e30 m50/m52

[sidewaysbill]

Hello guys ,  Im new on here just wondering if anyone is using vems on either a M50 or M52 bemer engine...?

[rob@vems.co.uk]

Theres a good number of BMW M50 and M52 engines running on VEMS in europe - most the the European guys dont come on here though.

IIRC GintsK has done one. I'll PM him to let him know that he's needed!

Rob

[GintsK]

Not true. I had plan put VEMS on M50 as my first VEMS project. But at that time VEMS was no support for overlapping dwell for COPs(now it is). Engine is revy and we put on them another stand-alone.

But technically there is no problems until you do not have PWM controlled stepless VANOS. M52 comes with simple VANOS, right?

simple VANOS solenoid is easy to control with configurable output.

Theoretically needs two pairs of maps for both positions of VANOSed cam. For this is no official support as I understand, though this is in firmware probably. But there is easy way: tune engine on both positions of cam, find area where torque graphs cross each other and configure VANOS triggering at this rpms. Then manualy compile one pair of maps.

And look here: http://www.vems.co.uk/forum/index.php?topic=185.0

[rob@vems.co.uk]

I know that Alligator in Sweden has a turboed E36 running VEMS.

You dont need to make the VANOS mapping system quite as complex, as with the 16x14 map you can set your breakpoints around the VANOS switching point which will help blend the two areas on the maps.

[dnb]

Rob, you do - otherwise how do you work out the optimal VANOS switching point?

[rob@vems.co.uk]

Okay VANOS function is as follows:

"At idle, the cam timing is retarded. Just off idle, the DME energizes a solenoid which allows oil pressure to move that cup gear to advance the cam 12.5 degrees at midrange, and then at about 5000 rpm, it allows it to come back to the original position. The greater advance causes better cylinder fill at mid rpms for better torque."

So from the point of view of mapping you have your idle load sites, then load sites from idle to 5000, then from 5000 to redline.

I would divide the map up to have 2 rpm sites for idle, another 8 upto 4750-5000, then 6 from 5050-5500 up to redline.

The single VANOS stuff is no different to VTEC or VVT on the Toyota Corollas.

I've just been told that we have overlapping dwell working now.

[dnb]

But Rob I've mapped a couple of Hondas and found huge gains in the midrange by throwing away the quoted VTEC switch points and working it out from the point of view of  raw performance rather than economy, emissions and all the other nasty things OEMs think about...

[rob@vems.co.uk]

Cool, theres no need to stick to the exact specs, I was using the stock figures to show how I'd set up the tables to cope with the cam change at a specific RPM. In order to get to there you must first start from here, and you might as well start from the standard timings and then play with the switching points.

As sidewaysbill has told me that he's going to use a different cam the whole VANOS timing will be completely different, but the way of setting up the map with Regions of Interest around the switch point will be the same wont it?

Rob

[dnb]

Yes, I'd use the concept of Regions of Interest around the switch point.  It is, as you say, the best way of making a smooth transition.

I'd also come up with a rough cut map with VANOS off and one with VANOS on to analyse where the switch point would be.  I'd then interpolate the 2 maps and make up a hybrid map with the VANOS switch at the point I deduced was best.

[sidewaysbill]

that all sounds very confusing...! thanks a mill for the info anyway more words of wisdom would be greatly appreciated. by the way what does PWM and COPs stand for....?

[dnb]

PWM = pulse width modulation
COP = Coil-on-plug (coils)

[sidewaysbill]

what would be the story with running it on e85 with vems...?

[rob@vems.co.uk]

The Swedish boys have got a bunch of cars running on E85 with VEMS.   

[sidewaysbill]

How much bigger would you want the injectors or could you run them on a longer duty cycle?

[Agriv8]

I have plans for switching to E85 when it becomes more availble Up-north.,

regards Agriv8