I was just leafing through some For Sale ads here on the forum for some TII parts, and I noticed a guy was selling a number of parts, including a blitz BOV, and a stock BOV.
Stock BOV??? I wasn't aware that the TII's had one. All ther other parts were TII parts, but maybe this is from a 3rd gen, if they have them??
Just wondering, never heard of it before.

 

It's actually a bypass, not blowoff valve. It bypasses the air to the TID rather than blowing it off into the atmosphere. The only real difference is that the bypass dosen't have a check valve on it. so by adding the check valve you can convert your bypass valve to a blowoff valve.

 

Does it still function the same? eg- waste gasses when under vacuum?
What is the advantage of an aftermarket BOV over the stock setup? (Beside the sweet sound!)

 

the stock BOV wont hold as much boost as an aftermarket one will. the stock bov will only hold about 9 psi. my blitz will hold something like 18 or 19 psi. not sure if thats the only reason to upgrade(probably isnt) but that is one reason to do so.

 

Yeah u need a better BOV cuz if u r running more boost than what it can handle then u put the pressure on the turbo and u don't want to do that....

 

A "blow-off valve" is just the common use name for what Mazda calls an "air bypass valve". They are exactly the same thing performing exactly the same fuction, whether it's recirculated or open-vented. A check valve needs to be added to open-vent the stock BOV due to it's light spring opening under vacuum, that's all.

 

I'm a total idiot so far when it comes to turbo setups, but I'm learning.....
Why the check valve??

 

So it doesn't open under vacuum, thus creating a vacuum leak, and only opens under pressure.

Chris

 

The check valve prevents a vacuum leak when the manifold is under vacuum.

 

Actually, Mazda calls it a "compressor bypass valve"...


-Ted

 

88 FSM, page 4B-50, bottom paragraph, "Air Bypass Valve".
89 FSM, page F2-43, second paragraph, "Air Bypass Valve".
Yeah, I'm a bitch!

 

I've been reading too many FD stuffs...



-Ted