Does the VANOS on these engines (S50/S52) turn on/off at a certain rpm or is it based on engine rpm and engine load? If it is based on rpm and load, are these discrete rpm and load values (on/off) or are there other variables involved (i.e. what gear the car is in, etc)?

I'm not an expert, but what I have heard is that it turns on based on RPM/Load, but then it shuts off at a specific RPM.

Under hard accelaration it comes on about 3800 and shuts off about 5100 or so.

to test the Vanos, high gear, low speed
throttle on, if the Vanos works, it starts every time at 2200U/min
with very noticable push


Igor

The Vanos doesn't really 'turn off/on', but anyway... At idle it's in the normal (retarted intake cam) position. Depending on H20 temp, load, throttle postion, etc., it will advance the intake cam at low RPM then return back to the normal position around 5k rpm.

What exactly are you trying figure out?

Alright i really no nothing about vanos. Any site or anything that can teach me more about it?

The Vanos doesn't really 'turn off/on', but anyway... At idle it's in the normal (retarted intake cam) position. Depending on H20 temp, load, throttle postion, etc., it will advance the intake cam at low RPM then return back to the normal position around 5k rpm.

What exactly are you trying figure out?
I am researching putting a standalone ECU on my car. I know several of them have the capability to control VANOS/VTEC type systems, and people have been successful doing so. But I wanted to have a better understanding of how the VANOS works so I can have a better understanding of how a standalone would control it.

post this in the FI forum, you will get a lot of answers there.

vanos is on/off at certain RPM's... depending on load, and on temperature.

what RPM and load to turn it on/off depends on the application.

vanos is on/off at certain RPM's... depending on load, and on temperature.

what RPM and load to turn it on/off depends on the application.
When you say application, do you mean NA vs FI? In my case it is for a NA application.

When you say application, do you mean NA vs FI? In my case it is for a NA application.

Yes. Even more indepth, what kind of FI matters a lot.

Does the VANOS on these engines (S50/S52) turn on/off at a certain rpm or is it based on engine rpm and engine load? If it is based on rpm and load, are these discrete rpm and load values (on/off) or are there other variables involved (i.e. what gear the car is in, etc)?

The DME will activate the vanos based on the demand from (you) the driver. Based on how much you press the throttle down, the DME will select the best map to make the power you request. If it needs to activate the VANOS to do that, it will.

http://www.bmwworld.com/technology/vanos.htm

VANOS operates on the intake camshaft in accordance with engine speed and accelerator pedal position. At the lower end of the engine-speed scale, the intake valves are opened later, which improves idling quality and smoothness. At moderate engine speeds, the intake valves open much earlier, which boosts torque and permits exhaust gas re-circulation inside the combustion chambers, reducing fuel consumption and exhaust emissions. Finally, at high engine speeds, intake valve opening is once again delayed, so that full power can be developed.

The Vanos doesn't really 'turn off/on', but anyway... At idle it's in the normal (retarted intake cam) position. Depending on H20 temp, load, throttle postion, etc., it will advance the intake cam at low RPM then return back to the normal position around 5k rpm.

What exactly are you trying figure out?


What's the best way to test VANOS function? Does it lose efficiency/functionality even in the absence of the "marbles in a tin can" sound or other audible problem?

My VANOS has been silent for 140k miles, but I'm curious if its still up to par in light of the mileage . . .

What's the best way to test VANOS function? Does it lose efficiency/functionality even in the absence of the "marbles in a tin can" sound or other audible problem?

Probably the easiest and quickest way to test it is to unplug the solenoid and see if you notice a loss of low end torque. If not then you may have a vanos problem. Obviously the most effective way would be to dyno it with and without the solenoid hooked up.

The 'marbles' noise doesn't automatically mean that the vanos is bad, so even if it's quiet, it could still be having problems. I've installed quite a few of the Dr. vanos kits now, and while every single car has seen a 100% improvement in the 'marble's rattle, only about half would see a 'big' improvement in low end power which tells me that the noise and the efficiency are not directly related.

OK, so now that I have a better understanding of how the VANOS works on the S50/S52 motors (I am assuming it is the same on both motors, but tell me if I am wrong), how effective do standalones control it?

OK, so now that I have a better understanding of how the VANOS works on the S50/S52 motors (I am assuming it is the same on both motors, but tell me if I am wrong), how effective do standalones control it?

Generally, not very well. Depends on the standalone and who's doing the tuning.

Matt, why do you say it does not work very well? Isnt it a simple on/off switch?

Dont you simply do a run with it retarded the entire time and then do a run where it is advanced all the time and then use the crossover points to tell you when to activate it?

Matt, why do you say it does not work very well? Isnt it a simple on/off switch?

Dont you simply do a run with it retarded the entire time and then do a run where it is advanced all the time and then use the crossover points to tell you when to activate it?

Yes, for a WOT map, but what about part throttle applications? It is not a simple on/off at 'x' RPM. Like I said in the other thread: an OBDI 413/506 DME has 5 different maps just for VANOS.

Why do you think MS has trouble running VANOS properly? The ECU matters. At very least you will need a AEM to do it right, but you are probably better off with a BOSCH Motorsport box or something of the like.

Turning it on and off is simple. Foolproof, even. Tuning the fuel and spark for the changes that result from turning it on and off is more difficult. The problem is that the same RPM/load point will have two different VE values for vanos being on or off. The stock ECU has two entire sets of tables for vanos being advanced vs retarded.

I believe you have the right idea regarding tuning.

Yes, for a WOT map, but what about part throttle applications? It is not a simple on/off at 'x' RPM. Like I said in the other thread: an OBDI 413/506 DME has 5 different maps just for VANOS.

:wave

Why do you think MS has trouble running VANOS properly? The ECU matters. At very least you will need a AEM to do it right, but you are probably better off with a BOSCH Motorsport box or something of the like.

I doubt anyone running MS on a vanos motor has enough data (dyno graphs) to even know they have a problem. They just turn it on at a certain RPM and off at a certain RPM and tune around the VE changes that way. :dunno

Turning it on and off is simple. Foolproof, even. Tuning the fuel and spark for the changes that result from turning it on and off is more difficult. The problem is that the same RPM/load point will have two different VE values for vanos being on or off. The stock ECU has two entire sets of tables for vanos being advanced vs retarded.

I believe you have the right idea regarding tuning.

Yes, 5 maps, just for VANOS advance/retard. And on top of that there are part and WOT throttle VANOS spark maps.

So 7 in all, just related to VANOS. Actually there are 9 if you include the speed limit VANOS map and the IAT VANOS map.

FWIW I dont think anyone has ms controlling vanos yet...

:wave



I doubt anyone running MS on a vanos motor has enough data (dyno graphs) to even know they have a problem. They just turn it on at a certain RPM and off at a certain RPM and tune around the VE changes that way. :dunno

I think MS can 'run' the VANOS. Running it and running it right are two difference things though. You might be able to get a good WOT map with VANOS on at 'x' RPM (based on WOT VE and a VANOS on and off map and crossovers), but PT is going to suck with VANOS turning on/off at that same point when you are at 1/4 throttle. VE is slightly different at 1/4 throttle compared to WOT. That would be why BMW chose load based and throttle postion maps for primary VANOS control rather than the 'x' RPM method.