Carb tuning w/O2 sensor

[Greg tripp]

Randy's right, The best place is in the collector. Two bungs are needed, one in each side for each bank. The LM1 is a great tool. first calibrate the sensor in free air...Easy to do. Then do one bank at a time. First test at idle. DO NOT use the clamps at the end of the exhast pipe as there is too much "free air" and the reading will be way too lean, probably 20 or more ( 20 parts air to 1 part fuel). Adjust your needle valves till the meter reads approx 14.2-14.5AFR. Next step is to go drive the car under load. The recording of the LM1 is great at this point as you can concentrate on driving instead of watching the meter. The number to shoot for is 13.5 AFR. My car was around 12(TOO RICH). I went down two jet sizes in the primaries and drove the car again. Bingo, 13.5!. Now WOT (wide open throttle). Find somewhere that is SAFE and open her up. The number to shoot for is around 12.5. You will be and should be on the rich side as you want to dump gas in. I was at 11. Down two jet sizes in the secondaries and right on 12.5!. Test the other bank the same way. Now I get better gas milage and unbeliavabley better performance with no stumble. There are alot of great features on the LM1. Rpm and graphing make it easy to use. Hope this helps for basic info.

Greg