Stefans BMW E34 535 turbo
- Stock BMW M30B35
- Siemens 788 cc/min injectors (low impedance, 2 Ohm)
- Stock coil (0.5 Ohm primary) and distributor ignition
- Flyback uses TS diode and 6.8 Ohm/50W resistor pack (no peak-and-hold)
- Manifold adapter with a Holset HX50 (66 in / 78 out, 25 cm^2 housing)
Short movie from the startup: (save as) [.MOV (24 MB)]
Launch and WOT run: (save as) [XviD/MPEG-4 (1.5 MB)]
The car is now running N/A for the annual inspection. Earlier we installed an MSD 6A CDI ignition box and it resulted in a slightly smoother engine (not much) and has off-loaded the onboard IGBT. Boost pressure is at 1.2 bars and it is running really nice, 1/4 mile trap speed on the street seems to be about 190 km/h. We haven't had time to investigate the EGO correction problem. When we get to it I suspect it can be blamed on the wrong PID parameters or something like that.. a few snapshots of the LCD page (07) might help finding that issue. The current parameters are what's in the user guide.
What are sensible settings for the EGO control ?
Specifically: Step size %, speed limit (or PID kp) and engine cycles before correction.
Does it really use the lambda target table ??
Are there conflicts with ALS settings?
The EGO Correction light in MegaTune flashes, there is not a steady green On signal. This is even with all conditions for enabling set at very reasonable values.
The firmware has been upgraded to 1.0.73 and the car has seen 6 months of daily driving. Now is time to up the boost, so an intercooler has been added. Some features that will be activated during the fall relate mostly to comfort driving and economy, idle control through an IAC and more tuning of the EGO control feature.
We had false triggering as soon as the wideband controller was activated, but it was solved through adding a 10K pullup at R30. By mistake I at first used a 1 MegaOhm? pullup, that did not work.. :-)
The car is now driven daily, some problems may have to be sorted out. One thing needs to be addressed: The stock ignition coil has a 0.5 Ohm primary and needs 2.5 ms dwell (it seems) but this may prove too much for the IGBT.
- Experienced same problem in similar setup. Our solution was to adapt waste spark coil. http://www.vems.hu/wiki/index.php?page=MembersPage%2FBengtR%2FIgnition
Solutions to the coil problem is either
- Add CDI box (not necessary at even double the power level)
- Replace coil
We're going to replace the coil to start with.
We removed everything related to the diagnostic connector and kept just some of the wires that went to the chassis connector (ignition, rpm, alternator, starter, oil pressure switch, cluster coolant temp, ..).
We then basically rewired most of the cable related to the Motronic harness - the injectors to get sequential firing and all the sensors because we made all new grounds and didn't want the signal wires to be cut short when connecting the Econoseal connectors of the VEMS Genboard. We did re-use all of the trigger cable and connectors! We didn't re-use the stock injector miniterm connectors, we got new ones from the VEMS webshop which are easier to disengage.
All in all I think me and Stefan spent about 4-5 evenings on the wiring, this could've been cut a lot shorter if we had done it before and knew how the stock harness was interconnected..
We re-used the "cable box" that encases the injector connectors. Very neat after we zip tied everything and closed it up.
Glory shot of the car.