Oil Control In Rb's For Circuit Drag Or Drift

[SiR_RB]

Like this that simonr32 did on his track 32 gtr

[fatz]

finally have track tested my car with catch can v4

and i can confirm its a winner, and i dont use this car like normal people, eg it will do 12 20 minute session each track day with two drivers

previously i would limit the revs to 7k at the track to minamise blow by with the above setup 8k is no dramas all day

setup

stock motor

anywhere between 280-340rwkw

mines cam baffles ( had these on v1-3 and did not do shit for blow by)

two catch cans

-12 vent oil cap to sump(DS)

-12 drain second catch can to sumop (DS)

-10 scavenge pump from catch can one sump ( have not had to use this yet, i assume i will in a few track days as the engine wears)

i have not depolyed the external scavange

will report back as the track days pile up and it slowely wears out

[Yeedogga]

I recently fabbed and fitted a new catch can on my RB25. It has ended up with a shitload of oil in it after a couple of track days.

Does anyone see any problem having the 2 crank breather lines AND the PCV going to the catch can?

Or is this excessive?

Track only car.

Motul 300V sure smells gooooood

[XKLABA]

In it is normal, coming out of it is what you are trying to stop

[menthol369]

So i killed an engine at winton a couple weeks ago due to oil starvation.
this was caused by the sump breather. i had a straight line coming perpendicular to the sump and the catch can wasnt high enough- all the oil pissed out while turning left.... and the rest is history

Now an easy fix for this would be to run a right angle and have it go directly up and through/around the inlet mani and meet up with the now moved catch can. But that would still let oil block up that breather and either build pressure or spit oil up and out ( just not the majority of it like last time)

im putting a sump baffle setup through it, but im wondering if the best way to avoid oil getting up to the breather ( drivers side above windage tray)
would be to box around it and drill small holes to allow oil back down?

what have other people done for this breather?

[KiwiRS4T]

I have two breathers in the sump running to a catch can positioned roughly where the battery used to be. One line goes to the top of the can the other to the bottom. They both act as breathers til the catch can starts to fill and at the end of the straight when I lift off the oil drains back down to the sump. There is more to it but its all in the thread. Have you got oil restrictors? And a baffled and /or extended sump?

[Badgaz]

I recently fabbed and fitted a new catch can on my RB25. It has ended up with a shitload of oil in it after a couple of track days.

IMG_3255.JPG

Does anyone see any problem having the 2 crank breather lines AND the PCV going to the catch can?

Or is this excessive?

Track only car.

Motul 300V sure smells gooooood

you don't need the pcv if you vent your catch can to atmo. just make sure you vent your catch cant appropriately e.g 2 x 5/8's in and 2 x 5/8's out so you don't pressurize your catch can.

[scotty nm35]

Vented catch cans are crap, on the road and track. Spraying oil vapours around your engine bay might sound good to you, but the guys driving behind will be very shirty when you spray oil around the track.

Most good race setups I have seen use multiple catch cans, the Sierra's ran a large baffled can with a pump to return the oil if the drain couldn't keep up.

[fatz]

dan swing over and climb under my car when you have a chance

[menthol369]

I've read a lot in this thread, its how I decided on what to run.

Setup is as follows

25/30 with vct

1.5 restrictors in front and rear, internal vct mod so the front feeds the vct as well.

Sump breather to catch can, both rocker covers to a separate catch can (moisture was building up heaps)

Over the track day I didn't get one single drip of oil out the covers, so I think the setup is good.. Just the geforces when cornering pushing oil out my breathers seems to be the issue.

I'm considering putting a breather which has to be under the windage tray which isn't ideal. Run that to the stock front breather on the 25 head which was blocked off.

That way the pressure has an escape no matter which way you corner.

[Badgaz]

Vented catch cans are crap, on the road and track. Spraying oil vapours around your engine bay might sound good to you, but the guys driving behind will be very shirty when you spray oil around the track.

Most good race setups I have seen use multiple catch cans, the Sierra's ran a large baffled can with a pump to return the oil if the drain couldn't keep up.

. If you are spewing that much oil out you have bigger problems than whether it vents to atmosphere or not.

[scotty nm35]

Judging by the size of the catch cans on the Sierra, they never quite sorted it out.

The track sorts out all your issues, one way or the other.

[djr81]

mines cam baffles ( had these on v1-3 and did not do shit for blow by)

Suspected this was the case. Good to get confirmation.

[XKLABA]

mines cam baffles ( had these on v1-3 and did not do shit for blow by

Suspected this was the case. Good to get confirmation.

Blow by is what gets past the Pistons,

I have the Hi Octane version of the mines cam baffles and same they don't stop the oil leaving the cam covers but what they do do is turn it from a fine mist to spray making the oil droplets heavier reducing the amount that can escape, this is why you should use one of those catch cans the sit on top of the engine in conjunction with the cam baffles

I have one of these which I put a baffle plate in them run two -12s hoses down to a Hi Octane catch can/washer bottle setup up front and after a day at SMSP-S I had very little oil in the lines as they get to the front catch and 0 oil in the lines from the front can going back to the PVC and rear turbo

[djr81]

Blow by is what gets past the Pistons,

I have the Hi Octane version of the mines cam baffles and same they don't stop the oil leaving the cam covers but what they do do is turn it from a fine mist to spray making the oil droplets heavier reducing the amount that can escape, this is why you should use one of those catch cans the sit on top of the engine in conjunction with the cam baffles

I have one of these which I put a baffle plate in them run two -12s hoses down to a Hi Octane catch can/washer bottle setup up front and after a day at SMSP-S I had very little oil in the lines as they get to the front catch and 0 oil in the lines from the front can going back to the PVC and rear turbo

Surely its just the foam in the things that coalesces the oil spray - much like the wire cages in the stock baffles.

The problem I have with the Mines baffles is they take their feed from the rear of the head which is exactly where the oil pools under acceleration which corresponds with the time you are getting the most blow by. Hence the suspicion that they don't work as well as advertised.

[SimonR32]

My High Octane (Mine's baffles) did very little to help the problem.

Venting the sump from the drivers side to a catch can made 100% difference, everything else was little help at best

[XKLABA]

I had to move the splash gaurds from the cams to under the inlets of the breathers so the spray from the cams isn't getting pumped into the breather in let, I also moulded the factory wire things into the inlet tract

Once the foam is oil logged then they aren't doing a great lot but still turning it from a mist to bigger heavier droplets and if you don't have the catch can on top of the motor they won't do much to help the problem

For track use I don't like the idea of running open lines from the sump to an external catch can, half the problem with RBs is getting the oil out of the head which is trapped there by the blowby venting through the oil returns so by running lines from the sump to the head you are creating alternative routes for the blowby to travel slowing down the air flow up the oil returns, by running them external you are reducing how much they can balance the air pressure difference between head a crank case and aswell giving an alternative path for the oil to leave your engine

[djr81]

Yeah the trick is not to push the blowby through the head - either by bypassing it or reducing blowby, or both. That and reducing the pooling of oil in the head is the key to it.

Problem is there is insufficient room in the engine bay for a cyclone type catch can which would separate the oil/air properly.

Speaking to a few people it can be the last few hundred rpm that is used that makes a big difference to the amount of oil spat out of the engine. Not quite sure why that is.

[menthol369]

So theoretically it would actually be best to have the sump breather go back into the cam covers, which would help push oil down the head drains if it has that external passage.

But by that logic the breathers at the back of the block are pretty massive and there are two... So the oil drains shouldn't have that much trouble draining..... Theoretically.

[SimonR32]

For track use I don't like the idea of running open lines from the sump to an external catch can

by running them external you are reducing how much they can balance the air pressure difference between head a crank case and aswell giving an alternative path for the oil to leave your engine

They relieve the pressure in the sump, therefore there will be less pressure in the head as well. Less pressure in the sump makes the oil drains work more efficiently. I have 2 lines (with no valve) going from the sump to the catch can and they never have given my oil a path to leave my engine.

Realistically my GTR is almost worst case scenario for oil problems, it's quick around a track (g-forces), cops a lot of boost and decent power, has no head restrictors plus runs slightly higher than normal oil pressure. I had severe oil control issues and the only thing that helped was vent from sump to catch can. Not only did it help but it 100% solved all my issues so in my opinion you're nuts for not liking the idea