HKS SSQ BOV Problem

[Zushi]

I have installed an HKS SSQ BOV on my CA18DET (I custom mounted it in front of my throttle body). I hooked the BOV up to the vacuum line that attaches right behind the butterfly valve(next to the battery ground cable that attaches to the engine). The line is a vacuum line, I can feel it sucking in when I disconnect the line. For some reason though my BOV doesn't work. It just doesn't work at all, no sounds of air leaking, just nothing. My BOV works too. I built up boost(by pressing the gas) and then manually pressed the little air inlet valve on the BOV and it did it's job. From that I was thinking that maybe I'm not getting enough vacuum through that line. Maybe I selected the wrong vacuum line? I was thinking that maybe I have an exhaust gasket leak that could be playing with my boost and vacuum or something. I haven't hooked up my boost gauge yet so I'm not exactly sure of how it is. If anyone has any ideas of why my BOV just doesn't work automatically, let me know. Thanks.

[Zushi]

Hey, I was thinking. Could it be that since I have my stock bypass valve hooked up maybe it's conflicting with my aftermarket HKS BOV. I have no clue about how to mess with the stock bypass valve. any ideas?

[boost_boy]

Quote »Could it be that since I have my stock bypass valve hooked up maybe it's conflicting with my aftermarket HKS BOV.[/quote] CA18's didn't come with a bypass valve, unless you got the old school model with the funny looking cylindrical valve thinga-majiggy on the intake manifold. Any line providing vacuum at idle will make your BOV work. If your BOV doesn't work under load between gear shifts, then something is wrong with the valve. JMO, SSQVs are the drama queens of all BOVs and some turboXS models just plain suck donkey cum!

Dee

[themadscientist]

two blowoffs equals dumb. You are probably on the right track with the interferance idea. It sounds like you have the right hose. Have someone cover whatever that other blowoff is so it can't vent and see what happens. the pressure will vent at the first blowoff it encounters which from your description is not the peice of crap SSQ. Sorry, I just can't stand those things.

[Zushi]

hey, well i think i have a bypass valve. when i let off the gas i hear a BOV type of sound coming from around the turbo, and through the air filter. Isn't that my bypass valve? the cylindrical thing on the intake manifold...is that the FICD solenoid valve or something? or AVC or something. well i opened up my BOV and i didn't see anything wrong? What could be wrong to make it not work at all? the spring to tight...to loose? how about like an exhaust leak or something. hrmmm

[themadscientist]

put up a pic if you can. CAs did not come with blow offs, SRs did mounted on the intercooler ahead of what would be the driver's side front tire. Your car may have an SR intercooler.

[boost_boy]

Quote »hey, well i think i have a bypass valve. when i let off the gas i hear a BOV type of sound coming from around the turbo, and through the air filter. Isn't that my bypass valve?[/quote] I'm surprise TMS didn't jump on this one, the noise you hear is called "wastgate flutter" which occurs when the excess boost created by your turbocharger gets the door (throttle plate) slammed in its face and then it's forced back to the turbocharger causing the air to reverse through the turbine which in turn makes a deep whoosh sound or intermittent preewwww sound kinda like a sick bird or something. (Corrected)

Dee

[USDM_OneVia]

Stick your hand in front of the BOV. Then reach up to the throttle body and give it a little rev. When it shuts, you should feel a gust of air coming from the BOV.

Do that and report back.

Joe

[Notchbackca]

the turbines can't reverse direction, but it does slam into them slowing it some in a very short amount of time which is bad and its not the waste gate that flutterseven if your BOV was venting it if you have it right next to or close to the TB it isn't going to do its job properly, it needs to be closer to the turbo so it can stop the shockwave from slaming into it, instead of getting it the second time around

[float_6969]

Quote »when i let off the gas i hear a BOV type of sound coming from around the turbo, and through the air filter[/quote]I've always heard it called turbo chatter, and the sound is actually from the blades cavitations through the air due to the increase in pressure placed upon them.

Quote »the turbines can't reverse direction, but it does slam into them slowing it some in a very short amount of time which is bad[/quote]The blades COULD reverse, but you'd have a to have a pretty bad exhaust leak, pre-turbo. But generally no, they can't, but they do slow way down, and it does put a lot of stress on the bearings and increases lag between shifts, which is bad

Quote »and its not the waste gate that flutters[/quote]Just explained that...

Quote »even if your BOV was venting it if you have it right next to or close to the TB it isn't going to do its job properly, it needs to be closer to the turbo so it can stop the shockwave from slamming into it, instead of getting it the second time around[/quote]This is not entirely true. The shockwave originates at the butterfly valve in the TB and travels backwards towards the turbo. You want the BOV closer to the TB to "catch" that shock wave early. In all actuality, it doesn't really matter a whole lot, as long as you have one. Having it after the turbo & before the intercooler won't waste cooled air, but the valve could be venting before the wave reaches it. Having it right next to the TB could have the opposite effect. I would imagine that the pulse travels as a high enough rate of speed, that the placement would make little difference.

[boost_boy]

Quote »the turbines can't reverse direction, but it does slam into them slowing it some in a very short amount of time which is bad[/quote] I didn't realize I posted that the blades reverse because that is truly not the case and I will correct my post, however, it is the wastegate that is fluttering and that's why it is called by most "wastegate flutter" . Like Ryan said, the blades can be reversed if your turbo is so screwed to the point where it's rotation is intermittent (stop and go) and then all of a sudden builds a healthy amount of boost only to have it not be used and forced back through your plumbing to a failing turbo kinda like my T3/T04E. Since I used a blitz bov on the hot side and the greddy Type R on the cool side, wastegate flutter is a thing of the past; I mean even at low rpm/low boost the greddy removes the excess boost while still providing the ultimate in sealing during high boost applications.

Went tuning yesterday between 15 and 23psi of boost on 93 octane and octane booster under heavy and light throttle conditions and even with a 3/4 dead turbocharger, if you have a good wastegate actuator or a good external wastegate and a good ventililating system (BOV), you should not be experiencing flutter. I've seen many new SSQVs, DSM, SR20DET, turbo XS, and 2nd gen blitz super sound BOVs leak at or before 15psi, so you have to really pay attention to what you buy and don't get complced because it's new.

Sounds are nice, but performance is what you are after. For the $$$$s the best bang for the buck is the greddy type R (1st) and the 1st gen blitz super sound not only for their loudness, but their ability to hold boost pressures well and above 15psi of boost.

Dee

[Notchbackca]

the shockwave from the throttle body doesn't just stop when it hits the blades it bounces back and forth thats why you get the flutter noise, the reason the blades don't stop and reverse is simply inertia and that doesn't change if your turbo is screwed, if they actually reversed youed end up cramming exaust gas into your cylinders and when your intake valves opened you would back fire

waste gate controlls boost level so the problem cause by a bad waste gate is boost creep

[xyster]

As I understand it, the sound you're hearing is called "surge". I'm a field service tech for a leading centrifugal blower manufacturer, and I deal with blower surge every day. The basic idea is simple: The blower impeller(s) push air into the pipe, pressurizing it. When the flow is suddenly stopped, by the throttle plate closing, a pulse of air moves backwards from the stoppage to the blower. When the pressure wave hits the impeller, the blades actually spin without moving any air (cavitating, I believe), because the pressure in the pipe is greater than the pressure the impeller is capable of producing. This continues until the pressure in the pipe and the turbo housing is equalized. Once the pressure is equalized, the blower starts pushing air again. This starts the cycle all over again. All this can happen in an extremely short time, making the "pssh pssh pssh pssh" sound. I see it in large industrial blowers too...albeit much more violent. That's how it works in our centrifugals; I assume it's the same for turbos.

[float_6969]

:withstup Thats exactly what I was trying to say, only I wasn't so eloquent. Nicely stated xyster. I deal with the same thing, only it's water and it usually will bust and impellor real quick. Air is a little more forgiving than the wet stuff....

Notchback, you're on the ball too man. Dee, I love you, but the only way the wastegate would make a noise like that is if you had fluctuating vaccumm-->pressure forces inside the intake mani. Once you close that throttle plate, the intake mani is under a vaccum. The intercooler piping is still pressurized.

[xyster]

you'd be surprised what air can do...surge in an air/gas centrifugal will kill impellers in a hurry too. We get blowers back on a fairly regular basis with shattered impellers. Normally, the air pulsation makes the cast aluminum impellers contact the cast iron casings at ~3600 rpm. heh...the result isn't pretty

[float_6969]

I can only imagine. We've got about the same rotational speeds too though, but most of what I deal with is plastic, so the damage is generally a pretty cheap fix.

[Notchbackca]

xyster is right on the money, the problem with the spinning backwards thing is if you were to apply enough force on the turbine blades to bring it from 100000rpms to 0rpm in less than second... everything that moves inside your turbo would tear itself into tiny pieces...