Some cars best to shift before redline?

[oohhh yeah]

For same cars...I noticed this last on the Mario Andretti's Hudson...it seems like power drops off at high revs. So, for some cars, what is the formula/way to calculate the best shifting spot/rpm?

 

[fifomaniak]

Go into car settings and see the graphs for power and torque figures. If they're dropping quickly from some revs, there is no point to rev the engine there, it's better to change gear. Check Alfa MiTo for example. 6000 rpm is peak I think, then it drops quickly.

 

[OK8]

Just like fifomaniak said, the power curves are where you'll find out when to shift. Too bad they aren't very accurate, it's difficult to tell exact revs, especially as they no longer list the max power and max torque RPM values like they used to in GT5.

I hope PD will give us the opportunity to view the power curves in more detail.

 

[Vegard]

Ideally you want a thrust curve.

Looking at the power curve and knowing where you "land" after a gear change can tell you what you need to know though. Remeber to take into consideration the actual gearing's effect on WHP.





You can also identify the cars that need an early upshift by looking at the speedometer and tachometer while accelerating in a straight line.

 

[oohhh yeah]

Ideally you want a thrust curve.

Looking at the power curve and knowing where you "land" after a gear change can tell you what you need to know though. Remeber to take into consideration the actual gearing's effect on WHP.

You can also identify the cars that need an early upshift by looking at the speedometer and tachometer while accelerating in a straight line

Can you elaborate on "gearing affecting WHP"?

I understand the answer to my question is the power graph, but I was wondering if there is a scientific formula if you want to accelerate as fast as possible, and not just by eyeballing/feeling when the car slows down.

 

[Vegard]

This only explains the difference.
To calculate it would involve drivetrain loss (no numbers available in GT6).

 

[Giygas]

A lot of the muscle cars benefit from shifting before redline, especially after tuning because the drop off is exaggerated with higher power.

The R18 TDI is accurately portrayed in GT6 as I believe I read somewhere that the drivers actually did shift somewhere around 5000 RPM when driving it, instead of the 7000 RPM redline.

 

[Malcolm Tucker]

The little red gear shift light comes on when the engine reaches peak power. For most cars that's quite near the redline anyway so that's usually the best time to shift up. I look at the power band graph to see how much it drops between peak power and the redline to decide when the best shift time is.

 

[Fuzzi0n]

I'd always recommend you check where the max power/torque are in the rev range in the garage, then look in the settings menu and see what the power/torque curve looks like. If it starts to drop off quickly after where max power is produce then you want to shift ~500rpm after that. For example, you have 500HP @ 7000RPM and it drops off really faster after that, shift around 7500RPM. Or you could have a car like my tuned M3 which produces max power right at the rev limiter, so you would just shift as late as you can.

 

[shirakawaa]

GT also somehow simulates the power wasted through transmission losses, and since the higher the rpm in any given gear, the higher the losses at the gearbox, the optimal shifting point often (not always!) is at or slightly below engine peak power rpm.

Proof: try making the engine power curve completely flat with the power limiter. Even though the power at the engine can be completely flat until redline, shifting at redline in such case will give you lower straight-line performance than shifting earlier.

 

[sik180sx]

Just like fifomaniak said, the power curves are where you'll find out when to shift. Too bad they aren't very accurate, it's difficult to tell exact revs, especially as they no longer list the max power and max torque RPM values like they used to in GT5.

I hope PD will give us the opportunity to view the power curves in more detail.

Max power and torque rpm is shown in the garage when looking at the vehicle you are currently driving.

 

[raytard]

Suzuka mini, stop before the line and do a pull to the first corner, coast through the course, and repeat, racing your ghost. You'll find your launch RPM and shift points through trial and error.

Every car has a prime spot. For some, it's on redline. For others, you may want to hold past redline (NSX winding to 9500 when redline is just over 8000 is an example). Of course, some want to shift early.

Like mentioned before, look at the torque/hp curves and where they fall off, early peaks means early shifts. You'll typically see it in motors with more low end torque (big displacement, diesels, etc).

 

[DBM]

Normally big NA cars will benefit from short shifting. where high rev turbo cars will not.
Also high rev turbo cars can benefit from closer ratio gears. where some of the more high torque cars, can get better times with only using 4 gears (depending on tuning and red-line position, buying all the mods can make a high torque engine, into a more of a rev friendly engine)

 

[shirakawaa]

By the way, keep in mind that optimal shifting points also depend on your gear ratios. The wider the difference between one gear and the next one, the higher the optimal shift rpm.

 

[oohhh yeah]

So there is really no formula except eyeballing the graph?

 

[z06fun]

The graph doesn't really give you all the info you need, so you have to eyeball it. Ideally, as the engine revs increase, if you can shift and get to an RPM that gives higher HP out of the engine, then you should shift. You want to be as close to the HP peak as possible all the time for best acceleration.

 

[GTP_CargoRatt]

The only real way to know is to take the car out on RouteX and experiment with different shift points and see which is quicker. I do it with every car I use for time trial events. Experimentation is the key, and there is no substitute.

 

[raytard]

oohhh yeah,

There are formulas, just look in the transmission tuning threads.

However, the best theory means nothing to reality. Even the best F1 teams still test and tweak based on what the driver's butt says, not the computers. What's faster on paper isn't always the same as on the track.

Use it is a guideline, a starting point, a reference, but not gospel. Even stuff that's "wrong", like a crazy long 1st gear, 2nd and 3rd way longer than average, and 4/5/6 being very close might be the fastest in a certain scenario (high hp RWD drag racing in the SS7 tunnel, for example)

 

[toni_cro]

sti's are prime example of this, most of sti's reach peak power around 6.500rpm but the redline is at 8k or there about
no reason to rev it so high, i shift around 7k in most sti's

 

[RSnider]

Go into car settings and see the graphs for power and torque figures. If they're dropping quickly from some revs, there is no point to rev the engine there, it's better to change gear. Check Alfa MiTo for example. 6000 rpm is peak I think, then it drops quickly.

Unfortunately, it isn't this simple. You must also keep in mind when you change up to a higher gear, you are effectively reducing the torque applied to the drive wheels (this is why cars accelerate faster in lower gears). So while shifting early can indeed keep the engine in the peak power band, if the torque reduction between gears is greater than the torque benefit from staying in the peak power band, you will be slower, bottom line.

Only in instances of severe power drop-off or ultra-close gear ratios is it advantageous to shift early.

 

[HuskyGT]

Sometimes you can feel it when driving and you get used to shifting at the best RPM's. The best example is when you equip the low RPM Turbo in some cars. Also in Muscle cars with big block V8's.

 

[Vic Reign93]

The two examples I use to show drastic power loss before redline are the Nismo 400R and Plymouth 440 Cuda.

 

[oppositelock]

So there is really no formula except eyeballing the graph?

In order to do this scientifically, you'd need a dyno number chart with readings in something like 100 rpm increments. Then you'd take the dyno numbers and transmission ratios, and create a spreadsheet which shows to total multiplied torque in each gear relative to speed. When the multiplied torque in one gear drops below the torque of the next gear, that's your shift point. However, since GT doesn't give us the detailed dyno info we require, yeah, we have to eyeball it.

 

[oohhh yeah]

In order to do this scientifically, you'd need a dyno number chart with readings in something like 100 rpm increments. Then you'd take the dyno numbers and transmission ratios, and create a spreadsheet which shows to total multiplied torque in each gear relative to speed. When the multiplied torque in one gear drops below the torque of the next gear, that's your shift point. However, since GT doesn't give us the detailed dyno info we require, yeah, we have to eyeball it.

Wouldn't you be looking at hp instead of torque? As that is what matters in straight line?

 

[oppositelock]

That's not how the math works in this case. Gears are torque multipliers, not horsepower multipliers. Here's an example:

This is your accelerative force at the wheels, basically what actually pushes you back in your seat in a real car. In the first two gears the engine hits redline before the torque line intersects the next gear, therefore we would shift at redline. In all following gears the lines intersects the lines for the next gear, and so we would short shift for maximum acceleration.

 

[RSnider]

Wouldn't you be looking at hp instead of torque? As that is what matters in straight line?

HP at the drive wheels at a given RPM is the same, regardless of gear position. However, the torque at the drive wheels at a given RPM is reduced as gear position is increased.

Power (in this sort of application) is defined as torque multiplied by an angular velocity. As vehicle speed increases, the wheels turn faster (ie - angular velocity increases). Selecting a higher gear reduces the torque supplied to the drive wheels, but at the same time allows the angular velocity of the wheels to increase; thus, at a given RPM, power stays the same while torque at the drive wheels reduces between each gear.

I'm tired and need sleep, so I hope my jumbled explanation makes sense to everyone else.