Without a doubt, the Evo 8 plastic DVs have been known to leak. There are many logs out there, but I haven't seen anything on the bench.

We were doing doing some benchmark testing to measure response times of various DVs and amazingly, here's what we found with the Evo 8's plastic DV:

http://www.youtube.com/watch?v=5ZjxL-Or0Eg

This thing leaks from 1 psi on . . .

 

Im glad I got a Synapse BOV

 

That is crazy! Thank god I just ordered my Evo 9 bov. Can you have a test side-by-side of the plastic bov vs. the metal one?

 

Good info! when i replaced my plastic bov with the synapse valve, it was actually cracked and it was only a few months old.

 

Agree side by side test between evo 8 plastic valve and evo 9 metal one. Perhaps even the HKS and Greddy ones.

 

The crazy thing is that the thing leaks at room temp without even going into underhood temps.

I have the metal one scheduled for some tests soon at operating temps.

 

This is nothing new, we've known it leaks since 2003 when the EVO first came out. There is a very detailed thread about leak testing from back then. And yes the differential can be up to 3-4psi at 20 lbs of boost.

Do you plan on summarizing your data in some graphs and tables?

 

agree
the test should be against the competition. a plastic bov is NO competition

 

 

HA! that was pretty cool, i mean i knew the thing leaked just never knew how easily i guess im glad i took mine off years ago to look at it and acidentaly dropped it and broke. i would like to see some more tested. dont want to read in detail a big fcken thread on bov's. either

 

There is a thread on here from back in the day on how to get a plastic valve to stop leaking. Basically crushing the spring by putting screws in the top of it. Worked surprisingly well but most of us just swapped to JDM MR valves prior to the IX's coming out

 

My bad, I thought I disclosed in the first line of the thread that EVERYONE knows this to be fact already. Regardless of how many threads there are on the subject, I haven't seen anything in a controlled environment where the effect is empirically measurable.

I'm only bringing it up because its something we came across.

I don't really know what good charts & graphs of a leaky BOV is going to do for anyone, but here's a graph that characterizes pretty much all of the diaphragm and even many of piston scrubbers (brass galling on Aluminum) BOVs in the aftermarket. These numbers are actually better than some brands out there.



Synchronic BOV is in color and all the rest is in black. The first trace on the left is when the BOV is actuated with a solenoid. So, everyone is getting the same actuating signal, which is pretty fast. So, both BOVs are triggering at the same time. You can see how much longer it takes for the diaphragm BOV to discharge pressure in the same volume tank. You can also see in the 3rd pair of traces how low the airspeed is on the discharge (not good for response). You'll also see how long it takes for the pressure to actually discharge. This is all in milliseconds.

Trust me, we've seen far worse numbers out there . . .

 

well the tests against the competitions were done by many owners, and the results are all on youtube.

nevertheless, despite the repetitiveness, this is merely an informational thread we thought some of the newer owners might be interested.

 

Would love to see one about the evo 9 metal bov. Perhaps if it does not work as well as we think, I would gladly switch to a synapse just because of this testing. However, for now my current set up does not warrant a new bov.

 

Seriously, all BS aside, I'm not posting this info to try to sell more of our BOVs. Just sharing info that you might not otherwise get without good scientific method applied.

Here's another vid on the plastic one:

http://www.youtube.com/watch?v=7uIM835T06A

The metal IX DV works pretty good and holds boost pretty good up to 25 psi at room temp and less at underhood temps. Crushing these OE DVs or adding bolts only serves to increase spring pre-load which shifts that response delay way further to the right on the chart above. They hold more boost, but the response detiorates massively.

With all of our testing, I have much more respect for the OE units and the fact that they are designed specifically to address a need for that given application. Almost all other aftermarket units (except Synchronic) are pretty much junk, designed for noise.

Here's what the metal one does:

http://www.youtube.com/watch?v=cJld1G9VPsY