQ where? you must mean at the drive wheels, which again means more horsepower.
Finally? I have never stated that it wasn't. That one is a little too obvious Mitch. Of course It does, I have never stated that it doesn't See what? I have never stated otherwise. Please show me one of my "numerous" examples. As you would say: Finally! We basically agree, forces cause acceleration, torque is a force. (By the way work is not "expended" during acceleration. Work is "done"). What I have to keep educating you about is that engines don't accelerate cars by making just tq. They make tq combined with rpm = horsepower. Of course you can, Your common sense has left the building. If you accelerate in one gear from 5,000 rpm to 8,000 rpm, the answer is like a car with 130 hp. If you accelerate in one gear from 5995 rpm to 6005 rpm, the answer is like a car with 342 hp. My answers are absolutely correct and they show how silly your little exercises are. Perhaps I just educated you regarding the silliness of your examples. Since one of the dictionary definitions of incredulous (I assume that is the word you were trying to spell) is "Expressive of disbelief" you are correct. I am incredulous regarding your posts. Read Jim Palmers writing again, VERY clearly you are wrong. This is such a basic, basic fact. If you don't understand this it show that your book smarts (i.e. lots of equations) aren't teamed up with common sense. I don't know how else to put it. Actually HP is computed from TQ and RPM, not just TQ. Which means HP is DERIVED from tq and rpm. How simple can it be? (common sense again). Not different? Then why do they have two different names? They aren't different? You're shooting yourself in the foot AGAIN. Of course If I'm the one making a true statement, I can hardly be the one confused about it. Again as you would say: FINALLY! This would be a baffling statement even from someone who took only physics 101 Are you sure it isn't 1.2 mph Mitch? Or maybe .9 mph? Are you starting to see the irrelevance of throwing around these kinds of numbers? Who says? And why can't you understand (since you say you took calculus) that as we add more and more gears we are indeed approaching a CVT. If the bigger tq, say 400lbs ft is made at 1500 rpm, and the one with lesser tq, say 350 lbs ft, is made at 5,000 rpm. The one with the "bigger TQ" will get its A$$ kicked, plain as day, but again it takes common sense to see this. Another one of your kind of, sort of, close, rule of thumb satements proven to be false. Who has the thick skull? I think your book learning didn't leave any room for common sense. I'm done, you're no fun any more.
In example 1 you rule of thumb would not pick a winner due to equal HP and equal weight; yet car V wins in the real world. In example 2 your rule of thumb indicates car F should win, when in actuality, car V wins. In example 3 your rule of thumb picks car F again, yet in reality, again, car V wins. You claimed this is due to Power under the HP curve. In actuality it is TQ that causes the power under the HP curve, thereby, TQ is causing your rule of thumb to be inaccurate. I spent some time looking this up: why don't you try reading some of these; you will find all of them in agreement with TQ is king. With selected quotes under the URLs. http://www.mustangsandmore.com/ubb/DanJonesTorqueVsHP.html Horsepower, being the rate at which torque is produced, is an indicator of how much *potential* torque multiplication is available. In other words, horsepower describes how much engine rpm can be traded for tire torque. The word "potential" is important here. If a car is not geared properly, it will be unable to take full advantage of the engine's horsepower. <later> Knowing the basic physics outlined above (and realizing that acceleration can be integrated over time to yield velocity, which can then be integrated to yield position), it would be relatively easy to write a simulation program which would output time, speed, and acceleration over a given distance. The inputs required would include a curve of engine torque (or horsepower) versus rpm, vehicle weight, transmission gear ratios, final drive ratio, tire diameter and estimates of rolling resistance and aerodynamic drag. <still later> In short, the V8 wins because it has more horsepower to trade for rear wheel torque, using transmission gear multiplication. What really accelerates a vehicle is rear wheel torque, which is the product of engine torque and the gearing provided by the transmission, rear end, and tires. Horsepower is simply a measure of how much rear wheel torque you can potentially gain from gearing. A teenager who actully understands http://www.rose-hulman.edu/~moloney/AppComp/2000Entries/Entry13/Entry13.htm http://www.g-speed.com/pbh/torque-and-hp.html HP is not measured directly, it is simply calculated from torque. <later> Now, it's important to understand that nobody on the planet ever actually measures horsepower from a running engine. What we actually measure (on a dynamometer) is torque, expressed in foot pounds (in the U.S.), and then we *calculate* actual horsepower by converting the twisting force of torque into the work units of horsepower. Brian Beckmans excellent series of "Physics of Racing" http://www.racerpartswholesale.com/physics9.htm http://wahiduddin.net/race/dynotest.htm http://www.allpar.com/eek/hp-vs-torque.html http://www.houseofthud.com/cartech/torqueversushorsepower.htm http://www.leecao.com/honda/vtec/commonmiss.html http://www.off-road.com/hummer/tech/power.html Its physics not me that makes you wrong.
