[RS Barn]

I finally descided to post some dyno graphs showing effect of cam timing on both N/A and SC cars. The variocam advances the cams at 1500rpm and retards them at 5500rpm. I have found when cam timing is set to factory specs there is a dip in power and torque just after 5500. I  take cars to dyno with cams set to factory and when i see dip, I advance the cams right at the dyno until I lose the dip. When I am happy with dyno curve I then recheck cam timing to see where it is for my database.

I have hundreds of dyno runs on file and this holds true throughout. On engines with agressive cams I use a switch for variocam so cams don't retard at 5500rpm as the dip get worse with longer duration cams. Some customers have seen me adjust cams at dyno and results.

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[Rap]

I can validate that.

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[RS Barn]

I followed the advice from cam manufactures when I started messing with more agressive cams. I asked them where to set them and their response was, wherever they work the best. So I followed this advice with stock cams and found I could eliminate the power dip. There aren't any problems with emissions, heat, longevity, tune ablilty , changing the climate or any other things people may want to try and scare you with. What works, works. 

I did confirm that the cam timing directions Porsche gives matches the degree specs they offer. So I'm still not sure why a slight difference improves the car. But it does. 

The OE 968 cams are really ideal for these engines as a street car. You cannot add lift, duration or change overlap and get better overall performance. Porsche really did their homework here.

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