Short Shifting a Deisel?

[LukeR94]

In my Audi A3 TDI, it seems faster if I shortshift 1st a lot, shifting at 2.5k (as 1st is incredibly short) and then short shift the rest of the gears also, shifting at say, 3.8k (instead of 5k(rev limiter)

I know its a deisel blah blah, im just curious, is it genuinly faster or is it just the wave of torque that makes it seem faster as the torque drops off after about 4k?

would be fastest to keep it in the power band (revs at which peak torque is produced and when it drops off)?

im no drag racer or anything just curious?

[LukeR94]

bump

[Chris Hinds]

Peak power in the latest A3 TDIs is at 3600-4000 rpm hence you are shifting up at peak power. Going beyond doesn't really gain you much as the higher gear drops the engine to only around peak power with a declining power band whereas shifting up at around or just above peak drops you to where the power band is rising still.

[LukeR94]

Chris Hinds said:

Peak power in the latest A3 TDIs is at 3600-4000 rpm hence you are shifting up at peak power. Going beyond doesn't really gain you much as the higher gear drops the engine to only around peak power with a declining power band whereas shifting up at around or just above peak drops you to where the power band is rising still.

Thanks!

exactly what I was looking for!

[Z.B]

Look up some power curve graphs. For max progress you want to be as high on the power curve as possible. Change at whatever point a lower gear would produce more power (forget about torque for this). Usually this means a few hundred rpm past peak power depending on gear spacing. So assuming peak power comes at 4000rpm I would expect to change at 4000-4500rpm. However a tdi will be close to max power by c3000rpm so doing what you suggest will be only slightly slower.