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  #181  
Old 03-23-2007, 03:08 AM
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Originally Posted by Old Sage View Post
If you spin an electric pencil sharpener fast enough it will make 500hp.

Who thinks you can bolt that into a 3600 pound Chevelle and run a 12?
Raise your hand.
Assuming a 90% efficient engine you are going to need to put 555.56hp into it as electrical energy (roughly 418.892kW of power) Also because torque in an electric engine is a function of current and rotating resistence that increases porportionally with rpm and because you aren't going to be able to put too much through it without melting it you are going to need a very high rpm (something over 250000rpm) and because rpm in an electric motor is porportional to voltage the power supply is going to have to make several hundred thousand volts. Meaning it isn't possible at all.

However if you could do all that and attach it to a specialised gearbox (like something from a jet engine) then yes it will move the Chevelle quite well.
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  #182  
Old 03-23-2007, 03:09 AM
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Originally Posted by SlickHolden View Post
First off i see your biggest floor.. Maths does and means jack shit in real world testing, I don't care how many times you try to convince people this maths statistic is the bees knees it's nothing in real world testing.. As as drivers of many cars as we all are we are telling you here and now this is real world car testing.. We are all in agrence well almost all that for best acceleration it's in the Best Torque range, Not the Best power range.. Race drivers have said it Truck drivers also what more do you need?.. Mathematics doesn't drive a car or truck.
I see your point but good engineering maths is invaluable, and from a design perspective is essential. Maybe not for dynos etc but the people who designed such equipment didn't just guess how it might work accurately. And if i was lucky enough to be commisioned to design an engines torque delivery i would focus on flexible inertia gas flow and valve timing (using a computer's mathcad/Floworks etc), just my 2 pence...i'm not saying your wrong.
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  #183  
Old 03-23-2007, 03:42 AM
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Originally Posted by hightower99 View Post
I say it again:

Power has ALL the Torque in it!
Torque has NO Power in it!
fine, but does that mean that people who like to have torquey engine should get red underneath their collar when they say so?
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  #184  
Old 03-23-2007, 02:41 PM
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Quote:
Originally Posted by hightower99 View Post
Thats sad... You are probably the type of person who thinks that "real-life" is indescribable using math...
Your problebly one of those people that thinks way to much with one hand on the keyboard

Quote:
Originally Posted by hightower
Fortunately there are mathmatic laws of physics that govern this universe (and more locally this earth). These are unbreakable laws, you know the stuff keeping us from driving around in perpetual motion machines....
Well they do say life's pretty straight without twisties.

Quote:
Originally Posted by hightower
Anyways simplistic, inaccurate math is pretty useless but good math is of great value when trying to figure out what is going to happen without actually going out and doing it.
So your saying people who talk the walk but never every actually walk it.

Quote:
Originally Posted by hightower99 View Post
Yes the highest rate of acceleration (m/s2) in any given gear coincides with peak torque (because you are making the most power per rpm) but that does not mean that to accelerate to 100km/h as fast as possible you should short shift to keep it in the peak torque. To accelerate to any given speed as fast as you can you must change gear so that when the new gear is engaged you are going directly into peak power again. Think about it.
Your wrong and have been proven this many times before.. How many times will you dribble the same argument when the facts have been repeated over and over again.
Why does my car accelerate fastest between 2800-4000RPM.. Torque in that RPM range is a low of 285Nm and a max of 293Nm @ 3600RPM and @ 4000rpm is 283Nm..
In that range power from 2800-4000Rpm is 75kw @ the max Torque 3600rpm it's 107kw by 4000Rpm it's 119kw Max power is 4800rpm 127kw @ that RPM Torque is 245Nm.. If it was pulling like a bitch there people wouldnt be shifting as fast as they could, And the only reason the cars gets shifted @ 5100-5200rpm is because it shifts 2nd gear just on the torque range and it's what give the car that leap forward of 15-20 kmh, Shift to early and you drop it short.

Quote:
Originally Posted by hightower
Yes changing gears changes the value used for the coefficient of rotational inertia, as well as the value for running resistence. The accuracy of the results from the math compared to real life is directly proportional to how accurate you are at providing the neccessary values.

I say it again:

Power has ALL the Torque in it!
Torque has NO Power in it!
You can say that till your blue but numbers don't infact show real life accuracy.
Quote:
Originally Posted by jediali View Post
I see your point but good engineering maths is invaluable, and from a design perspective is essential. Maybe not for dynos etc but the people who designed such equipment didn't just guess how it might work accurately. And if i was lucky enough to be commisioned to design an engines torque delivery i would focus on flexible inertia gas flow and valve timing (using a computer's mathcad/Floworks etc), just my 2 pence...i'm not saying your wrong.
Nothing beats getting it on the road as there are many factors more then numbers, They do there job then they hand the engine to the developers and they drive them for such long periods in house then on roads, And as they say you can't beat real road driving when getting everything right. It's why they spend so much of there development doing it's the critical time of a new engine and car.
Even new cars with only upgraded engine components get the same treatment.
Computers do just about everything now but nothing beats getting behind that wheel and ironing all the glitches and problems.

Hightower only talks numbers and graphs he's got to really understand that while at first important many are talking about real life experience's and he dismisses them because it's not his belief or what he's numbers tell him. I was one not long ago that believed Torque wasn't the be all and end all, I would have sat here arguing the same that it's the power not the Torque just look at F1 cars etc. But my opinion changed with experience on the road with more attention to the car and how it worked with dyno graphs and where the best range for fastest acceleration was it matches my feeling i was able to pull around cars with less throttle with the same acceleration because i knew the area of the car which RPM. I know even save fuel from being a smarter driver after it, Not much but 20-30km extra today is pretty good.

If i did a search i might be able to find myself arguing against Torque.
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  #185  
Old 03-23-2007, 05:46 PM
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Quote:
Originally Posted by SlickHolden View Post
Your wrong and have been proven this many times before.. How many times will you dribble the same argument when the facts have been repeated over and over again.
Why does my car accelerate fastest between 2800-4000RPM.. Torque in that RPM range is a low of 285Nm and a max of 293Nm @ 3600RPM and @ 4000rpm is 283Nm..
In that range power from 2800-4000Rpm is 75kw @ the max Torque 3600rpm it's 107kw by 4000Rpm it's 119kw Max power is 4800rpm 127kw @ that RPM Torque is 245Nm.. If it was pulling like a bitch there people wouldnt be shifting as fast as they could, And the only reason the cars gets shifted @ 5100-5200rpm is because it shifts 2nd gear just on the torque range and it's what give the car that leap forward of 15-20 kmh, Shift to early and you drop it short.
It is true that in a given gear peak torque corresponds to peak acceleration. However, if you could keep the engine at a single engine speed while road speed varied, the best acceleration would be obtained by running at the engine speed for peak power not peak torque.

This is inevitable because of the relationship between force, work, and power. You can argue that in the real world this isn’t true and the math is wrong. But if you don’t believe in the math then you don’t believe in torque. Since torque is just a concept of physics, and physics could be considered the application of math to describe real world phenomena.
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  #186  
Old 03-23-2007, 06:01 PM
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Quote:
Originally Posted by SlickHolden View Post
First off i see your biggest floor.. Maths does and means jack shit in real world testing, I don't care how many times you try to convince people this maths statistic is the bees knees it's nothing in real world testing.. As as drivers of many cars as we all are we are telling you here and now this is real world car testing.. We are all in agrence well almost all that for best acceleration it's in the Best Torque range, Not the Best power range.. Race drivers have said it Truck drivers also what more do you need?.. Mathematics doesn't drive a car or a truck.

You are both right and wrong. Math does mean very much in the real world. Math allows us to predict physical phenomena. The engineers at the automotive comanies have computer simulations based on mathematical equations for the performance of each of their vehicles. These simulations allow them to make design decisions in the compuer world to make their jobs easier in the real world when it comes to fine tuning their vehicles. Math has helped humanity to predict the real world since it's inception.

On the other hand, math is only a way to explain phenomena and in itself is meaningless without a physical understanding of what the math means in the "real world".

On the matter of torque and acceleration you are right. It is force that causes a body to move. More force causes a given body to move more quickly. This also is math or at least the equations used to convey/quantify this is math.

Power is the rate of work. Dynamometers do not measure power. They calculate power from measuring speed and torque.

If a vehicle accelerated based on power and not torque there would be no need for transmissions.
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  #187  
Old 03-23-2007, 06:14 PM
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Quote:
Originally Posted by Alastor View Post
It is true that in a given gear peak torque corresponds to peak acceleration. However, if you could keep the engine at a single engine speed while road speed varied, the best acceleration would be obtained by running at the engine speed for peak power not peak torque.

This is inevitable because of the relationship between force, work, and power. You can argue that in the real world this isn’t true and the math is wrong. But if you don’t believe in the math then you don’t believe in torque. Since torque is just a concept of physics, and physics could be considered the application of math to describe real world phenomena.
My cars a Auto so for me it's hard to keep the one spot..
But if i shift manually i can hold revs in spots...
So if I'm in 2nd gear and RPM is @ 3000rpm, I can floor it and it will through me into the seat no matter the speed it's doing...
Also if it's slightly wet i can hold 1st gear till 3500rpm hit full throttle and wheel spin to cut off, But if i was to repeat that @ max Power it just wouldn't happen.

I'm not saying power is nothing never have, I'm saying Torque is more important then i thought it was before much more important, If i could increase one thing in more in my car it would be the Torque, As Higher Torque makes day to day driving easier..
So when i did some modifactions to my car, Like Exhaust cat Cold Air Throttle body, The biggest place i felt the improments in was the mid range the Best Torque area.. I can only guess on power improvements to be honest.. I think power is up 7-16kw I go with 140kw up from 127kw. Torque 305-320Nm Up from 293Nm, It's my best calculations from what the individual parts offer power wise.
Quote:
Originally Posted by BradG View Post
You are both right and wrong. Math does mean very much in the real world. Math allows us to predict physical phenomena. The engineers at the automotive comanies have computer simulations based on mathematical equations for the performance of each of their vehicles. These simulations allow them to make design decisions in the compuer world to make their jobs easier in the real world when it comes to fine tuning their vehicles. Math has helped humanity to predict the real world since it's inception.

On the other hand, math is only a way to explain phenomena and in itself is meaningless without a physical understanding of what the math means in the "real world".

On the matter of torque and acceleration you are right. It is force that causes a body to move. More force causes a given body to move more quickly. This also is math or at least the equations used to convey/quantify this is math.

Power is the rate of work. Dynamometers do not measure power. They calculate power from measuring speed and torque.

If a vehicle accelerated based on power and not torque there would be no need for transmissions.
He only see's Calculations and lines. You will have a hard time telling him he is right and wrong.
Electric cars with 1 gear have a Torque range straight across the board from start to finish, I remember Jason plato doing a test in monarco the one where Rodger Moore took a electric car for a test drive, He was impressed with the torque that was available from start to finish, And he said nothing would beat it from the lights.. Now i'm sure everyone would love that.
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  #188  
Old 03-23-2007, 06:18 PM
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Quote:
Originally Posted by SlickHolden View Post
He only see's Calculations and lines. You will have a hard time telling him he is right and wrong.
Electric cars with 1 gear have a Torque range straight across the board from start to finish, I remember Jason plato doing a test in monarco the one where Rodger Moore took a electric car for a test drive, He was impressed with the torque that was available from start to finish, And he said nothing would beat it from the lights.. Now i'm sure everyone would love that.
I do see calculations, I'm an engineer what do you expect .
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  #189  
Old 03-23-2007, 09:26 PM
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Quote:
Originally Posted by thirdgen.org forums
Peak HP - 283.5 @ 5300 rpm
Peak TQ - 406.7 @ 3500 rpm
The two curves cross at 5300 with tq and hp both at 283.

The tq curve looks exactly as I had pictured - no problems there with 406 ft/lbs of rear wheel tq :-). However, the hp curve is VERY FLAT from 3500 all the way to 6000 rpm. At 3500 hp is 265, it peaks at 283 @ 5200, and is still at 260 @ 6000 when the dyno run stops. The hp curve is basically a flat line from 3500 to 6000 rpm, not necessarily a "bad thing", just not what I expected. It looks like a curve that someone cut the top off of - there really is no hp peak.

The car still runs 12.5s @ 107 at the track, so it's running good.
Real life results. I can show you plenty of cars that put out 260-280hp and won't run near a 12.7. It's the torque that does it.
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  #190  
Old 03-23-2007, 11:00 PM
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Quote:
Originally Posted by SlickHolden View Post
My cars a Auto so for me it's hard to keep the one spot..
But if i shift manually i can hold revs in spots...
So if I'm in 2nd gear and RPM is @ 3000rpm, I can floor it and it will through me into the seat no matter the speed it's doing...
Also if it's slightly wet i can hold 1st gear till 3500rpm hit full throttle and wheel spin to cut off, But if i was to repeat that @ max Power it just wouldn't happen.
But this isn't a fair comparisons because they don't occur at the same road speed. It has already been stated that as speed increase it takes more energy to maintain the same acceleration.

Quote:
Originally Posted by Bob
Real life results. I can show you plenty of cars that put out 260-280hp and won't run near a 12.7. It's the torque that does it.
Well if that is the case, then somebody should call these guys out for “sand bagging” when they tested this car.

http://www.mpt.org/motorweek/reviews/rt2620a.shtml
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  #191  
Old 03-24-2007, 01:37 AM
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Originally Posted by Alastor View Post
It is true that in a given gear peak torque corresponds to peak acceleration. However, if you could keep the engine at a single engine speed while road speed varied, the best acceleration would be obtained by running at the engine speed for peak power not peak torque.
Would this be the case when we use a CVT transmission (like the original Variomatic as invented by DAF?)
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  #192  
Old 03-24-2007, 02:27 AM
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Quote:
Originally Posted by BradG View Post
I do see calculations, I'm an engineer what do you expect .
Are you!
Quote:
Originally Posted by Alastor View Post
But this isn't a fair comparisons because they don't occur at the same road speed. It has already been stated that as speed increase it takes more energy to maintain the same acceleration.



Well if that is the case, then somebody should call these guys out for “sand bagging” when they tested this car.

http://www.mpt.org/motorweek/reviews/rt2620a.shtml
It doesn't matter if it's 1st gear or 2nd gear it pulls the hardest the same 2800-4000rpm. And that speed could be 1st gear 25-30kmh and 2nd gear 75-90kmh.. You always run out of puff when the revs get near shift point..
I was even able to kick down back to 1st gear @ around 30kmh and chirp the rear wheels in the dry in a straight line not long ago.. Not long ago i was spinning the rear in the rain @ 80kmh that's 2nd gear going straight, As i said the car will not spin to high in the rev range in 1st.. So if i'm spinning in 2nd gear @ 80kmh what gives with 4000rpm @ 50kmh in 1st? I got more power there but less torque. It wont spin it might chirp but that's it.
But even on a dyno I'm sure it's not going to be as happy as it is where i believe it is for best acceleration.
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  #193  
Old 03-24-2007, 08:42 AM
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Originally Posted by henk4 View Post
fine, but does that mean that people who like to have torquey engine should get red underneath their collar when they say so?
The point is that they shouldn't say they like a torquey engine.

They should say they like engines with power from idle.

Everyone keeps saying "yeah you can really feel the torque in the low revs" and "wow the torque really pulls from down low" In every case the feeling can be totally attributed to having more power at low RPM.

The whole "torque is best" idea started way back when people realised that even an engine that pulled hard from 1000rpm was only making say 50 odd HP at that rpm and it just didn't sound cool to say "Wow you can feel the 50HP rip the wheels lose" because 50 is only a small portion of what the power rating of the engine was, say 250hp. People realised that at the same rpm the engine was making 263lbs-ft. of torque and that it sounded great when you say "Wow the feeling of 263lbs-ft. of torque is awesome"
Hence the whole idea of "torque is best" is born from nothing but the human brain's ability to distort the value of numbers when comparing it to reality.

Here try this: Step 1: Put some sort of cover over the dash so you can't see the speedometer or tach. Get your favorite loud music and play it through earphones (not your car stereo) Put the car in first and accelerate at WOT until the car stops accelerating, Use a timer, start it when you start going and stop it when you think you should shift up to the next gear.

Step 2: Stop the car and change to 2nd gear. Again with a cover over the dash so you can't see the speedometer or the tach accelerate from standstill with WOT until you are traveling at constant speed. Use the timer again and stop it when you think you should shift up.

Now take the cover off the dash, put away the music and follow step 1 & 2 again this time watch the tach and check where it was when you thought you should change gear in both 1st and 2nd...

You will be surprised with the results if you believe that "torque is best" and you will be happy if you know that power is what matters.
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  #194  
Old 03-24-2007, 09:17 AM
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Originally Posted by Alastor View Post
But this isn't a fair comparisons because they don't occur at the same road speed. It has already been stated that as speed increase it takes more energy to maintain the same acceleration.



Well if that is the case, then somebody should call these guys out for “sand bagging” when they tested this car.

http://www.mpt.org/motorweek/reviews/rt2620a.shtml
Quote:
Originally Posted by motorweek
impressive for a heavy mid-size luxury sedan
don't compare a car that weighs two tons and is geared as a luxury car to a sportscar. Also, you're comparing 388 ft lbs from the engine to 400+ ft lbs at the wheels.

Quote:
Originally Posted by hightower99
The whole "torque is best" idea started way back when people realised that even an engine that pulled hard from 1000rpm was only making say 50 odd HP at that rpm and it just didn't sound cool to say "Wow you can feel the 50HP rip the wheels lose" because 50 is only a small portion of what the power rating of the engine was, say 250hp. People realised that at the same rpm the engine was making 263lbs-ft. of torque and that it sounded great when you say "Wow the feeling of 263lbs-ft. of torque is awesome"
Hence the whole idea of "torque is best" is born from nothing but the human brain's ability to distort the value of numbers when comparing it to reality.
I know its hopeless to argue with you, but please make a half assed attempt to understand... No one denies power is important. Power is related to the rate at which the cars kinetic energy and therefore speed can increase.

But POWER is made through TORQUE. Do you have any practical experience whatsoever with drag racing? Why is it that real racers strive for a flat TORQUE curve? Because you accelerate on the TORQUE curve. On the other hand, infamous "Dyno Queen" Supras can make huge power numbers... but because their torque curve is so low from zero to 7000 rpm they don't win races.




Oh and your sig
"porting and polishing is bad"
just makes me laugh.
But sure, go against every racer, dyno, and strip time for the past hundred years. your probably right anyway.

"its all about velocity"
Good point good point. Which is why all carbuerators, heads, etc. are measured in cfm and NEVER ft/s. but you'll probably say that this is because people like to say "wow you can really feel that 800cfm" rather than "wow you can really feel that 50 ft/s"

"Reciprocating = old tech, Rotary = future"
Funny will rotary still be the future when we run out of gasoline in 50 years?
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Last edited by Bob; 03-24-2007 at 09:32 AM.
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  #195  
Old 03-24-2007, 09:22 AM
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Hightower, you still haven't sent any pictures, dyno charts, etc of anything you've worked on. Why not?
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