Evo9"Miss Rose"

BEST THREAD WITH THE BEST INFO. and helpling alot of people. nice thread we need more of these...jj 008 look forward in seeing more info about BOV especially Evo IX's MR DV...

jj_008

iTrader: (8)

I concur. I loosened up the FORGE RS and it held exactly the same as it did tightened up, 38psi. Of course, it doesn't really matter because the valve will open up w/ 8 in-hg. Absolutely amazing .

Unfortunately, the HKS will not open up under vacuum at all. I had 20in-hg on the gauge and it would slowly leak down to zero. The diaphram on it works backwards. It will seal under pressure, which makes no sense since the design alone allows it not to leak. Under vacuum, the diaphram leaks. Which is totally opposite to what you would want. I am going to send HKS USA an email to see if there is some reason for this.

The HKS has a 3rd chamber in it that must help move the valve.

The stock valve would leak at 3in-hg.

trinydex

iTrader: (12)

iunno man... that thread has good info in it but recommends running hte type s in the worst way possible.

the best bov is by far the 1g wtih dejon tools leak stop kit, with the greddy type s being the purple remodded version of the 1g.

this is from the ultimate bov thread and is consequently the correct way you're suppose to run a type s and the correct analysis of what the ports are intended for:

dejon tools has a pnumatic switch that is swtiched at 15 psi. this is basically a three way valve. when it's above 15 psi the valve directs air, let's call it "up" and when it's below 15psi it directs the air "down".

now your typical mitsu bov is actually a complex unit. it's not just a spring and valve type bov.

you don't need me to dra pics of a normal bov and how it works so this is the extra punch in a mitsu valve.
there are four holes in the mitsu bov, the first is the large one that all the air goes out of, this i will call the recirc hole.
the other is the hole at the top that makes the bov look like a ww2 tank, i will call this the manifold pressure hole.
the third is in the bottom of the flange where all the air comes in and goes out the recirc hole, i will call this the valve hole.
and the fourth and most important is the tiny hole next to the valve hole which i will call the bleed hole.

so basically the manifold pressure hole lets the bov sense when there is boost and when there is vac. the bleed hole on the other hand routes some air to the bottom of the diaphram (down) to try to let the valve open quickly and alleviate compressor surge. this is the reason why 1gs always retain that stock like drivability.

now the dejon tools leak stop kit says, this is not enough. you plug the bleed hole from the bottom and drill another bleed hole in the side of the flange, this way instead of air ALWAYS going into the bleed hole from the bottom whenever there is boost, you can PICK when the bleed hole gets air!!!!

this way you get the best of both worlds!

so the switch crams air up when you're on boost and then directs the air down when you're off boost. this translates into you can hold as much boost as you want when you're on boost, and you can vent as easy as pie when you're off boost.

gt40: I have been running this and it really does work if you are obsessed about boost leakage. I don't really think it makes a whole lot of difference in hindsight over my crushed 1g power wise. My logs do show a bit flatter boost and it really opens the instant you lift the throttle so there is zero turbo surge.

You can just order it all modded for you if your lazy

this is the only bov you'll ever need and it all costs less than 100 bucks.

matt55

iTrader: (12)

B/c the HKS SUCKSSSSSSsssssssssss for driveability











Really bad

Joey B

iTrader: (15)

jj_008 - I think because the HKS operates as a push valve rather than a pull valve (pushing the valve open into the air stream, which is supposed to help hold it closed and hold more boost). Most by-pass valves are a pull. I'm sure it also has something to do with the duel piston design. I guess we'll have to see what they tell you.

BTW, do you have the older one with the adjustment or the newer one without. I'd like to know your finding if you have the older (for adjustment purposes on my 2g). HKS says not to mess with it and that's why they got rid of it, however, the valve has caused surge because I think they have it set tight from the factory. And the messed up thing is even with the valve recirc'd, they bleed off too much air at times and stave the engine (causing the car to die and have idling problems after a rev, i.e. rpms coming back down to idle)

jj_008

iTrader: (8)

All valves, except the HKS, are a push style (air hits piston until it over comes the spring and manifold pressure). The HKS will never open w/ boost pressure because the valve stays shut w/ boost pressure. The HKS is not a duel piston either. It has a plastic piece that slides back a little bit to relief part throttle pressure. BTW, I took apart every blow off valve in the test, except the OEM. The HKS BOV is a ***** to take apart too.

I do have the older one w/ the adjustment screw and I am w/ HKS 1000%. They should have never put it in. The screw allows people to preload the spring, which in turn makes it harder for the valve to relief under partial vacuum. The spring does absolutely nothing in regards to BOV's ability to hold boost. If you have an adjustment screw, back it all the way out. (I swear to God, if someone tells me it makes there HKS BOV sound different by doing this, I am going have Warrtalon ***** slap you).

SuperHatch

iTrader: (23)

Now Now, no physical threats please....

damianhindley

iTrader: (4)

I tested my stock bov (plastic) with 12,000miles on it last night, started leaking at 13psi. by 20 psi it was very bad, I tried to push it to 25psi and it was as bad as a hole in the piping. Was very loud. I wanted to push it to 30psi but my feed line into tester from my air nozzle could not beat the leak of the bov. Good job my forge gets here tomorrow

damianhindley

iTrader: (4)

Quick question tester guy. My car bucks like a ****, at like 5%throttle. Is this also due to my lame stock bov? Its as if the thing is staying a tad bit open and messing up the maf signal at very low throttle. thanks

Joey B

iTrader: (15)

Sweet jumpin BOV Batman....I freakin typed it backwards. I was reading what you said and thought why were you restating what I already said. Proof reading goes a long way

And looking even at the diagrams for valve operation, it looked like a duel "valve", but I guess it's called a duel "stage" just operating off the same shaft.

As for HKS, unless they made sure they had the weakest setting on their new valves (and I doubt it, because of others complaining of having surge or maybe it's just the HKS way) it'll just repeat what the old one does now without touching the screw.

I agree that the adjustment screw shouldn't be on there. It's like giving a monkey a big red button and saying "Don't push this". It's going to happen.

Funny thing about this valve is why the hell would you make a $250 valve that doesn't work very well concerning idle and surge issues (unless you run stand alone or equivalent to properly VTA) to turn around to make a band-aid fix that costs you another $135 (i.e. - EIDS - was told by HKS to buy this even though I had my valve recir'd....not a chance). I figured the v2 you have possibly fixed such a problem. Nope. The only difference HKS said was the screw.

If you do find out more about the valve when playing with the screw, I'd love to know what the results are. HKS claimed if you loosened the screw it would hold boost as much and relieve sooner. That didn't make a whole lot of sense looking at the internals, but I figured they might know something I don't without some testing like you're doing to verify.

And BTW - adjusting the screw makes the HKS BOV sound different

jj_008

iTrader: (8)

Usually, bucking at partial throttle release is due to having a "tight" BOV. A stocker usually doesn't have that problem unless the diaphram isn't working properly. If the problem continues after you swap BOV's you may want to look for other issues.

BTW, it is better for driveability to have air leaking into the intake pipe (after MAF) then to have none at all which can cause stalling.

jj_008

iTrader: (8)

HKS is correct. The screw does nothing in regard to how well it holds boost. I won't be playing w/ the screw either. The Evo needs it all the way out in order to "help" the stalling issues w/ this BOV.

Joey B

iTrader: (15)

Damn proof reading got me again. It was supposed to be wouldn't hold boost as much but would relieve sooner.

I really need to stop trying to type so damn fast and reread.

Curt@MrLed

iTrader: (107)

over 2 years there has been a conclusion that tial, and the forge bov have the best results on our cars..

Joey B

iTrader: (15)

Evo wasn't around in the states when I got it for my 2g (1998). I got the APS valve instead for the Evo. And that valve works awesome.

Fool me once....