Cosworth Ecu's for Dummies

I have been looking at what options are available for my 1989 2wd Sapphire Cosworth. 

There are two things to consider for a cosworth the computer (ecu) and the chip you are running with it.
Mine has a standard computer (L6) and I havent opened it up yet to see whether it has an aftermarket chip.

In New Zealand and Australia there is not alot of cosworths or tuners around. And I have struggled to work out what computers come with what cosworth vehicles, and what you can interchange.
A few of the owners in NZ have opted for aftermarket computers suck as Link, Autronic etc

James at Motorsport developments gave a brief summary of the different types of computers.

L1, yellow global mod screw, ecu has mounting wings

L6, white global mod screw, ecu has mounting wings

L8, white global mod screw, ecu has no wings,

P8, no global mod, no wings

http://passionford.com/forum/technical-help-q-and-a/346481-cosworth-ecu-identification.html

N.B. The First 2 letters refer to the name of the ECU, the screw he is talking about is externally on the ecu see pic , they are different colours, and the wings he is talking about is the external casting onto the casing of the ecu. 

It is also shown and discussed in great detail  in this great website:

http://www.bigturbo.co.uk/main1.htm

L1

L6

L8

P8

The chip from within the ECU that gets replaced is shown on the pic below, (N.B. This particular one is an aftermarket chip)





With the ECU's I am going to stay with the L6 for my particular car (down to cost), and get a chip sorted to suit. 

For a 2wd removing the L6 and replacing it with a L8 is a common upgrade.

One of the benefits is that the L8 allows lambda closed loop , (which most modern cars have), which uses readings from a exhaust sensor and the computer / chip optimises the fuel / air ratio for lower rev range to replace the mapping of the chip. In the upper range it will revert back to the chip readings.

With the L8 closed loop conversion you also need to change the TPS (throttle position sensor from a PF01 (2wd) to PF09 (4wd) and  the wiring to the TPS from the ecu as well. And you will need to put in a lamda (exhaust) sensor.

TPS sensors are explained also on http://www.bigturbo.co.uk/

 

More information on the closed loop is available from this other great UK website and supplier:

http://www.motorsport-developments.co.uk/closedloop.html