Bleed valve?

Where do I get a decent bleed valve from?

 

Are there good and bad ones?

 

Found this one on Ebay, is this the type I'm after?

 

Not sure if I need a 2 or 3 way one?

 

http://cgi.ebay.co.uk/Under-Bonnet-Bleed-Valve-Lockable_W0QQitemZ8060001280QQcategoryZ72205QQrdZ1QQcmdZViewItem

 

Thanks

I use a ball and spring type that i got off e bay.

I don't like this type of valve, they are very crude and unpredictable.

Much better to use a 'ball&spring' type, they cost almost the same but give you nice spoolup and boost control (when setup correctly of course!)

I've got two of those on my car.

A friend of mine makes boost control valves. They are the ceramic ball and spring type, not the bleed valve type.

 

This is his website http://www.gb-ent.com there is also some good information as too why boost control valves are better than bleed valves. I think the design of bleed valves makes them prone to spiking.

 

I used to have a BCV on my current car. And I know a lot of people use his valves. They don't cost to much more than a bleed valve either.

I don't like this type of valve, they are very crude and unpredictable.

Much better to use a 'ball&spring' type, they cost almost the same but give you nice spoolup and boost control (when setup correctly of course!)

I've got two of those on my car.

Sounds good , do you know where I can get one from?

 

I've looked on Ebay and Google and I'm just finding the same type like the one above.

This is a version, although there was a guy from Australia selling them for less, and they were of better quality than the rest.

This is a version, although there was a guy from Australia selling them for less, and they were of better quality than the rest.

I'm confused John, the seller states " PLEASE NOTE.....THIS IS NOT A BLEED VALVE.....IT IS A PRECISION MADE BOOST CONTROLLER".

Exactly, it is not a bleed valve.

Bleed valves are just controlled leaks.

 

This one resists airflow until a fixed pressure point, *then* allows it to flow..

No bleed.

Taken from my friends site http://www.gb-ent.com

 

Boost Control Valve

 

A BCV is a small device, which essentially acts as a mechanical air pressure switch. A small ball bearing within the valve is held, under pressure, onto a seat by a spring. Air pressure acting on the ball causes it to lift off its seat once a preset pressure has been reached, as determined by the spring pressure on the ball – which can be adjusted of course. Once the ball has lifted off its seat air can flow through the valve. As the air pressure acting on the ball reduces below the spring pressure, the valve closes preventing air flowing through the valve. In essence no air passes through the valve until the spring or ‘cracking’ pressure has been reached.

 

If the BCV is placed in the turbo to waste-gate actuator pipe it acts as a boost controller. The valve can be adjusted to give the desired boost pressure by simply adjusting the spring pressure. (This is done by lengthening (lowering the boost) or shortening (increasing the boost) the spring in the valve.) One of the excellent characteristics of this valve is the way the boost is controlled. Due to the way the valve ‘cracks’ open once the spring pressure has been reached – no air is acting on the waste-gate actuator until this time. This means that the boost is much more aggressive and rises much more quickly than a standard turbo car. This is because normally a waste-gate actuator actually starts to open the waste-gate at very low boost levels, gradually opening wider as boost rises until it is fully open – at which point maximum boost has been reached. This has the effect of smoothing the boost all the way until maximum boost is reached. Since a BCV prevents air getting to the waste-gate until the preset boost level is reached maximum boost is reached more quickly making for a more exciting launch!

 

 

 

A Bleed valve

 

A bleed valve – as the name suggests, bleeds air from the waste-gate actuator fooling it into thinking there is lower boost than there actually is. This doesn’t change the way the waste-gate actuator works, so the waste-gate still begins to open early; meaning that although the boost level is higher, as defined by the amount bleed dialed into the bleed valve, spool time is not as quick as the GBE BCV

If a bleed valve doesn't actually change the way the waste-gate actuator works then isn't that we want, just letting it achieve a higher boost.

 

If a manufacturer like Toyota designed the waste-gate to open gradually then isn't that the best way?

 

I'm still confused as to which is best for the turbo's and engine!

The standard setup is best for the turbos, engine and transmission. Left untouched.

The standard setup is best for the turbos, engine and transmission. Left untouched.

It is.

 

I'm getting 1 bar now with my full decat, just want to raise it to 1.2 bar.

 

I've looked on here, Ebay , Supraforums and Google and I still cannot find much in the way of bleed valves.

 

Does this look any good, all I'm looking for is a decent quality one?

 

http://cgi.ebay.co.uk/NEW-TURBO-BOOST-CONTROLLER-VALVE-SUBARU-TURBO-CAR_W0QQitemZ8060689535QQcategoryZ72205QQrdZ1QQcmdZViewItem

 

Looks just like this one

 

http://cgi.ebay.co.uk/Under-Bonnet-Bleed-Valve-Lockable_W0QQitemZ8060001280QQcategoryZ72205QQrdZ1QQcmdZViewItem

These are all bleed valves.

They'll also do the job if you insist.

These are all bleed valves.

They'll also do the job if you insist.

Thanks for the reply John!

 

I always try if I can to get decent quality parts , there doesn't appear to be much choice though.

Actuators pressurise according to how much air the ECU allows to build up inside them. When the pressure exceeds the force of the actuator spring then the wastegate starts to open.

On the face of it, it's a simple setup.

In the case of the supra it's a bit more involved, what with all the actuators and the sequential.

 

But for max boost when both turbos are online it's similar to most other turbo engines out there.

It is.

 

I'm getting 1 bar now with my full decat, just want to raise it to 1.2 bar.

 

 

Hi mate,

 

I had exactly this and found that the diameter of the hole in the Restrictor ring needed to be enlarged by 6mm (ie 3mm filed off all the way round). This gave me 1.2Bar. Garage charged me £20

 

J

Hi mate,

 

I had exactly this and found that the diameter of the hole in the Restrictor ring needed to be enlarged by 6mm (ie 3mm filed off all the way round). This gave me 1.2Bar. Garage charged me £20

 

J

Yeah that - except I filed it myself. Do you have an FCD?

Mines the same, i think the restrictor rings are set to produce about 1.2 bar in the coldest of weather, for safety. Now that it has warmed up a bit its making less boost. If i had a boost controller set to 1.2 bar, would it then make 1.2 bar whether the weather was hot or cold, or would you have to turn the BC up even further to get 1.2 in this weather?

I dont think the ring would have the same affect on each vehicle. I dont even know what size diameter everyone else gets theres at. Mine wouldnt go above .85 bar when I fitted it. This was during the colder weather. The restrictor ring does exactly what it says restricts EG flow. I filed it down and now get 1.1bar upto 1.2 even in todays weather. If you use a BC to set the boost then it will boost to the set level but I'm not sure what affects the back pressure could cause?

Its just that i know a few people have the restrictor rings made up to 1 bar and have a BC for when they want to up it to 1.2, so they are driving a little more safely for everyday driving. Couldnt see that hurting anything, could it?

Not too sure m8, however I am quite happy with my 1.1+bar and I rarely get the opportunity to push it to these levels just short sprints here and there.

Hi mate,

 

I had exactly this and found that the diameter of the hole in the Restrictor ring needed to be enlarged by 6mm (ie 3mm filed off all the way round). This gave me 1.2Bar. Garage charged me £20

 

J

I used to get 1.2 bar until I fitted the new and more efficient SMIC , getting 1.0 bar now.

 

I though about enlarging the restrictor ring but fitting the bleed valve will allow me to adjust it with the changes in outside temperature throughout the year.

I used to get 1.2 bar until I fitted the new and more efficient SMIC , getting 1.0 bar now.

 

I though about enlarging the restrictor ring but fitting the bleed valve will allow me to adjust it with the changes in outside temperature throughout the year.

 

 

That is exactly what i do with mine.

Thanks for the reply John!

 

I always try if I can to get decent quality parts , there doesn't appear to be much choice though.

 

Get a boost controler, bleed valve is a crude and sometimes unpredictable modification unless done with extreme precision

Get a boost controler, bleed valve is a crude and sometimes unpredictable modification unless done with extreme precision

A boost controller would be good, but I'm not prepared to spend that sort of money if a bleed valve will work.

 

I'll be very careful when adjusting it.