Engine design, rev limiter, free revving..

I am planning to ED a 530iA soon. This will be my first BMW. I have a set of questions

1) BMW Engine/transmission design really intrigues me and I want to know a lot more about it. Please point me to some good sources (preferably meant for dummies so that content is easy to understand) where I can find detailed information on topics like direct injection, forced induction, engine management maps, automatic transmission science, turbo charging, super charging, torque vs HP concerns etc. The information on bmwusa.com and bmwworld.com are good starting points which I have already read and I want to know more.

2) It is said that BMW I6 engines are free revving. In my test drives I have felt what it means, you just floor and the engine revs without hesistation. But what causes an engine to be free revving? Why isn't some other engine like a Ford free revving?

3) What is the rev limit on a 530iA? Is it dependent on the gear you are in?

4) In Steptronic with manual mode, why doesn't the engine just upshift when you have hit the rev limit?

5) How much is the breakin RPM on a 530iA? I have heard some people say 4K while others have said 5.5K. What is the maximum speed you can attain at such RPMs? I am thinking of reaching close to that speed on the autobahn during ED.

6) What needs to be 'broken-in' in an engine? Engine is mostly metal and oil, so it should be set to perform to the fullest from day 1? Am I missing something basic here?

Awaiting replies..

1) www.howstuffworks.com www.google.com

2) the engine has double VANOS and 4 valves per cylinder, this causes the engine to breathe easier than a fixed timing/valve lift 3 valve per cynilder (example) ford engine

3) 7000 (probably?)

4) because youre in manual mode and you have control. bouncing off revlimit wont break the engine

5) just drive it normal

6) just like brake pads and rotors, the surfaces on the piston rings must mate to the cylinder walls. there are different theories on breakin in procedure, i tend to follow the "drive it normal w/ few spurts to 5k" theory

Abe

Originally Posted by Suraj

I am planning to ED a 530iA soon. This will be my first BMW.

Congrats! You will love it and the trip!

Originally Posted by Suraj

3) What is the rev limit on a 530iA? Is it dependent on the gear you are in?

6800 RPM I believe...maybe 7200. The rev limit is the rev limit...doesn't matter what gear you are in...it doesn't change dependent upon the gear in the tranny.

Originally Posted by Suraj

5) How much is the breakin RPM on a 530iA? I have heard some people say 4K while others have said 5.5K. What is the maximum speed you can attain at such RPMs? I am thinking of reaching close to that speed on the autobahn during ED.

To be sure, ask when you pick up the car and check the manual but it usually is 4500 RPM that you should not go past (speed is irrelevent, it is RPM that you should watch). That kind of room will allow you easily to get past 100 mph in 6th gear.

What's breakin RPM???

Originally Posted by Suraj

4) In Steptronic with manual mode, why doesn't the engine just upshift when you have hit the rev limit?

Step will do exactly that if you put it in drive sport (DS) mode. Floor it an hold on!!

I've never tried putting it in M(anual) mode and flooring it without shifting - but I think if you don't shift, the computer puts the car in DS mode automatically and shifts accordly.

Again...I could be wrong since I haven't tried that. (nor do I really want to )

Originally Posted by Nickmitbm

What's breakin RPM???

4500

Originally Posted by Suraj

1) BMW Engine/transmission design really intrigues me and I want to know a lot more about it. Please point me to some good sources (preferably meant for dummies so that content is easy to understand) where I can find detailed information on topics like direct injection, forced induction, engine management maps, automatic transmission science, turbo charging, super charging, torque vs HP concerns etc. The information on bmwusa.com and bmwworld.com are good starting points which I have already read and I want to know more.

What you're asking for is a more advanced understanding of engine design, but to get that you have to understand the basics first. Somebody mentioned www.howstuffworks.com which is a good source, but also check out AutoZine Technical School. That should keep you busy for awhile. If you want to tinker and see how changing different parameters can affect vehicle performance, try out www.cartestsoftware.com/ There are also a ton of good links to read up on at the Stealth316 Tech Index. Beyond that, I could recommend some good automotive / engine engineering textbooks, but they're rather pricey and would be tough to find used (ebay).

Originally Posted by Suraj

2) It is said that BMW I6 engines are free revving. In my test drives I have felt what it means, you just floor and the engine revs without hesistation. But what causes an engine to be free revving? Why isn't some other engine like a Ford free revving?

- short and aggressive gearing with prompt downshifts (auto)
- lightweight flywheel (manual)
- low inertia drivetrain with weight optimized components.
- vibration free operation (inherent in the Inline-6 configuration) and low NVH
- good top-end power (4 valve per cylinder engines have the advantage, but 3 and 2 valve engines can have great top-end also)