The definitive GT5 transmission tuning guide.

[grenadeshark]

Its pretty spot on. There is a margin of error as it only desplays mph and no fraction, however as you enter the data you notice a pattern of less or more mph between incraments.

Honestly, wouldn't calculating it every 500 rpm be nearly as accurate and a lot easier?

 

[AssassinTuner]

I just hotlap whatever tracks being used for the tune, it gives insight on gearing for specific corners.
In other words a quicker fourth in an example might be faster in general, but on the current track it means an extra shift right before 3 turns, and not being able to hold proper rpm's through a long high-speed sweeper, which means I'll make fourth longer for those corners because it gives me an overall gain in time around the track.

That is precicely why I'm including an adjuster per gear by mph.

 

[AssassinTuner]

Honestly, wouldn't calculating it every 500 rpm be nearly as accurate and a lot easier?

To be honest every 1000rpm would be okay, I just want more precise redings when calculating a rpm drop they don't always or often fall on a X000 or XX00rpm.

 

[grenadeshark]

That is precicely why I'm including an adhuster per gear by mph.

You do realize that your tuning is accurate on HP. It is also accurate on power to the wheels on given gearset.

But, if you were to change the final gear or any individual gear, that will change the power to the wheels. Again, I realize this is not actual power, but an effect of the gearing reducing the load on the engine.

This still doesn't change the fact that the tires spin faster with shorter gearsets. Any TQ multiplying people do is just calculating what is actually happening versus trying to say that the gears are actually creating torque. Only the engine creates torque.

 

[AssassinTuner]

You do realize that your tuning is accurate on HP. It is also accurate on power to the wheels on given gearset.

But, if you were to change the final gear or any individual gear, that will change the power to the wheels. Again, I realize this is not actual power, but an effect of the gearing reducing the load on the engine.

This still doesn't change the fact that the tires spin faster with shorter gearsets. Any TQ multiplying people do is just calculating what is actually happening versus trying to say that the gears are actually creating torque. Only the engine creates torque.

Yup if you change the gearing you have to redo your shift calculations. That's true, & not disputed.

The adjuster is to cater the gearing to the Track first

 

[grenadeshark]

Yup if you change the gearing you have to redo your shift calculations. That's true, & not disputed.

Ok, I just wanted to make sure as there are some people on this forum that still dispute the "tq multiplication" theory of gearing. Once they realize that it is just a way to show mathematically what is occurring and that we are not actually saying tq is created, they generally back down.

 

[AssassinTuner]

Ok, I just wanted to make sure as there are some people on this forum that still dispute the "tq multiplication" theory of gearing. Once they realize that it is just a way to show mathematically what is occurring and that we are not actually saying tq is created, they generally back down.

Tq vs speed

What you gain in tq from gearing, you loose in speed, what you gain in speed you loose in tq. You are getting more tq in first gear for example, just at a slower speed

Its like leverage (let me see if I can recreate the drawing they love to use) its clear.

Its summed up to this quote.

In order for a smaller force to produce a greater force, the smaller force must travel a greater distance.

That was drilled into our brains in Mechanics school.

I can easily use 10pounds of force to lift 100pounds of weight. that's 100pounds of lifting power from only 10pounds of power.

 

[AssassinTuner]

You can pic a car you have already tuned & I can put up a gearbox for it. Providing I have the car.

 

[grenadeshark]

You can pic a car you have already tuned & I can put up a gearbox for it. Providing I have the car.

I have a really good 240 rs from the 80s. We could use that if you have one.

 

[AssassinTuner]

I have a really good 240 rs from the 80s. We could use that if you have one.

A what? Grab a premium so I can buy one easy and put it to the same spec. I only have 330cars.

 

[CSLACR]

Ok, I just wanted to make sure as there are some people on this forum that still dispute the "tq multiplication" theory of gearing. Once they realize that it is just a way to show mathematically what is occurring and that we are not actually saying tq is created, they generally back down.

That was the question, yes.
You should know, while torque is the measure of which horsepower is created, horsepower is the only thing that matters in "go fast" terms.

Torque is the power of a single stroke, and lets you know (at peak tq) where the engine produces the most power, ie, runs most efficiently, however horsepower is what makes you move faster than a snail, as horsepower is torque multiplied to display the actual driving force at the wheels at a given rpm.

So I disagree with torque ever being mentioned when it comes to shift points, because it has absolutely nothing to do with when to shift, or how fast a car will go, diesel engines are a prime example of this.

http://www.howstuffworks.com/question622.htm
http://www.howstuffworks.com/horsepower.htm

 

[AssassinTuner]

That was the question, yes.
You should know, while torque is the measure of which horsepower is created, horsepower is the only thing that matters in "go fast" terms.

Torque is the power of a single stroke, and lets you know (at peak tq) where the engine produces the most power, ie, runs most efficiently, however horsepower is what makes you move faster than a snail, as horsepower is torque multiplied to display the actual driving force at the wheels at a given rpm.

So I disagree with torque ever being mentioned when it comes to shift points, because it has absolutely nothing to do with when to shift, or how fast a car will go, diesel engines are a prime example of this.

http://www.howstuffworks.com/question622.htm
http://www.howstuffworks.com/horsepower.htm

Its calculated off hp, but You are right though, its the hp that's used for the calculations, not the tq. Goal is to get the hp at exit rpm as equal to the hp at entry of the following gear.

Grenadeshark
THIS is where maximizing the use of the power curve comes in. The hp curve

 

[grenadeshark]

Seriously, HP and TQ are factors of each other. If you know one, you can calculate the other. HP is a measure of heat (or work*), TQ is a measure of force..

Just typed in HP vs TQ in the first page to come up on google.

"The Case For Torque
Now, what does all this mean in carland?

First of all, from a driver's perspective, torque, to use the vernacular, RULES :-). Any given car, in any given gear, will accelerate at a rate that *exactly* matches its torque curve (allowing for increased air and rolling resistance as speeds climb). Another way of saying this is that a car will accelerate hardest at its torque peak in any given gear, and will not accelerate as hard below that peak, or above it. Torque is the only thing that a driver feels, and horsepower is just sort of an esoteric measurement in that context. 300 foot pounds of torque will accelerate you just as hard at 2000 rpm as it would if you were making that torque at 4000 rpm in the same gear, yet, per the formula, the horsepower would be *double* at 4000 rpm. Therefore, horsepower isn't particularly meaningful from a driver's perspective, and the two numbers only get friendly at 5252 rpm, where horsepower and torque always come out the same.

In contrast to a torque curve (and the matching pushback into your seat), horsepower rises rapidly with rpm, especially when torque values are also climbing. Horsepower will continue to climb, however, until well past the torque peak, and will continue to rise as engine speed climbs, until the torque curve really begins to plummet, faster than engine rpm is rising. However, as I said, horsepower has nothing to do with what a driver *feels*.

You don't believe all this?

Fine. Take your non turbo car (turbo lag muddles the results) to its torque peak in first gear, and punch it. Notice the belt in the back? Now take it to the power peak, and punch it. Notice that the belt in the back is a bit weaker? Fine. Can we go on, now? :-) "

It doesn't matter whether you talk in HP or TQ, you can calculate the other and still get meaningful measurements to compare with.

 

[grenadeshark]

That was the question, yes.
You should know, while torque is the measure of which horsepower is created, horsepower is the only thing that matters in "go fast" terms.

Torque is the power of a single stroke, and lets you know (at peak tq) where the engine produces the most power, ie, runs most efficiently, however horsepower is what makes you move faster than a snail, as horsepower is torque multiplied to display the actual driving force at the wheels at a given rpm.

So I disagree with torque ever being mentioned when it comes to shift points, because it has absolutely nothing to do with when to shift, or how fast a car will go, diesel engines are a prime example of this.

http://www.howstuffworks.com/question622.htm
http://www.howstuffworks.com/horsepower.htm

Dyno's measure tq and then create a HP curve via math. To say that TQ has nothing to do with going fast is a misnomer.

Please explain how TQ has nothing to do with going fast? Diesels produce massives amounts of TQ at low RPMs, but do not produce lots of TQ at high RPMs. That's why they are slow by your measurements. Show me any car that produces 700 lb/ft of torque at 7000 rpms and tell me it is slow.

 

[CSLACR]

Seriously, HP and TQ are factors of each other. If you know one, you can calculate the other. HP is a measure of heat (or work*), TQ is a measure of force..

Just typed in HP vs TQ in the first page to come up on google.


It doesn't matter whether you talk in HP or TQ, you can calculate the other and still get meaningful measurements to compare with.

So you're going with the first page to come up in google search over science? Okay....

Torque is meaningless in speed terms.
Torque is the power of a single stroke.
Horsepower is the power of the amount of strokes your engine makes per second.

 

[grenadeshark]

So you're going with the first page to come up in google search over science? Okay....

Torque is meaningless in speed terms.
Torque is the power of a single stroke.
Horsepower is the power of the amount of strokes your engine makes per second.

Your diesel reference makes no sense. You are comparing the two values as if they are independent of each other. If you know one, then you have the other. TQ measures force and HP measures heat/work.

So, I could tell you that my car creates 500 lb/ft of torque at 6000 RPMs. You could use this information to say that my car also produces 571 hp at the same RPM.

In reality, you can use both as a measurement of the ability of a car to go fast. HP continues to increase as an engine revs while torque generally does not. The sole reason we talk about HP in a sense is it allows you to easily gauge a cars performance as torque does not. HP generally goes up, TQ generally goes up then back down.

If you said you had 300 lb/ft of torque at 3000 rpms with a 7000 rpm redline, no one would really know how fast your car can potentially go.

If you said you had 300 hp @ 3000 rpms with a 7000 RPM redline, people would be like WOW.

 

[AssassinTuner]

So you're going with the first page to come up in google search over science? Okay....

Torque is meaningless in speed terms.
Torque is the power of a single stroke.
Horsepower is the power of the amount of strokes your engine makes per second.

Its just semantics.

Tq is the power of the engine, hp is a representation of that power put to use.

CSLACR is right though technically. I've never used tq to calculate a shift point, they would be pretty low, lol. The right way to do it is hp.

Your hp tells you how your tq is working for you at a given engine speed.

 

[grenadeshark]

Its just semantics.

Tq is the power of the engine, hp is a representation of that power put to use.

CSLACR is right though technically. I've never used tq to calculate a shift point, they would be pretty low, lol. The right way to do it is hp.

Your hp tells you how your tq is working for you at a given engine speed.

Well the idea is people use TQ multiplied by the transmission gear ratio.
HP doesn't change much over a given high RPM range, but torque does.

Lets do some math.

A car making 300 hp @ 7000 rpms

The same car making 300 hp @ 8000 rpms.

Does this car pull the exact same amount (just as hard)at both 7000 and 8000 rpms?

The answer to this question is EXACTLY why torque matters.

 

[CSLACR]

Your diesel reference makes no sense. You are comparing the two values as if they are independent of each other. If you know one, then you have the other. TQ measures force and HP measures heat/work.

So, I could tell you that my car creates 500 lb/ft of torque at 6000 RPMs. You could use this information to say that my car also produces 571 hp at the same RPM.

In reality, you can use both as a measurement of the ability of a car to go fast. HP continues to increase as an engine revs while torque generally does not. The sole reason we talk about HP in a sense is it allows you to easily gauge a cars performance as torque does not. HP generally goes up, TQ generally goes up then back down.

If you said you had 300 lb/ft of torque at 3000 rpms with a 7000 rpm redline, no one would really know how fast your car can potentially go.

If you said you had 300 hp @ 3000 rpms with a 7000 RPM redline, people would be like WOW.

Yes, you can use torque to figure out horsepower, but if you have the hp, why mention the torque at all?
My point isn't that torque cannot be used, but rather since we have the hp figures, we don't need the torque readings.
Even at low idles engine run 10 strokes a second, so "torque" as people know it is useless.
Tell someone your engine makes 600lb-ft of torque, and they'll probably think it's fast, but what they don't know is 600 lb-ft @ 1800 rpm is only 206 hp. Still impressive for low-rpm grunt, and useful for towing, it's no faster than 206 hp @ 4000 rpm's.

HP measures heat/work.

Not heat. Work. 33,000 pounds per minute. Heat may or may not be a by product of the work, but has no direct correlation to HP.

 

[grenadeshark]

Yes, you can use torque to figure out horsepower, but if you have the hp, why mention the torque at all?
My point isn't that torque cannot be used, but rather since we have the hp figures, we don't need the torque readings.
Even at low idles engine run 10 strokes a second, so "torque" as people know it is useless.
Tell someone your engine makes 600lb-ft of torque, and they'll probably think it's fast, but what they don't know is 600 lb-ft @ 1800 rpm is only 206 hp. Still impressive for low-rpm grunt, and useful for towing, it's no faster than 206 hp @ 4000 rpm's.

Not heat. Work. 33,000 pounds per minute. Heat may or may not be a by product of the work, but has no direct correlation to HP.

See my last post and answer it. Then you will see

 

[CSLACR]

A car making 300 hp @ 7000 rpms

The same car making 300 hp @ 8000 rpms.

Does this car pull the exact same amount (just as hard)at both 7000 and 8000 rpms?

Yes it does.

 

[grenadeshark]

Yes it does.

Redo your math

Here is a simple test. Get in the game, find a car with a flat power curve. Shift into 4th or a higher gear. Why does the car seem to take longer to accelerate the closer it gets to the redline? Again, the answer is why TORQUE matters. Granted, find a slower car so wind resistance/tire resistance isn't a large factor.

 

[AssassinTuner]

Well the idea is people use TQ multiplied by the transmission gear ratio.
HP doesn't change much over a given high RPM range, but torque does.

Lets do some math.

A car making 300 hp @ 7000 rpms

The same car making 300 hp @ 8000 rpms.

Does this car pull the exact same amount (just as hard)at both 7000 and 8000 rpms?

Bro your at a wall if your talking shift points, even gears really. Hp is more important to what we are doing. The power curve that's most important is the hp power curve.

The tq is important, but shown put to work at a given rpm, that is what hp is.

This is one of the reasons I don't need peak tq to make my calculations, but benifit from using peak hp

 

[grenadeshark]

Bro your at a wall if your talking shift points, even gears really. Hp is more important to what we are doing. The power curve that's most important is the hp power curve.

The tq is important, but shown put to work at a given rpm, that is what hp is.

This is one of the reasons I don't need peak tq to make my calculations, but benifit from using peak hp

My point has always been that we are measuring TQ output to begin with. Does a car accelerate hardest at its TQ peak or its HP peak?

Its' TQ peak. The reason we continue accelerating past the TQ peak is because of the effects of gearing. That is all. The higher RPM we get, the less TQ the engine creates. But, the effects of gearing counteract this to create continued acceleration at the wheels.

We shift when the TQ output in the next gear is higher then the TQ output in the previous gear. It's that simple.

The basic reason for the multi speed gearbox is to more efficiently use the available torque to accelerate the vehicle - Carroll Smith

HP is a calculation that makes it easy to understand the general performance of a vehicle. TQ is what you actually measure.

Referring to the previous example:
Car making 300 @ 7000 = 225 TQ
Car making 300 @ 8000 = 197 TQ

The car pulls harder at 7000 rpms then it does 8000, BUT physics tells us it can pull no harder then it currently is at 8000 rpms and therefore you should continue along the rpm range if possible.

 

[CSLACR]

My point has always been that we are measuring TQ output to begin with. Does a car accelerate hardest at its TQ peak or its HP peak?

Its' TQ peak. The reason we continue accelerating past the TQ peak is because of the effects of gearing. That is all. The higher RPM we get, the less TQ the engine creates. But, the effects of gearing counteract this to create continued acceleration at the wheels.

We shift when the TQ output in the next gear is higher then the TQ output in the previous gear. It's that simple.

HP is a calculation that makes it easy to understand the general performance of a vehicle. TQ is what you actually measure.

This entire post is incorrect.
Especially the bold part.

You clearly do not understand what horsepower is.
Read my links.

 

[grenadeshark]

This entire post is incorrect.
Especially the bold part.

You clearly do not understand what horsepower is.
Read my links.

I am sorry. A car does accelerate hardest at the point where the TQ output * gearing is the greatest.

It doesn't mean you should shift at the TQ peak. You have no links, but please do explain what you mean.

 

[AssassinTuner]

My point has always been that we are measuring TQ output to begin with. Does a car accelerate hardest at its TQ peak or its HP peak?

Its' TQ peak. The reason we continue accelerating past the TQ peak is because of the effects of gearing. That is all. The higher RPM we get, the less TQ the engine creates. But, the effects of gearing counteract this to create continued acceleration at the wheels.

We shift when the TQ output in the next gear is higher then the TQ output in the previous gear. It's that simple.

HP is a calculation that makes it easy to understand the general performance of a vehicle. TQ is what you actually measure.

Referring to the previous example:
Car making 300 @ 7000 = 225 TQ
Car making 300 @ 8000 = 197 TQ

The car pulls harder at 7000 rpms then it does 8000, BUT physics tells us it can pull no harder then it currently is at 8000 rpms and therefore you should continue along the rpm range if possible.

Wrong!!!!!

It will accelerate faster at it's hp peak it will tow a larger load at peak tq

I've never drove a car that accelerated slower as it revved higher..


Give you an example. (imaginary car and specs)

Your cruising on the highway at 75mph in 5th gear running at 3000rpm. your car makes peak tq at 3000rpm and peak hp at 6500rpm.

You want to pass a Truck in front of you.

Are you going to

A) hit the gas as your at peak tq?

B) up shift to get to a lower rpm and have more of your tq power curve to work with, and then hit the gas?

C) down shift getting you higher in the rpm's & into the hp power curve, and then hit the gas?

 

[grenadeshark]

Wrong!!!!!

It will accelerate faster at it's hp peak it will tow a larger load at peak tq

I've never drove a car that accelerated slower as it revved higher..


Give you an example. (imaginary car and specs)

Your cruising on the highway at 75mph in 5th gear running at 3000rpm. your car makes peak tq at 3000rpm and peak hp at 6500rpm.

You want to pass a Truck in front of you.

Are you going to

A) hit the gas as your at peak tq

B) up shift to get to a lower rpm and have more of your tq power curve to work with

C) down shift getting you higher in the rpm's & into the hp power curve

?

You guys are seriously not even reading what I wrote...

ITS THE EFFECTS OF GEARING THAT ALLOWS A CAR TO CONTINUE TO ACCELERATE PAST THE TQ PEAK.

To answer your question. You are going to do whatever makes the TQ output to the wheels the greatest.

Remember that torque is just a measure of force delivered in a twisting motion. The key word is FORCE -- don't be thrown off by the fact that it's twisting. The important thing to remember is that force is what determines acceleration. Work is the use of this force across a distance. Power is a measure of how quickly this work is done. So once you realize that, horsepower is just a unit of power: it's basically how effectively you can apply the torque of the engine.

Take an engine with no gears. Allow it to accelerate up to its maximum RPM. Measure the amount of torque produced, then measure it again at the TQ peak. Once we add gearing, it makes sense to continue to move up into the RPM band. But without gearing an engine would produce the most acceleration at its TQ peak.

 

[CSLACR]

I am sorry. A car does accelerate hardest at the point where the TQ output * gearing is the greatest.

It doesn't mean you should shift at the TQ peak. You have no links, but please do explain what you mean.

http://www.howstuffworks.com/question622.htm
http://www.howstuffworks.com/horsepower.htm

No, torque output is not actually multiplied by gearing, I thought you said this yourself.
Horsepower is torque per second, essentially.
Torque has to be multiplied by engine rpm's to understand what your driving force at the wheels is. HP, is the driving force at the wheels.

Horsepower = Driving force at the wheels.
Torque = The power of one engine stroke.

No engine runs at 1 stroke per minute, so torque is never the formula that makes you go fast, it's the combination of torque and revolutions that make engines powerful.
The combination of torque and engine revolutions is called... horsepower.

it will tow a larger load at peak tq

Not true either. As per reasons above.

Take an engine with no gears. Allow it to accelerate up to its maximum RPM. Measure the amount of torque produced, then measure it again at the TQ peak. Once we add gearing, it makes sense to continue to move up into the RPM band. But without gearing an engine would produce the most acceleration at its TQ peak.

No. Peak horsepower.

 

[grenadeshark]

No, torque output is not actually multiplied by gearing, I thought you said this yourself.
Horsepower is torque per second, essentially.
Torque has to be multiplied by engine rpm's to understand what your driving force at the wheels is. HP, is the driving force at the wheels.

Horsepower = Driving force at the wheels.
Torque = The power of one engine stroke.

No engine runs at 1 stroke per minute, so torque is never the formula that makes you go fast, it's the combination of torque and revolutions that make engines powerful.
The combination of torque and engine revolutions is called... horsepower.

I am going to post this again. To answer your question about TQ, we already went over this. Gearing reduces load on an engine which allows it to do put more FORCE down to the ground which in turn increases acceleration. The way we calculate this mathematically is by multiplying the TQ created by the gear ratio minus drive train losses.

Remember that torque is just a measure of force delivered in a twisting motion. The key word is FORCE -- don't be thrown off by the fact that it's twisting. The important thing to remember is that force is what determines acceleration. Work is the use of this force across a distance. Power is a measure of how quickly this work is done. So once you realize that, horsepower is just a unit of power: it's basically how effectively you can apply the torque of the engine.

No. Peak horsepower.

The reason why your logic does not work here is just because the engine is spinning faster does not mean it is able to produce the same amount of force. That's why we have HP calculations. An engine with no gearing produces the most FORCE at its TQ peak.
If we were to put a load on the engine at the TQ peak and the RPM peak, we would find out that the engine will spin fastest at its TQ peak, not its HP peak. This is because the load will slow the engine down. It's only when the load is small enough to not be noticed by the engine that continuing accelerating past the TQ peak is beneficial. I have covered this extensively and it is why we use gearing.

Gearing reduces load on the engine which allows it to continue to accelerate past its TQ peak and still carry the weight of the vehicle.