Perfect shifting

[Stiv]

Hi everyone,

There is a nice calculator at http://www.perfectshifting.com/

I always thought the perfect shift point (for max acceleration) in any gear is at max HP, around 6300 RPM.

This picture shows it a little bit different (it's made for Yaris TS 1.8 stock)

http://img62.imageshack.us/img62/6034/yaristsshiftingpoints.gif (http://img62.imageshack.us/i/yaristsshiftingpoints.gif/)

Any comments?

[tcpty]

Good to know!! you did it with a 5 Speed tranny, just like mine!

Today I'll have a drag race with an Advance :) so I'll do it below 6

[tcpty]

Can you post the numbers you used for the math?

Wow ! tried to use the calculator but the account was "suspended" :(

[Stiv]

Very interesting. Maybe they exceeded the bandwidth :)

Our car has C56 transmission http://en.wikipedia.org/wiki/Toyota_C_transmission#C56
If I'm not mistaken, it has max 173Nm at 4400rpm and max power of 133HP at 6000rpm.
Max rpm is about 6400.
And you have to draw torque curve at the third tab. Mine was aproximation, let's say 90% accurate.

[tcpty]

Thanks Stiv ! :)

[Stiv]

No problem mate :)
And if you look at the graph, and we know we have a bunch of torque at 2500rpm, you will see that the most economical way to drive (best mpg) is around 80kph in 5th gear ;)

[BuildCode]

I wish that site was working. I have used http://www.bgsoflex.com/shifter.html in the past for a previous car, but that site is also not working.

[tcpty]

No problem mate :)
And if you look at the graph, and we know we have a bunch of torque at 2500rpm, you will see that the most economical way to drive (best mpg) is around 80kph in 5th gear ;)

I appreciate that... :w00t:

but I appreciate more the "fun" :burnrubber:

Hahahaha

[tcpty]

I wish that site was working. I have used http://www.bgsoflex.com/shifter.html in the past for a previous car, but that site is also not working.

Is there any other "working" site with a calculator like that ? I've googled to no avail.. :iono:

[Stiv]

I just checked, both sites work fine :)

[Stiv]

Well, it seems I made a (big) mistake in torque diagram, it wasn't 90% accurate, more like 60% :bs:

This time it's way more accurate. Even front area is included.
The torque chart is derived from a stock dyno chart made found on this site.
This is no error with drivetrain loss. I put 0 because dyno test was performed on wheels, not the engine itself.

So here are my screenshoots:


http://img683.imageshack.us/img683/5122/39341987.png

http://img21.imageshack.us/img21/5519/52297358.png

http://img192.imageshack.us/img192/9868/99074360.png

http://img521.imageshack.us/img521/2244/58714516.png

http://img34.imageshack.us/img34/1779/37042968.png

[CASTREX]

Nice ! SO YOU HAVE TO RED LINE IT ON EVERY SINGLE GEAR...:evil:

THAT'S WHAT I DO EVERY TIME