I think this might the best “aftermarket” BOV for the Evo X.

Found this from Super Autobacs Tokyo, this is basically a re-worked stock bov with higher tension spring. I wanted something that would hold boost better and quicker response than stock BOV, while still maintain the same drivability, ie: quiet, no boost surge with smooth on/off throttle. So could this be it?

From the moment I began to do the first pull, oops…boost cut!! Looking at the log quickly to conclude I over-boosted to 30psi , which is a good sign that the Coto Sports holds boost better

Went back to my maps and reduced the WGDC and went for another pull, I could tell immediate difference in the first 50 feet where the boost rises, its spooling quicker than before and boost becomes immediately accessible in 2500rpm. This reminds me the feeling when I had stock turbo, I missed this feeling! Even when running full throttle acceleration boost kicks in quicker, it felt like I cannot stop accelerating LOL. It’s still saturday morning so I’m not getting used to it yet, passing is scary because I need less throttle input than before.

Sound wise, it is a little more pronounced than stock bov in high boost, otherwise it is quiet like stock in low boost. It vents quicker than stock, but the smoothness is maintained. I could achieve the same boost level with 5-6% less WGDC, so the turbo is working less hard for the same power.

Summary: A truly direct replacement BOV that holds boost much better than original, Mitsu should have used this on every Evo X so that we don’t have to shell out for one Highly recommended!

 

Great review; is there a way for us to similarly modify our BOV? Can we swap springs?

 

I don't think they can be opened--some people crush them a bit in a vise to get them to hold more. Tial just released a valve and I'm holding my breath, hoping it works.

 

So you purchased this in Japan?

 

yes... he has a cool *** thread where he took pics of all of tokyo bay autobacs... to the op ... i hate u... lol j/k

 

Sooo, link to buy it and price, lol?

I am probably going to crush mine though, but if i end up having to buy one this might be it.

 

That's the catch--he buys the stuff in Tokyo. So, $230 BOV and I'd guess $900 airfare.