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I am starting down the road of a stand alone ECU install on my TPC supercharged 1990 C4. The Unichip system on my current setup only allows me so much precision to control the system. I know the Unichip and 2 extra injectors is a decent system that works the way it was meant to. However I have a sickness that always makes me look for new and better options. The install will include the VEMS ECU which I also have to install an EGT sensor, and intake temp sensor (AFM is removed), new fuel injectors, new fuel pump(not necessary but while I am updating injectors), new wideband O2 sensor, and down the road, direct ignition with 2 Bosch coil packs. I opted for the Bluetooth connector so I can have various gauges on an Android device as well as connect to the tuning software. Gus on the Stand Alone ECU thread gave me good advice to document and record everything. Will also keep backup of everything done. I am sure I will be relying on the collective knowledge of Rennlist for more ideas and help.
Thanks Raceboy for the VEMS, extra parts, and all the support. He has been a great help.
I think a proper new ECU and traditional 6 injectors is the way to go. You should look up user Juha G in the 993 forum, he took a similar path a few years ago when adding his TPC using a (motec?) ecu including a custom intercooler. Really nice setup.
Slow going as I have been at a tennis tournament and the state zoo this weekend through today. I did get a used DME harness in that will replace the one in my car that has been modified to work with the Unichip piggyback.
I plan on cleaning it up and new wrap. I do have to install one diode in the harness at the connector for the Idle Bypass to work smoothly.
Will plan on hooking up the unit tomorrow night to see if I can download the 964 maps in to the tuning software to keep as a backup.
These are 2 Bosch 0221503002 coil packs in a custom bracket and custom adaptors. They are from Raceboy and where installed on another car, but taken off in order to return the car to stock for sale. There is some more detail on the last few posts of the below thread. For my install, I am going to start with original coils and distributor, however after everything is running comfortably, I plan on ditching the distributor for this route.
If you are going to map this yourself or having someone doing it, make sure you enable the timing retard ramp up function if there is one.
Normally, timing is retarted according to the boost and rpm. But that is not enough in cases where you suddenly go from small throttle or idle to heavy throttle. What happens is the SC bypass will turn off and boost will hit VERY quickly. There is lots of potential for detonation when this happen.
The ramp function will help this by detecting a sudden ramp up in boost or big change in throttle position, and retard additional timing for a short time.
For example, on the TPC UNIQ system, I set the function to detect a 40% throttle jump. When that happens, retard an additional 3 degrees for .x (don't remember) seconds.
Before getting too far along, I have decided I should go through all the training information on Vemstune. They also have videos which is nice for people like me that hate instruction manuals.
Also, thanks Raceboy for the 964 config file. Now I have a backup and also something to review as I go through the training.
Will finish up the harness hopefully this weekend. The 3" aluminum tube came today to replace the section where the AFM sits.
In order to avoid detonation with sudden rise of temperature and/or rpm/boost, there is a MAT retard table that is configurable with regards to TPS and MAT. On top of that well tuned ignition table is sort of essential to standalone ECU and I have provided Michael a tuned 993 ignition map with TPC supercharger...
Would anyone know which of the idle bypass wires has the positive input? I know from the schematic that the blue wire is connector directly to the DME at pin 4. The other line runs through other connections as in the attached schematic.
08-13-2014, 08:10 AM
VEMS and TPC Supercharger
