This very correct comment: Is why Torque is the boss IMO. Horsepower is simply a way of describing where Torque is at, via rpm. I personally think this discussion comes down to our understanding of what Horsepower really is. I think some think it is more than simply torque * rpm, and actually something on its own (?). Pete
Okay, thanks to 4RE Bob, I have a couple of new links that are worth a read. The first site in particular discusses the Hp side very effectively ... The first link: http://www.allpar.com/eek/hp-vs-torque.html The second link: http://www.houseofthud.com/cartech/torqueversushorsepower.htm Looking at the first link first , first of all I have to admit I am wrong to 4sfed4 regarding all dynos measuring Torque and then calculating power, ie: Very interesting ... and I have learnt something . Here is an interesting quote regarding gears and why you have to rev past peak torque to optimise acceleration: Here is an interesting quote looking at it from the Hp side: Again I think it makes life easier for some if they think in terms of Power, because they are able to ignore Torque, rpms and transmission gearing. But note that it is the maximising of the output torque that is important. Another interesting quote that discusses CVT's also: This authors sum up: Now lets move on to the second site: I like this quote as a good sum up: Also of importance to our discussion about Torque being generated at 0 rpm and causing acceleration ... which some disbelieve: Make your own conclusions ... Pete
We've gone through this before but you just don't get it. These are your examples not mine. And they are goofy examples at that. I am not discussing this thread using RULES OF THUMB, I've told you this before. Is your memory as lacking as your common sense? Why is this so hard for you to grasp? Mitch, just using the first link to say "torque is king" is nothing short of myopic. I'll pick a few quotes out of the first link you list here: http://www.mustangsandmore.com/ubb/DanJonesTorqueVsHP.html "Power measures the rate at which work is performed" Mitch, how can you not understand that accelerating a car is performing work, and thus a measure or how much power is being applied per unit time? "At first glance it might seem that, given two engines of different torque output, the engine that produces the greater torque will be the engine that provides the greatest acceleration. This is incorrect and it's also where horsepower figures into the discussion." Torque is King, right Mitch? "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. (this is what I have also said before Mitch). 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" (emphasis mine) I guess this guy is a fu*& up too Mitch. He thinks proper gearing takes advantage of the engines horsepower, NOT its torque. But torque is KING, right? "It's the torque applied by the tires to the ground that actually accelerates a car, not the torque generated by the engine.( I have stated this also Mitch) HORSEPOWER (emphasis mine), being the rate at which torque is produced, is an indicator of how much *potential* torque multiplication is available. In other words, HORSEPOWER (emphasis mine) describes how much engine rpm can be traded for tire torque." Again with the HORSEPOWER, Mitch, did you forget to tell this guy that torque is king? "Ideally, a continuously variable transmission which holds rpm at an engine's horsepower peak, would yield the best possible acceleration." Now he is talking about CVT's Mitch, just like me. Why did you refer me to this guy if he agrees with me? I think it's because you're like a kleptomaniac that really wants to get caught, just to get it all over with. "Generally, we are concerned about the average acceleration over some distance." This guy talks in real world terms like I do, why would you direct me to his link? "In any case where both engines are optimally geared, the V8 will win because it simply has more HORSEPOWER" You should sue this guy Mitch, he's practically slandering you. And all this from just the first link I should read so that I can learn and be smart and rational like you? Give me a break. As is shown in that first link you directed me to, right Mitch? Man, you are stretching farther and farther.........
In the end we all agree that it is the torque at the driving wheels that provides acceleration, even all the links provided. Another quote from my second link: Thus note it is Torque you feel by the seat of your pants ... and thus what a G force indicator will record. Pete ps: teak360, the examples Mitch has shown prove that it is more than simply Hp that provides the acceleration potential of a particular vehicle. Like you have stated the gear ratios, etc. have to take advantage of the Torque at high rpm, etc. Thus Mitches 'real world' examples prove that it is more complicated than simply the car with the more Hp wins ... it should but it does necessarily mean it will, as Mitch proves. Thus to calculate the acceleration potential (of a particular REAL vehicle) you need to take the Torque curve, rpm, gearing, etc. into consideration ... otherwise you are only approximating. Saying that it is a GOOD approximation that requires little effort to do.
, gee I am glad I represent Torque in that calculation ... but I am equally sure teak360 is glad that he is rpm. Not sure teak360 will be happy about being a component of Mitch though Pete
Actually power IS being developed within the steam engine at o rpm. It is in the form of the expansion of gasses inside the cylinders. Initially this horsepower is simply converted to heat, eventually enough heat (thus expansion) occurs to apply enough force to the pistons to start them moving. Please don't tell this to Mitch, he might have a coronary.
I will admit I have felt pretty pissed at Pete and Mitch. But if I had to pick a couple of guys to go up against seemingly insurmountable odds with, it would be these guys. I think between the three of us we would NEVER FU&^ING give up.
You are expending energy, but the work being done to heat the gasses can be measured in watts, horsepower, etc. Hey Pete, lets start arguing about trains for a while.
Okay my son (2 years old) loves his Thomas the tank engine train. It has to be the most loved thing on this planet. This little battery powered train (which produces I have no idea how much power and torque, and could not give a raspberry about) must have done something like 2 million miles by now and he only got it for Christmas. The first thing he does when he gets up (after sleeping with Thomas) is to either have a look at his Thomas poster, or put Thomas on the track and give it a push. While this might seem a little too much, I have watched and played with him and he is learning lots. He now knows how to disconnect the carriages, connect them back up again, how to stop Thomas with the little lever thingy, how to change the trains direction at those junction thingies. Also when the battery runs out, while he is not exactly happy, he soon moves on and starts pushing it around, etc. He also likes to change the track around ... In a few months he will move on, or maybe when his birthday comes around and he gets something newer, but if he doesn't it does not worry me as I used to push toy cars around all day long ... and still do, just now I am in the inside pushing pedals Oh and he loves to watch his Thomas DVD too, it is like he has never seen it before ... and loves to chat to you about what is happening All good fun. Pete
Hmmm, lets see: - 4 is the obvious answer, a bit like Power except in this case it is 100% accurate all the time. - It also could be a reference to a occassional 4 seater car. I've said all I need to say on the Torque versus Hp debate. If you have actually read any of my replies you will see we agree on many things, but the main problem I have with your generalised comment that "Power is all that is required to calculate potential acceleration", is that it is not a real world situation. In the real world gear ratios are not perfect and do matter, as backed up by the links I have supplied. Unlike you I understood Bob's comments and thus discussed them and clearly pointed out the facts. The other problem I have is that I do not 100% believe that you understand that Power is simply describing the Torque curve and RPM. I think you believe Power is something else ... not sure what? You seem to have been brought up in believing you win debates by sarcastically treating other people, or by bullying them ... What I need to be convinced that "Power is all that is required to calculate potential acceleration" is for you to do the maths, like we have been doing. Mitch has over and over again disproved this with practical examples (which you choose to ignore ... because you do not understand, and that the real answer lies in mathematical proofs, supported in practice). Yes Power is all that is required to calculate an approximate acceleration potential, BUT Torque (curve), rpm and gear ratios, etc. are required to calculate the actual acceleration at any single point in time and thus required to map out a vehicles true acceleration potential. In simple language, a 400 hp, vehicle weighing the same as a 350 hp vehicle, should out accelerate it. But this does not always happen due to badly spaced gear ratios or other reasons. Note also that at any give point in time either vehicle might be leading the acceleration race, as that changes as the Torque curve changes, ie. the 400 hp vehicle might actually lead the race for the first 2 seconds because it is putting more Torque to the rear wheels, but the 350 hp vehicle might be the first to the end of the 1/4 mile, because it has managed to put more Torque to the rear wheels longer. Pete ps: I am satisfied with my beliefs and I have far more important things to do in life ... but I must say this does help my boring day at work pass quicker
You are claiming that all you need to use is 1) HP and 2) weight and you can determine various performance parameters. A) I claim you cannot: you are yet to demonstrate you can. B) Since several exapmles have been shown that contradict your "all you need is 1) HP and 2) weight" statement, I have degraded its importance to no better than a Rule Of Thumb. In fact, its just plain erroneous, but I was trying to be gacious. So, if all you need is HP and weight: Car A) 3200 LBs 375 HP with 3.03 rear gears Car B) 3200 LBs 375 HP with 4.11 rear gears Two cars of equal weight, and equal power, using the same engine (Can't get much more comparable in the prescribed parameters) same weight, same power.... Which one wins? Why? Does this indicate that you need <gasp> knowledge of the gears even to compare cars with comparable power and weights? What was it about HP--oh, yeah, its used to select what gears to use! TQ is what actually causes the acceleration! OK, another example: Car A) 3200 LBs 375 HP with 3.53 gears Car B) 3200 LBs 375 HP with 9.88 gears Which one is faster? Why?* Thereby both examples, and the earlier examples end up requiring more input data than just 1) power and 2) weight? Thereby, you rule of thumb is crumbling towards the ground; since is plainly states: Here we have a situation where a different parameter changes the result, a parameter you claimed that was NOT EVEN necessary for the calculation, and it changes the result--in a fundamental way (time, speed,...). I knew it, you took the bait! It actually took me a long time to find this piece of bait. Notice what the bait says: "horsepower describes how much engine rpm can be traded for tire torque." HP is simply used to determine gearing, but that it is TQ that causes acceleration. As we have already seen, TQ[tire] is proportional to TQ[engine] once a gear has been selected. No, what the author said is that HP telly you how to choose the gears, not that HP causes acceleration. But what that suthor really said is that your whole argument was wrong. In replay: So, that author admits that it is tire TQ (TQ[tire]) that accelerates the car! Can you argue your way out of: TQ[tire] = TQ[engine] * tranny * diff / Rolling radius? The differential ratio is obviously not changing durring an acceleration run. The rolling radius of the tire is certainly not changing durring the run. The tranny ratio is not changing durring the time spent in one gear. So, one a gear has been selected, TQ[tire] = TQ[engine] * constant! Or TQ[tire] is PROPORTIONAL to TQ[engine] Therefore, that author admit that it is engine TQ[engine] * tranny * diff / rolling_radius that accelerate the damnable car in the first place. This is, has been, and remains my argument. TQ cause acceleration, not power! You just admitted it. TQ causes acceleration! You lose. But wait you say; your argument has been that ALL you need is 1) HP and 2) weight to do computations of performance. Once you start to require gearing,.... you argument is lost. Sorry. ------------------------------------------------------------------- *The second example show that it is possible to have so much TQ multiplication in the differential (or tranny) that attempting to use the TQ will smoke the tires through the first 3 gears (TQ is greater than the 1Gs traction limit for the tire), not to mention the fact that the car runs out of revs in 6th before 70 MPH! And even discounting running out of revs, the car has to do 5 shifts (0-60) where the lesser geared car only has to do 1 (0-60) or 3 (1/4 mile) or 4 (1/4 mile built engine and rear gears). Therefore, there is a region in the space of acceleration where too much HP is NOT wanted. In this region, the driver wants just enough TQ to get the tires up on the traction curve, but no so much they spin without transmitting large forces to the pavement.
Can we rearrange that statement ... er, I do not want to multiply with teak360, or respectively you Mitch Pete ps: Now waiting for the redefinition of 'potential acceleration' from you know who .
The bait was delicious, there was just no hook in it. You can't fish without a hook Mitch! Of course it is tq at the tire (thus a linear force at the tire to asphalt contact patch) that determines acceleration. I have even stated so in my previous posts. You act as though this is a revelation. "you lose" You sound strangely reminiscent of General Custer. Mitch, you have taken my basic statement of truth and turned it into the Fchat equivalent of the Congressional Record. Let me state it once more as simply as I can: Max hp at the engine determines a cars accelerative potential. Max tq at the engine does not. In other words HORSEPOWER RULES It's almost like saying "the earth orbits the sun". Oh wait, forget I said that Mitch, don't want to start any arguments.
So, if all you need is HP and weight: Car A) 3200 LBs 375 HP with 3.03 rear gears Car B) 3200 LBs 375 HP with 4.11 rear gears Two cars of equal weight, and equal power, using the same engine (Can't get much more comparable in the prescribed parameters) same weight, same power.... Which one wins? Why? By the way, I never claimed that max TQ was anything other than where max acceleration in any particular gear happens. It is the TQ curve that rules.
At this point, the tires and traction would be the deciding factor. In a straight line, if the 4.11 geared car broke the tires loose too much and/or the 3.03 geared car were right on the limit of adhesion for those tires, the 3.03 should accelerate faster up to a point (the point at which traction/grip no longer matter, say 60mph). After that point, assuming the 4.11 geared car has a driver that shifts quickly and precisely, the 4.11 car would be faster.
Again you are adding variables, the potential variables are endless. (By the way, in your example; depending on the transmission ratios the cars could be made to accelerate at exactly the same rate, or either car to be made the winner over a certain distance) Until you start muddying the waters again with any number of the infinite variables available, they will have equal accelerative potentials. (by the way, this is true even if one engine make TWICE the max tq of the other). Again, I think you are looking at this problem having been too long immersed in charts and graphs and ratios, etc, etc, and with too much exposure to the typical variables most people confuse themselves with being thrown in to the mix. Of course max tq is where max acceleration occurs in any GIVEN GEAR. This is the most simple of physics. But, it is also why people get confused and equate engine tq as the definer of car performance. Max tq in a given gear also necessarily defines a given SPEED. If you were to change the gearing so that the engine is running at MAX HP at this given speed, the car would accelerate HARDER than it does at max engine TQ at that given speed. Again this is counterintuitive and hard for most people to grasp. At any given speed, a car accelerates hardest at MAX HP. Not max tq. Through tq multiplication, you will ALWAYS have the greatest potential torque at the rear wheels, at any speed, when the engine is at MAX HP. Not when the engine is at max TQ. Do you understand this? A couple of simplified sentences throwing in different rear end ratios and the like do nothing to change these facts. If you want to get the most work done in a given amount of time you have but one choice: APPLY THE MOST HORSEPOWER over that given amount of time. A horse dragging a weight up a hill is doing work and is applying horsepower. He is applying NO torque at all. Yet he can still drag, and even accelerate up the hill. Mr. Ed will be so dissapointed when you tell him that "torque rules". When the space shuttle is accelerating up through the Florida skys, its engines are developing massive horsepower, but no torque at all! Will the astromauts FREAK when they hear torque rules? Sh%$, they don't have any! I can build a car that develops zero torque, not even at the wheels, that will do the 1/4 mile in 6 seconds! It is called a rocket car. But it CAN'T do it without making HORSEPOWER. Again Mitch, I am not talking about cars with specific gear ratios, etc. That is not the point of this whole debate. That debate would be how to maximize a cars acceleration given a specific set of parameters. Different thing.
Sorry teak360, you are fill of BS! You stated very clearly that, and I quote (teak360): This has been proven 100% WRONG again!!!!!. It is actually a relevant statement in theory only (Bob knows this, but you cannot understand what he is saying), thus in the real world all those variables that Mitch adds are required. This is our point. You cannot keep saying these unbelievable comments: This is the whole point and disproves that the theoretical comment (and I quote again): except as a VERY rough comparison between 2 cars, and you do not know the real details. I'm sorry teak360, every time you open your mouth (er, write another post) your credibility gets worse and worse. This is the facts: 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. Move out of your 1/4 mile brain numbing thinking teak360 ... there is far more to life and cars. Thank you Mitch for finding the perfect way to finally prove to other readers what acceleration is all about ... as you did on the other post. Why people cannot simply understand the force balance equation I cannot understand, it is so logical and the basis of accelerating masses, ie: F (for) > F (against) the mass will accelerate. Pete
