[kot]

One of the major differences bw BMW-330i and 325i is the 3-stage intake manifold.
Does anyone know how the 3-stage manifold works?
Any informed opinion is welcome. Facts are even more welcome

KOT

[foofighter]

this may not answer all of it but found it on wikipedia

The Valvetronic system is the first variable valve timing system to offer continuously variable timing (on both intake and exhaust camshafts) along with continuously variable intake valve lift, from ~0 to 10mm, on the intake camshaft only. Valvetronic-equipped engines are unique in that they rely on the amount of valve lift to throttle the engine rather than a butterfly valve in the intake tract. In other words, in normal driving, the "gas pedal" controls the Valvetronic hardware rather than the throttle plate.[1]

First introduced by BMW on the 316ti compact in 2001, Valvetronic has since been added to many of BMW's engines. The Valvetronic system is coupled with BMW's proven double-VANOS, to further enhance both power and efficiency across the engine speed range. Valvetronic will not be coupled to BMW's N54, "High Precision Injection" (gasoline direct injection) technology due to lack of room in cylinder head.

Cylinder heads with Valvetronic use an extra set of rocker arms, called intermediate arms (lift scaler), positioned between the valve stem and the camshaft. These intermediate arms are able to pivot on a central point, by means of an extra, electronicly actuated camshaft. This movement alone, without any movement of the intake camshaft, can open or close the intake valves.

Because the intake valves now have the ability to move from fully closed to fully open positions, and everywhere in between, the primary means of engine load control is transferred from the throttle plate to the intake valvetrain. By eliminating the throttle plate's "bottleneck" in the intake track, pumping losses are reduced, fuel economy and responsiveness are improved.

It is important to note however, that the throttle plate is not removed, but rather defaults to a fully open position once the engine is running. The throttle will partially close when the engine is first started, to created the initial vacuum needed for certain engine functions, such as emissions control. Once the engine reaches operating speed, a vacuum pump run of the passenger side exhaust camshaft (on the N62 V8 only) provides a vacuum source, much as a diesel engine would, and the throttle plate once again goes to the fully open position.

The throttle plate also doubles as an emergency backup, should the Valvetronic system fail. In this case, the engine would enter a "limp home" program engine speed would once again be controlled by the throttle plate.

Valvetronic has so far been limited to BMW's mass-market engines, with no high-performance M-series car using the technology. The Valvetronic hardware adds a great deal of mass to the valvetrain, limiting maximum engine speeds (~7000rpm peak rpm in N52) and making it unsuitable for the high-revving M engines.

[ward]

there's 3 different lengths of intake runners possible

[Mackskibum]

I did some research on this topic- there appears to be two differences between the 325 and 330. One is the intake manifold, the other is the ECM programming. I went to www.realoem.com and looked at the following:

ECM- same part number
Injectors- same part number
engine wiring harness- same part number
intake manifold- different part number, core rquired.

My guess is that the intake manfold and reflash are all that is required, and the intake is much less than the upcharge to the 330, hence the core charge.

Waiting for Dinan.....

[kot]

Originally Posted by ward

there's 3 different lengths of intake runners possible

That I understand... what I want to understand is how does the engine power ( ) benefit from having these 3 different lengths of air intake pipe and what is the algorithm it's using .

[ward]

then you need to research how different intake runners effect engine power at different RPM's



certain RPM's produce better power with short runners, others make better power with long runners

[Xinlitik]

does it look like it would be possible to give a 325 the 330's power for less than the upgrade? I dont want the other stuff bundled w/ the 330, just the extra hp =/

[bavarian19]

I think its much more complicated than just the manifold and software. If it were that easy, I probably would have done this a long time ago...

[E90Boy]

Originally Posted by bavarian19

I think its much more complicated than just the manifold and software. If it were that easy, I probably would have done this a long time ago...

No one tried it yet so we don't know, why you try it?

[bavarian19]

Originally Posted by E90Boy

No one tried it yet so we don't know, why you try it?

No, but I highly doubt it would be that easy... Plus, what dealership would do the flash without charging you an arm and a leg, and then voiding your warranty...

[ward]

here we go again.......

c'mon guys.......