When to shift for maximum acceleration ?

[cyberbrutus]

I always shift between 5000-5500 in S mode and am wondering if there is a secret shift recipe for maximum acceleration.
Should I shift at different RPMs in different gears ? Does chipping/HFC/Intake change anything ?
I know there are a couple of race car drivers in the forum and was wondering if they can shed light on this topic.
I have 8 speed tiptronic with padel shifters.

[MilesM]

Doesn't mean I'm going to know the optimal RPM to shift at for every car, because every car is different.. Lol.

That said, I've found that with my 6 speed Tip it grabs gears around mid 5000's to just under 6000 when launching. Under normal acceleration it runs to redline before it shifts, not sure if my tune and other mods have raised the redline.

[v1nyd]

Well every engine mod you do depending on what it is will definitely effect the car on a dyno...and on a dyno is where you'd be able to see where your car is performing at RPM wise. But in reality for a 8 speed automatic it's not going to matter much to you unless you're racing this thing down a 1/4 mile.

[cyberbrutus]

Doesn't mean I'm going to know the optimal RPM to shift at for every car, because every car is different.. Lol.

Lol...I knew you would respond..

How do you calculate in a race car situation? Dyno or any other tools ?

[cyberbrutus]

Well every engine mod you do depending on what it is will definitely effect the car on a dyno...and on a dyno is where you'd be able to see where your car is performing at RPM wise. But in reality for a 8 speed automatic it's not going to matter much to you unless you're racing this thing down a 1/4 mile.

My coworker has the 8 speed too..I want to win just in case we decide to race.
Thats the reason why I wanted to know the ideal shift RPM.

[v1nyd]

My coworker has the 8 speed too..I want to win just in case we decide to race.
Thats the reason why I wanted to know the ideal shift RPM.

gotcha, in that case bragging rights is well justified.

[B8_Jim]

You'd have to do some math for the 8speed, but ...

http://www.audizine.com/forum/showth...-with-APR-tune

[cyberbrutus]

You'd have to do some math for the 8speed, but ...

http://www.audizine.com/forum/showth...-with-APR-tune

Thanks Jim. I will post my findings.

[ljnaum26]

Its weird, sometimes i feel like my car pulls harder in D than sport. Anybody ever notice this?

[cyberbrutus]

My car pulls hard only in S mode. But if I let the car shift, the results vary every time. Thats why I take over manually and shift it.
Btw, I dont know if you guys know this but APR Valet mode is not fool proof on cars with padels. You can run the RPMS higher than 4000 if you shift manually.

[MilesM]

Lol...I knew you would respond..

How do you calculate in a race car situation? Dyno or any other tools ?

Instinct, Sound, Feel. There are shift lights, but those are just references.

[fredjones]

Shift preference has changed in my car as my mods have changed. With stage 1 I rarely like to go above 4000rpm before I shifted. With the stage 2 I find myself keeping it in a gear up to 5000rpm because the boost just keeps pulling. I also have found the stock tiptronic transmission program does not know the ideal shift points to use with the stage 2 and a lot of times I will use manual mode to get it to shift just where I want. Too bad the transmission can't be reprogrammed too.

[B8_Jim]

You'd have to do some math for the 8speed, but ...

http://www.audizine.com/forum/showth...-with-APR-tune

I got curious - the tighter gear ratios of the 8 speed changes things a bit, but not that much...

This is using the gear ratio info from http://models.audiusa.com/a4-sedan/d...#chassis_specs, and the Audi "idealized" torque curve so the real world will vary a bit...

[TheBigLebowski]

Get a stick and solve all of your problems.

[alk]

How will having a stick help you shift at the optimal shift point if you don't know what the optimal shift point is?

[Frings]

A little off topic but sorta on topic. Where's the rev limiter on the 2.0T?

[ultra]

lol@S-mode

[gunsmoker]

I got curious - the tighter gear ratios of the 8 speed changes things a bit, but not that much...

This is using the gear ratio info from http://models.audiusa.com/a4-sedan/d...#chassis_specs, and the Audi "idealized" torque curve so the real world will vary a bit...

I did such a plot some time ago using a closer approximation of the torque curve and the 6MT ratios. My conclusion was that 1-2 and 2-3 shifts were good at red line and for 3-4, 4-5, and 5-6 there was like 500 RPM before red line where the higher gear had more torque. In reality I start shifting to second at 5500 because otherwise there isn't enough time under hard acceleration to avoid getting the boot by the ECU. Haven't had the chance to get close to red-line in 4th yet.

[B8_Jim]

I did such a plot some time ago using a closer approximation of the torque curve and the 6MT ratios.

What did you use for a closer approximation ? From what I've seen it varies car to car and ambient conditions...