Simple, the single spring feels and works great, but will leak boost big time. I have personally tested mine with the single spring tightened down very far and still couldn't get it to hold more than 19 or 20 psi. My stock diverter valve holds 21 reliably. I put in both springs and BAMMMM! 22lbs on pump and 26lbs on race.

 

odd, mine shows no signs of leaking...i peak at 23psi in 5th gear. Is this the bov you run? I may try both springs again eventually now that I have more crap on the car.

 

Mine is the RRE version which has a recycling tube in the adapter that goes between the two chambers. It is posible that that tube is the culprit for me being able to hold only 19 to 20lbs. But it sound like most of you are more interested in the whoosh sound and smooth idle. I don't care about whoosh, and my idle is fine. There is no free lunch, though, and I do put up with worse-than-stock drivability issues with this BOV set for max power.

 

I am running the Type-S with stock cams and the single spring mod. Also the lower (smaller) port is open. I started with the adjustment screw at about 2 turns in. I have gone up another 4-5 turns and am still getting a weird flutter or stutter at mid to high rpm, light throttle openings. Like when trying to accellerate slowly at freeway speeds, then letting off the gas a little to hold speed. The car jerks and the BOV makes a chut-chut-chut sound.

It works great and sounds awesome when driving hard, it is only when trying to cruise on the highway that it gives me trouble. Any suggestions?

EVOlutionary

 

my setup has a sweet sound anything above 1 psi. try it with 2 springs in and tighten to what i have shown on page 1 picture. what intake are you running?

 

I don't agree! I made over 24 passses last year comparing 1g, crushed 1g, type s with large spring, small spring, always only using the upper port. I made several 11.90 passes with ONLY THE SMALL SPRING tuned about 5 turns in. On the two 1g's the car ran 12.02 to 12.18, crushed was always faster. The type s would run 11.92 to 12.05 no matter what spring I was running and MPH was always within 1 mph. Tells me none of combos from the type s were leaking. Now, this may not be the case with everybody so bolt on YOUR PARTS and go do some testing (which smoggy does).

Now that I have the big turbo on and running 26psi daily I did put the large spring in and have it turned in about 3 turns, seems to hold perfect. I will let you know when the track opens.

 

4RT,
Thanks. That was a very informative post. I definitely need to do some more testing. I've blocked off the little tube that goes between the two chambers, have both springs in, and have them tightened down so that there are only 4 or 5 threads left on the adjustment screw. With this setting, I know I'm maximized for racing, but I get off boost flutter/bucking at steady speeds and the car is more stall prone than with the stock BOV. The last time I tried the single spring, the little tube was set up to recirculate. Maybe with it blocked off, it will hold boost like yours.

In any event, I'll probably just leave both springs in and lighten setting as much as possible to make it an even smoother everyday driver.

 

I have it stock just tuned right. It leaks like hell with the single mod

 

FYI, I am running the RMR intake and I/C pipes. I had the problem even before installing the I/C pipe.

A question - on the picture on the first page, what is the blue hose on the 2nd BOV nipple connected to? Also - it appears that my BOV is different; the secondary nipple is in a different location than the one on the first page of this thread. Does anyone know of a first and second design?



EVOlutionary

 

exact thing happened to me, the single spring makes a good sound but leaks boost big time.

 

it is connected to a port on the flange. .. i bought the exact bov from burningmoney97.

 

Now why would you do the single spring mod? It seems that it would hold less boost?

 

it sounds better, a little different, but it leaks boost badly, at least thats what my gauge said, also i think the 05's run a tiny little bit more. i like the sound but am thinking about switching back to stock if i go to the track.

 

same here... no issues at all.

 

Well, pick your poison: David Buschur and Shiv both don't trust BOVs not to leak. Shiv recommends very stiff springed aftermarket BOVs and DB just said in another post that he doens't even use BOVs in some of his cars in order to eliminate the possibility of them leaking altogether. Drivability suffers somewhat though on both of these approaches...