How do you increase Torque?

[2ndclasscitizen]

Uhhh, I dont know what "trucks" you've been around, but the ones here rev to 5000-6000RPMs... Like my moms blazer that I mentioned, it revs to 5500RPMs, making peak power at 4400RPMS, but pulls the hardest around 2000-3000RPMs, where its making very little power, but a good deal of torque.

I think you might be getting a confused by what some people mean by "truck." When I referred to trucks, I wasn't talking about big pick ups and SUVs like a Blazer, I (and I'm sure the other non-USA participants in this thread) meant truck as in:



The diesel engine in these sort of things redlines at around ~3500rpm.

Oh, and in our work truck (identical to the pic) I can get a jump on a car at the lights by slipping the clutch well and keeping it at ~2000rpm. Once it gets past around 2500rpm it slows way down. In fact our old truck (an older model NPR) actually had on the tacho a blue line from 1750 to 2500rpm where, surprise surprise, it accelerated fastest, dropping right off after that as you got near peak power.

[SlickHolden]

Looks like what i moved my brother in, And i got it in my driveway Ask bluey it's tight as a fishes a spot.
http://www.ultimatecarpage.com/forum...0&d=1154161492

[nota]

You quoted the question but when bennett answered he said "never went over 3750rpm" so either he isn't the perfect example of precise measurement that some people think he is or there is some other problem.

It's not him that has the problem, believe me, because here you go again nitpicking wordage in a self-centred attempt to distort meaning & intent. No he's not 'answering - he was telling .. in conversational interview style, that he used 3750rpm as the optimal shift-point because the damn thing stopped increasing its acceleration unless upshifted at those revs - on the racetrack AND on dragstrip

Also about oil surge, That normally happens under extreme cornering loads, Do you think a stock '68 monaro is capable of enough cornering load to actually cause enough oil surge to break the cam shaft into 7 pieces?

You only highlight your lack of knowledge and experience via words like these. From personal experience from almost 40 years ago, my Dad's basic old '69 Falcon wagon gripped enough to suffer oil surge on 6" rims & 185mm Dunlop Aquajet radials!

Oil surge was a huge issue (and still is) in production-car racing. You can't seriously tell me that it wasn't (isn't) in similar US racing series? Or is this because you won't accept such realities unless there is a "perfect example of precise measurement" ..

Be it a Monaro from 1969, a Torana XU-1 from 1972 or a Commodore from 1984, he could still remember the exact engine revs he was using, where he would change his shift points as the fuel load lightened, how he had to 'drift' the car a certain way through certain corners to minimise oil surge in the engine and how he would mentally goal-set each lap to maintain his concentration.

http://www.drive.com.au/Editorial/Ar...rticleID=20046

No I didn't. Are you assuming that his shift timing is the only factor that made him a winner in drag races?

No, but HE says is was a significant factor. [/tired of it]

[nota]

I think you might be getting a confused by what some people mean by "truck." When I referred to trucks, I wasn't talking about big pick ups and SUVs like a Blazer, I (and I'm sure the other non-USA participants in this thread) meant truck as in:

The kind of trucks I used to drive were typically redlined at around 2100 rpm, with 1850 the usual upshift-point

These days some of those BIG trucks have amazing acceleration. In wife's Falcon I recently followed an unladen 40 foot semi up a highway on-ramp, expecting to pass - it took 3/4 throttle just to stay with it!

[2ndclasscitizen]

A couple of thousand nm of torque will do that

[henk4]

I accept your challenge.

Assuming total vehicle weight of 40 000 kg
two trucks otherwise identicle except that truck A peaks at 430hp at 3000rpm while producing 753lbs-ft. of torque. and truck B peaks at 1640hp at 20031rpm while producing 430lbs-ft. of torque.

Acceleration to 100km/h (27.78m/s) and assuming constant engine speed takes Truck A: 47.6s
Acceleration to 100km/h assuming constant engine speed takes Truck B: 12.5s

Truck B wins.

a Formula 1 truck?

[-What-]

Wrong.
Generally trucks dont have good acceleration times(0-60 and such) because they lack top end torque.

You have got to be kidding me.

Got to be.

This throws you and everything you've said before this in the garbage. You are so wrong...buddy.

But you aren't the only one wrong.
.....................

Why do you think Ferrari, Saleen and such strive to achieve high power outputs? Why doesn't torque/lb estimate acceleration as effectively as hp/lb? Certainly you have noticed that there are many cars with higher torque/lb ratings LOSING in acceleration "races" to cars with significantly lower torque/lb rating....Viper...*cough*....F430....*cough*....sh ouldn't the Viper stomp ALL Ferraris?

Why do trucks get off the line with so much ease? Because they have plenty torque down low that multiplies with the rpm to provide instant, plentiful power....while something like a RX-8 has to wait until 7000 or so rpm to "go" because it doesn't have the low-end torque of a truck. Top-end power would work for a truck, but it would be impractical. The engine would stress way too hard and not last very long...and burn hella fuel.

THIS WILL BLOW YOUR MIND
Yes, the "g" graph will follow the torque curve. Why? Because acceleration increases fastest at the maximum torque point...but don't be confused. Hold on for this...acceleration is HIGHEST at the maximum power output. The acceleration may not be increasing as fast after the torque maximum, but it is increasing...all the way up until MAX POWER. The "feeling" that this gives you can confuse you. As the acceleration slows, it "feels" like you are slowing, but you aren't. YOU ARE STILL INCREASING YOUR ACCELERATION after the torque max...just at a slower rate...but you ARE accelerating faster up until the power peak. I hope you aren't confused.


To sum it up...
"Rate of acceleration" max occurs at torque peak.
"Acceleration max" occurs at power peak.


This is why the Viper feels faster than the F430 to some, but in reality, the F430's can accelerate as fast or faster than a Viper despite the F430's major torque disadvantage.

[henk4]

You have got to be kidding me.
es, the "g" graph will follow the torque curve. Why? Because acceleration increases fastest at the maximum torque point...but don't be confused. Hold on for this...acceleration is HIGHEST at the maximum power output. The acceleration may not be increasing as fast after the torque maximum, but it is increasing...all the way up until MAX POWER.

and this is why the guys in the monaros shifted up one gear before reaching Max power, because the engine would continue in the range where the rate of acceleration in the greatest...

[hightower99]

Wrong!.. And maybe you should read me before quoting me with your gospel..
I said a truck with no load will and bloody hell they do move very fast indeed with out loads, People get behind them and think this truck without a load will hold me up, Wrong it will power away with ease it surprises them not me, Now tell me is this 300hp or 200 hp engine going to make a 3000+kg truck semi move that fast?.
Trucks don't have a whole heap of gears to keep in the pulling range for nothing, They have them gears to keep in the torque range, Because that is what pulls them and there loads.. Truck drivers don't rev there engines they change early to keep the torque area to keep them moving forward faster and faster, There little power won't do the pulling it's the 600-700+Nm torque that does it.
I know this because my mate drives B-Doubles for a living, My uncle drove them all his life and my grandfather also..

I mean doesn't it in anyway question your theory or are you to blind and always right to actually question yourself?
If a cars engine was installed into a Truck, Say a Holden Commodore SS 5.7lt LS1.. 2001 version was 299Hp 465Nm.. Will that engine pull a truck and it's load?. Same power but is let down by torque.
Even if not possible to fit think about it.

First, for me quick acceleration is <6 sec. to 100km/h. So even the 500+ hp trucks without the extra sleeper cabin and without a trailer struggle to get anywhere near that.

So to answer your first question yes 300hp is more than enough to achieve the acceleration rates that 3 ton+ trucks can do. Do you realise how much power 300hp is? (roughly 226200 Joules per sec. !!!)

Trucks have alot of gears because they have a really short operating range (maybe 3000rpm) so they can't make big jumps in ratio like a car does.

How does it question the theory (it isn't mine) that power over speed is what gets you going? When I plug the numbers into the math they work.

To answer you second question: It doesn't matter what peak torque the engine makes if the peak power is the same then they have the ability to do the same amount of work.

You expect me to believe that a 19 year old kid has driven cars that cost more than his life? Well if you have I can see where you get this "idea" of power moving the cars. With the turbo cars the turbo lag creates that illusion, and most of the other are pretty peaky (making more torque in the higher RPMs).
Like I said before, go drive a V6/V8 truck and come back to talk to us.

Of the turbo cars only the 944 had noticable lag... Did you miss the part where I said I have driven a corvette stingray... that would be a 1968 one with a L88 in it. Not exactly a "peaky" engine. Even that one didn't accelerate on the torque curve.

The torque curves for each gear (yeah, gears multiply torque remeber?) matches *EXACTLY* to the G-forces... Care to explain?
And once again, IF hp trully did move the car, the graph of G-forces would look like the hp curve right?

They don't match! look at them they don't touch, the shapes are different and you have cut the thrust graph to fit as best you could. HP doesn't accelerate the car on it's own it is highly dependant on velocity. I have explained why several times I have shown the math which is standard text book stuff.

How do you derive torque from power, when power is just a calculation of torque? If you know the power, then you already knew the torque before hand.

Quite easily torque is equal to power divided by speed. If you know the power then it is not always the case that you know the torque (maybe the computer didn't tell you at the time), but you can certainly figure it out.

Uhhh, I dont know what "trucks" you've been around, but the ones here rev to 5000-6000RPMs... Like my moms blazer that I mentioned, it revs to 5500RPMs, making peak power at 4400RPMS, but pulls the hardest around 2000-3000RPMs, where its making very little power, but a good deal of torque.

By Trucks I mean tractor trailers, 18 wheelers, Semis, that sort of thing. You will be hard pressed to find a diesel (anywhere) that redlines at 6000rpm. the highest I have heard is 5500rpm.

By the way here is a quote from the website you posted:

A further understanding of the relationship between Power and Torque reveals that the shift point calculations can be greatly simplified by looking at the Power curve.

Recall the formula P=Fv. Moving around the terms, you get a=P/(mv). This means that given the velocity of the car, the mass of the car and the power transmitted from the engine to the tires, the acceleration can be calculated from a=P/(mv). This means that the higher the car velocity is, the less acceleration you can expect.

Note that the power curve of a car can be obtained by P=2πΓ(ω)ω. If we take our Skyline's torque curve after the peak torque, we can obtain a power curve like P=2πω(-2.568ω+580.32). If you plot this power curve, then you know that it peaks at a certain point and then falls all the way from there. (Officially the peak power point is at 6800RPM but our peak based on our simplified torque curve most likely won't yield the same power curve and hence the same peak power point.)

From the power curve, we know that if we want to maximize the acceleration of the car, we don't need to up shift before the peak power point. This is because if we shift up, we get lower RPM and hence less power from the engine. Note that the velocity of a car before and after the shift remains the same. However, the acceleration of the car is greatly reduced because power is smaller at lower engine speed.

It is easy to see that to maximize acceleration, we need to keep the power from dropping. That means we should shift when we are after the power peak and if we don't shift at the next instant, we will find that we get less power from the engin by avoiding the up shift. That happens when we get the same power from the engine when we shift up. Suppose P is the power at the optimal shift point. By solving the quadratic equation: 2π(-2.568ω2+580.32ω)-P=0, the roots we obtain are the optimal shift point (ω) and the engine speed at the next gear after the shift (ωgk+1/gk). Note that the sum of the roots equals the negation of the second term divided by the first term, so we have the following equality:

gk+1 2π(580.32)
ω + ----- ω = − ---------------
gk 2π(-2.568)

Solve for ω, we get exactly the same equation we have in our previous discussion.

580.32
ω = ------------------------
2.568(1 + gk+1/gk)

Thanks for proof of the theory

Also about the Tesla website. They are not giving any specific information, they simply say "constant acceleration to 6000rpm" but seeing as it is just commercial text that could mean strong, roughly uniform acceleration to 6000rpm. Anyways it is a mute point because you will notice that to achieve a constant rate of acceleration (according to the laws of physics) the power needs to increase with speed. In the tesla car it does just that, increasing at a linear rate with speed. Unfortunately this won't lead to constant acceleration (as power required goes up exponentially not linearly). To validate the result an actual test needs to take place.

If you are as tall as you claim this is bullshit and you know it - you just wont fit in these highlighted cars, and you will really struggling to get in the Murci.

Really so you can tell me exactly how long my neck and back are? Yes head room and leg room is tight (oddly still comfortable in the mini) but not impossible. Still a comic thing, seeing me getting into and outof those cars.

The equation ignores how much grip the vehicle has, just a minor factor in acceleration last I checked......

No it doesn't running resistence has a term for grip included.

It also shows that it is a equation for motive FORCE. Forces are measured in NEWTONS, like torque. You have fraudulently tried to pretend this is equivalent to power in this case, whist arguing that that are completely separate elsewhere.

No I haven't I have shown that motive force is derived from (not equivalent to) power. It is also obvious that torque is not equivalent to motive force.

Good scientists look to try to prove themselves wrong, charlatans who try and get kudos are the only ones who try and prove themselves right - and end up looking very foolish when they get found out.

If you are stupid/naive enough to believe every theory thought up is perfect and holds to scrutiny then I'm very glad I'll never have to use anything you design.

When you think up a theory you then try to check if it actually works, if it works in the experiment you made then you check the other variables that were not checked in the original experiment. If everything stands up then there is no reason to change your theory. You change theories when you hit problems that give results that don't agree with the theory. I do not think that every theory is perfect, I believe that theories that have been tested to exhaustion testing all variables involved will in the end stand the test of time. Theories that have proven themselves become laws. I believe Laws to be perfect and more than able to hold up to close scrutiny.

[hightower99]

Let's look at what an authority on the matter has to say...
Isaac Newton found that the acceleration a body undergoes is a combination of it's mass and the forces acting upon it. So F=m*A The higher the net force for a given mass yields a higer acceleration. The force we are concerned with here is the propulsion from the wheels of the vehicle, which is determined by the torque to the wheels and the radius of the tires. A higher torque (through whatever means more torque, different gearing , etc) yields a higher acceleration. The fact that acceleration is more difficult at higher speeds is because of the wind resistance lowering the net force on the vehicle.

The motive force (the force at the contact patch between the tire and the ground) is derived from power and speed. Acceleration is achieved by the left over force after over coming running resistence, which is the sum of wind resistence, rolling resistence from the wheels and climbing resistence. The rate of acceleration is calculated by dividing this left over force by the rotational inertia coefficient times the mass of the vehicle.

Oh, and in our work truck (identical to the pic) I can get a jump on a car at the lights by slipping the clutch well and keeping it at ~2000rpm. Once it gets past around 2500rpm it slows way down. In fact our old truck (an older model NPR) actually had on the tacho a blue line from 1750 to 2500rpm where, surprise surprise, it accelerated fastest, dropping right off after that as you got near peak power.

You get the jump on cars at the lights for a few reasons: 1. you are heavier giving better traction allowing you to put all the grunt from the engine into the ground, 2. at about 2000rpm you are making way more power than a car is at 2000rpm in fact you are probably making more power even if the car dropped the clutch at 4-5000rpm. The reason you slow way down at 2500rpm is because then you are moving at speed and the power needed to continue acceleration has gone up enough that the power you are making isn't enough to maintain acceleration. By the way the blue lines on the old truck are where the engine is working most efficiently (using the least amount of fuel per unit power) This does coincide with peak torque.

It's not him that has the problem, believe me, because here you go again nitpicking wordage in a self-centred attempt to distort meaning & intent. No he's not 'answering - he was telling .. in conversational interview style, that he used 3750rpm as the optimal shift-point because the damn thing stopped increasing its acceleration unless upshifted at those revs - on the racetrack AND on dragstrip

So you agree that it is an inaccurate and biased result.

You only highlight your lack of knowledge and experience via words like these. From personal experience from almost 40 years ago, my Dad's basic old '69 Falcon wagon gripped enough to suffer oil surge on 6" rims & 185mm Dunlop Aquajet radials!

Oil surge was a huge issue (and still is) in production-car racing. You can't seriously tell me that it wasn't (isn't) in similar US racing series? Or is this because you won't accept such realities unless there is a "perfect example of precise measurement" ..

Ok I didn't know that. I honestly didn't think stock cars from that time could corner hard enough to cause oil surge. Yes oil surge is a problem, but for the stock monaro to corner hard enough to cause enough oil surge to cause catastrophic engine failure and break the camshaft into 7 pieces surprises me.

a Formula 1 truck?

yeah that is the rpm required to produce 1640hp from 430lbs-ft. of torque...

[-What-]

and this is why the guys in the monaros shifted up one gear before reaching Max power, because the engine would continue in the range where the rate of acceleration in the greatest...

I don't know about the situation with these Monaros...I'm sure it is somewhere in this thread, but...if you want to achieve the fastest acceleration times, you want to keep the engine at the point of MAX acceleration...which is where max power is achieved.

If the greatest possible acceleration is your goal, Max Acceleration > Max Acceleration Rate.

This is like Max Speed > Max Acceleration if your goal is to go as fast as possible.


Max Power=Max Acceleration

Max Torque=Max Rate of Acceleration=Max G's=Max Acceleration "Feeling"


Am I making sense?

[henk4]

Max Power=Max Acceleration

Max Torque=Max Rate of Acceleration=Max G's=Max Acceleration "Feeling"


Am I making sense?

almost, but why are we then being "fooled" by physics if we "feel" the max acceleration at "Max torque" and not "max acceleration" ?

[-What-]

almost, but why are we then being "fooled" by physics if we "feel" the max acceleration at "Max torque" and not "max acceleration" ?

Just to clear things up so no one is confused by your wording, max torque delivers maximum increased rate of acceleration.

The reason physics "tricks" us into "feeling" more from a fast rise in acceleration rather than a constant, higher acceleration is a phenomenon known as "acceleration stress". I'd rather you research the term instead of me explaining it to you.

[Alastor]

I don't know about the situation with these Monaros...I'm sure it is somewhere in this thread, but...if you want to achieve the fastest acceleration times, you want to keep the engine at the point of MAX acceleration...which is where max power is achieved.

If the greatest possible acceleration is your goal, Max Acceleration > Max Acceleration Rate.

This is like Max Speed > Max Acceleration if your goal is to go as fast as possible.


Max Power=Max Acceleration

Max Torque=Max Rate of Acceleration=Max G's=Max Acceleration "Feeling"


Am I making sense?

No.

When you have a limited number of gears maximum acceleration in a given gear does occur when the engine is making peak torque. The rate of change in acceleration, jerk or jolt, is unimportant to this topic. Not to mention that amount of jerk is going to be dependent on the shape of the torque/power curve, and an ex termly flat torque delivery will result in little to no jerk.

I also take issue with any accleration measurment that is dependent on “feeling”.

The fact that acceleration is more difficult at higher speeds is because of the wind resistance lowering the net force on the vehicle.

Even if you ignore friction and look at an ideal case, it takes more energy to go from 30 MPH to 60 MPH than it does go from 0 MPH to 30 MPH. Therefore, in order to maintain the same acceleration at a higher velocity the rate of energy generation, power, must be increased.

[henk4]

The reason physics "tricks" us into "feeling" more from a fast rise in acceleration rather than a constant, higher acceleration is a phenomenon known as "acceleration stress". I'd rather you research the term instead of me explaining it to you.

I am afraid that will give me research stress...