[Mk2] [Turbo] Should I feel hot air from my BOV?

[Shmed]

When my car is idling, I get a constant 'blow' of hot air from the SSQV. Is that normal?

I have no issues creating boost, and the car seems to run fine.

[Peter Gidden]

If it's leaking, even at idle, that's not good on a Rev1/2.

[Shmed]

I really must update my profile....

It's rev 2 car with rev 3 top end of the engine.

The ssqv literally blows like a hair dryer on idle, is it not meant to?

[badgerbob]

Not supposed to nope. how have you got it installed? i.e. where have you taken the signal line from. id check this isnt kinked,blocked, split etc

[ashley]

The ssqv literally blows like a hair dryer on idle, is it not meant to?

That's not right mate

Have you had your car mapped yet?

[bobhatton]

At low speed below boost the engine is sucking so how can you get any air blowing out of the bov?

[T.F.S.]

At low speed below boost the engine is sucking so how can you get any air blowing out of the bov?

Exactly my thoughts...

[2mad]

I've got a hks bov and its closed at ide.
Yours may have a weak spring . It should still be usable though because of the way its designed. Soon as the cars on boost it will force the bov shut.

At low speed below boost the engine is sucking so how can you get any air blowing out of the bov?

The turbine is still turning so as a result the turbos blowing, even at idle.


Kev.

[Shmed]

The ssqv literally blows like a hair dryer on idle, is it not meant to?

That's not right mate

Have you had your car mapped yet?

Not yet, have just done the next 500 miles running in so changing to full synth oil and doing another few hundred miles, then ready to map. Can't wait!

I thought the same about there being no boost at idle, perhaps something is plumbed in wrong, though everything seems to work fine?! It definitely blows out the bov though

[Shmed]

I've got a hks bov and its closed at ide, it may have a weak spring . It should still be usable though because of the way its designed. Soon as the cars on boost it will force the bov shut.

At low speed below boost the engine is sucking so how can you get any air blowing out of the bov?

The turbine is still turning so as a result the turbos blowing, even at idle.


Kev.

Didn't see your post, but I think that makes sense. The turbo wheel will still spin with the exhaust gas so would still create some 'boost' through the hot pipe. Does the spring on the hks hold the bov open? Then boost pushes it shut and the spring pushes it open again when there is no boost?

Main thing I thought was a problem was the heat it is pushing into the engine bay though, so would probably prefer it to be fixed.

[2mad]

I've got a hks bov and its closed at ide, it may have a weak spring . It should still be usable though because of the way its designed. Soon as the cars on boost it will force the bov shut.

At low speed below boost the engine is sucking so how can you get any air blowing out of the bov?

The turbine is still turning so as a result the turbos blowing, even at idle.


Kev.

Didn't see your post, but I think that makes sense. The turbo wheel will still spin with the exhaust gas so would still create some 'boost' through the hot pipe. Does the spring on the hks hold the bov open? Then boost pushes it shut and the spring pushes it open again when there is no boost?

Main thing I thought was a problem was the heat it is pushing into the engine bay though, so would probably prefer it to be fixed.

I think this is how it works . .

The spring holds the bov shut at idle,
Boost forces the valve shut,
The diaphragm overwhelms the spring and pulls the valve open when you lift off the throttle.


Kev.

[Shmed]

If the spring is weak, do I need a new bov? Like the look of the forge kit at Camskill, anyone got one?

[Shmed]

Just read this which suggests I might be able to adjust it to stop the vac opening the bov.

1.) The blow-off valve should never make any sound while accelerating. The only time it should ever be audible is when it's activated by throttle lifts. There are some cars that will experience a vacuum/pressure/vacuum/pressure change in the manifold under part-throttle lifts. This rapid positive to negative pressure change can cause the valve to open and closed repeatedly, giving you this "fluttering" sound that you described.

2.) Yes, all of the Super Sequential Blow-Off Valves are universal, and all of our vehicle specific kits use the same valve.

3.) If you are recirculation the valve on your EVO and are still experience "stumbling" problems, I would check the installation. Make sure the rubber O-ring is in good condition and is seated properly. The second thing to check is the C-clip (expansion ring). The C-clip has a top and bottom to it. If you look closely one side has a flat surface, and the other side has a round surface, be sure that the flat side goes towards the flange (O-ring side) and the round side towards the valve. You will need C-clip pliers (expansion ring pliers) to do this.

4.) Do not touch the nut on the back of the valve ! (I wish we never put that on there ! ) Adjusting that nut does NOT change the opening rate, efficiency or timing of the valve. HKS valves are "pull-type" valves, meaning they have to "pull" open against the boost for them to open. The more boost you run, the more the boost pushes them closed. Some vehicles have more vacuum than others. If high enough, it is possible for a vehicle's vacuum at idle to accidentally pull the valve open, causing a vacuum leak. It is for this reason that HKS employees an adjustment nut on the back of the valve to allow the spring tension to be adjusted, ensuring that the valve is closed and not leaking while the vehicle is idling. If you have played with this nut, I would suggest getting it back to the middle adjusting point while being VERY careful NOT to let the nut fall out, or turn it too tight as to puncture a hole in the blow -off valve diaphragm. As long as it's not leaking at idle, your fine.

5.) To test your blow-off valve, start the car, let it idle, and open the hood. While looking at the valve, rev the car quickly once and stop. Although no boost is ever generated at idle, this throttle on-off sequence should be enough to engage the blow-off valve, and you should be able to se the valve actually open and then close. If it does not do this, check all that I have mentioned above.

If you are still in need of assistance, please feel free to contact us.

Thanks

Ryan Bates
Sales & Tech
HKS U.S.A., Inc.
(310) 491-3307

[2mad]

Just read this which suggests I might be able to adjust it to stop the vac opening the bov.

1.) The blow-off valve should never make any sound while accelerating. The only time it should ever be audible is when it's activated by throttle lifts. There are some cars that will experience a vacuum/pressure/vacuum/pressure change in the manifold under part-throttle lifts. This rapid positive to negative pressure change can cause the valve to open and closed repeatedly, giving you this "fluttering" sound that you described.

2.) Yes, all of the Super Sequential Blow-Off Valves are universal, and all of our vehicle specific kits use the same valve.

3.) If you are recirculation the valve on your EVO and are still experience "stumbling" problems, I would check the installation. Make sure the rubber O-ring is in good condition and is seated properly. The second thing to check is the C-clip (expansion ring). The C-clip has a top and bottom to it. If you look closely one side has a flat surface, and the other side has a round surface, be sure that the flat side goes towards the flange (O-ring side) and the round side towards the valve. You will need C-clip pliers (expansion ring pliers) to do this.

4.) Do not touch the nut on the back of the valve ! (I wish we never put that on there ! ) Adjusting that nut does NOT change the opening rate, efficiency or timing of the valve. HKS valves are "pull-type" valves, meaning they have to "pull" open against the boost for them to open. The more boost you run, the more the boost pushes them closed. Some vehicles have more vacuum than others. If high enough, it is possible for a vehicle's vacuum at idle to accidentally pull the valve open, causing a vacuum leak. It is for this reason that HKS employees an adjustment nut on the back of the valve to allow the spring tension to be adjusted, ensuring that the valve is closed and not leaking while the vehicle is idling. If you have played with this nut, I would suggest getting it back to the middle adjusting point while being VERY careful NOT to let the nut fall out, or turn it too tight as to puncture a hole in the blow -off valve diaphragm. As long as it's not leaking at idle, your fine.

5.) To test your blow-off valve, start the car, let it idle, and open the hood. While looking at the valve, rev the car quickly once and stop. Although no boost is ever generated at idle, this throttle on-off sequence should be enough to engage the blow-off valve, and you should be able to se the valve actually open and then close. If it does not do this, check all that I have mentioned above.

If you are still in need of assistance, please feel free to contact us.

Thanks

Ryan Bates
Sales & Tech
HKS U.S.A., Inc.
(310) 491-3307

Good fined, If you have a version 1 ssqv2 with the bolt and lock nut on the back you could try adjusting it.

Looking at this diagram . .



I would try screwing the bolt in this should push the spring forward and apply more force to shut the valve.


Kev.

[Shmed]

From memory, I don't think mine does have an adjuster on it. Might just get a new bov...

[Al-sw20]

Just take off the BOV and improve response

[Shmed]

Just take off the BOV and improve response

I'll take that one under advisement I think. From what I read, having a bov or recirc improves response and also prevents compressor surge, so don't think I'll be whipping it off just yet.

Are the forge Motorsport bovs any good?

[Shmed]

Took the SSQV apart and found that the plastic 'cross' that goes round the shaft had separated from the rubber seal, so was not pushing closed on idle. Anyway, clipped it back together and now it doesn't blow at idle. Happy days, mapping soon

[2mad]

Great stuff

Good luck with the mapping.

[Daemonslayer]

cant see no reason why a bov shouldnt blow at idle.
Mine does.It did it when it was brandnew and does it today.
Point is its vacuum controlled.So under Vac its always open - it only closes under boost situations which in my eyes is perfectly correct.
I have a ct15b .- and its impressive how much air it can blow by only idle (-exhaust).Is a benefit too that it opens under idle - this leads to the assumption that it would react quiet fast under gearchanges i would say.

If yours doesnt blow at idle i would assume your wastegate is controlled by a boost controller?Otherwise i cant imagine a gen2 or gen3 does behave different then my engine.

correct me if iam wrong.

iam with "2mad" completley saying:

The turbine is still turning so as a result the turbos blowing, even at idle.
Kev.