got another quick question .. i heard that if u run a intercooler w/ no bov that it was a very bad thing?? any truth to that?. is it not good to run an intercooler w/ out a bov.. or would it been fine?.. now i know that its bad to to have a bov period but i'm askin' intercooler w/ not bov.. for say a couple of weeks??

taylor

 

Well, it's mostly bad to not have a BOV on ANY turbo setup. That includes those with and without intercoolers. The Blow-Off Valve or BOV acts as a vital pressure release under boost + closed throttle situations. Now when you're boostin and you all the sudden take your foot of the throttle(shifting) you create a pressure "backflow". When you take you foot of the throttle, the thorttle plate closes and causes a pressure build up in the intake tract. Now with no where to go, the pressure rebounds towards the path of least resistance, IE the turbo. So when this pressure wave hits the turbo it causes the turbo to stop spooling, or even spin opposite it's proper direction........which is VERY bad seeing how the turbo is also connected to your exhaust tract, and would be basicaly trying to pump exhaust back into your engine in this senario........a BOV prevent's all this by opening when it sense's vaccume in the intake manifold and boost in the intake tract.

Cliff Notes: No BOV = BAD

 

The whole reason for a BOV is to bleed off excess boost pressure in the manifold when the the throttle plate closes suddenly. The reason this is bad is because the denser air can hit the throttle plate and be reflected back toward the compressor wheel in the form of sound energy, which attempts to stop the turbine shaft suddenly. This is a lot of undo pressure on the turbo, and this effect running through an intercooler can actually use the intercooler as a reverb chamber that may or may not amplify this sound energy depending on design.

The bottom line is that typically if you're running a FMIC, you're normally running more PSI than the wastegate can cope with in event of a sudden close of the throttle plate. This of course can have other undesired effects such as boost spiking, additional turbine stress, etc.

 

 

I wouldn't run a turbo car a couple blocks without the complete setup in place.

 

now i know that its bad to to have a bov period but i'm askin' intercooler w/ not bov.. for say a couple of weeks??

 

Agreed

 

Having an intercooler doesn't make it any less bad to run without a BOV.

 

you're not gonna hurt anything for a couple of weeks. if turbos were that fragile, no one would use them.

just make sure you do a proper cool-down procedure before shutting off the motor with or without the BOV... more so without since the backspinning caused by no BOV can abuse the oil in the bearings.

 

called a shop.. here is the answer i was lookin' for: boost goes from turbo to intake manifold and with no bov it goes back down from the intake manifold in to the turbo.. cause there is no bov.. stick on an intercooler then you have hot air going out the turbo through the intercooler and then you have cold air going into the intake manifold.. when you left off the gas now instead of hot air going back into the hot turbo.. you have cold air going into the hot turbo.. which will shock it, which is bad!!

taylor