28i optimum gear changes for performance

[Avallon]

Apologies in advance for the complete newbie question but I've had my 28i for a bit now and I'm never quite sure whether to overtake cars when doing 50-60 mph in 3rd or 4th.

Is there a guide for optimum gear changes for performance (1-2, 2-3 etc.)?

[SO8]

What feels best ?
A 50mph overtake ... that will be 3rd then. Get it done asap and that way if on the wrong side of the road you are there for less time

[techathy]

If you really want to work out the numbers then start with this:
https://drive.google.com/file/d/0B8QVp_ ... sp=sharing

Download/copy to google drive & play. You'll need to find the gearing for your car & have an approximate power curve.

[Avallon]

thx

3rd at 50mph seems fastest initially but then the power seems to drop off - it's hard to say though as I don't tend to spend a lot of time overtaking

The spreadsheet looks quite scary!

[Ed Doe]

^the power won't be dropping off but the torque will which will mean it'll feel like it's not as punchy. It'll still be pulling hard up to the last few hundred rpm from the red line.

In general the lowest gear possible will give the best in-gear acceleration from any given speed.

[techathy]

thx

3rd at 50mph seems fastest initially but then the power seems to drop off - it's hard to say though as I don't tend to spend a lot of time overtaking

The spreadsheet looks quite scary!

It's not really. Fill in the white bits with accurate data (torque preferably at the wheels, gear ratios, tyre size & vehicle weight) & out pops speed & thrust for each gear. Plot it all on a graph & you can see what gear gives you the most acceleration at any speed. I took the graph out because google docs messed it up massively. Anyway you end up with something like this -

Say you're accelerating from 100km/h (62mph), you could be in second gear but you'd almost immediately need to change into 3rd so you'll be better off to drop down to 3rd

Looking at that graph I've got gearing & crank output for a Z4 35i w/DCT 'box.