Dual VANOS control strategy and some other questions

[Turbo-Brown]

Guess it'd be called the control strategy anyway!

Can anyone tell me what the electronics side of the Dual VANOS system as found on the S50B32 does?

I'm guessing that's each unit receives some kind of PWM signal based on throttle position and revs?

However, it must be more complex than that as there seem to be two cam positions sensors involved too which I presume form part of a closed loop system to tell the ECU where all it's pulsing has moved the cams to?

I'm guessing it'd be a bit dangerous to run the system open loop if what I've assumed is correct as the cams could continue to advance and advance untill the valves hit the pistons?

If I'm wrong though, surely any ECU capable of giving a mapped PWM output could be used to control the VANOS?

Finally, I know you can use two exhaust gears from a B30 to lock the cams on the B32 in their advanced position, but is there any way of just limiting the movement of the cams in the B32 so that simply switching the VANOS units on makes them advance as far as they can without the need for closed loop control, and switching them off lets the cams retard again?

If so then I guess your PWM map could read just all 0s and 100s?

Thoughts, comments and experiences appreciated as always guys

Cheers!

Alex

[jaistanley]

Interesting question. One I've been meaning to ask before.. Would like to run megasquirt or vems on my conversion and loose the maf.

Pectel and Motec ecus can out put these sinals but thats of no help with the control strategy. Perhaps someone can get their hands on the ECU control strategy/tech documents.

Have you tried www.e36coupe.com ? Those guys might have an idea.

Jai Stanley

[Turbo-Brown]

I've got this OMEX ECU that I bought after their sales chap promised me faithfully that it could control Dual VANOS but I see that they exclude VANOS from their functions list for the same ECU, so now I'm not so sure

Will register over on the E36 thing and see if they can shed any light too, cheers Jai

[gareth]

your GT6 is going to get a serious techno-shock when this all happens!

one small step for man, one giant leap for triumph-kind!!!!

[Turbo-Brown]

yeah, I'm on chassis design 3 now having spent about 3 hours this morning very carefully measuring up the engine and box to make a better 3D model of it all than I'd done previously.

Question is, do I really need tha VANOS and if so, can I control it without spending a fortune.

Be interesting to be able to play about with the settings of the system to see what effect it has on power and torque through the rev range.

[gareth]

cheaper than new cams each time certainly!

[Morat]

turbo-brown...
a mate of mine owns this TR6. Well, it was once a TR6 anyway

[GermanGorilla]

Hi,

I read your post with interest.

I do not believe that what your after is possible.

My understanding is that the Vanos although activated by the
solenoids, is actually controlled by a 'worm drive' driven by Oil pressure.

Its the Oil pressure that moves the cams, which in turn tells the ECU the
position of the cams for fueling etc.

Even if you can active the solenoids, at the correct timing point,
how would you tell the ECU of the actual position of the cams
for fueling etc ?

Motec, Pectel, EFI, all offer far more functionality that the standard
Siemens ECU.

For pure Track use, locking the Cams is great, as it means that
Cams are locked in their ultimate performance position,
so using in the main high revs works fine, but the down side
is that on a road car you will loose power and torque low down and may
even suffer running issues with over fueling etc.

As a suggestion, why not lock the exhaust cam with the B30 Sprocket
and only use the Vanos on the intake.
Not sure if 'Emerald' can handle single Vanos,
but many of the cheaper after market ECU's can.

You may suffer a little loss lowdown due the exhaust cam always being at
it fullest open, but would still retain a realistic MPG for a road car.

An M3 S54 Engine with the Cams locked, at 2 Degrees TDC, and with
higher rated injectors will make on standard cams 360 BHP with the
MAF removed and will do about 7 to the gallon, think about it !

You have the S50B32 Power but with only the Vanos on the Intake.

Regards,

The Gorilla.

[Turbo-Brown]

turbo-brown...
a mate of mine owns this TR6. Well, it was once a TR6 anyway

Cool! Looks like a Vincent Hurricane only wider

I'm beginning to think that the feedback that the two cam positions sensors must be vital to the operation of the VANOS or as you say Gorilla, the ECU has no idea where the cams have got to.

Does occur to me that if a mechanical stop could be incorporated into the VANOS mechanism so that the solenoid valves could be opened, allowing the oil pressure to advance the cam timing from it's idle position up to the stops, you could just run it as an on / off system which would eliminate the need for the closed loop system involving the cam position sensors.

There is another twist to this though in that if the cam position trigger wheels move with the cams, which I reckon they must, you'd need some trick software to still be able to calculate for sequential ignition / injection as the reference point would be moving around.

Not really fussed about running sequential as long as I can keep the direct fire coils, although even that's not too much of a concern, it's just neater than going to a coilpack.

[Huge]

turbo-brown...
a mate of mine owns this TR6. Well, it was once a TR6 anyway

Cool! Looks like a Vincent Hurricane only wider

Ha Ha! It IS a Vincent Hurricane and the chassis is widened and lengthened and the GT6 lump has gone into landfill to make way for the full-house TVR Tuscan 340HP racing engine...
I know this chap and as an ex 325 Touring owner, he'll be made up to have made it onto the zone.
I have been in this 'thing' and it feels faster than my Kawasaki ZXR600 sportsbike and much, much scarier. Suffice to say he fitted a NOS system last weekend..

Sorry this is a bit off topic, but interesting nonetheless. If you're ever offered a Tuscan engine, grab it quick, an E30 would be the perfect home for it..

[Gunni]

The vanos system is driven by oil pressure,
if you open the solenoid completely IԚ´m sure you will damage something with the 100bar of oil pressure.

as the ecu reads up in the map that the exhaust cam is supposed to be there and the intake there,
it opens the correct solenoid until the settings are found, after that it closes the solenoids and the cams are "locked in place" then on the next instant it checks all paramaters and does the same thing again,,

This is how I think it works, but here is another idea,

by controlling PWM on both sides of the gear you can have one side give less pressure and the other more, thus moving the cam when the cam is in the right place pressure is equalized and the cam locked??

[Turbo-Brown]

Hmm that's probably a good point about something going pop with the oil pressure.

Anyone know how much pressure the single VANOS system operates under, or indeed if the two systems are interchangable?

This has turned out to be quite an interesting discussion

[Gunni]

100bar , ,
And according to the e36coupe forum they are indeed interchangable,

When I got back to my S50 I think IԚ´ll just go standalone and locked cams,

[Turbo-Brown]

And according to the e36coupe forum they are indeed interchangable

Really?!

Now that is interesting!

Right, where can I get myself a single VANOS control unit?!

I am right in thinking that the single unit is just an on/off device that works on the exhaust cam aren't I?

Presumably I could use the exhaust wheel from the B30 on the inlet cam of the B32 and then use the single VANOS unit on the exhaust cam controlled as a switched arrangement using a 0-100% PWM thing?

[Gunni]

The S50B30 uses a variable motion cam, not a on off switch like the early non-m vanos units,

How much does yoru gt6 weigh ;)

a S50B30 makes 180hp@4000rpm and your gt6 weighs about what, 900kg at the absolute most?
thats 200hp/tonn @ 4000rpm , and you still got about 3000rpmԚ´s to go all with more HP,
286hp/900kg = 317hp/tonn and you want more then that? Thats not fair to the rest of us..

IԚ´d say adjustable cam gear and standalone will make the ideal solution,
youԚ´ll be running alpha-n and could run any intake and size, making up that way for the "loss" in low end VE
by not using the vanos,

[GermanGorilla]

Hi,

The main reason for the Vanos Failure is that the front covers are held
on by 5 Alloy bolts.

When these fatigue, as they do at around 30,000 or so miles they
tend to start cracking off, and with 100 psi you can imagine the outcome.

I have seen complete units blown clean off the front.

The whole service kit is about 20.00 per side from BMW, so whatever
you do I would recommend that you replace the O rings and 5 bolts.

Also on the Intake side a bleed screw with mesh filtre can get blocked up
and this again can cause problems of too much pressure.

Hope this helps,

Regards,

The Gorilla.

[Turbo-Brown]

yeah, am trying to keep the weight below 900kgs if I possibly can so I don't suppose I'd miss the operation of the VANOS in terms of the power.

Should really just do the B30 cam gear swap and be happy with having a 3.2 motor with throttle bodies that should hopefully make 300 odd bhp, although I'd prefer 330 if I could get it, nice round number.

Sounds like the service kits are a good idea whether the VANOS is being used or not though!

[Andy335Touring]

what about keeping the standard ECU/VANOS/etc and just get a remap ?

Immy, who is now helping Sal run the Zone shop was well impressed with his remap on his breadvan, trouble is i can't remember which company did it ?

[Turbo-Brown]

I've only got the ECU with none of the keys, cluster or other gubbins I gather you need to get it to work

Is there an EWS or something? All just little bits I've picked up from other people's questions about the conversions.

Think I'd need the 4 Lambda and so forth with cats too which, although I've got for the car, I'd rather not use if possible...or if I do they'll only be for the MOT.

Aside from the possible lack of VANOS, I can't see any real drawbacks to using something like an Emerald

[jmc330i]

I've only got the ECU with none of the keys, cluster or other gubbins I gather you need to get it to work

Is there an EWS or something? All just little bits I've picked up from other people's questions about the conversions.

Thats a bit of a bugger

If you havent got the ECU, ignition key and EWS module all from the same car, the engine will not start. The ECU is pretty much useless.

I was going to say, that apparently its possible to use the original ECU to keep the Vanos operation along with Emerald/MS for fueling/spark so you get rid of the MAF.

Im not sure if the ECU will run the Vanos etc without the EWS bits connected, so it might not be an option anyway.

Think I'd need the 4 Lambda and so forth with cats too which, although I've got for the car, I'd rather not use if possible...or if I do they'll only be for the MOT.

Should only be 2 Lambda sensors and they will need to be fitted whether the Cats are there or not.

In theory, you shouldnt need the Cats because of the age of the car, although that might change if the car needs to be SVAd because of the work you have (or will have) done.

[billgatese30]

i thought if you got a remap they could also falsh the ews module and therefore not require the coded key?

[Turbo-Brown]

Believe it or not I have had the engine running with just the ECU, but I seem to recall Ian332isport saying that's possible but it won't pull the car along

[GermanGorilla]

Hi,

Turbo-Brown- you have the ECU, correct ?

So you only need a EWS and then an Antena.

The EWS is not car specific nor is the Antena.

EWS and Antena would be quite cheap second hand, and you can request
duplicate keys from BMW by using the Bar code on the ECU.

I would think that 250.00 all in would do it.

You could waste more than that trying things that may not work.

Hope that helps,

Regards,


The Gorilla.

[Turbo-Brown]

Fair point!

Don't suppose anyone knows how much we're talking about to change the cam gears to the B30 ones so as to remove VANOS from the equation completely?

Is it just the gears I need or is there more to it than that?

Sorry to keep going on about this guys and many thanks indeed for all the help thus far

[tim_s]

I can sync EWS for you through carsoft if that helps, never done it before though but have the lead and software that i use for daig etc.

[Turbo-Brown]

Hey Tim, might well have to get back to you on that!

Gonna start work on the new chassis over the next few weeks now I've got the design of it to a stage where the suspension, steering rack and engine can all fit around eachother so once I've got something that resembles a rolling chassis I'll probably be quite keen to get the engine up and running by hook or by crook

[GermanGorilla]

Hi,

Turbo-Brown- you will need 2 x 3.0ltr exhaust sprockets as you will
be 'locking' both cams into position.

You will need to make some type of Vanos cover plates, so that when the
Vanos is removed you can seal off the recesses that the solinoids etc
sit in. This will also need a gasket and a good one due to the oil pressure.

You need to time your cams in to the position you intend to run, you may
well retarde them a little, from the full open position,
so as to try and achieve better lower down torque.

This is a well proven modification, more so for race cars, but you will loose
and element of the S50B32 tractability, and also remember that it is
a very peaky type engine so using lots or revs all the time may not
suit ?

Hope that helps,

Regards,

The Gorilla.

[Turbo-Brown]

Wicked, many thanks Gorilla

Would have thought that if there's nothing for the oil to push against it should be under any great pressure anymore?

Don't suppose anyone's got any power plots for an S50B32 have they, any state of tune will do

[gareth]

would you not be better blocking off the oilways? purely guessing but if they vent back to the sump unregulated, it could drop the oil pressure.

i have never looked at one of these engines by the way but it could be an issue... not one that mr broon can't get over though i reckon!

[Turbo-Brown]

Think there's a seperate very high pressure pump for the VANOS which doesn't supply anything else isn't there?

[Gunni]

i think that the exhaust cam on a 3.0 runs as a pump ,, then there is a accumulator on the side of the block that holds pressure,

I remember it all looked real strange when I took my S50 apart

[gareth]

more bmw wierdness! i'll just stick to my chain driven single cam, thanks!!!!

that said, another cam would not go amiss!

[Turbo-Brown]

Oh, I thought that the pump for the VANOS in the 3.2 was in the little lump at the front of the sump along with some kind of scavenge pump?

Most probably getting my wires crossed though!

[Gunni]

I donԚ´t know about the 3.2 but this is what I remember about the 3.0

[jaistanley]

To be fair I think you've given up on the control strategy too soon.

There are plenty of ECU's on the market capable of running dual VANOS. I can understand you not wanting to try your hand at gettin megasquirt or VEMS to run it if you have no precident but the info is out there somewhere! A quote from the Motec (very expensive ECUs though) site:

"Fully Variable Camshaft Timing - MoTeC is proud to be the industry leader in the aftermarket for controlling engines with fully variable camshafts. We have several special modes written to allow full control of up to 4 fully variable camshafts per engine such as the Dual Vanos BMW V8 using our M800/880 series of Engine Management Systems. Special Ref/Sync modes were written to allow the tuner to use the stock trigger wheels and sensors. Camshaft timing can be independently adjusted for each cam in 1/2 degree increments based on RPM and Load. With full adjustment of camshaft opening and closing points, the engine's volumetric efficiency curve can be stretched providing optimum cylinder filling over a much wider range of RPM, increasing the average horsepower and ultimately making the car faster. "

The signal, I can only imagine, is a PWM sent to an electronic actuator. Regardless of what pressure the oil is running at, a suitable control signal will be all that is required. It is quite possibly a closed loop system, feeding back from the cam position sensors, or has it's own vanos position sensor. If it isn't, the ECU would only have to output an appropriate signal based on a mapped table of throttle position against RPM (or possibly MAP instead of throttle pos).

The comment about the cam position sensors getting varying readings with VANOS advance may or may not be valid. If the pick-up is on a portion of the cam that moves, then yes, or if it is on the chain driven side then no. It's not an enormous step to take the variable signal and subtract the value of advance/retard from the vanos lookup table/output.

I recently asked a guy selling Megasquirt's about this and he said it'd be fairly easy to configure to output a constanly variable signal based on the above, but as you said you'd need to know the control strategy to give you the building blocks. Apparently VEMS is a bit better at this type of thing but I haven't looked into this at all yet.

This has to be something that is over-come soon. More and more cars are coming with constantly variable cam timing meaning there is a large gap in the market for cheaper ECUs that can run it. A phone call to a few ECU companies technical sales departments will shed a lot more light as I'm no good with these ECU things, I need to learn more!

Just my ten pence worth dude.