Hi, I am a new Evo owner in Hong Kong. I just got a Japanese version 280hp Evo 7, which should have similar power to a Evo 8. When I visit my mechanic, he told me there's a problem with my car. he said it's not as powerful as other Evo 7 and Evo 8 he's driven. He temporarily hooked up a turbo boost meter and we went out for some testing. The problem was found! The peak boost was only 14.5psi, all the way from 4000-7000rpm, it was really stable at 14.5psi. The stock figure should be 19psi@4000rpm tappering down to 16psi@7000rpm. He could not explain why such a low peak boost.
Please give me some suggestion.

 

take it to the dealer, since the 19.5 psi is a STOCK level

 

The Mitsu dealer in Hong Kong do not carry Evo, my car was a grey market import from Japan. There is no warrenty.

 

just put a mbc on it
mbc= manual boost controller

 

Check for loose connection.

 

Check the connections to the boost solenoid.. also see if the restrictor in the hose going to the boost solenoid is still there.. if the restrictor was missing (maybe he had an aftermarket setup in the car before it was sent to you) it could show lower boost settings when returned to stock.

If you need info on the restrictor (boost control solenoid) do a search for it, but it should be about 1"-3" from the end of one of the hoses on your solenoid which is under the air box.

 

He said he already checked all connection, he advice me to install mbc and a list of other mods. But I want to drive it for a while before I start doing any modification. I really want to find the problem, it should be fixable.

 

Before I put a MBC on it I would check the fittings and make sure the lines dont have any kinks.....

There may be a reason that your car is only running 14.5 psi... I would get a datalogger and make sure that there isnt any excessive knocking causing the computer to lower boost....isnt this a failsafe on these cars.....


If everything checks out then it might just be the boost controll sylenoid..

 

Good catch, MalibuJack.

 

He doesn't think there is any leak because the needle on the boost meter was very stable. He said the needle will be very twitchy if there is any leak. Any comment?

 

I had a black zip tie from the factory on my intake (before the MAF) that was pinching my hose to the factory boost control solenoid. I was driving with a steady 10.5 psi for about a month before I got a boost gauge

 

I had that same zip tie. It's really tight and it underneath the airbox so you would never really see it.

I came across it when I installed my MBC, and that made a huge difference. As long as you don't have a leak somewhere, changing to and MBC, EBC, or other boost control and you should be good.

Take care,

FB

 

Are you sure. Ask him if he'd remove your airbox? There is a brass restrictor in the the vaccuum line closest to the front of the car i think,

 

he thinks I might have a special version of Evo 7, which has a special computer that limits the boost to 14.5psi. The simple solution now is to install mbc. Make any sense?

 

Never heard about a special version of Evo 7. Maybe the mechanics is BS so you will spend extra money on Mods.