Question : BOVs

[NateD4]

Does anyone have any experience with decent BOVs?

I'm curious what issues people have found with different brands etc...

[caffeine]

I'm interested in this as well. Some of my friends say that the sound gets annoying after a while but it should be pretty easy to turn any bov into a recirculation valve.

[timg]

I've used the 1G DSM BOV, Tial BOV, and now have a Synchronic DV. The 1G DSM is dirt cheap, works well, and isn't super loud. The Tials are quite popular, very high quality, and not as loud as some other aftermarket BOVs. You do have to be sure that you use the correct spring though. The Synchronic is actually a diverter valve rather than a BOV. I did that because the BOV is often open under idle and low load. I would prefer if it recirculated air back to before the turbo (post filter). The thought of having a massive gaping hole in your intercooler piping that sucks in unfiltered air when the BOV is open (low load and idle) has always bothered me.

Tim

[NateD4]

Has anyone ever heard of BOVs being electronically controlled? Just curious.

[RedZMonte]

nope. BOV work off vac and boost pressure. Wastegates can be controlled usinga a Electronic Boost Controler. I have a 1G DSM BOV, simple, reliable and sounds good. I now have a Greddy Type S Knock off and it works fine and is adjustable for higher boost pressures and was cheap at silicone intakes.com. The real Greddy Type S or Type R are good valves and medium sound, Blitz and HKS BOV's are popular and loud. Tial are pretty mild. im happy with my cheap knock off other then i had to buy a greddy flange to match the bov to weld it up, doesnt come with one. mine just dumps, if its open under idle a little you can buy a small filter for an old chevy valve cover and clamp on to it if to filter it if its an issue and is much easier then recirculating it..

[NateD4]

I don't want the sound at all. I'll probably recirculate it.

I want in car boost adjustments. Is there anything off the shelf?

[NateD4]

From what I can remember a BOV releives the pressure and load on the compressor and prevents damage to the throttle body and the engine. It also removes the load from the compressor to keep it from bogging down with the sudden change in head pressure.

The waste gate would effectively throttle back the turbine to adjust boost and adjust the load to prevent stall/surge of the compressor and most importantly over speed of the rotating assembly.

Correct me if I'm wrong on the above.

The question I really have is whether anyone runs one or the other or if they always run both.

I'm pretty sure I've seen a few OEM applications that run both and some that don't run a BOV.

[caffeine]

All turbo setups have a wastegate afaik, because if not, boost would keep building with no end. If you used a bov to release excess boost, you would still be working harder than needed to spin the turbo, and wasting that energy.

Not running a bov is not the end of the world but will result in compressor surge whenever the throttle is closed after boosting. (Air that was being forced into the intake is now forced back to the turbo and slows the impeller). Not running a bov or bpv will shorten the life of the turbo.

If you want an in-car boost controller, there are quite a few off the shelf electronic ones, and I don't see why you couldn't run a manual boost controller in the car; they just have to be dialled in every time you change boost levels.

[RedZMonte]

in that case a simple diverter valve should work fine for you, it will recurculate the boost and tipically is pretty quiet, siliconeintakes.com has them. the boost control is done with a boost controler connected to the Wastegate. the wastegate is what controls the boost levels, the boost controler allows you to adjust the boost level over the gates spring pressure. many Electronic boost controlers are avalible from cheap to very expencive. its good to have a BOV/Diverter but not required, it helps prevent back spool which increase spool up times after letting off, also is supposed to prolong the life of the turbo... my 1990 TGP didnt have one (not from factory) and turbo was original 150k+ miles untill i added one... sounded cool but that was about it, no performance gain. a Manual Trans i guess is more important to have a BOV then a auto, relieves pressure between shifts.

http://www.siliconeintakes.com/index.php?cPath=11&osCsid=ccd0e203b8129355db398cd059f4d626

S

[timg]

You really need both. They are not interchangeable. There are solenoid based PRV (pressure relief valves) used in industrial blower/compressor applications. I'm sure that one of these would work in a car if you wanted.

Tim