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With a T5, you can use a MBC to get the pressure up. But most will pressure the MBC from the turbo compessor housing hose barb. The pressure drop across the IC will make the boost pressure droop badly at higher rpm's.
With a ball-spring MBC you will get pressure in the lower gears and you need a new throttle techique to not spin the tires in 1st gear.
In cold weather, the boost will come on too fast and pressure overshoots will trip the fuel cuts.
You can pressurize the MBC from the TB or manfifold and remove the boost droop to a large extent. But this creates pressure feedback time delay and make the pressure overshoots worse.
I had a pop-off valve at the TB to vent some of that and the MBC was fed from the TB as well. I put a 33 ohm resistor on the MAP sensor output wire. This shifts the fuel cut and helps elimiate fuel cuts for 15 psi of boost. The T5 compensates by the O2 sensor feedback and mixures are fine. With a 2.3 liter engine, I don't know if the fuel pressures are higher or the injector capacity is higher. But with all of the stuff that I had to do to make this work, it was an intersting learning point, but perhaps not really very practical.
Much of the turbo boost delay is readly boot lag created buy the ECU and the BPC valve. The BPC valve is a variable bleeder valve which causes the wastegate to open too soon. That creates the boost lag. On the street a boost delay means slow. Power delayed is power denied.
Some cautious types who did not want to loose the APC function and who did not want more boost add a dawes MBC in series with the BPC. Turbo spoolup is greatly improved. This can also be used with the T7 ECU's. There are some practical detail to doing this, but thats another story.
With any mod, you are your own warranty. If you don't understand the basics and risks, leave some things alone. Do lots of reading and learn from other peoples mistakes :)
posted by 65.68.10...
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