I spent about two hours on the dyno (Carburetor Connection in Totem Lake, WA) today with Chris Powell of Chris’s German Auto Service (Redmond, WA). Chris has many years of experience building and tuning hot rod 911’s and race cars. He’s more familiar with Motec and Haltec (he’s a dealer), but more importantly he knows stand-alone tuning of air cooled 911’s backwards and forwards.
I had not spent a lot of time tuning the full throttle portion of the tables and the dyno graph shows it. Here is a graph showing the before and after power curves.
Here is the final form.
There were a few hiccups along the way; such as realizing the head temp was bouncing around enough at the start of a pull to dip into warmup enrichment and briefly mess up the mixture. Once that was figured out, I dropped out the warm up and we finished dialing the fuel at WOT.
With fuel looking good, we started playing with the timing, but found there weren’t any gains to be had there over the ignition table I was already running.
Final numbers were 234 wheel HP and 230 wheel lb/ft. Corrected with 15% driveline loss that is 275 HP and 270 lb/ft at the crank. I’m fine with those numbers. The motor feels smooth and responsive and happy throughout the entire rev range.