BMW E30 323 with M20B25 Turbo
The engine
- Inline 6 cylinder BMW M20B25, 2.5 litres, ignition order 153624.
- Wastefire ignition with Ford EDIS wasted spark coils (stock 60-2 trigger wheel)
- Sequential fuel injection with no cam sensor and low-Z 720 cc/min injectors
- Custom engine harness
The turbo system
- PPF turbo manifold (pulse-split)
- External wastegate 50 mm from Boström Turbo Teknik
- 3.5" downpipe and exhaust system out through the (no muffler)
- Dump valve by Simon Marmander
- Custom large intercooler
- Holset HX50 turbo
The config and tables will be updated on this page, and documented properly given some free time. Here they are: [config.txt] and [tables.txt]
Bear in mind that fuel has not been set properly, including afterstart and other enrichments.
Update 2006-07-17
I removed the damaged P259 and soldered in a new FET driver and the board seems to be healthy again.
Tonight we established that the injector FETs work as they should.
I measured with a high quality Fluke that the AC voltage between ground and injector - was about 2.0 VAC with the engine free revving at 2500-3000 rpm with the "new" high impedance injectors (380 cc/min injectors from a BMW S38 M5 engine).
- Can I assume that the injectors are not what is causing the engine to not run on 6 cylinders ?
- 2VAC doesn't mean too much. It depends if it's a true-RPM or measures-peak, but displays assumed (as if it was sinus). But it doesn't sound too good in any case, as 2 * 2 * sqrt(2)=5.7V peak to peak, that is not like an 1..12V signal (11V peak to peak). Most AC meters have restrictions on freq (maybe measured freq too low?)
The problems seems ignition related as I can't believe that the injectors are not working. With a spark plug with a removed electrode we tested how long the spark could jump for all six spark plug wires, we got about 15 mm.
I'm going to double check how the ignition drivers are wired to the coils again tomorrow. Meanwhile, here is the directory with the config.txt and tables.txt, along with the .msq file for MegaTune users.
Help?!
Trigger? Wheel errors ? log ?
Changes from 2005
Ignition coils
Above 6000 rpm and some boost this engine ran into a problem with the ignition dwell. The Ford EDIS coils need 4 ms dwell but that was simply not possible since the method used in firmware at the time did not make it possible to use overlapping dwell. At 7000 rpm one revolution of the engine takes 8.57 ms and there are three ignition events. The time between each ignition event is 2.86 ms on a 6 cyl engine, and there is currently 400 us "coil off time" which means an effective 2.46 ms dwell on coils that need 4 ms. The problem would be more serious on a 8 cylinder engine.
The coil dwell limitation had not been resolved by spring 2006 when the car was on the road again. The [high power ignition coils] from Swedish company "Biltema" were chosen and driven in "dual out" mode, which means wasted spark. This has worked well, we have not found their limit yet.
Injector FETs
We have established that poor quality fuse holders caused 2 injector drivers to break. These holders were replaced with more reliable holders with spade connectors that attach directly to the fuse.
I have replaced the damaged FETs, testing on the engine stille to come.
Injector Flyback
The GenBoard/Manual/PowerFlyback has been installed and made a tremendous difference with the injectors. We have found a setting for the injector characteristics that work, more tuning will probably change this but it runs well at idle and the map seems properly flat and uninteresting in this area.\n
injopen = 0 injocfuel = 400 usec
Extra pins
No stepper motor chip in place, leaves many EC18 pins free for use.
| EC18-5 | Ground for SCL and SDA |
| EC18-10 | SDA (PD1) - on JP1 connector (current default for AntiLagSystem) |
| EC18-11 | SCL (PD0) - on JP1 connector (current default for shift cut) |
Q: How to enable shiftcut? Through grounding of MCP3208 pin 7?
I can't find a good reference information on this. I will update Wiki accordingly if the answer is given here.