ok.. i'm going to chime in on this thread.. i just installed upper and lower ic pipes... and now same problem.. about 14 psi... i think i found out the problem from reading this thread.. when i removed the stock housing from the turbo outlet... i also replaced the small hose with a longer piece (so it would be easier to install) but after reading this thread i checked and the smaller hose that i removed has a "pill" in it... what are my options just put the smaller hose back on? now i do have a flash 21 wot tapering to 19... if i put on an mbc will that solve my problem too? suggestions.. and who can explain why the pill makes such a huge differance.. (explain with little words) LOL.

 

Just put that line with the pill back where it belongs. This allows the boost control solenoid to properly regulate the boost. Without it, you get minimal boost.

 

ok.. i may do that.. but i do have an mbc just sitting around.. if i install it.. will this fix my problem... also remember i'm flashed to 21 psi.. will this matter?

 

If you install the MBC, the pill issue will no longer matter, and you will have full control of the boost. Also, if you install the MBC, the BCS will be rendered useless, so the flash-controlled boost will no longer be in effect, although the ECU will THINK it's still controlling boost, which is fine.

 

cool.... thanks for the help.. now that $$ i thought i wasted on the mbc was worth it after all...

 

ok I have a bit of a boost issue that has got me puzzled to no end. My car spikes to 21psi in 3rd,4th and 5th gear but as soon as it does it rapidly drops to 10-14psi. I have a mbc installed and the bcs disconnected. I do not have an aftermarket re-circ valve yet. I've had the car a few months now and it seemed to have good boost pressure with little pressure drop before I installed the mbc. what should I try to hunt down now as a possible cause?

 

The first step is a boost leak test. Whose MBC?

 

A stock Evo's boost control will reduce boost as more airflow increases, to maintain the factory tune. An EBC or MBC will make this problem go away.

 

it is a Joe P mbc, looks exactly like an extreme mbc. According to my autometer boost gauge I'm hitting 21psi with it tapering slowly at first then within a 1500-2k rpm range it drops to 12-14 or so. I'm a little wary of turning the boost up more b/c i'm spikeing 26-27psi in second gear. I bought the car used so I have no idea if the previous owner did any ecu flashing or not.

 

Kevin:
Also remember to keep the boost solinoid pluged in after MBC inst. or else you will get an ECU fault.