axl911

Hi All,

The 993 has 3 lines going to the oil tank: 1 crank vent, and 2 oil breather lines (one going to before and after throttle body in the intake).

TPC Supercharger install calls for leaving one of these open to the atmosphere or use a small K&N type breather filter. I am wondering should I just leave both of these open to the atmosphere. Would this create a problem in the oil circuits?

Reason I am thinking of doing this is to prevent oil vapor from being sucked into the intake which can increase detonation.

thanks,
anthony

95993Cabrio

Sorry to bring this ancient thread back to live but I always has this same question. Does anyone try to block out breather 1 and 2 to the intake. And connect the breather 1 and 2 hoses from the oil tank to an open system oil catch can?
The reason to do so is to minimise any possibility of oil getting into the intake and the chance of any vacuum leak?
Just assume that this is for a track car and not road use to avoid breaking the law.
Will this mod hurt the engine or the oil circulation?
Thanks

george996

If you disconnect the breather lines then hose no. 2 needs to open to atmosphere to allow for blow by to escape under loaded conditions, otherwise the oil tank with over pressurize. Breather line 1 has a restrictive orifice at the tank and i think its there to suck a little crankcase out of the engine when at low load. I think you could block breather line 1 as long as the other is open to atmosphere. I have been looking at adding some type of collection/breather canister but haven't found one.

95993Cabrio

Thanks for the advice. Will this open air oil catch can(breather) system introduce more oil leaks since it has a positive crankcase pressure?
Also, for hoses Breather 1 and 2 (one going to before and after throttle body in the intake), does anyone know the air flow inside them?
Cheers

pp000830

If you rout the vent tube like the blow-by tubes in the old days under the car the oil vapor won't condense and accumulate on surfaces in or on the body. If you live in CA it can put a little smile on your face every time you fire up your car, thinking about how the dogs of emissions regulation madness would break out in a full on rabid display if they knew what you did!

george996

sorry for the delayed reply. My idea was to install a mist eliminator in line 2 and keep it connected as designed. Then drain it periodically.

Regarding flow rates, I ran the engine at idle with line 1 and 2 disconnected and could not feel any flow in either. I imagine at full load there is some flow and that is when oil makes its way into the throttle body.