Ok, I've had my share of boost related problems in both my evo and other cars I've owned but this one is just bugging me to death...

I know what I need to do (boost leak test, rule out the gauge being the issue, rule out the mbc, WGA, etc...) but before I can do these tests I thought I'd do some searching (I did and as usual- the search took me to several unrelated threads) and maybe post a thread.

The turbo is a stock evo 8 turbo 04'... I've replaced all the vacuum lines so no restrictor pills are in the hoses. I currently have a Hallman Pro RX MBC that has never given me an issue, and a CHEAP Megan racing boost gauge.

Over the last week my boost has dropped from 20 at WOT to 18 and now to 15. I turned it up a half turn and could feel the difference but it didn't register on the gauge. It spikes to 18 real fast then just goes to 15.

I don't dare do any higher until the new gauge I ordered gets in. My first instinct was that the gauge is on the fritz. An Autometer did the same ting to me several years ago and I thought it was my MBC...

So once I get the new gauge installed I guess we'll see if that's it. I don't hear any audible boost leaks, but will need to perform a boost leak test and fix what leaks I find (we all have leaks lol)... But I'm wondering could the Hallman be biting the dust? Maybe it's leaking?

OR is my WGA going wacky and 15psi it's it's default?

I've had a WGA go out before too, but what that did was give me unlimited boost- quite the oposite in this situation.

Any ideas?

 

if you felt a difference in power when you adjusted your mbc then its probably the gauge.

 

yeah for sure... That's why I already have one on the way. But I'm also not sure if I feel the power drop. Eyes can play tricks on you.