Question about HP/Torque and Shifting

[barak181]

Hey, all. So, while I'm not really a newbie to GTS, I do still pretty much consider myself a newbie to simracing. A lot of times I look at settings and I'm not really sure what I should take away from them. Like this. I'm signed with Renault Sport for the Manu Series. The Megane's not the fastest car in the world, so I'm looking to eek every bit of speed and acceleration I can out of it. Am I reading this right? To me, that graph says max horsepower and torque both happen before max RPMs and actually drop off quite dramatically at max RPMs. Should I be short shifting a little bit for max acceleration and power?

 

[fisheye]

Shift just before the rev limiter kicks in.

 

[VFOURMAX1]

Hey, all. So, while I'm not really a newbie to GTS, I do still pretty much consider myself a newbie to simracing. A lot of times I look at settings and I'm not really sure what I should take away from them. Like this. I'm signed with Renault Sport for the Manu Series. The Megane's not the fastest car in the world, so I'm looking to eek every bit of speed and acceleration I can out of it. Am I reading this right? To me, that graph says max horsepower and torque both happen before max RPMs and actually drop off quite dramatically at max RPMs. Should I be short shifting a little bit for max acceleration and power?

View attachment 881163 View attachment 881164

Torque seems to peak around 3500 rpms and really starts to drop off after about 5500 or so RPM's.
Looks like you have reached the Maximum HP at about 6800 RPM and anything past that the HP and torque are both declining so I would shift around the 6800 point as max rpm trying for maximum speed and if trying to fuel save probably about the 5500-5700 rpm range.

This is just my opinion looking at the graph, on track testing will give you the best results when things like aerodynamics are also in play.

 

[RussRobit]

Go to the garage and find the rpm at peak hp. Then go to the track and find the rpm drop between gears. To maximize hp usage you should land at the same hp in the higher gear as you had in the lower. Eg. If the rpm drop is 1000, envision a level line 1000rpm long and fit that line between the upslope and downslope of the hp curve. If the line slants down to the left, shift at max rpm else shift where the line meets the downslope. Look at the transmission graph, the rpm at the top left corresponds with the auto shift point. That's a good place to start.

 

[Vegard]

If you're running stock gears I would recommend shifting slightly past peak power which means 6550-6600 rpm.

 

[NJ72]

Torque seems to peak around 3500 rpms and really starts to drop off after about 5500 or so RPM's.
Looks like you have reached the Maximum HP at about 6800 RPM and anything past that the HP and torque are both declining so I would shift around the 6800 point as max rpm trying for maximum speed and if trying to fuel save probably about the 5500-5700 rpm range.

This is just my opinion looking at the graph, on track testing will give you the best results when things like aerodynamics are also in play.

This is not how it works in the real world as the wheel-torque is also a factor of the gearing - 99% of cars actually benefit from shifting at the limiter.

For a more in-depth explanation see here:



Also, based on the logic of 'max power is 6800, so shift then' - you would realistically want to shift at a point where you land back at the same point on the other side of the power curve, so essentially at about 7200 rpm so that when you land back down at about 6600 rpm you are at the same level of power, but on the way back up said curve.

Either way, the LAST thing you want to do is shift at peak torque unless that is EXACTLY at the limiter.

 

[fastone371]

From real world experience you want to run the engine well past peak HP to get maximum performance. HP really should not figure into the equation as much as it does because it is not a measured value, it is an equation based on torque and RPM's yet it plays a huge part in the performance of your car.

 

[Vegard]

From real world experience you want to run the engine well past peak HP to get maximum performance.

It all depends on the shape of the power curve and the spread of the gear ratios.
But for your typical road car with a peaky power curve and spread out gears it's a good rule of thumb.

 

[GTV0819]

Good thing this Gr. 4 Megane is not a CVT unlike some of them in real life.

 

[breeminator]

Also, based on the logic of 'max power is 6800, so shift then' - you would realistically want to shift at a point where you land back at the same point on the other side of the torque curve, so essentially at about 7200 rpm so that when you land back down at about 6600 rpm you are at the same level of torque, but on the way back up.

If you replace the word torque with power, that is correct. I think you meant power anyway, as peak torque is at 4000rpm in the graph in the OP, so your figures of 6600 and 7200rpm are based on the power curve, not the torque curve.

 

[NJ72]

Apologies, for the second part of the explanation I did indeed mean power, not torque. Good correction.

Point still stands, though. If you're shifting at peak power (or peak torque for that matter) you're not doing it right.