I know people do catch cans and what not, even drain backs.

But has anyone just taken the fittings off the valvecover, and routed them into the exhaust at a slash cut?

What would be the pro's / con's of doing it this way?

I would assume the vaccum being pulled by the exhaust is better, and you also would never hafto empty a can, just let it burn off in your exhaust.

thoughts?

 

how would you know if your turbo was burning oil? you wouldnt be able to tell the difference. why not just make it go back into the engine?

 

you could tell if your turbo it blowing oil by checking the pipes, or by just taking off the hose going to the exhaust.

If your going to loop it back to the engine, then were talking about an open-breather set up again, with a catch can. If you dont breath it, it will just route the pressure back into the motor, effectively doing nothing, just making extra tubes going round.

 

I think it would work just fine as long as you designed it properly. You could create a venturi vacuum from the exhaust and the more exhaust you flow, the more vacuum you would generate. But I don't think it is as simple as just adding a slash cut in the exhaust...

You might end up pressurizing your crankcase and reach a negative effect.

 

glove i did this but used a catch can inline with the lines to the slash cut to stop excessive amounts of oil taking a ride out the tail pipe. i also used a drain back style catch can.

never had an issue with the setup.

 

whats the point in using a can at all then? why not just bypass it all together?

except maybe to regulate how much oil drips down.


The only thing I can think of that might happen, is if you somehow create enough boost to completlely presurise your exhaust (god knows how much that would take) so that the boost actually backpressures back into your crank from the exhaust, but I would imaging thats extreme like 100 psi.

Are there any pro's that can chime in on this?

 

do you enjoy the smell of burning oil and smoking out your exhaust?
just stick to what works

 

gotta love the smell of burnign oil when your boosting in the morning on the way to work......least everyone will see ya with cloud of blue behind ya....good idea....
stick to what works.

 

lol +1 boostedrexy

 

Piston rings don't create a perfect seal, they allow a little of the combustion gases to get past. This pressurizes the crank case, so the manufacturer puts a PCV valve on to vent the pressure. On a turbo'd motor, there is a lot more combustion gas getting past (compared to NA at least), so you need, or at least could benefit, from venting it better. Well, when you vent it, there is some oil vapor in the air in the crankcase. Instead of blowing all that vapor out, you use a CAN to CATCH the oil and still vent the pressure.

Now, you're going to ask how it will benefit you by venting the crankcase. Well, you want as little pressure as possible so the pistons can move down freely instead of having to work against pressure in the motor. It's like stuffing a garbage bag into a trash can. If all that air is in the can, it's hard to push it down. But if you have a vent in the can, the bag could go down easily...

 

Piston rings don't create a perfect seal, they allow a little of the combustion gases to get past. This pressurizes the crank case, so the manufacturer puts a PCV valve on to vent the pressure. On a turbo'd motor, there is a lot more combustion gas getting past (compared to NA at least), so you need, or at least could benefit, from venting it better. Well, when you vent it, there is some oil vapor in the air in the crankcase. Instead of blowing all that vapor out, you use a CAN to CATCH the oil and still vent the pressure.

Now, you're going to ask how it will benefit you by venting the crankcase. Well, you want as little pressure as possible so the pistons can move down freely instead of having to work against pressure in the motor. It's like stuffing a garbage bag into a trash can. If all that air is in the can, it's hard to push it down. But if you have a vent in the can, the bag could go down easily...

 

Look at funny cars and top fuel cars. They use a slash cut. And no can..... but it only works in the fastest cars on the plant..... but what do they know.

 

but honda tech says that the proper way to vent the crank case is to just run some big shiny AN line and fittings into a can with a bunch of filters on top. god forbid your not on the bandwagon and use a method that actually works better.

 

I THINK THEY USE A PUMP THE REMOVE THE CRANKCASE PRESSURE. I THINK MOROSO SELLS ONE. IVE SEEN THE DOMESTIC GUYS USE THE PUMP INSTEAD OF A CATCH CAN. BUT AS FAR AS IN THE EXHAUST IT DOESNT MAKE SENSE TO ME.

 

with the slash cut pipe in the exhaust you have to put a check valve on it. they sell it in summit and jegs

 

you would really need a way to regulate and monitor the amount of crankcase vacuum being applied. You can and will benifit from a negative pressure in the crankcase but to much is no good as it will start to pull oil from surfaces requiring lubrication such as cylinder walls and bearings from to much vacuum.

there is a fine line there and i personally dont know enough info on how much vacuum would be acceptable. Find an old schooler thats done things lie this and they can tell you more info or do some research online and im sure you will come up with a general amount of vacuum thats acceptable

 

the last top fuel car i saw had a pump on it to keep the crankcase under vacuum at all times.

 

If you run the lines straight from the valve cover to the exhaust, or use the block nipples on the back, you "CAN" wind up essentially pouring large quantities of oil into the exhaust, without either baffling it, or having some sort of "catch can" to retain the liquid. On hard launches, in an unbaffled system, the oil will slosh back and run up the oil return galleys. Before i baffled my system, there was enough slosh that I would overfill a 1qt catch can on launch, then going down the track, it return to the pan via the drain back. You may not see this if you use just the valve cover, and not the block fittings though, but it is possible

 

works better? how about trying it and letting us know? maybe the top fuel cars can do that simply bc they run for seconds and are not daily driven. one time down the strip and they need rebuilt....try again.
once again, spend the extra cash and do it right.

 

if you know what crankcase pressure is then common sense says that a vacuum in the crankcase is better then letting the pressure find its own way out. people "do it right" as you put it because its simpler. if i had choice to do it like everyone on honda tech or install a vacuum pump setup, i would go with the pump setup.

but im lazy so i do it like the rest of honda tech.

 

for those of you who are new or forgot there was a detailed test done on all the diff types of crankcase evac done, WITH data to back it up

https://honda-tech.com/forums/showth...ight=crankcase

 

i didnt read everything, but my o.o2 is, the slash cuts work well on everything. including v8's but v8's dont move nearly the ammount of oil our engines do.

you can do the slash cut but chances are the venturi effect will pull oil out hte tail pipe.

since i went with the t1 style can with 3 filters, i have had no issue.

 

yeah insted of the slash cut try running a/n lines to your ac system and thread them on the fiting then when you turn on you a/c it will pull the presure...then it wont have to force its way out...just hit the a/c button when your boosting..it will owrk good. and smell great....

 

stick with what works

 

+1 for felix and t1 couldnt be happier.

corey, so your saying mounting a catch can, drilling holes in your valve cover, getting the right lines, and plugging the hole where the stock unit goes is easier then putting fittings on your valve cover and running the hoses into the exhaust?
Please do it and give us a right up....maybe ill consider selling my $600 setup =-P