Stock tune: when to shift?

[ElAviator72]

When should I shift for max acceleration effort from a dead stop?

The Ecoboost seems to be happy to sail all the way to redline, but I know that with a stock tune, the torque and HP curve tails off at 5000 RPM.

I've tried shifting at 5 grand, but it feels like I'm short changing the engine and not getting all she can give. I'm coming out of a car that made power to almost the redline...;)

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[Sterling Archer]

 

[OppoLock]

When should I shift for max acceleration effort from a dead stop?

The Ecoboost seems to be happy to sail all the way to redline, but I know that with a stock tune, the torque and HP curve tails off at 5000 RPM.

I've tried shifting at 5 grand, but it feels like I'm short changing the engine and not getting all she can give. I'm coming out of a car that made power to almost the redline...;)

The powerband is one factor, but you have to take gearing and torque multiplication into effect as well. Even though the power in the EB drops off around 5k, that doesn't mean that you should shift that early. Rudimentarily speaking, say you're in a lower gear making X output. Even if you could be in a higher gear making Y power, (let's just say it's at a higher point given a power curve), it might not be beneficial given the overall power being sent to the wheels after you factor in the gear ratio's multiplication. And you also have to think about what happens when you short shift; your short shift could put you in a less-than-optimal portion of the power band.

Someone here with more expertise could probably give you concrete numbers using a program that includes a graph, the transmission's gearing, and a final drive.

 

[DB23]

The dynos will tell U that stock it really falls off around 5500-5700 rpm so shifting right b4 you fall off that cliff at latest is generally the way to go to stay in the power band.

 

[PRG3k]

What about 1st gear? Shouldn't you just ride that fucker out?

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[EcoSwag1990]

When the dash lights up red

 

[Herr_Poopschitz]

Using a dyno plot and knowing what the rpm drops to on the upshift will tell you. You want to find the points that allow the most area under the curve.

 

[phunk]

Generally you always shift at redline. In most performance cars, even at the peak of your powerband the next gear up will not be able to overcome the torque multiplication and over power the gear below it... Unless your torque falls off really steep.

This is a popular graph floating around the internet that demonstrates the torque multiplication for each gear with 3 different final drives in a Honda/Acura. Notice at no point in the recorded powerband does a higher gear overcome a gear below it. You can make a graph the same as this using your gear ratios and dyno graph and verify for your personal vehicle.

 

[JohnDoe]

Whenever you short shift, you're going to be at a lower rpm on the next gear, so try to keep that in consideration. How low in the powerband do you want to be in the next gear?

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