SharkTuner Mk2

a complete tuning system for the Porsche 928

The JDS Porsche SharkTuners for the Porsche 928 allow the optimization of the fuel and ignition maps to ensure optimum performance from the engine. This is particularly important if the engine has been modified in any way e.g. change of exhaust system, supercharger. The original SharkTuner Mk1 connected via a "ribbon cable" to the ECU for 85/86 928s. The SharkTuner-2 for 87+ replaces the original ROM's with programmable memory modules ("PEM's") and connects via the diagnostic connector. This page covers the SharkTuner-2, for info on the SharkTuner Mk1 see this page. Complete information on the SharkTuner family is available on the JDSPorsche website.

The SharkTuner-2 is a hardware interface between the LH ECU (fuel injection computer) and/or the EZK ECU (ignition computer) and a laptop computer. Programmable memories (PEM's) replace the factory ROM chips, a slave microcontroller in the SharkTuner acts as an interface between a laptop computer and the ECU's, and a custom Windows program running in the laptop provides access to both the LH and EZK ECU's for real-time diagnostics, adjustments, and data logging. For tuning, a wideband-O2 (WBO2) sensor is required to provide a measurement of the air/fuel ratio (AFR). The SharkTuner is powered by the diagnostic connector fitted to all 87+ 928s, the WBO2 can be powered from the factory NBO2 sensor connector or a specially-wired connection. 

Sirius Cybernetics LLC (Jim Corenman) is an agent for JDSPorsche for SharkTuner sales and support for the Americas, Australia and Asia. (For sales in the Mideast and Europe, contact JDSPorsche at We are also the developers of the Sharkplotter software, which allows post-processing SharkTuner log files to update fuel and ignition maps-- no longer do you need to drive with one hand on the keyboard and the other on the wheel.

Sharktuner 2 complete with a connecting cable for '87+ (S4 and later) 928's, and one set of PEM's (programmable memory modules) is $990.00 plus shipping (see below). This, and a WBO2 sensor/controller, are all you need to tune and diagnose the LH and EZK.

Extra PEM programmable memory modules for 87+ cars are $100/ea, one each required for the LH and EZK.

PEM's can be supplied pre-loaded for S4, GT or GTS (please specify) and can be installed without a Sharktuner, to make your car "Sharktuner-Ready". We are also developing a line of "Performance PEM's", which are pre-tuned for those who want to plug-and-go. These provide enhanced performance out of the box, and are "Sharktuner Ready" as a base for further tweaking.

Here is the Sharktuner 2 user manual for more information (click the link to open, right-click to download).

New!!! We have also done some introduction and how-to video's which are available on youtube, click here

Shipping options: A SharkTuner-2 with PEM's and cables can ship within the US in a medium Priority Mail flat-rate box for $23, including insurance. One or two PEM's can ship in a small Priority Mail flat-rate box for $7.50 with insurance. We can also ship Express Mail, UPS or Fedex with delivery as quick as your pocketbook is deep, or overseas via Post or courier as you desire. Send an email to: with your requirements and we'll be happy to help.

Every SharkTuner purchase also includes our award-winning "Sharkplotter" software, which provides a powerful tool for reviewing and processing log files. Now you can tune by just driving around!

And please read the manual first, it will make everything much more clear!

Happy tuning!


To order a Sharktuner, either send an email with your details, or use our handy shopping cart below. Standard shipping is via Priority Mail, if you need it quicker/slower be sure to send us an email with your requirements, and of course additional charges may apply.

SharkTuner-2 with two PEM's (optionally without), one Diagnostic cable (select below), USB cable and Software CD:

Currently Out of stock, please check back or inquire.

Additional Diagnostic Cable (select type):
Additional PEM's (great for borrowing your friend's Sharktuner!). Two required, one for the LH 2.3 and one for the EZK ECU: