[Javier]

those 1/4 mile times are spot on. i did 14.7 in my 328i and 13.5 in my 335i
damn close

[Oulixes]

A very good model, thanks, dougman.

[egtlover74]

What about 335is ? I would love to see the power chart on that.

[Kevin Harney]

I am all for the 335i, JB3, Proceed, 335is, 335d comparison!!! Love to see that. Maybe throw in an M3 for good measure !

[Spoolin335]

Very interesting!

[328skidpad]

thanks man,
I have been a honda and bmw forum member for over 10 years. Posts like this explain why I i come here every day and go to the honda forum once every few months.

Thanks for sharing the knowledge...

An education is the only thing in life that can not be taken away from you.

[pscmj84]

Not sure if anybody has ever heard of Car Test software before, but it is a pretty neat piece of software that lets input all the car's parameters and calculates the acceleration times. You can even line up different cars for a drag race where it shows the G forces and speed of each car as it accelerates down the track. It has a lot of options for customization to allow you to make your results more accurate (tire grip, shift times, etc.). I've only messed with the DOS version, which is available below. I used to run it in Windows XP just fine, but I haven't tried running it in Windows 7 yet. They also have a version made for Windows that might work better, but I think you have to order it from their website.

http://www.cartestsoftware.com/cartest4.5/index.html

[driverman]

Originally Posted by dougman

What makes the car accelerate is wheel torque. When you shift up, you move to a different (higher) part of the torque curve, but you ALSO change the ratio between engine torque and wheel torque. Only when the first effect is greater than the second should you shift before redline.

Great posts dougman. Thanks.

Most enthusiasts don't understand that the best shift points for maximum acceleration are determined by engine torque curves AND tranny gearing.

For example, during a performance run, when we shift from 1st to 2nd, we are past the torque peak of the engine. Therefore, when we hit 2nd gear, we usually get more torque out of the engine. BUT, we are also in a higher gear and we lose the torque multiplying effect of lower gearing.

Therefore, we don't want to shift until the gain in engine torque from dropping back into the engine's powerband exceeds the loss in gearing advantage from the upshift OR we hit redline. In most gasoline powered cars, this occurs at redline. If people are interested, I'll provide an in-depth example.

I've done a survey on this and most enthusiasts think you should shift at max torque or max HP because they don't account for tranny gearing.

[DESI4life10]

Awesome job.

Very informative indeed :-)

Thanks for posting.

[Hisam135i]

quite interesting, thanks for taking the time to run all these tests pretty damn accurate results as well

[TommyK]

wow thats really well done thanks for taking the time