alexjc4

As you know my car isn't quite run in yet having been rebuilt by Redtek, but there's nothing like the confidence a fresh engine, and the deep need to amortize the cost associated over as many years as possible, to turn one's thoughts to long term plans...

I missed out on a s/h TPC kit earlier in the year, good fortune as it turned out, but in the long term either that or ITBs and sexy headers are on the card.

So to lay the groundwork, I've been looking at standalone ecu options, as there's no point doing either on the above without proper engine management. I love the motronic in all its eighties glory but it just won't cut it for what I want.

I had a cam and a rom chip from redtek as part of the rebuild and this still needs fine tuning and we will press ahead with that as I want a good base before I fit the standalone, and besides I paid for it already. I'll dyno the car once Redtek have finished their work to see what i paid for. The I'll set about the standalone project.

So what ecu? Motec, the m84 is great value but everything you want is an expensive option a wiring harness or adapter will cost a bomb, what else?Link g4+/Vipec, Syvecs, Emerald, DTA, GEMS, Megasquirt, Haltech, AEM....

By chance really I did some research on VEMS, originally a fork off the Megasquirt project, but now a product in its own right with no hardware or software shared. The latest versions look a great spec, SpeedDensity, AlphaN or Hybrid, Wideband O2 built in, windowed knock built in, launch control, antilag, boost control, really good idle control etc. And it comes in a 55pin motronic (thats us btw) plug and play version with a decent base map. So you can lose the AFM, add a TPS and IAT and keep everything else stock. All for the price of Ninemeister's Motec adapter harness.

Anyway one is being built for me in the next couples of weeks, so wish me luck!

Btw I have SW chip going cheap if anyone's interested, they are as good as you hear.

sc

PMed you about the SW chip.

robt964

Subscribed

Sire

yeah interested.

alexjc4

Replied

Cosmos99

Looking forward to this. I am hoping to do stand alone this winter

alexjc4

I have tried to gather all the info require to spec a pnp system for my 1989 964 C4, some details may vary with spec options (ac, cruise etc) and model year. Let me know if you see any booboos.

The car as it is 25/06/2014

Mechanical

3.6L
6 cylinder
Upgraded "cup" cam of unknown lift and duration
Decat pipe
Permanent 4WD with centre and rear active differentials

Management

55pin Motronic
Twin spark
Twin distributor
Twin coil (not coilpack or cop)
Standard 218cc/min at 3.8bar high impedance injectors
2 wire style Bosch ISV
Intake "resonance flap", vacuum actuator, electrically activated
Carbon canister vacuum switch

Sensors

VR crank trigger on flywheel 60-2, missing tooth is 84 degrees BTDC
Hall sensor in distributor
4WD wheel sensor on rear diff, Hall
2x ABS wheel sensors
Cylinder head temperature sensor (NTC)
2 knock sensors
Narrowband O2 is fitted to most models, but this car had a factory option selected to remove this
Standard AFM (Flap style)
AIT (NTC type inside AFM)
Altitude potentiometer
Standard idle and wot switch (no analog TPS)

PLAN

To begin with I will keep the twin coils and distributors
Fit an analog/potentiometer TPS
Remove AFM and add a separate MAT.
Add wideband 02
Convert to Speed Density (MAP) operation
Test idle and review if AplhaN+Map compensation would be better

Questions

Continued operation of HVAC (this car does not have AC)
Continued operation of ODB for ABS and 4WD diagnosis and testing
Operation of "central informer" check engine light

References

Dme pin out here:
http://www.vems.hu/wiki/index.php?pa...scheCarreraTwo

further information (some for 993 specifically)
http://www.vems.hu/wiki/index.php?pa...PorscheCarrera

Injector info
https://rennlist.com/forums/964-foru...injectors.html

Standard DME coil dwell time table
https://rennlist.com/forums/964-foru...-issues-3.html

UncleRemus

Alex,

I'm probably going to tackle the M84 I have in the next year. I have stock ignition and fuel curves from the motronic, and I have lots of other curves I've downloaded from searching forums. If you decide M84, we can collaborate.

bigunit_271078

Reading your threads make my brain hurt Alex. I shall subscribe though as no doubt I will learn something even if I have to re read it 10 times!!!!

alexjc4

Lol In the last week I have entered the inner sanctum of the nerd gods and I have doubled my knowledge but I still feel like total noob!

alexjc4

Worth saying that I'm following in the footsteps of Gus who is running VEMS on his VRAM 964, and Ducks964 who is about to take delivery of his VEMS for his TPC kitted 964.

Also, despite all the info I have collected, without a supplier who could configure the inputs and outputs and provide a base map that takes care of all the details (resonance flap, dwell time, flyback, isv control etc etc) , this project would require a level of time and intellect I lack.

Cheeksyboy

Subscribed.

If you need me to drive whilst you map this one...like we did for the Skyline, then happy to help!

Still trying to get started on learning 'how to make my car handle'

dave964diver

Subscribed

robt964

I can't see any reason why the HVAC would not continue to work normally. To my knowledge it has no inputs from the Motronic.

Likewise the ODB for ABS etc should also fine? The comms doesn't come via the motronic. I think I believe it may use different connections on the plug altogether.

Infact all these can be confirmed by taking a look the wiring schematic. (shuffles off to find schematic)

alexjc4

Yeah, i think you are right about the AWD/ABS as they are separate systems, but there are two pins in the dme which are marked heater blower and a/c - the later is probable either "idle up" or to cut the a/c at WOT.