Dwell time under LPG fuel questions????

[rossi46numberone]

Hi,
I 've activated the the switching map function for running my Bi-fuel sys,and I wondering if I have to keep the same Dwell ign time for these different  fuel type,do I need more charge time in LPG ?
Driving my 4 passive coils directly from the IGBT,is there a risk to burn them with too much Dwell time?
Do I have to cooling them with an additionnal fan or something like that?

Michele.

[Ignitec]

On all cars with aftermarket LPG systems sme dwell is used for both fuels. Try same dwell and see, and if you see misfiring, raise dwell time a little bit and test coils for heating (by hand in idle). You probably won't need any dwell correction.

[rossi46numberone]

That's what I was thinking....
In fact until today,I've always ran in one map mode with only one set up the 2 fuel type and no issue about missfire.
Now working with 2 # map,and I've decreased my Dwell from 3.2 ms to 2.8ms(to prevent IGBT's overheat) some missfire occur in LPG fuel when boost increase at mid Rpm ??
For info,3.2 ms is the Oem spec from Bosch @ 13.2v

[rossi46numberone]

Tried with 3.2ms both map,and no success.....
I've Made some test and it seems these missfires come when I push hard on the throttle at low/mid  Rpm,and only on LPG fuel...
Ignition trouble??

[Ignitec]

Small LPG injectors?

[rossi46numberone]

In fact a fews days ago the first ignition EC36 pin 11 igbt stop working(burn ),by chance i've got 8 IGBT's output and I was able to  change the first wasted-spark output pair using the second w-s pair,and now this issue appear only on LPG mode, in petrol no missfire in all working conditions.
Before that crash I never had any kind of issue or missfire in both fuel type......
Is it possible that a burned IGBT can create some trouble in another part/output of the genboard?
Is it possible the ignition have lost power by eventual electrical current defect and regarding the fact that the LPG  is more sensitive to ignition quality???

[rossi46numberone]

oupps
Found the probleme....It was a the first cyl dead coil.....

[boostd audi]

fried an igbt?  can you use another in meantime?

[rossi46numberone]

Checked this morning,
The pin 11 IGBT dead,I 've changed-it and the problem sovled.
I 've reduced my Dwell from 3 ms to 2ms and the car seems working the same way before the "crash"....
I think I will swap for the Vag active coil's in Vems shop.
Do they work with 12v trigger or 5v logic?

[boostd audi]

4 pin VAG coils.. from web shop

Ignition Coils
Pin, sq.mm, Color(1.8t), Function
1 1.5 Black/Lilac    +12v to Relay J271, terminal 2/ 87
2 1.5 Brown          Ground to connection 85(with VSS) to T14a/7 (near battery) to center plenum chamber
3 .35                   Coil Triggers             
4 1.5 Brown/Yellow Ground to connection 281 to cylinder head.

I use 2.9ms dwell time, and the trigger edge is -ve. I have used these coils to over 120 whp/cylinder so far with no misfiring.
Hope this helps,

[rossi46numberone]

Thanks!!
What about the input trigger signal?
+5v  logic or +12 v

Regards,Michele.

[Ignitec]

They're triggering with 5v. You can use very small dwell, I used 1.8ms for 270kPa, and no misfire at all.

[lost]

I think you need +12.

It works from stepper output

[mattias]

You don't need +12V, you need sufficient drive current - which the stepper motor drivers can provide. The logic outputs by default have a resistor to limit the drive current, it's too big for driving these coils directly so a resistor is mounted parallel to the standard one to lower the resistance and increase the drive current.

[rossi46numberone]

Without being boring, so I can use The EC36 logic level.
Are you talking about The Two micro resistor "510"& "5100"when There Is No IGBT 's On The genboard mounted?