The compressor of the stock turbocharger is "out of it's map" by the time you get up around 23-24 PSI anyway (and even less at higher elevation), but the MAP sensor is unable to identify boost levels above that number anyway. It's a 3 bar sensor (bar being a measurement of pressure) that identifies the first bar as vacuum (of which a diesel has none). So really, we're looking at a 0-5V, 2 bar sensor. The maximum that the sensor would be able to really identify would be 29 PSI, however, no 0-5V sensors actually put out 5V at max due to resistance and other voltage losses. Typically, you're looking at 4.3 to 4.5 volts. In addition, just the way the voltage is interpreted inside the PCM sometimes causes a lower boost reading as well.
It's really not that big of an issue since boost values really aren't that important in the grand scheme of things....it's just a "fun" gauge to watch when you don't care about fuel economy.
A "boost fooler" certainly won't hurt anything. If you've already got it on the way, I would use it. Set your maximum boost to 20-23 PSI and have fun.
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Tuning, PCM flashing, and burning chips for 7.3s since 2008. Repairing all aspects of 7.3L Powerstrokes for 25 years.
Eight 7.3L PSDs in the driveway including a 1994 Crown Vic and 1973 F100/2002 F350. Looking for the next victim.
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Thu, September 8th, 2011, 09:30 AM
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