fuel mixture question

[Joe Craven]

I have access to a smog dyno and I put the VW on it last night to find out what the CO was under load. The car ran clean under full throttle and the CO was at 7%. This seems rather high so perhaps I lowered the Control Pressure to the fuel distributor too much. 46psi is the current setting. Anybody have an idea what the CO should be set at approximately for maximum power?

VW GTI Cup

[Joe Craven]

I found a reference on the Racer's Group website in that they found on a Porsche that it made maximum power at 13:1 which corresponds to approx. CO=3.5%.

Joe Craven

[machschnell]

I checked the handy Bosch Automotive Handbook, and on page 518, about 3.5% (halfway b/t 2.5 and 5) roughly corresponds to the torque peak in a small graph they had.

PJ

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83 Rabbit GTI - future ITB