MembersPage/MarteleurTim (2006-03-16 04:43:08)

I want to turbocharge my BMW 518i E28 M10 engine by using VEMS


Installation specific


Current plan for Ignition

I keep the distributor, lock plate in the distributor and rotate so that the inductive pickup triggers 50-60° before TDC, remove vacuum hose.

Q: Will this signal be controlled by an ignition IGBT and fire the coil by another ignition IGBT?

A: The input from the distributor trigger is sent to trigger input #1 in the EC36 connector. The ECU then calculates coil dwell and timing advance, and then fires the coil at the right time using one IGBT, also in the EC36 connector.


Changed trigger/ignition plan:

I keep distributor only for distribution. I use Hall sensor on crank as a trigger input for the VEMS.

Q: So actually I have to lock the plate in the distributor and remove the vacuumline in order to lock the vacuumadvance and let the distributor only distribute the spark?

A: With the distributor used only for spark distribution, and not timing advance, none of what you described is necessary. The poles in the rotor cap are fixed, that is all that matters for spark distribution.

Q: Do I need a triggerwheel or can I just bolt on two magnets 180° separate on the standardcrankwheel?

A: With many auxiliary belts (air conditioner, servo steering, ..) this can be a problem to fit correctly. The main concern is that it must be rock solid and accurate, and be appropriate for the sensor you will use with the trigger solution. With a good Hall trigger (Honeywell GT1 is recommended) you don't have to use magnets, two slots or fields in a ferrous material is all that is needed and can be fastened in many ways depending on how the stock crank pulley is designed. In this day and age of cheap digital cameras, pictures still speak more than a thousand words, so get some snapshots.

OK here is a pic from the crankpulley:

PICT0042.JPG


ITEMS TO BUY:

I recommend buying a pre-assembled Genboard to avoid this part of the project, but in case you feel confident with electronics and like the idea of saving some money - then go ahead. I would advice you to fully populate the board with as many fuel injector FETs and ignition IGBTs as you can afford - they can be used for a lot of other things and the minimum I'd recommend is 6xFET + 5xIGBT. That allows you to run a direct-fire (distributorless) setup in the future.


Q: What about TPS? Should I look for a TPS with WOT switch and potentiometer?

A: A true potentiometer type TPS is recommended for full use and control. A WOT switch is not much use, it can be used to raise boost target with BoostControl. In MegaTune you configure and calibrate the maximum and minimum TPS values (idle and WOT). You can also set the idle threshold value (1-2%).

Only in some cases do you really need to know the exact position of the throttle plate. You can use a resistor grid with the stock "on/off" TPS, to make three distinct positions/resistance values (idle, in between, WOT). It has worked really well on this car: MembersPage/MattiasSandgren/BmwSevenTwentyEight

The basic idea is to connect the TPS In (EC36-1) to a pullup resistor towards +5V (EC36-28) and a pulldown resistor towards GND. The pullup resistor is shorted by the WOT switch (raising TPS In to +5V) and the pulldown grounds the signal. To protect from a short (should never happen), connect a resistor between GND and the pullup resistor and Idle-switch so that there is a minium resistance to be met between +5V and GND at all times. Use 1K resistors, or similar size. I'll make a pretty drawing if/when I have time.