I have been suspecting that my 03 Evo has been wanting in the power department., it's mid range is rather lacking. I put a Defi-D boost gauge on it this weekend, and it's only seeing about 10-11 psi max. At idle it runs about -19ish. Sometimes running it up in 4th I can hear a whooshing noise under the hood.

I took it to the dealer this morning, they can't find anything wrong with it. They told me if it doesn't show up on their computer, they can't do anything about it. How does a leaky BOV show up on a computer? I'm hoping that the Defi is doing it's job, I guess I'll go redo all the connections for the plumbing, visually everything looks good. If I get the same numbers, then I guess I'll know.

Perhaps I need a new Mitsubishi dealer?

 

You cold need a new BOV the one that comes on the car is knowen to leak, pretty much its a plastic POS so try changing that out but i think u might void your warentee so do it at ur own risk

 

most likely you have a leak in some of the intercooler plumbing. I would tighten all the clamps on the intake plumbing. trying a new dealer is always an option, and you can request that the dealer test the diaphram in the stock BOV and see if there is a problem with it's function. Good luck

Greg

 

My intercooler took a hit from some unseen force, I looked at it carefully and didn't see anything other than a handfull of bent fins. I was going to try and straighten them out some.

When I put in the Defi, I saw that the boost recirc valve had it's bottom fitting loose. I tightened it, it's not the first time I have had a fitting come loose. I looked around at the other fittings, things seemed tight.

I have heard that the stock BOV is nearly silent, I can clearly hear it sans radio, some times over the radio. I don't have any other Evo's to test against. I have thought about going to the dealer to test drive one to compare against.

What should the stock vacuum reading be?

 

the factory valve is silent only when you are using the factory intake tube, if you go aftermarket suction tube with the factory valve it is freakin loud, it is louder than a turbo xs valve on the same evo. oh by the way, turboxs valve's are pieces of cow poo. the hang up and wont release pressure, causing the evo to go stupid and make you limp home