VEMS w 60-2

[kamuto]

I have started 60-2 without cam sync 5 cyl wasted spark setup on vems.

[90/90qs]

what was your strategy for configuring ignition / injector timing?

[a4kquattro]

I have started 60-2 without cam sync 5 cyl wasted spark setup on vems.

you are mistaken.

while it is possible to start a 5 cylinder without cam sync by chance (you get a 50% shot at it depending on the rest position of the engine if the secondary trigger is grounded out so as to always trigger), waste spark is not possible. there are 8 ignition phases. The I5 fires every cylinder 72 degrees apart, with no overlap in cylinders. you need 10 phases to fire all 5 coils, which is something vems has not yet supported.

[kamuto]

nope, you are not right it's hard to understand but it works you just set 10 cylinders wasted spark, only 5 ignition events used, with strange ignition outputs sequence and it works perfect.

[kamuto]

I'll put configuration screenshots tomorrow maybe.

[Erikk]

Normal fireorder: 1-2-4-5-3 - Same output with "10cyl wastedspark" should be 1-5-2-3-4

1 Fire
5 Waste
2 Fire
3 Waste
4 Fire
1 Waste
5 Fire
2 Waste
3 Fire
4 Waste


With injection divider 2, you should be all set.

Reference tooth table
0 , 12 , 24 , 36 , 48 (but reversed)
Next trigger tooth = 12
Number of cylinders = 10

[kamuto]

yes thanks to gintsK for advice about firing order

[90/90qs]

It's been a while since I posted here but I've gotten most of my issues sorted out and I've been driving the 90 around this summer in shakedown mode. I'm learning a lot (one item at a time) about VEMS configurations and scraping funds together for a dyno tune, but in the meantime I was hoping someone could look at my ignition map and let me know if there are any alarming values.
I know these are dependent on the individual engines and so on, but I'd feel better if someone said "yea, that'll do for now" -because sometimes I can't resist the urge to step on it.

[a4kquattro]

Can you post your working waste spark config please?

[ejfluhr]

I know this is a necropost, but I wanted to thank the members who provided the information above for how to set up VEMS on 10-cyl wasted spark mode. My race team has a 7A on VEMS chasing trigger problems and a very intermittent misfire. The ECU is reporting primary trigger errors - sometimes bad tooth length at low RPM and "Less Primary Triggers" occasionally at high RPM ~4500 when the misfire occurs. We are running an 034 aluminum flywheel and comparing that to the factory, the gap between teeth is ~1mm smaller, so we suspect that is the cause. We installed the VAG 60-2 sensor on the crank and switch between the factory VR sensors and the 60-2 by moving the hall input the 60-2 and reprogramming for wasted spark. Marc S. suggested doing this temporarily and got us most of the way to a working config, but we had the ignition order wrong and this thread guided us to the fix. The engine seems to be running smoothly enough for some track testing to see if this resolves the trigger problems. I know trigger issues are commonly reported with VEMS but my father runs a 3B at 400HP using the Fidanza aluminum flywheel without any problems.

I have to say that being able to switch between factory sensors and the 60-2, for back-to-back testing, with the plug of a connector and re-programming of VEMS is quite nice. I wish that could be a permanent feature.

[ejfluhr]

Follow-up: we just ran our first (and only) endurance race with this setup. It worked quite well. We had a few rare ignition misfires...hopefully that is a tuning issue with the 60-2 sensor as we may not have a well-dialed ignition MAP table yet. We had Mark mod the ECU to take the 60-2 directly so will be moving back to standard 5-cylinder sparking for the future. But for anyone in a pinch, 10-cyl wasted-spark mode works...