Yeah yeah, I can already hear you guys "SEARCH!!!!" but I did, for 2 days and have found some useful info but nothing specificly for me.

Anyway, I've been a member for a little while with a boosted Mirage, but I just bought an EVO a few days ago. It has a Hallman MBC (not sure which model specificly) and a autometer boost gauge. The first few days, the car boosted 19-20psi with a taper to 16-17 psi like normal. Just this morning the car won't go past 15psi, and will taper to almost as low as 12-13psi. I haven't touch anything. The car doesn't feel significantly slower but I can feel some slightly lost power.

Many people say boost leak and then in all the topics I've search it just turns into to "why didn't you search" and little arguments :P I know 11psi is stock wasteate, but it's not that low.

But anyway, the car is all stock except the MBC and I didn't touch it, just this morning I can't get over 15psi. Any suggestions?

 

are u sure the boost controler is hooked up the correct way? u may have it in wrong and are just getting wastegate pressure.

 

Make sure the vaccuum lines are still on the MBC.

 

if ur spiking to 21 but tappering that bad... your MBC is installed fine.. its a major boost leak

 

check your lines and caps.

 

No spiking to 21psi, it goes the 14psi and tapers to 13psi. But anyway, I already checked all the MBC to wastegate and compross housing lines. But I think I may have found the culprit.

As I said the car still feels strong... well I found a pin hole and loose line from the boost gauge to the intake manifold so I'm 90% sure it's just that :P It's always the little stupid things...sigh.

It's pouring out now so when I get a chance to fix it, I'll come back and let you guys know how it works. I hope it's just that and nothing else. After all the boost issues with the Mirage I'm about all boosted issued out... sigh