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Jim2 Jim2 is offline
7.0:1 > 11.3:1
Join Date: Oct 2003
Location: Calgary
Posts: 1,864
Bob, +1 or 2 on the O2 sensor and Gage (wide band). Personally I don't feel data logging of the O2 is required because once you have verified and set up your mixture the instrument will have less value, but not a bad idea to leave it installed.

The narrow band O2 set-ups are less $$ but they are off the scale in the 12s - better suited to grocery getters running 13+

Wide band O2s will give you the kind of accuracy you are after in your question #2. Note that readings do seem to fluctuate a little, perhaps .2 - .3. There may be variables that effect
CIS AFRs such as inlet charge temp, ambient temp etc. You may find it difficult to get dead nuts repeatability, but you will certainly have the accuracy you need.

Your point number #3: EGT will fluctuate with AFRs and timing, but there is nothing specific you can do to effectively "turn down" your EGT, besides fattening up your mixture or advancing your timing, but these two variables need to be set to a specification range in order for your engine to run optimally. My personal opinion is that an EGT Gage will be of little value for the street, though if you run on the track it can indicate an altered setting of the two above variables. I once found my EGT was up about 100 F and I discovered my advance/retard plate in the dist was sticking.

Good that you are interested in these issues as the 911 turbos see significant thermal load, and cost $$$ to repair.

Old 02-23-2007, 05:27 PM
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