Porsche Electronics Specialist

Cambridge, England

MORE POWER FOR 84-86 16valve 928S(2)

This product is a pair of LH (fuel) and EZ-F (igntion) ECU replacement EPROMs for the MY85 - 86 Euro 16v 4.7 litre 928 models.

They offer significant power and torque improvements for a very modest outlay. These cars have very conservative ignition timing to take account of the variable fuel quality available in the 1980s. With modern 98 octane fuel, it is possible to reduce these safety margins and gain substantial power improvements across the whole rpm range. These improvements are shown on the graph above.

The results shown above were made on a completely standard 1986 928 16v with 120k miles.

The LH ECU has also been remapped to eliminate the weak fuelling in the mid range and over-richness at high load/rpm. The result is smoother driving under all conditions. The fuel cutoff "rev limiter" has been raised from the standard 6390rpm to 6550rpm.

In order to guarantee safe operation, it is essential that your 928S is in good condition. This requires:

1) A MAF within calibration i.e that can set a minimum of 1% tailpipe CO with the idle adjustment CO potentiometer within range 300 to 500 ohms.

2) Injectors cleaned, balanced and flowing within speciification.

3) Confirmed fuel pressure and fuel flow rate.

4) 93 US/AKI (North America) or 98 RON (Europe) Octane fuel must be used.

5) As we cannot verify the condition of your application, using these chips is at your own risk.

** The MY 84 with the 928 618 123 00 LH fuel injection ECU is not suitable for the modified LH EPROM, the correct LH Euro ECU is 928 618 123 02 (Euro 16v). But you can also use the 03, 04 and 05 from the US 32v 86/86 without modification with my chip.

The EZ-F EPROM can be used for all EZ-F ignition ECUs 928 618 124 00/02/03/04/05/06. This list also includes the 05 fitted to the US 32v 85/86.

The original ignition EZ-F ECUs 02, 04 and 06 fitted for the Australian, New Zealand, Swiss, Swedish and Hong Kong markets were even more downgraded than the 00 and 03 versions used for the rest of the world, so the performance improvements will be even larger than the gains indicated above.

Link to 16v chip install instructions.

Prices per pair are: 115 GBP + VAT and postage for UK customers; $170 USD plus postage for US/Canada; 140 Euro + VAT & postage for mainland Europe.

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