| Because....when you close the throttle, there is a large portion of "metered" air that is now configured with the appropriate amount of fuel that your ECU is expecting to go into the combustion chamber. All is well if you "recirc" thie air back into the system. With a BOV you're venting to atmosphere, BUT THE FUEL IS STILL THERE, washing out your cylinder walls to be be expressed through your manifold or pushed past your rings into your crankcase as "blow-by" This Rich condition created by the BOVs is further compounded by the addition of larger breathing mods as they hold even more air than stock. Bernie is correct in that "in general" this (BOV/Rich condition)which is NOT taking place at idle and has no effect on an idling car. What is being discussed is what happens every time you hear your BOVs hiss at you and is relative to the amount of boost you just created. Low boost: 3-7lbs is usually not an issue. See for yourself on the freeway: Boost the car (with BOVs) release the clutch at highway speed(off throttle) savor the pretty hiss sound the valves make and coast for a few hundred yards. Engine will die, re-engage clutch and you just jump started your car at 70mph.....yea! IMHO I think that alot of us were attempting to correct this with the "flower pot" mod, but I believe that the use of BOVs are the real issue. Most common spirited street driving scenario (moderate traffic or stop sign to stop sign)with BOVs= Boost, let-off throttle to appreciate pretty swoosh sound, release clutch and apply brakes to prepare to stop the car, rich condition, engine begins to die, feather the throttle to correct the A/F mix while stopping the car, don't forget to shift down through your gears(most helpful in pulling the missing air back into the intake) to keep choaking engine running, car arrives at designated stopping point, engine now settles into normal idle. This only takes a few seconds to correct, then car idles fine. Light changes/traffic begins to move, stay prepared to do it all over again should you want to quickly negociate your car towards the next stop .....kinda of a pain in the ass and I don't let anyone else drive the car for the additional ware on my starter should they attempt to hold the clutch and roll into a normal stop after boosting. This all goes away with the RECIRCs Hope this helps the confussion
Gotta....Have....More.....Boost!!!!!!
|
