changing v3.3 board hall setup to VR setup

[Timmo6]

Hello all,
I have a V3.3 board configured for primary trigger Hall sensor. I now will use the board on a bmw m30 6cyl with VR sensors.
How can I configure my board to accept this type of trigger?
thanks
Tim

[PeepPaadam]

I assume your M30 engine uses older trigger arrangement with two VR sensors on the flywheel (so-called Auditrigger)? If so, I suggest you go to the scrap-yard and buy E34 535 crank pulley that has 60-2 trigger wheel machined in it. It will bolt right up to older M30 and so does sensor bracket and you will have nice working 60-2 trigger.

To turn your HALL setup to VR, you'll need to unsolder one blob and solder the other one, also remove R30. Detailed instructions are found here: http://www.vems.hu/wiki/index.php?page=GenBoard%2FManual%2FInputTriggerHardWare

For secondary VR, you'll need additional LM1815 chip that is not soldered from the factory and it's much more hassle with auditrigger than to change out the crank pulley (it was an hour job when I did that).

[gunni]

I second the 60-2 arrangement.
everything available for next to nothing,.

[Timmo6]

ok thanks guys,
maybe its then more easy to keep the board in its Hall-setup
and use the damper as atriggerwheel with 3 bolts 120° apart?

[GintsK]

3 bolts will cause imprecise cranking advance. 60-2 is better choice.

[rob@vems.co.uk]

Sorry to disagree but the 3 tooth+1cam sync option is well regarded as the best trigger you can use as long as they are placed accurately and not much further away than 60deg BTDC.
I didn't believe it at first but the proof is in the maths and the implementation.

Here's a two tooth setup on the http://www.theoldone.com/ website


It would be better to stay with a hall sensor like the Honeywell GT101 as you just dont have the noise issues that occur with VR.

[GintsK]

Rob, if engine use light flywheel, or high CR, or it is really cold or weak battery or combination of these, ECU with so simple trigger have no any capabilities to give precise advance on low crank speeds, because huge speed variations during this 60degries.
I believe VEMS use last possible tooth for advance calculation wit multitooth wheels. And why not use this feature?
But one trigger tooth per event I want to consider as old school.
 In Latvia climate it is not usable - you can stay without car on cold winter morning because of too advanced spark event. No one OE no more use this type of triggering. And it was also rarity in 80-s.

 E.g look at Subaru 6 teeth trigger wheel. They use ~60deg tooth for advance calculation on running engine, but ~5deg tooth for cranking. Same with BOSCH hall sensors in distributors: one edge for running, other for cranking...

Gints

[gunni]

GM also uses 60-2 style setup for advanced crank speed measurements to detect knock or irregular firing between cylinders.

[rob@vems.co.uk]

As Gunni says the multi-tooth issues are for missfire and irregular running detection.
Its the Swedish guy's who really advocate the use of the simple trigger, they're the ones that won me over with the idea.

When it comes down to it, its everyone's choice, I have never had a problem with a 36-1 and the ones from Triggerwheels are ideal in the UK so I always point UK users there.

[Timmo6]

well, I used to have a simple trigger with hall-setup on my bmw 4cyl m10b18 without any issues
but as the m30 engine has the two sensors on the flywheel I thought that perhaps they could be used,
but that's not true I guess

[PeepPaadam]

They can be used, but simpler and better is to change out to E34 M30 crank trigger wheel.

[GintsK]

As Gunni says the multi-tooth issues are for missfire and irregular running detection.
....

IMHO primal point for multi tooth wheel is to achieve more precision in spark events during dynamical situations. 60-2 bosch use from mid of 80ies. And I suppose not for misfiring or knock (?!) detection, but primary for precision.
some quotes from wiki:

1.1.x overlapping dwell and timing from last tooth

Since 1.0.49

    * compiled with -D ONLY_LAST_TOOTHTIME allowed extremely fast revvup MembersPage/YasecElise to start

2004-07-27

    * multitooth setup improved.
    * Dave will test it soon (and document the new variable), and than it worths to upgrade (with multitooth setup).
    * preparations done for time from last possible pulse