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 2006-07-22
This thing is a rocket ship! But there is a couple of mechanical issues:
- The stock differential gave up
- There is too much pressure in the coolant system (don't know how bad it is)
The two VEMS Genboard issues are:
- The RPM signal is not steady
- EGT rises several hundred degrees above normal when rpm goes up
We have no wheel errors and the engine seems to run just fine. So how serious is this ? What is this "up and down" behavious that I can't seem to see on engines with the simple trigger setup?
We use firmware 1.0.38 and MegaTune with an upgrade vemvsv3.ini for that firmware.
- Datalog with shaky RPM signal : [here] (6 cyl with VR sensor and 60-2 wheel, BMW M20B25)
- Datalog with good RPM signal : [here] (4 cyl with Honeywell GT1 Hall sensor, simple trigger)
Update 2006-07-19
Sometimes when looking for something you are blinded by not double-checking what worked before. It seems something crawled up and died inside the inlet of the intercooler. :-)
I never thought to look at the MAP gauge in MegaTune before - last night I noticed straight away that something was wrong. It never showed more than 80 kPa while free revving the engine - it should be close to 100 kPa (atmosphere). We removed the pressure pipe from the inlet of the throttle body and the engine transformed, it really woke up (night and day) when we removed this restriction.
I'll be back tomorrow with a tuning update.
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, unfortunately the P259 was also damaged and removed, testing on the engine shows the board to be healthy again.
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.