Hi guys it's my first post and it is about shifting

[kabanashvili]

I have a BMW E34 525i (M50B25) with manual transmission. and i was wondering in order to get maximum performance is it better to shift before the redline starts? (before 6,500 RPM) Thank you

[genphreak]

No worries!

Yes- but not by much.

The idea is to keep the engine in a range where it generates maximum power. An M50B25 doesn't generate as much power above 6,300 as it does at say, 4500- so you are best to shift before it drops off- and that is before redline on most engines- but it does depend on which gear you are shifting to: There are larger differences between the lower gears than the top ones (http://www.bokchoys.com/differential/GearRatios.htm).

Look at the power curve and see where the maximum power is created. If driving fast (rather than for economy) you need to work the gears to keep the engine in that range, knowing where it drops off is critical. I don't know, but maybe someone will have a link to a dyno test or something that will show you...

In mine, I just drive to what I feel is 6000 (I try not to watch the tacho under Wide Open Throttle). Your ears can tell you when the engine is up the top and when familiar with the car your other senses can tell you when the gs are going to be better in the next gear). That's when to change. Not sure if you get much by going past 6,300. On an M30 its worse- on larger road-going engines they like to generate power lower (and create better torque). It varies a little with a chip, and a lot with a bigger cam & tuned length extractors.

BTW, a hearty welcome to the oldest and best Bimmer board on the 'Net. It's kinda slow, a tad quiet, but we're focused and most of the luminaries are lurking around. Other boards are full of people in need of instant gratification and those that would be better off with a an Asian yoghurt carton and an F1 pit team instead of a global community from which to seek advice.

Your M50B25 is probably the best e34- good economy, great feel, perfect balance and if you need it to, it can move. They are also very reliable (IANAL, as with any car, (but more so with e a bimmer) it is best to fix things before they fail and cause a bigger problem. I've had one for a while now as my daily driver. Was going to part it and keep key bits for the Touring but its too much fun. So it stays on the road and has become a magnet for upgrades parts when we find them... It even has roof racks so we can bring big things home!

[whiskychaser]

It is a 20 year old car so redlining it isnt going to extend its life expectancy by much. IMHO, driving an E34 - or any other car- is all about empathy and feel. If it feels right, I see dont see why you cant run it up to the limiter. If you are asking for forgiveness in case you blow it up, you will get none from me

[632 Regal]

A test post with no intention of follow up... almost a spam. Such a generalized question too.

Critical thinking on this could get a person banned.