redtopz

When we race our C5 T1 cars at Cal Speedway, we hit high lateral G's on the oval at full throttle in 4th gear for several seconds. It causes our oil to puke up into the intake creating clouds of smoke out of the exhaust. This is dangerous for the engine and we do tend to see engines fail at this track. I had a CEL flashing for my entire race a couple weeks ago and I only started with maybe 1/2 quart extra oil. The oil burning slows down after we get about a quart low on oil, but I don't really like that as a solution.

I have a catch can for the valley cover and was thinking about adding a 2nd one for the passenger side valve cover which vents directly to the throttle body. However, I don't think another catch can will really solve the problem because the oil will still be removed from the engine and trapped in the can (and probably overflow the catch can into the intake). So I was thinking about swapping the valve cover plug from the driver's side to the passenger side and venting the driver's side valve cover when I race at Cal Speedway. It seems like this would solve the problem on long left hand banked sweepers/ovals. Anybody tried this?

Bill.

trackboss

I've thought of doing that as well in the past, but after consistently seeing low oil pressure on my display I realized that in my case the motor needs a dry sump to go back on track. The vent doesn't solve the oil starvation problem.
If your motor lets go, especially at the speeds you reach at cal speedway, you may lose your entire car or worse.

yakisoba

In the old motorola corvette series, they solved this with a dry sump. Has more benefits, but one main one is the prevention of oil starvation engine loss after high speed high G turns.

sebdavid

Wouldn't an Accusump solve the issue?

redtopz

I kept an eye on my oil pressure and it stayed around 47 psi. I'm more worried about popping a piston from all the oil getting mixed in with the fuel and lowering the octane level. Also about losing so much oil. We are not allowed to run a dry sump with the LS6 engines in T1 even though they can be used on the C6's . I will be trying this the next time I run at Cal Speedway. I think it should work and I can't see any downsides. Since the oil is being thrown up into the passenger side head it makes sense to vent from the driver's side head at that track.

mountainbiker2

I have the same problem with high rpm left hand turns. I ended up putting on two catch cans. One for the valley cover, the other on the passenger side valve cover. After many trail and error, I ended up doing this with the hoses. See pictures. The big hose and big loop really helped out. The oils velocity slows down and it's going against the g-force. I had to empty the catch can a lot before this setup, but now, it's much less. Might work for you.



Steve A.

gkmccready

If the C5 DIC is like the C6 it's really slow reacting. My C6 *never* showed the oil pressure in the teens while the data logger clearly shows up...

redtopz

Thanks for those pics Steve. That's an interesting solution the way you routed the hoses. I understand your point gkmccready and for all I know the oil pressure could be dropping briefly. It's also hard to keep watching the guage at that speed.

travisnd

I don't see why your idea wouldn't work. Currently the oil is getting hung up in the passenger side head and forced through the fresh air feed into the intake. I run two cans on my car, but only ever see a little oil in each one. My car is a 2001 so it does a good job eating oil on its own. I don't run any tracks with long extended sweeping turns either.

Jason

Instead of looping that back into a catch can, could you just route that hose towards the driver's/left side and cap it so the oil would run back into the head when the G-Forces were lower?

mountainbiker2

I don't think capping it would be a good idea. It needs to vent.

redtopz

I thought about that and that would probably be fine since the crankcase pressure is being vented from the valley cover. What would likely happen is no oil would pass through the hose since the pressures on both sides would be equal. The TB actually pulls crankcase gasses (and occasionally oil) from the passenger side valve cover with a slight vacuum. A catch can will help remove the oil prior to entering the intake manifold. But in my case at Cal Speedway a catch can would probably overflow and I want to prevent the oil from leaving the engine in the first place. Drawing from the driver's side would probably solve the problem or just plugging both sides would work too. I think the slight vacuum in the crankcase is beneficial to a healthy engine so I will try my idea first and see what happens (only at Cal Speedway).

travisnd

My understanding is that the line from the passenger valve cover to the TB is supposed to be the fresh air feed line. It's the air source to balance the pressure expelled through the PCV system. However, under extreme situations it can push oil out the line as you're seeing.

RX-Ben

I used to think my oil pressure was steady until I started logging it. What looked like a constant 55 was dipping into the upper 20s/30s on sharp turns.

longdaddy

very clever with the hose loop directed sideways

Dirty Howie

Bill

Plug the fitting on the passenger valve cover. Then put a barbed 90* fitting into the oil fill cap. Run the TB line to the fill cap. You will get a fraction of the oil now as it must go up to fill cap. Then put a catch can in this line too and you will keep all that oil out of your intake. This is what I had to do on my built C5.


DH

fatbillybob

Steve! You are a genius! What a great idea thanks for sharing.

mountainbiker2

I tried this DH. Didn't work as good as my setup now. As you can see in the picture, the filler cap use to have a line from it. I blocked it off, because it didn't work that good.

Steve A.

Dirty Howie

Okay, I do see that you have a fitting there. Well it worked for me

Maybe a combination of your loop coming off the filler cap would be even better ??????



DH

redtopz

Yeah, I think you are correct . At least at idle and part throttle. I just wonder if that is still the case at full throttle when there is more crankcase pressure and the TB is fully open drawing in air to the intake. Seems like flow might reverse directions in that case, but I'm not sure. Maybe a one-way valve on that hose would work only allowing air to flow to the valve cover and not visa versa, as long as it could open under very low pressure differentials.

It's possible no oil was going from my passenger side valve cover to the TB and all the oil was coming from my catch can overflowing/splashing into the intake manifold. The intake manifold is definitely drawing a strong vacuum from the valley cover and through catch can. My friend with a bmw was showing me how they have a factory oil separator that has a return/drain line to let oil flow back to the wet sump. It has a check valve so no oil can go from the sump up to the catch can. This seems like a great idea and I might try to use one of his extra separators on my vette. I just need to figure out where to return the oil to the sump.

Thanks Howie. I'm surprised that worked so well for you because the valve cover port has a nice baffle system underneath it to help block oil from getting to the port. The oil cap is directly above a valve spring with no baffles. I know this because I installed a vacuum pump on a drag car I used to have and it pulled off where the cap is located. But if it works it works!