Hopefully this post can help out and give something to the community....this car and its poor running cost us a lot of time and effort till we developed this fix.

After having an 85 manual 928 that was doing our heads in with poor running, AFM problems, and ignition issues (and attempting to repair them all one by one without a lot of joy) we had a look to see what was around to replace the ECU simply with something programmable....no real joy.

Problem is that the early girls used a much different crank pickup to the later cars having a 100 tooth trigger wheel - and the solution from what had researched was to fit a later model 60-2 trigger which is a massive amount of work - we decided to go about it differently.

Working with a local company - Adaptronic ECU - we wrote a special crank trigger mode to read the early reluctor, and then customised the ECU firmware to work with the 928 twin distributor spark system - which meant we could replace the two factory computers with the one simple programmable system.

The wiring is simple and neat, and the new ECU goes back in place of the originals - you just have a lot more room to play with now!

Base file and setup calibration we carried out on the chassis dyno to give perfect running, starting, idling, and full power operation. We run the system in Speed Density mode to get rid of the old Air Flow Meter and all its associated issues. The Adaptronic has an in-built MAP sensor so no extra bits needed.

The result is fantastic and painless, and pretty cheap compared to anything else we can find.
The tuning software for the ECU is free and can be downloaded off the web. We can supply a base tuning file that will run your 928 perfectly which you can then tweak yourself if you want.

Drop me a PM if you need any help with this - hopefully it saves a lot of headaches!

 

Neat, Do you have something for US cars?

 

I believe the US cars are identical so it shouldn't be an issue. Let me know of any differences you know of. For later model 928s we just change the crank triggering back to a conventional Porsche 60-2 arrangement and it works no problems at all.

 

Do you plug in the stock wiring harness into the new ECU, or do you need to rewire the system? You said the wiring was simple, I'm trying understand how simple.

 

+++^^^^^^

Was thinking same thing!

 

First off, the 85 Euro (S2) has a Mass Air Flow sensor (MAF), not an AFM.

What is a "MAP sensor"? Where is it built in?

The S2 twin dizzy motor is unique to the 84-86 Euro (ROW) cars. 85 & 86 US cars were 32 valve (S3). There are a lot of differences.

Last, and I admit it sounds a bit snarky, but the graph shows around 255 hp. That motor was rated at 310, and it's considered to be conservative (supposedly, cars were dynoed at almost 330 hp straight off the showroom floor). Where did the horsepower go?

 

Ok, MAF (Mass Airflow Meter) AFM (Air Flow Meter) same thing, same part
The MAP (Manifold Air Pressure) sensor is built into the new ECU and allows the system to run without needing the factory airflow meter.
The whole thing is a lot lot simpler when there is only one distributor - interfacing to these needed some tricky software that's for sure, but it works really nice.

As for the power reading - we run retarder style dynos in this side of the world with electric load brakes, rather than an inertial style Dynojet - so the cars always read lower than manufacturer crankshaft power claims due to the driveline loss that goes on in the car. Add around 25% to our HP at the wheels figure to get it similar to what a Dynojet would read.

Hope that helps.

 

As for wiring its a 12 wire hookup - not super difficult at all

 

MAP is much simpler. can you piggy back a TPS input as well?
AFM uses a physical "door" to measure the air flow, where as a MAF uses a heated wire system.

im a big fan of Dyno Dynamics. steady state is the way to go for a dyno. Dynojets are easy to get "good numbers on"

 

Pretty cool. Does the box have knock sensor(s) input? (S2/S3 can fit one.)

Torque does not seem plausible. Even if mislabeled, 485 Nm = 357 ft lb.

 

Torque shown on the dyno plot is torque generated at the rear wheels, at the physical tire tread - which is obviously engine torque multiplied by the final drive ratio and the gear ratio the vehicle was tuned in (fourth gear in this example). There is no way of accurately measuring crankshaft torque without removing the engine and putting it on an engine dyno so we stick with the raw reading for best resolution.

We can interface a knock sensor - but didn't in this example - the implementation of the ECU was to make the engine run properly again rather the specifically optimise the output for a given application - it was terrible the way it was bucking and falling flat at 4000rpm.

The thought was there to interface a linear TPS signal, but its not really needed as we use a feature that give 'predictative' accelerator pump function rather than requiring a TPS to generate it.

The ECU can do a ton of other stuff, map for boost applications, full throttle 'flat shift' upshift, traction control etc. Its all factory in it if anyone wanted to have a fiddle. You can also plug your laptop in and datalog whenever you want. Does some neat things.

 

Very cool.

The 85/6 USA and 84/5/6 Euros actually are very similar.
Our 84 Euro ran a slightly tweaked 85 USA controller.

 

Martin,

Always good to read about such achievements especially if they have potential for other owners- well done. There may well be an eager market for owners of the earlier models that Sharktuner does not cater for [as I am aware] if "the price is right".
John Speake has done something similar with MAP as an extension to his ST2 kit for the later LH/EZK models. How does your system measure MAP? By the sound of it you must run a live vacuum line to the computer module instead of a transduced signal via a sender unit.

Also intrigued by your comment about the dyno numbers. As I am aware dynojet usually measure rwhp and convert to flywheel bhp by adding a [presumed?] 15% to account for driveline losses but maybe there is more science to it than that.

Rgds

Fred

 

Fred
The MAP sensor comes inside the Adaptronic ECU. In the case of the 928 there is already a factory line that runs to the ignition ECU that simply plugs straight into our unit. Simple as that

 

Sharktuner Mk1 will tune 16v and 32v 84-86 cars.