Building a Porsche 3,0l 944 turbo
Started this project during last autumn by dismantling the whole engine, originally 4cyl / 2,5l / 8v, turbocharged & intercooled. With a crankshaft from a 3,0l engine and Darton MID sleeves it will have 3,0l displacement. Piston oil squirters and a crank scraper / windage tray are added. Original head is changed to one from normally aspirated, it allows bigger intake & exhaust valves ( 48 & 42 mm ) and turbocharger is Garrett GT3582R. Full 3" exhaust. Larger intercooler pipes and bigger intercooler ( 16x12x3 inch core ). Bosch 044 fuel pump. Custom intake with ITBs ( from Suzuki GSX-R 600 )
Now the details that affect VEMS specs and installation.
- original Bosch Motronic sensors will be used
- water temp x2 , oil press, knock
- exceptions are MAT and MAP, these will be from VEMS web shop
- original wiring loom will be used
- fuel injectors are SiemensDeka
- Static Flow Rate (GAS): 86 lb/hr @ 43.5PSI (300kPa) = 903cc/min, 10.88g/s
- Coil Resistance: 2.35 Ohms / Low Impedance / Low-Z
- Ignition for starters wasted spark, with option to COP
- TPS will most likely be the one that comes with ITBs
- For trigger see below
Trigger
primary (crank)
* toothcount ?
- missing tooth ?
- VR / HALL ? Anyone knows this ?
Porsche 944 turbo Trigger: 132teeth on flywheel, VR sensor and Crank home (1 pin on flywheel 58,5 dec BTD, if i remember right) VR sensor. No cam sensor) And no missing teeth!
Are You doing Plug and Play to motronic harness? Same project. Yes.
secondary (cam)
* VR / HALL ? Anyone knows this ?
There are doubts that both of them are VR, so investigation is needed.
For both sensor, measure all pairs of pins, in both direction (with a 3 pin connector this is 3*2=6 measurements). Write them here.
OK, what I now know is this. Info above about flyweel teeth count, pin on flywheel and sensors type are correct, that pin position has just to be confirmed. I bought yesterday a book "Bosch Fuel Injection & Engine Management" and it describes this system
" For the most accurate measure of engine timing and speed, Motronic systems read the position of the crankshaft directly. Special sensors pick up signals from the flywheel teeth."
"The rpm sensor ( also called the engine speed sensor ) is an inductive-pulse sender that picks up pulses from a toothed wheel, usually the flywheel. The rpm signal can be displayed on a scope just as it is sent to the control unit, one blip or spike for each tooth. It is so accurate it can sense an rpm chance while the crankshaft turns only a few degrees.
The TDC, or reference mark sensor ( reference from cylinder no1 TDC ),is triggered by a set screw on the flywheel. each time the srew passes the TDC sensor, the sensor signals one blip for each crankshaft revolution. Both ensors are magnetic, with a soft iron core that stores the magnetic field. When a tooth in the flywheel or the reference sensorpin moves though the magnetic field, the change induces an electrical voltage in the winding. This voltage is he input signal to the control unit. The sensor is known as a passive diffusionfield sensor, because it does not require a current supply."
I have these both new sensors, identical, at home, I will post their Bosch number here as I return home. I guess this makes the system what is called the Auditrigger.
Shopping list
Assembled v3.3 controller
- 1-wire interface no
- ignition driver 4
- Knock and EGT yes
- LCD and PS2 yes
- MAP connection 400kPa onboard (5/3mm pneumatic)
- mounting-style screws
- PowerFlyback yes
- primary_trigger VR
- secondary_trigger VR
- EconoSeal36-Wire
- Econoseal18-Wire
- EGT sensor (K-type) Size 2mm
- K-thermocouple connector
- mounting-style panel-mount
- Sex pair
- mounting-style flyback
- Sex pair
- Wideband O2 sensor
- Wideband connector
- With wire with crimped wires
- MAT sensor
- Pneumatic valve 3way
Questions
How shift light output is done?
Is it possible to do two-level boost control, where boost level is changed by push-button?
I want the original boost gauge in instrument panel to be functional. The problem here is that it is electronic, ie. the Motronic's KLR ( boost & knock control unit ) feeds it. So it needs output from Genboard. Oher peoples obsevations how the signal is handled can be found here
http://forums.rennlist.com/rennforums/showthread.php?t=313463&page=2&pp=5&highlight=boost+signal
Is it possible to get such output, and scale it a bit differently? Now the gauge shows 1,0 when MAP is athmospheric, and I would like it to mean 1,0bar boost...
More questions
Do I need PowerFlyback when using low-impedance injectors??