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RarlyL8 RarlyL8 is offline
Crotchety Old Bastard
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Join Date: Jan 2000
Location: Huntsville, AL
Posts: 14,081
CIS became more complex through the 19 years it was used on the turbo. The 965 has layers of switches, sensors, EZ69 timing control, etc. that all must be considered when any tuning changes are made. If any subsystem is eleminated or bypassed (such as Lambda on the late 930s) they must be compesated for. If you find a situation where the idle or AFRs become unstable I would hook everything back up and see where the baseline is. You can really get things out of wack in a hurry once the baseline is lost.
If your Lambda system is bypassed you cannot overlook the still needed function of the frequency valve. It will function in open loop but you must compensate for the lack of signal during events that normally are run in closed loop. Idle mixture should be adjusted with the sensor in place if Lambda is to be left intact as that is the baseline under those conditions.
RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds
'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8
Old 04-03-2013, 05:45 PM
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