I know that this subject was discussed before, but would be good to know:
Do I need this BOV for an original car with stock (19PSI) boost pressure?

I see many EVO owners talking about BOV leak, but I couldn't understand if this leak is due to high turbo pressure mod, like 22+PSI, or the OEM plastic is a piece of crap.

 

Generally the OEM diverter valve is fine for OEM boost levels.

There have been isolated instances of OEM boost leaks but most of these were from loose hoses rather than a DV problem.

 

thanks

 

I pressure tested my stock BOV and it held fine until 23PSI. At that point, it just gave up.

 

I wouldn't be surprised if there is some variation in the stock plastic BOV, and some may hold boost better than others. This being my guesstimation, I popped for the $120 MR unit, which seemed like a very reasonably priced upgrade.

 

Good to know. My OEM bov has held up fine until now. I can not boost past 20psi. So now I will be installing my Greddy type-S tomorrow.