First Drive Review of Toyota FT-86 / Scion FR-S Mule! [Car magazine]

[serialk11r]

I think you guys don't understand what I'm talking about. Torque isn't what pushes you into the seat, acceleration is. You have to know exactly how much the car weighs, exactly how much acceleration you have, exactly how big the wheels are, exactly what the gear ratio and final drive ratio are, and exactly the speed of the engine to know what torque is.

You can't feel torque as a number, you can only feel it changing because it is proportional to acceleration.

If you were put in any car without being told these specs, and you were asked to guess how much torque there is, you wouldn't be able to do it. Even if you were given the displacement (which puts you in a pretty small ballpark of possible figures) you wouldn't be able to. You can't just sense what the gear ratio unless you have a stopwatch and you measure how fast it takes to rev however much rpm, and have something to compare to.

I was calling bullshit on the 170 ft-lb number, because it is simply not possible to spit out an accurate number for the maximum torque of the engine just by sitting in the car. If you still don't believe me, maybe you should go relearn some physics.

[SUB-FT86]

Originally Posted by serialk11r

I think you guys don't understand what I'm talking about. Torque isn't what pushes you into the seat, acceleration is. You have to know exactly how much the car weighs, exactly how much acceleration you have, exactly how big the wheels are, exactly what the gear ratio and final drive ratio are, and exactly the speed of the engine to know what torque is.

You can't feel torque as a number, you can only feel it changing because it is proportional to acceleration.

If you were put in any car without being told these specs, and you were asked to guess how much torque there is, you wouldn't be able to do it. Even if you were given the displacement (which puts you in a pretty small ballpark of possible figures) you wouldn't be able to. You can't just sense what the gear ratio unless you have a stopwatch and you measure how fast it takes to rev however much rpm, and have something to compare to.

I was calling bullshit on the 170 ft-lb number, because it is simply not possible to spit out an accurate number for the maximum torque of the engine just by sitting in the car. If you still don't believe me, maybe you should go relearn some physics.

Peak acceleration happens near redline and peak torque happens way before that. HP is also minimal in the low to mid range.

[serialk11r]

Nope peak acceleration does not happen near redline, maximum power does not mean maximum acceleration. Power is acceleration times speed. Acceleration is force over mass, and the force is the radius of your wheel times the torque coming out of the driveshaft.

If the car weighs just 100 pounds less, in a 2500 pound context, and then they make 1st gear shorter by 5%, we are changing acceleration by 10%, yet I doubt a human being can stare at the tach and tell you what is going on. A 10% difference is almost as big as the difference between the low speed and high speed cams on the S2000.

[SUB-FT86]

Originally Posted by serialk11r

Nope peak acceleration does not happen near redline, maximum power does not mean maximum acceleration. Power is acceleration times speed. Acceleration is force over mass, and the force is the radius of your wheel times the torque coming out of the driveshaft.

If the car weighs just 100 pounds less, in a 2500 pound context, and then they make 1st gear shorter by 5%, we are changing acceleration by 10%, yet I doubt a human being can stare at the tach and tell you what is going on. A 10% difference is almost as big as the difference between the low speed and high speed cams on the S2000.

I don't understand where you are coming with this which is funny because I always like your write ups. In torqueless engines I feel no motivation, not even a hint or push so I know horsepower is not doing its job in the low to mid range. Example!

My aunt owns a 2004 Mercury Mountaineer V8 with 4500 lbs of curb weight and it comes with a measly 239 hp@5500 rpms but it comes with 282 lb ft@3000 rpms and I could feel the torque push me in my seat under 3k rpms. So you're telling me that under 3k rpms I was feeling a lot of horsepower? Under 3k rpms my aunt's truck was probably making 175 hp with 275 lb ft of torque. There is no way 175 hp offers a lot of motivation in a 4500 truck with 500 lbs of people in it.

[tranzformer]

Originally Posted by SUB-FT86

I don't understand where you are coming with this which is funny because I always like your write ups. In torqueless engines I feel no motivation, not even a hint or push so I know horsepower is not doing its job in the low to mid range. Example!

My aunt owns a 2004 Mercury Mountaineer V8 with 4500 lbs of curb weight and it comes with a measly 239 hp@5500 rpms but it comes with 282 lb ft@3000 rpms and I could feel the torque push me in my seat under 3k rpms. So you're telling me that under 3k rpms I was feeling a lot of horsepower? Under 3k rpms my aunt's truck was probably making 175 hp with 275 lb ft of torque. There is no way 175 hp offers a lot of motivation in a 4500 truck with 500 lbs of people in it.

This.

[Redliner]

@sub-ft86
Here are my thoughts:
You can't really feel the torpue, but you could think so, cause hp at low rpm can feel so much more powerfull than at high rpm. What invests Power to accelerate you is Power and not torque. Power is in principle energy and torpue is not. Power= ((Pi*rounds per sec.)/30)* torque so coming to a conclusion: You need revs or torque to get the power which you need, cause you need kinetic energy which comes from powerin this case. You only need torque to get it.
Don't really know how to explain it. But i'm studying mechanical engineering, so i should know what im talking about.

[Marrk]

Originally Posted by serialk11r

I think you guys don't understand what I'm talking about. Torque isn't what pushes you into the seat, acceleration is. You have to know exactly how much the car weighs, exactly how much acceleration you have, exactly how big the wheels are, exactly what the gear ratio and final drive ratio are, and exactly the speed of the engine to know what torque is.

You can't feel torque as a number, you can only feel it changing because it is proportional to acceleration.

If you were put in any car without being told these specs, and you were asked to guess how much torque there is, you wouldn't be able to do it. Even if you were given the displacement (which puts you in a pretty small ballpark of possible figures) you wouldn't be able to. You can't just sense what the gear ratio unless you have a stopwatch and you measure how fast it takes to rev however much rpm, and have something to compare to.

I was calling bullshit on the 170 ft-lb number, because it is simply not possible to spit out an accurate number for the maximum torque of the engine just by sitting in the car. If you still don't believe me, maybe you should go relearn some physics.

I am going to choose to understand that as a friendly recommendation. :happy0180:

We should be respectful of our fellow forum members. :happy0180:

Good luck, sir! :happy0180:

[tenyearguarantee]

serialkiller is right.

torque is a property of an engine that describes it's ability to turn.

being pushed back into your chair is a result in a quick increase in acceleration. An engine with a good torque figure implies a greater ability to increase acceleration.

torque is cause, acceleration is effect.

And i am a mechanical engineer

[Spaceywilly]

Originally Posted by tenyearguarantee

torque is cause, acceleration is effect.

Exactly, that's why "you can't feel torque, you can feel acceleration" doesn't make sense to me. Torque applied to the tires which push against the ground directly causes acceleration. Torque at the wheels is equal to torque at the crankshaft multiplied by the various transmission and tire geometries. Countering that torque is inertia caused by the mass of the car and drag caused by air resistance. More torque=more acceleration=being pushed back into your seat.

Torque is force, HP is work. Work is force applied over a distace. In this case, the distance is rotational and measured in RPMs. HP is a measure of an engine's ability to make force (torque) at a given RPM.

[SUB-FT86]

Originally Posted by tenyearguarantee

serialkiller is right.

torque is a property of an engine that describes it's ability to turn.

being pushed back into your chair is a result in a quick increase in acceleration. An engine with a good torque figure implies a greater ability to increase acceleration.

torque is cause, acceleration is effect.

And i am a mechanical engineer

But this is what I said.

[SUB-FT86]

Originally Posted by Redliner

@sub-ft86
Here are my thoughts:
You can't really feel the torpue, but you could think so, cause hp at low rpm can feel so much more powerfull than at high rpm. What invests Power to accelerate you is Power and not torque. Power is in principle energy and torpue is not. Power= ((Pi*rounds per sec.)/30)* torque so coming to a conclusion: You need revs or torque to get the power which you need, cause you need kinetic energy which comes from powerin this case. You only need torque to get it.
Don't really know how to explain it. But i'm studying mechanical engineering, so i should know what im talking about.

I don't know which car you have driven before but this makes no kind of sense. There is no way especially in a N/A engine that hp at low rpms feel stronger than hp at near peak. Horsepower is dominant at higher rpms and torque is generally superior at lower rpms in most cases. Just look at a dyno sheet for christ sakes.

[CyberFormula]

Torque in a truck is high so the engine can turn...and hull stuff.
But their acceleration isn't HIGH because they're heavy usually.


High torque may transfer as high acceleration, but like a previous member said, it depends on other factors.

[SUB-FT86]

I get what serial is saying now but it's essentially the same thing we're talking about here. Torque=Acceleration. I definitely agree with that.



Torque, moment or moment of force (see the terminology below), is the tendency of a force to rotate an object about an axis,[1] fulcrum, or pivot. Just as a force is a push or a pull, a torque can be thought of as a twist.

[Spaceywilly]

Originally Posted by CyberFormula

Torque in a truck is high so the engine can turn...and hull stuff.
But their acceleration isn't HIGH because they're heavy usually.


High torque may transfer as high acceleration, but like a previous member said, it depends on other factors.

That is because of gearing. Think about riding a bike. Your legs generate a certain force which pushes on the pedals. The pedals turn that force into torque on the gears, which multiply the force and then apply it to the bike wheel. In low gears, the torque is multiplied by >1 (let's call it 2, not realistic but bear with me) which results in every lb/ft of force on the pedals generating 2 lb/ft on the wheel, but only 1/2 the distance (if you move your leg 6" the wheel only moves 3"). That force will accelerate the bike at a certain rate based on apparent weight (which would be higher going up a hill, or lower going down a hill), wind resistance, and friction in the chain/gears/bearings. Your legs are able to create that force up to a certain pedal speed, at which point you shift gears to get a gear with lower torque multiplication, but higher speed. You will then continue to accelerate because the inertia is less since you are now moving, but you won't accelerate as quickly as before because torque is reduced. If you could pedal at infinite speed you could always be in the lower gear and accelerate instantly. Your ability to generate force at a certain pedal speed is HP by the way.

When choosing gearing, you basically have a choice between ability to turn stuff (torque) and speed at which you are turning (rpm). Let's say you had the same engine in a truck and a car. The truck would choose gears with higher torque multiplication but less acceleration. The car would choose gears with higher acceleration but lower torque multiplication. If both vehicles weighed the same, the car would accelerate faster, assuming the engine was powerful enough to overcome inertia. But, once you added more weight (say attached a trailer), the car would just bog down because there wouldn't be enough torque to overcome the inertia. In this case the truck would accelerate faster. So, to expand on my previous post, torque causes acceleration, unless it is overcome by inertia. You can think of a free body diagram with torque causing a force on a wheel in one direction (say counterclockwise) and inertia going the other direction (clockwise). The extent to which torque is greater than inertia determines the amount of acceleration, but eventually you run out of engine speed and must change gears, so if you have too much torque (cause by having truck like gears) you will end up accelerating slower because every rotation of the crankshaft results in less rotations of the wheels. I hope that made sense...