Quote from AndRand :

So how much longitunal force curve from replay analyser is different than torque curve?

Not a great deal. The shape of the slip force curve shouldn't make too much difference, but softer braking stiffness will increase the torque robbed by the wheel inertia. I do my testing with maximum tyre pressures to help minimise this effect (not actually tested how much it helps though).

On the whole I think the curves are certainly accurate enough for just about any purpose.

Quote from Bogey Jammer :

Problem: the common memory hacking softwares can't log the desired values continuously, so a specific tool must be developed. For my case, I want to do it but I have skills with the Python language only, and I don't think it is memory reading capable.

It is possible, I'm creating it now.

of course it is, and how is it going?

btw. I just made it in half an hour: revs vs. longitudinal tyre force thus to get absolute numbers you got to determine it using tyre radius. But I think it was more important to see it in revs function which you can see clearly. cheers it can be bit distorted by corner steep - I made it at KyotoRing and didnt always manage to go horizontally in turns.

For your project I think it is easier to substract air drag, but it also can be done thru memory scan.

Andrand, check Bob Smith's achievements on this kind of method, you seem to not take in account some parameters mentioned by Bob, turbo lag for example.
About my theoretical method, I grab the actual pure engine torque value, I don't need to post-process it. My current task is to write a program to plot it, and it would be more difficult than expected.

main problem with my chart it takes into account air drag. So the graph for the 1st gear is the most liable. I dont know what do you mean with "turbo lag"? I think you make torque chart to show it.

What I think is that torque chart has some purposes - main purpose is to determine max points to get gearing right and to know the best range of use.

Keep us posted Bogey Jammer, this is really interesting

@AndRand: Check this topic, full of good words
The turbo lag delays the maximum theoretical available torque when you accelerate. The boost is not instant because the turbocharger has roll inertia and needs time to spool up (to around 300 000rpm depending of the device size). Twin-turbo layouts are designed to reduce this phenomenon by using two small turbochargers instead of a heavy lonely one.

You must not try to remove the aero drag force from your chart because it does not affect the tire longitudinal force value. This is actually the force developed by the tire surface on the ground against everything else, including aero drag. BUT you have to filter the tire resistance, which depends on pressure, car static weight and weight transfert, wear on the road surface, deformation constraints, AND AERO LIFT FORCE which pushes the car (or pull for street cars) on its tires depending on the speed, thus changing tire deformation.

Why don't the devs release those graphs ? Even NFS show that ~ ~ ~

Isn't it awful if you drive a XRR and when you ask the pitcrew for torque/power curve they say "No such info."

First test with the UF1000:



:wtf2: the curve is not perfect, what a disappointment :melting:

My magic torque value is influenced by longitudinal acceleration. When I apply or release brakes, or initialize a turn, the value is altered. Note that the throttle is always full opened when a new point (green dot) is created. I modulate engine revs with brake action.

It stills surprise me, LFS may have quite complex formula to compute the torque at engine output. I'm still investigating it but tbh I don't have an explanation to this yet.

Quote from Bogey Jammer :

@AndRand: Check this topic, full of good words
The turbo lag delays the maximum theoretical available torque when you accelerate. The boost is not instant because the turbocharger has roll inertia and needs time to spool up (to around 300 000rpm depending of the device size). Twin-turbo layouts are designed to reduce this phenomenon by using two small turbochargers instead of a heavy lonely one.

I got a car with TT but one for one side of V6

A twin-turbo? which one?

About the torque curve glitch I think it is affected by engine's moment of inertia. Torque output is lower when accelerating and higher when decelerating. See how LFS physics are detailed! I wonder how far the devs modeled the engines.
The evidence of this phenomenon can help to setup gear spacing, but I now doubt that real life dynometers make accurate measurements, more than engine they must take the moment of inertia of transmission and wheels as well.

Concerning my program I'll add a longitudinal acceleration filter, then my curves should be good.

Here is the XRT dynochart shape:



Longitudinal acceleration filter helped a lot, but maintaining the car at 0±0.01G to log valid points is hard and measurement takes several minutes.

On the pic you can notice that the turbo boost can't be maintained at full below a critical engine angular speed, and produces cloudy curve below it.

well, it is much different from my charts of longitudinal tyre force. XRT has a peak point at 1st gear arond 5800rpm. You didnt show the values but it looks much different What is intriguing me in my charts is why the torque is suddenly going lalmost ineary down on higher gears - aero drag?

My values are attached in the rar file above. I had ≈338 N.m at rpm peak ≈4000rpm. Garage shows 345N.m @3896rpm, not bad but more measurement accuracy would be great.

andrand I said that aero drag is not involved in the shapes in your charts, and the curves are not scaled to show engine torque output.
Moreover as mentioned many time before, you are obviously affected by turbo lag and moment of inertia, that's why you've got delayed peaks especially at lower gears. The force peak at 5800rpm for the XRT means that there's indeed a big problem. Please read and understand what was already said about this method, give this aero drag shit up.

Well, when I compare my charts with [post=324280]those made by BobSmith[/post] I can say they are pretty similar or by wheel4hummer . The results sampled at the wheel and with turbolag you have to deal with racing and I dont know why you have to filter this out.

An optimal known torque curve is ideal to setup gear spacing quickly. I agree you have to deal with turbo lag and moment of inertia while racing but predicting these parameters requires engineer skills and lot of data of the car and engine design. I think I already look like a geek about all of this, most people don't need it to enjoy the game. Work with a filtered torque curve is a lot easier than with turbo lag and inertia, I wonder how you will succeed with this mess.