there is so much misinformation, rampant speculation and ill advised opinion in this thread its not even funny. there are more than a few things stated in here showing that there is little or no understanding as to how A) engines fundamentally work B) engine management works C) what triggers fuel cut D)
the car has been to one shop, one person for tuning and in my opinion the owner of this car has been shortchanged by every party involved in the process and not given the benefit of a person's full attention to the car. compression isn't going to be a factor that triggers fuel or boost cut, or even so much as sputters. compression is not 10.5 to 1 on these engines stock and the computer is not tuned for that. compression is not even that high on a standard mazda3 2.3 L3 engine. mazda hasn't sold a 4 cylinder engine with anywhere near that compression ratio - and not in america mind you - since 2001 on the japan spec FS-ZE. even if a computer were tuned for that ratio, the argument that a piggyback is incapable of making adjustments to account for a mere half point drop in compression renders that system effectively worthless. i've seen less advanced turboed engines with a point and half drop in compression run fine on stock computer with no other piggyback interference whatsoever. whether or not the engine is direct injection is not going to be the deal killer either. you do not need high compression to make direct injection work. having direct injection allows for higher compression ratios where otherwise not possible. if the compression ratio were the issue here, you would see problems at idle and prior to any kind of boost before you saw them anywhere else.
if anything, running lower compression would by all logic presented lessen any chance of the ECU triggering a fuel or boost cut. your engine would naturally run richer from the get go, combustion temps would cooler, the car would be making the same or less power prior to any tuning, etc etc.
there seems to be this misconception that one lone factor induces fuel/boost cut, as well as one misconception that one lone factor induces throttle plate closing on this car. if either of these were true, you would not have engineers chasing thier tails trying to isolate it. simple voltage clamps would solve your problems. i am not at all surprised that even with standbacks, XEDEs, MAP clamps, electronic boost controllers, boost cut defensers that people still have these problems - albeit to an extent lessened.
i think people have jumped on the fact here that one tuner who seems to have his rep and ego been really trumped up gave up on the car after what sounds like one day of work after the car sat in his hands with chris on his back. rather than throw ideas out there, some of which are frankly devoid of facts entirely, perhaps it would be more prudent to start with the basics. check the standback connections. check the connections of every sensor. people are making power on these cars when they have been tuned by competent and willing folk. 4DRHTRD was making a ton of power and running a lot of boost, even with the XEDE wired in totally wrong. our car has made quite a bit of safe power, tuned both by us and by another shop. the potential is there if things are done right, and its more beneficial to focus on that then it is to saying what he has won't work because one person's abilities were not sufficient enough to tune the car.
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