ok so i read the topic about BOV's but i still dont really understand it. i understand the concept but i dont think the topic really hit the spot im looking for. i was just wondering when would i need to upgrade my BOV from the stock? since i dont want to upgrade it and lose power you know?
thanks,
denver

 

When your boosting more than stock.stock bov will not hold the boost.

 

If you recirc you won't lose power. It's just VTA, which can cause a rich condition between shifts and a small lag in power after the shift. I found that my stock DV (diverter valve) was leaking at 14 psi, so I replaced it. You can replace it at any time without any loss in power. The only potential drawback would be compressor surge with a spring that is too stiff.

-Paul

 

can you explain to me what a compressor surge would be? this is my first turbo'ed car so im still researching as much as i can...thanks for all your help. what spring rate would be best then if im only boosting stock for now.

 

Compressor surge is when the turbo has supplied more air into the intercooler and piping than the engine can use, and instead of the air going out of the BOV or DV, it has to go backwards through the turbo. This is very hard on the turbo as the exhaust gases are spinning the turbo one way and this backed-up air is trying to spin it the other way. It will cause your car to jerk a little and will cause a flutter sound. I hope that explains it well enough.

-Paul

 

ahh i see interesting..so the way to stop the compressor surge is to put more boost then right? how bad is the compressor surge for the car itself? i mean will it eventually break the engine down? im trying to figure out the order in which i want to mod. so that's why i want to know thanks again..great help!

 

Too much boost can be a cause of compressor surge. Suppose you somehow had 20 psi of boost at 2000 RPM. The engine can't use that much air at 2000 RPM and it has to go somewhere, so it goes backwards through the turbo. The other way to have compressor surge is if the BOV or DV doesn't open when you let off the throttle. That can happen when the spring in your BOV is too stiff. It does happen more often under light boost, so bringing the car to higher boost and then letting off can help stop compressor surge due to a spring that is too stiff. I hope I haven't made this too confusing. As far as damaging the engine, comressor surge doesn't really hurt the engine, but it's really bad for the turbo.

-Paul

 

Get an APS bov and be done with it.

It was my second mod.

 

where can i get an APS bov?

 

I have a question then - if i just decide to get a BOV for the sake of getting one in order to boost higher down the line....... is that worth it ??

 

I found that my stock DV was leaking at anything over 14 psi, so it's possible that even at stock boost levels your DV is leaking. It's not going to hurt anything to upgrade sooner unless you set up the valve too tight and have compressor surge.

-Paul

 

^^^

sounds good paul - thanks for the info

 

I believe I got mine from Rally Sport Direct, check the vendor classifieds, they are kinda hard to get.

 

That sounds cool - i may get an HKS also