Wow, the torque difference between 3000 and 4000 rpm is most impressive! From the looks of that torque curve, the boost enrichment delay yields a major efficiency improvement.
Odd as it may sound, I am thinking about this Leask modification to improve my fuel mileage. I drive my 1977 930 a lot. I am getting around 13 mpg in mixed driving (3.0 turbo, stock 6.5 compression ratio, SC cams, K27-7200, euro exhaust and 8:39 ring and pinion). I can't seem to get much better the 16 mpg in steady highway driving.
I sense that the much earlier boost with the cams and K27 are bringing on fuel enrichment too early. (I have the boost enrichment WUR for the Euro 3.3 turbo.) This is not the only problem - I think that the stock distributor is mismatched to these cams and turbo, too, but it seems like turning down the boost enrichment would help. I am sure that I would do better if I could make myself lighten up on the throttle, too.
So, would the Leask kit be a good solution? Where do I get information about it?
__________________ - Craig 3.4L, SC heads, 964 cams, B&B headers, K27 HF ZC turbo, Ruf IC. WUR & RPM switch, IA fuel head, Zork, G50/50 5 speed. 438 RWHP / 413 RWTQ - "930 is the wild slut you sleep with who tries to kill you every time you "get it on" - Quote by Gabe Movie: 930 on the dyno