Veelen

I am changing my 1975 911 Carrera 3.3 old distributer ignition system to an electronic ignition system supported by a Motec management system.
Basis spec's: 3,3 liter pistons, compression 10,5:1 twin spark, RSR cams and using 102 octane fuel.
Any ideas on the mapping of the timimg will be appreciated. I have run out of time and will not be able to run the car on a dyno before the first 2 races.

Howard

Veelen,

I'm not familiar with the Motec system, but I am running a very similar engine. I have a 3.4 liter 10.3:1 cr running Webers, with GE80 cams. I have experimented with several settings and have found that ( against suggestions from others) at idle (950 rpm) the initial advance is 16 degrees, at 3000 rpm an additional 16 degrees, and at 8000 rpm another 4 degrees for a total of 36. The advance on my system is linear so you should be able to fill in the gaps at various RPM levels when you map your Motec setup. With those radical cams you may find that it won't idle below 1100 rpm,you could go with 18 degrees at idle then 14 and another 4 at 8,000, but never exceed 36 degrees in any event.

Steve W

Take a look at this map. It's a fuel and ignition map Chris Bennet had made for his 3.4L, 10.5cr, twin plug programmed in the chip of the factory Motronic system. You need to look at his homepage to determine if any of his mods are similar to yours.

<a href="http://members.rennlist.org/messinwith911s/DMEMapTwinPlug34.htm" target="_blank">http://members.rennlist.org/messinwith911s/DMEMapTwinPlug34.htm</a>

<a href="http://members.rennlist.org/messinwith911s/" target="_blank">Chris Bennet's Page</a>