MembersPage/GintsK/BMW (2007-02-08 09:42:04)

GK: Audi 5cyl trigger support is very welcome!! But i still haven't found overlapping dwell implementation. Is there some hope on it ?


Hello! Next question:

What I need to run 6 BMW COPs like wasted spark? I mean to ignite 2 coils at time in 3 coil pairs. This kind of settig allow to rew up engine up to 8000 with 5ms window for each ignition event. Is this able with current firmware? Or here need to make changes in hardware?

A: Running wasted spark would not give you a longer window between sparks, only difference if you configure and run dual output firmware is that you dont need a camsync sensor. Most COP coils available want about 2mS dwell time, and you have approx 2.1mS at 8000 rpm on your engine. The problems you read about was someone who wanted for some reason to wire up his BMW using a coil pack from an old Ford that wanted 4mS dwell.

GK: Ooh yes You are right. I only have 2.5ms window :( But as I remember BMW OE dwell is much longer than burning time. But burning time on BMW coils is 2.2-2.5ms... In past I saw this on scope. With 2ms dwell, there will be spark, but with less energy


About this engine: this is small stroke 6cyl engine with aggressive cams and target redline at 8000rpm! This project definitely need overlapping dwell control. 2ms dwell will be too small.

Q: Will Genboard firmware have this feature in near future? When? Thanks!

UPD: maybe this kind of dwell is present? Anybody?

A: This is currently not supported, but this is in line for development, and will hopefully be supported before the spring //Emil


Please add your coments for my first VEMS project. Here is inconvenient to find rigt thread for newbie... :(

For first want to put VEMS on BMW M50 modified engine with COPs for dragrace.

It is 6cyl 24V DOHC engine bored up to 3L. Deeply rebuilded head, very agresive cams for this stroke. Custom make intake system with large reciever. And more.

and more

All of theese functions is useful or even prerequisite for succeseful drag with revy engine.

Q: Is here code for some of theese useful functions?

A: There is a function called AntiLagSystem in which you can retard the ignition advance and add fuel, this is to give more boost off the line. Progressive shift lights can be made with the "misc outputs", check the MegaTune software.

GK: Thanks. It is little better


Q: Is today from MegaTune is reachable all functions? And there is nothing else?

MegaTunix is an alternative, but no longer in development as far as I understand it. OtherTuningSoftware/PSITuner could turn out good. MegaTune can be used for all functions, with a few reservations that I can't remember of the top of my head.


Q: Is thomething miss here?

A: Why not fully populate the board with 8 ignition drivers (IGBT) ? You naturally need 1 injector driver per injector (8 max), the two superfluos drivers can be used for misc outputs or other high power usage on your 6 cyl engine. As you will build the board+case yourself, I recommend buying a few misc parts for connecting the serial port, LCD and EGT (cable + connectors).

Q: What high current circuits you mean???

A: Idle air solenoid, the stock unit on older M20 engines need two drivers that can handle at least a 1A load with flyback (coil load). I don't know about what comes with the M50 engines, I think the unit is hidden below the intake manifold.


GK: EGT is not priority.

ExhaustGasTemp should be a priority for you, it lets you know you're safe and is a very good tuning tool.


Q: May be better is to put Genboard PCB inside Motronic ECU?

A: The Genboard case is much easier to work with and will allow better cooling/clamping for the injector (FET) and ignition coil drivers (IGBT). I assume you have the 55 pin connector, it will be a lot of patch work to make it work with the original harness - it's a better idea to custom make your own harness, and within reason to also re-use some parts of the stock harness.