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Old 06-05-2018, 11:23 AM   #6
The Radium King
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Originally Posted by jdh39fp View Post
It appears the tutorials and information has been taken down from the renntech board. I got my original question answered privately (don't try to use the 2001 Motronic 7.2). Others have also shared some nightmare stories about trying third party racing ECU's on Porsche engines though a few have them working.

I am now am on the path of comparing wiring diagrams between the 2002 and 2001 and creating a spreadsheet from scratch to document the necessary wiring changes. Others have created these but they also seem to have all been taken down from the forums. I am close but the diagrams I have have aren't yet telling me the whole story.
so, your car has variocam, which is on/off cam timing adjustment.
your engine has variocam plus, which is variable cam timing and duration adjustment.

the latter requires more ecu brain power to operate, and physically more wires. for this reason porsche moved from the 7.2 dme which is in your car, to the 7.8 dme which is what the engine needs.

you have two options:

1) put a 7.8 dme in your car, or
2) run your engine with w 7.2 dme.

the former is the more seamless of the two, but there is a complication; the 7.8 dme also introduced CANBus communication, which is a multiplexed signal over a single twisted pair of wires, vs the previous 'wire per signal' approach. this means that the conversion also requires changing a number of other controllers in your car - gauge cluster, abs pump (which requires changing wheel speed sensors) hvac controller (probably not an issue for you). and, of course, a number of pinouts have to change, and the other things that come with the conversion (non-return fuel lines, etc.; as per pelican).

the latter is possible and referred to in todd's renntech thread. there was a (nla) module you could get that took an rpm signal and converted it into variocam plus inputs (requires logic and maps of cam timing and duration vs rpm and, presumably, engine load, iat, engine temp, etc. - most could be gleaned from porsche info on variocam plus, and probably squeezed into an anduino-type thing). OR you could run your variocam plus like a standard variocam and just have it turn on/off; cam change-over will hammer things, but all you need is an rpm-driven (or, presumably, variocam signal-driven) window switch. heck, i've even read of racers welding the cam into the high rpm position and being done with it.

Last edited by The Radium King; 06-05-2018 at 11:28 AM.
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