DwayneC

The old form got archived as I was posting. From the last forum:<br>>>><br>how about a three-position toggle switch in the dash that selects between stock boost, .8 bar and 1 bar?<p>a plug-in module that snaps into the ECU with 3 different boost, spark and fuel maps, could be wired up to the switch. the program could include a provision that the ignition be turned off and restarted before a new program would take effect in order to keep drivers from switching between programs while the engine is running. unless there is a safe way to apply different ECU maps to a running motor.<p>quick trip to the store or the dry cleaner? set the switch to stock and go.<p>leaving late for dinner at the in-laws? switch over to .8 bar and you'll be there on time.<p>joining the local A4 club at the base of a great canyon run? click over to 1.0 bar and blow the injectors clean.<p>i know that some of the turbo manufacturers that specialize in other marques make brains that control boost, etc. that can be installed in glove boxes or hidden elsewhere. can anyone comment on the feasibility of this in an A4 application? <br><<<<p>Here's an easier method to get what you describe:<p>If you don't always want to run at a full 1.0BAR of boost just get a 1 BAR chip and DON'T always put the peddle to the floor. You only get full boost at wide open throttle.<p>Driving down the highway you'll find that your engine will usually run under vacuum (NOT boost) regardless of the chip you have installed - unless you are going *very* fast or passing.<p>DC<br>94 S4 with 21 PSI (1.4 BAR) boost at WOT, usually - but not always :-) , 1.0 BAR vacuum on the highway

donp

Wetterauer offers a switchable chip in europe (I assume they still do). I asked about it some time ago. They had planned to offer it in the US but OBDII system freaked out when the software was switched and it put on the CE light at random so they do not offer it here.

Sean G

I recently completed my boost gauge install and have been able to observe the boost conditions on the engine through a variety of driving situations. Here is what I have observed:<p>When the car is cold and I first start the engine the gauge reads about 18 In/Hg of vacuum. Once warm it idles at a solid 20 In/Hg of vacuum. As I push the accelerator the gauge moves up (decreasing vacuum) to a reading of zero (atmospheric pressure). When I accelerate a tad faster than a casual "normal" acceleration the gauge moves into positive pressure territory. While decelerating/coasting (foot of the gas) the<br>gauge reads 25 In/Hg of vacuum.<p>Here is what I have found to be the most interesting: The majority of the time while driving the engine is in a vacuum state! Cruising at about 70-80 MPH the gauge reads 10-12 In/Hg of vacuum! Moderate acceleration only reads 2-4 PSI of boost! Now this may seem like stating the obvious, but boost pressure really only increases when you give it some serious gas such as in a passing situation. Make a quick acceleration and the gauge reads 6-8 PSI. Floor it and pressure jumps up to 14-15 PSI (can you say Wett chip?) but then drops back to about 11-12 PSI. Ease off the gas even slightly and the boost pressure quickly drops.<p>What does all this mean? Normal everyday surface street driving involves vacuum (as in a normally aspirated engine) the majority of the time. Boost<br>is only being called for under specific conditions and only momentarily.<p>Now the real question is whether or not these "momentary" increases in stress due to higher boost cause any significant extra wear on the engine....<p>Sean<br>97 1.8Tqm<br>

ReyHey

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