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911st 911st is offline
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Join Date: Jan 2004
Location: Sacramento
Posts: 7,269
Jim, I have not done the vacunm sensing mod my slef. I guy named Lee Rice was famous for this years ago and it was called the Rice Fueler. Howver, I have talked to others that have converted there WUR them selves. There is not change in how the WUR is hooked up. What I belive is done is to modify or remove the spring that has to be pushed to triger the boost enrichment. Then vacunm holds the WUR in cruse / idle mode. Then when vac is reduced or goes away the enrichment cycle is trigered.

The AFR's are a curve because the metering plate dose not advance in a liner manner with changes in air flow. Work to correct this and gain full travel and you will not need to lower CP for more fuel. There are three ways to effect this. One is to relocate the metering arm pivot so with smaller changes in the metering plate position, the pin progresses further keeping the MP more up in the cone. Another is to add volunm to the top of the metering plate so air flow dose not start spilling of the end of the plate toward the end of its travel. The third is to reenginer the cone the plate advances in. It is even possable if one wanted to go to the effort to have the AFR curve be straight or even invert to more fuel is added in upper WOT rpms instead of getting leaner, up to the flow capacaty of the head.

Euro v US head. If I had a good US head I would not change it. It is possable to buy a $330 controler to drive the Lambda valve on the head. This becomes a fueler. The duty cycle of the Lambda valve is usally kept arould 50%. You use this driver to just act as a fueler by setting it to 25% and reset you CO. Then based on load and rpm you can start increasing the duty cycle up to 75% to gain more fuel. If you do not need much more fuel, it can be used to actually tune the AFR curve taking fuel out of the fat area and putting it back up top. Cool stuf and actually kind of easy to accomplish and can give an advantage to the USA/Lambda heads. Kind of an IA on demand.

Old 03-14-2009, 01:24 PM
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