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IMONBOOST IMONBOOST is offline
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Join Date: May 2001
Location: San Juan, Puerto Rico
Posts: 373
Garage
Issued tuning mixture vs boost?

Since I purchased the turbo 3.6, first thing I did was install a Wideband Zeitronix and then a turbologic ball-bleeding manual boost controller. I set the boost to 13.5psi max and the car was running amaizing but leaner than I would like it to run, about 12.7 AFR at top rpm on third (did not dare to test fourth gear).

So I adjusted the mixture screw about 1/4 of a turn clockwise (richer). Now, the car apparently idles on open loop pretty steady at 12.8 AFR because I don't see the AFRs beign forced to 14.5 like it used to on idle. When crusing, the AFRs do still pull to 14.5. Now when on WOT, the car feels significantly slower and the peak boost on third droped to around 11 psi and the AFR at redline is about 12.0. So AFRs look good but car is slower loosing some boost.

My understanding of this is that before I was benefiting (faster) from the leaner condition at the expense of killing the engine.

Is my reasoning correct, can I then work with the mixture and manual boost controller to get the 13.5 psi but staying below 12.2 AFRs on redline?
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Old 07-31-2010, 05:47 PM
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