KG engine head modifications

[Christo Atanasov]

Hi all,

First I really does not know for which subforum is my question - for MB specific, or for WR specific, because it is KG specific :). 

I have an '85 Audi 200 with KG motor for some reasons it has static CR of about 9.9:1 (too many head removals and regrinding of the head) so for now I drive with boost of about 0.2bars. Now I plan to use another head from WC engine (solid lifters) and make some modification of it chamber (about 3cc more volume - cutting edges beside of valves in order to achieve something like this http://quattro.elit-auto.com/temp/Image015.jpg). Then I plan to put Multi Layer Steel head gasket from 2.5TDi engine which is approximately 1mm thick, so I think I'll finish with static CR of slightly under 8.5:1. I know that factory CR for KG engine is 8.8:1, so my MAC-05A wants to manage ignition of engine with such CR. First question is - how this difference from 8.5 to 8.8:1 will affect performance. How about if I swap camshaft with WC camshaft. It has about 10 degrees longer intake and exhaust phases and 10 degree overlap between exhaust close and open of the intake valve. You can seen camshaft specifications at Huw's website: http://www.humanspeakers.com/audi/engines.htm (very useful information. Thanks a lot Huw!) I think that with this setup will be better if I lower static CR. This wide phase camshaft may give me higher dynamic CR, so I think my ignition ECU will be happy with it.

What do you think - what will be better choice, to go with WC camshaft, or to keep my original KG camshaft, maybe a little bit retarded - intake to start about TDC, instead of those 4 degrees BTDC.