Out of curiosity, I decided to make a pressure tester to see how much pressure each of the blow off valves I own could hold before it leaks.

Stock Valve: It held to about 10psi and started leaking. It was a really slow leak though.

Forge RS: With it screwed all the way in, it held 38psi. The only problem I had w/ it was w/ the connection to the stock hose. I had to really crank the clamp down in order to not have it leak. I didn't have this problem w/ the other valves.

HKS SSQV: This bad boy can hold whatever you can throw at it. Of course, the design of it is the main reason. I had it cranked up to 60psi w/ no leaks . This is my project BOV. I think I have found the issues it seems to have on our EVO's w/ the recirculation kit. I am going to do some more testing on it. I like the design of this BOV, I just need to work on the driveability portion of it.

This weekend I will be testing my older Forge DV w/ the green, yellow, blue, and red springs. Should be fun .

 

You should also test the JDM MR/IX DV. It would fit into you comparison nicely.

 

if you can, do the turboxs as well.

 

I doubt he just has every random BOV sitting around...

 

/\ Hahah... Hey let me know how it goes with the different colored springs of the Forge DV. BTW, Warrtalon, would you happen to know what each color holds up to?

 

Nice to see our RS valve holds exactly what we have spec'd it to hold! A little higher actually!

 

I am running my Ghetto Stock plastic BOV and retested it after 6 month, still holds 30PSI before very minor leak.

 

thank you for this service, this portion of truth is very beneficial to the community.

 

I thought I was doing pretty good having 4 BOV's. If anyone wants me to test a BOV they own, just send me a PM and we'll work something out.

 

Did you try the Forge RS bov at less than full preload on the spring? It seems to hold good at less than full preload also.

Brian

 

The order is the following (with estimated manifold psi): Green (18psi), yellow (23psi), blue (28psi), red (40psi). I will see how close my estimates are this weekend. I won't be using the shims. That would take forever .

 

Those numbers are pretty close, HOWEVER, it should be understood that those PSI ratings for our standard valve springs are not that of the spring pressures alone. Those PSI ratings will also take into account the pressure reference to the top of the valve adding force holding the valve shut which is what the valve will see under normal operation (with no leaks anywhere else in the system). The spring pressures alone are less than those figures.

 

I tried a few times, but I was having issues w/ it leaking at the hose. I never got a good number, but w/ the valve turned about half way out, I was close to 20psi. This is just an estimate since I couldn't the tester to hold the pressure.

 

The pressure numbers I quoted are w/ the top port hose connected. I would like to think nobody runs a BOV w/o the top port connected .

 

I just don't want anyone to confuse "spring pressure" with "test pressure".