i suck at making titles that make people wanna read my stuff

[bimmertech]

here is a little tech for ya, not 5.0 so i posted it here in talk. friday at work i was helping my buddy diagnose an engine noise on an 04 545i. in the process i lifted the oil fill cap and the engine died. i asked why this happend and nobody knew, so i got to looking into the technical data that is available to me from bmw.

i already knew the engine in question was equipped with variable cam timing, variable valve lift, and infinetly variable intake runners.
the interesting thing i found while searching for the reason was this engine COULD actually run with no intake manifold or any other type of throttle blade substituted.

the reason behind this is the varaible valve lift. i cannot direct the link to the bmw site for legal reasons, but i did find this site which some might find interesting.

http://bmwworld.com/technology/valvetronic.htm

so the reason why the engine died(instantly) when i pulled the oil fill cap was the sudden change in vacuum. the intake manifold is filled with a very large amount of vacuum due to the small amount of valve lift at idle.

 

[DFG 5OH]

intresting...

 

[Blackened302]

ahh, yes, interesting

 

[MysteryMachine]

gotta watch taking them caps off while running i did that on my aunts car one time after changing the oil and oil flew out into my eyes. BMW's might be made different but I learned never to do that again

 

[DARK-5.0]

Damn, thats crazy. I knew they had all the variables but thats sweet that with everything being variable, the engine can run without anykind of throttle blade. Haha

Jeremy

 

[bimmertech]

Damn, thats crazy. I knew they had all the variables but thats sweet that with everything being variable, the engine can run without anykind of throttle blade. Haha

Jeremy

just wait till you work on an n73tu. that's the v12(760) with vanos, valvetronic and direct injection. talk about crazy. it has a magnesium upper intake that you have to replace if you scratch it.

they still have a throttle body, but it is always open unless there is a fault with the vanos, valvetronic, or diezza(intake manifold).

it really makes you second guess the arguments you here about throttle body size.

 

[DARK-5.0]

Yea exactly. I knew there was an end to the tb size when I was over on turbomustangs and theres multiple guys running 9's with the stock tb. Oh well. I knew the 760 motor was rediculous to work on. BTW, I'm coming up in the morning to drop off my grandmas 323i. So I'll see ya.

Jeremy

 

[bimmertech]

I knew the 760 motor was rediculous to work on.

for some reason i am the only guy on the blue team that "gets" to do the non return valve recall. the second one i did i had an injector hold-down bridge break on me, not my fault-just crappy metal. anyways the car sat on my lift for 5 days while they got a new one "express" delivered from germany. i eff'n hate those cars.

 

[DARK-5.0]

Thats too bad, makes me wanna start working right now.............Anyways, we can talk in the morning.

Jeremy

 

[urban96]

crazy technology