CarNDrvr

Is there something that is supposed to be done to evacuate crank case pressure when a supercharger is added? My car leaks a little oil from somewhere...haven't figured out where yet...only under hard acceleration. It is not leaving any drops, but it is burning off the exhaust and causing smoke from under the car. I am sure this is a result from the supercharger forcing more air into the engine. Is this normal? It is only making 7lbs of boost.

krivera

LOL :lol: i am having the same problem... but i am running 10lbs of boost and i guess i never noticed?? the way i have my car setup is i have both of my breathers coming from valve covers going into my k&n air filter but yes under hard boost i am leaking oil from somewhere to? i have not found out how to fix the issue? any ideas?

8388

Did it just start ? More than likely it's blowby, a small amount is a sign of ring wear. Too much blowby could be a sign of a more serious problem. Take your oil fill cap off, and rev the engine while placing your hands over the opening, if you feel air hitting your hand, you've got problems, caused by Running lean, or detonation.

You may consider doing a leak down test, or a compression test and compare all the #'s from each cylinder.

lead foot 85 vet

It was the intake gasket on mine....I replaced the silicone and leak went away..........also you can't get it to boost by reving the engine so your not getting a true blowby test............try having your wife ride under the hood and then boost on the highway. :cheers:

8388

If you have a hole in the piston, or a ring land burnt out, you don't need boost to feel the air hitting your hand. You'll just have to trust me here.
Been there many times. Although the idea having someone under the hood while hauling azz down the Hwy, doesn't sound all that bad, I have a few friends I wouldn't mind trying that with.

Mo_Bandy

"Although the idea having someone under the hood while hauling azz down the Hwy, doesn't sound all that bad"

They call that agony of DA FEET!!

:D :D

I have enough trouble finding room to put stuff under the hood ... dun think the wife would like that.... she'd rather drive :crazy:

Ok, it seems to me I saw something once on one of the F body sites that mentioned putting a check valve on the breather hose... I could be full of bologna... but it might be worth a look...

Mo

8388

Ok, it seems to me I saw something once on one of the F body sites that mentioned putting a check valve on the breather hose... I could be full of bologna... but it might be worth a look...

You should have a one way valve on any vacuum line, that can become pressurized under boost, especially those leading from the crankcase.

Mo_Bandy

Guess that answers that :lol:

So are you saying I should look up that site? This is the brether hose from the valce cover that goes to the K&N... I would think that would always have a partial vacuum...

Mo

8388

This is the brether hose from the valce cover that goes to the K&N
Mo [/QUOTE]

K&N located where ?

(stock) way of evacuating the crankcase is via a pcv valve, which gets it's vacuum from the intake manifold, which by design is a one way valve. I still run a backup one way valve on this line to ensure vacuum only.

gcrouse

Yes, Kevin's got it right: Manifold PCV vacuum port plugged. Breather in each valve cover with 5/8" hose running straight to the supercharger air intake. And no PCV valves anywhere. This will vent the engine adequately and the SC will even help apply some crankcase vacuum.

Although the more serious problem here is if you're building enough crankcase pressure to cause oil leaks you've definitely trashed rings or pistons.

krivera

Yes i was wondering why ATI ran the hoses from the valve covers(no PVC) to the air filter?

gcrouse

The PCV is a vacuum valve; when the intake has really high vacuum (throttle closed) the little ball inside closes it off. When the intake has no vacuum or is pressurized (like under boost) the PCV is wide open and that pressure is going straight into your valve cover! No wonder you have crankcase pressure and oil leaks. And possible tuning issues because of the air leak?




[Modified by gcrouse, 11:40 AM 7/23/2002]

8388

I'm not totally agaisnt bringing the a hose from the valve cover to the filter infront of the blower, but you may be introducing alittle hot oily smoke which tends to promote detonation under some conditions.

krivera

George....you car looks like a beast! i like the runners and what rpm do you take your beast up to?

AKS Racing

Not to mention the fouling factor associated with the introduction of oil into the intercooler. As an added bonus, the oil is still a liquid, albeit very small droplets of liquid, and when the velocity drops (i.e. inside the intercooler), the higher the probability of disengagement of the droplets.

All of the above is not a good situation.

I have my factory PCV valve still plumbed to the intake, but the R valvecover is plumbed via -12AN line to an oil collection sump (Morosso makes a nice unit), which in turn vents to the atmosphere through a small K&N filter. No more oil bath every time I go under serious boost.

Aaron

texican2K

Here is what some of the turbo cars are using and the technology seems right. You might want to check the tech info page and then the kit they sell for the GT3000.
http://www.krankvent.com/

Good Luck
HLV
t2k

8388

Here's my set up, a pcv on one side and a K&N on the other. The red fitting you see on the pcv line, is a one way valve to insure no pressure to the crank case. This set up is clean and efficient.

CarNDrvr

8388...Sam, is that you? That looks like your car (from what I can remember). This is Shane.

8388

Hey Shane long time no see. Whats up. Kevin was telling me about your vette, didn't know this was you. :cheers:

Tomas

Hello

I have my crankcase ventilation from both valvecovers like this.



regards

Tomas