My project car is a BMW E30 from 1984. In 1996 the car had been rebuilt and got a 325i engine with a TD04 turbo.
Since then it has got some major improvements like limited slip differential, intercooler, water injection, etc.
Engine management remained Motronic 1.3
Now it suffers from the lack of engine control, sometimes knocking sometimes coughing, that's why I'm here, and want to see a GenBoard inside! :)
Current setup
These are engine outlines (and details) before changing anything:
- Engine: M20B25 (325i from ~1987) 2500cc, 6 cyl inline, 12 Valves, SOHC (stock, but lowered compression) [Engine bay(huge pic)]
![[Engine bay(huge pic)]](http://quasar.dynaweb.hu/~lezsi/bmw/original/PICT0004engine-bay.JPG){kind=link}
Trigger
- stock 60-2 VR crank-trigger from Motronic 1.3, stock coil, mechanical distributor (guess it has no mech. advance), stock sparks. See MembersPage/GergelyLezsak/Trigger
- some inductive sensor from ignition cable (cyl. 1?) for cam position. See MembersPage/GergelyLezsak/CamPos
- Ignition outputs: wasted spark seems like a good choice for this engine. More: MembersPage/GergelyLezsak/Ignition
- Fuel injection: Bosch injectors from E36 325i (part no. 0 280 150 415) maybe 190 cc/min @3.5bars. R=~16 Ohms
- Staging injector: Bosch no. 0 280 170 400. It comes from the jetronic cold start inj. (not a PWM system!), maybe 113 cc/min @3 bars, R=~3 Ohms. Actually switched by ~half throttle pos.
- Adjustable fuel pressure regulator (home made, seems working, no fuel pressure meter altough)
- Water injection. High pressure pump (headlight washer), unknown injector. Actually switched by ~half throttle pos.
- Turbo: Mitsubishi TD04-11B (it's a small one from 324d), internal wastegate with stock (direct pressure controlled) mech. actuator arm
- Idle control : stock solenoid, Bosch part no. 0 280 140 524
- Intake: guess it's stock AFM with direct filter. Factory throttle pos switch (3 state; idle, between and WOT)
- Sensors 2: Two coolant temp (seems stock) at thermostat housing.
- 1. (one pinout) shows 120ohms @25c
- 2. (two pins) shows 2.18kohms @25c (this one sounds pretty standard temp sensor)
- Sensors 3: There's no O2 sensor, and there's no IAT (excepting the one may be included in AFM housing -which has to go either). There will be a WBO2 mounted, I guess
- consider ExhaustGasTemp
Project plan
Current goal : Achieve maximum power output from current mechanical design with reliability in the long run. Good driveability and fuel economy is also in sight.
Future plan : Additional mechanical improvements possible (larger injectors, big turbo, etc.)
Suggestions
How to start? -I think it's easier to go by little steps. Maybe I try to control EFI first and leave ignition to motronic.
Issues with this configuration:
- I have to share crank VR signal between two computers. Measure the mean voltage (DVM, DC Voltage measurement) on the VR transmitter pins (on the ECM side, while ignition is on). engine need not run. If it's 0V (likely) sharing the 60-2 crank VR signal should be smooth.
- TPS is also problematic, I need to replace WOT switch with potentiometer, therefore I'll lose acceleration ignition retard - I guess.
- with a good MAP sensor the lack of TPS is bearable. You'll need TPS for a nice boostcontrol though.
- M18x1.5 mm female thread in exhaust after the turbo would be nice for WBO2
Suggestions are appreciated...