Oil Control In Rb's For Circuit Drag Or Drift

[djr81]

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.

No it doesn't help in the way you've described because the sump itself is where the blowby goes and where the "high" pressure is. The idea is to reduce the blowby gasses that have to go through the head - either by directing them to the catch can or around the head into the breather system (via the filler cap mod). I favour the former simply because it reduce the velocity of the gasses in the breather system and therefore makes it less likely they will entrain oil. Also you don't want the whole system pressurised as it just costs you horsepowahs.

In a wet sump the only thing returning oil to the sump is gravity and the oil has to pass the blowby gasses going in the opposite direction.

[XKLABA]

I'm trying to upload a pic of my bay but it won't let me

Menthol,

It's not that it will push oil down but reduces how much air is flowing up the returns trapping the oil in the head, people under estimate how much blowby come out of these things under high boost applications,ie 20psi+, next time your car is on the dyno see if you can watch the breather outlet, it will shock you

Simon,

While it will greatly reduce the amount of air pressure is the crankcase, air will flow the path of least resistance and if that is via the two lines running to the catch can then that is where the air will flow and it will take the oil with it, if the catch creates a restriction then it will leave via the oil returns again trapped the oil in the head

I have seen too many times setups running from to low in the crank case ( mine included which come from the block ) where the lines leave without passing through the cam covers and they end up filling up the catch can leaving the sump with out enough oil

If the pickup is to low then around a high speed high power corner the oil will cover the pickup and the blowby will pump the oil up the line to the catch can, but if you are not having issues with yours then you obviously have it sorted , if it aren't broke don't fix it

[XKLABA]

The goal is the reduce the air flow/speed up the oil returns through the block and head, this can be done several ways

[GTR_JOEY]

Another way to increase vacuum in the crankcase and rocker breathers is to also run a large diameter line from the catch can to the intake pipe. This will induce a lower then Atmospheric pressure AND it allows you to run a sealed catch can and make it more legal if you choose to do so...

Down side is if you choose to seal the catch can there may get oil in the intake

[GTR_JOEY]

Looks a little less clean in the engine bay too

[djr81]

Another way to increase vacuum in the crankcase and rocker breathers is to also run a large diameter line from the catch can to the intake pipe. This will induce a lower then Atmospheric pressure AND it allows you to run a sealed catch can and make it more legal if you choose to do so...

Down side is if you choose to seal the catch can there may get oil in the intake

What you are describing is the stock setup for the GTR's with a Nismo can fitted.

[GTR_JOEY]

Yep, I wonder how well it would work with a vented catch can

[XKLABA]

Another way to increase vacuum in the crankcase and rocker breathers is to also run a large diameter line from the catch can to the intake pipe. This will induce a lower then Atmospheric pressure AND it allows you to run a sealed catch can and make it more legal if you choose to do so...

Down side is if you choose to seal the catch can there may get oil in the intake

In theory that's sounds good but what it does is increase air velocity up the oil returns/catch can lines increasing the amount of oil leaving the engine, and is how my setup is currently done for legal reasons and why so much thought had to go into it and it's proven to work with 22psi boost and 400kws at all 4 on SMSP-s which is a tight twisty track that does a good job of showing a setups short comings

[djr81]

Yep, I wonder how well it would work with a vented catch can

Wouldn't work with AFM's because the feed is downstream of them.

[GTR_JOEY]

Do you have an oil return line from your catch can to the sump mick?

If it was draining back when the engine is in vacuum that would be a solution?

[GTR_JOEY]

Wouldn't work with AFM's because the feed is downstream of them.

This is true, would be ok for MAP though

[GTR_JOEY]

I realise that an oil return is no good for E85

[XKLABA]

Do you have an oil return line from your catch can to the sump mick?

If it was draining back when the engine is in vacuum that would be a solution?

Yeah, -12 line from bottom back of front catch can to fitting in block next to starter motor with a one way valve on it

It can't until engine is off as the vacuum is running through the catch cans

[menthol369]

I'm trying to upload a pic of my bay but it won't let me

Menthol,

It's not that it will push oil down but reduces how much air is flowing up the returns trapping the oil in the head, people under estimate how much blowby come out of these things under high boost applications,ie 20psi+, next time your car is on the dyno see if you can watch the breather outlet, it will shock you

Simon,

While it will greatly reduce the amount of air pressure is the crankcase, air will flow the path of least resistance and if that is via the two lines running to the catch can then that is where the air will flow and it will take the oil with it, if the catch creates a restriction then it will leave via the oil returns again trapped the oil in the head

I have seen too many times setups running from to low in the crank case ( mine included which come from the block ) where the lines leave without passing through the cam covers and they end up filling up the catch can leaving the sump with out enough oil

If the pickup is to low then around a high speed high power corner the oil will cover the pickup and the blowby will pump the oil up the line to the catch can, but if you are not having issues with yours then you obviously have it sorted , if it aren't broke don't fix it

yeah exactly what happened to me, Did you just bore a hole in your crank and weld -12s into that?

i was thinking about doing this but was worried about the strength in the block walls.

if this can be done it would save me alot of headache

[GTR_JOEY]

Dunno how boring a hole into the crank and attaching a hose to it would go

[GTRPSI]

I think he meant top of the sump.....

[ScreamerNewbie]

yeah surely not the best I have 2x -12 on the highest point of my sump, and iv only had the issue of puking when I over fill my sump.

seeing as I run e85 I don't drain mine back to sump either

would be interesting to know how else you could get the vents higher.

next time ill just go drysump, LESS HASTLE!!

[KiwiRS4T]

Hardly less hassle but certainly as better solution if you have money to burn. I have managed without but if I had a 600kw build I would at least look at an accusump If not a full dry sump.

[XKLABA]

I drilled and tapped 3 holes in the block ( 2 x -12 and 1x -16 ), placement of these holes is very important for block strength, get it wrong and shit can turn bad pretty quick

I also have the water jackets half full of grout and a platinum racing adaptor plate which ties the girdle and block together

The Accusump is a really really good band aid, but and ounce of prevention is worth a pound of cure, set your oiling system up right from the get go and it shouldn't be necessary

[ScreamerNewbie]

I have a 600hp 25/30 driftcar, about to turn it up a bit for racewars next yr, hoping to go 800rwhp, but on current set up its running 6.5L trapdoor extended sump, 2L accusump, 2 sump breathers. 2x1.2mm restrictors, blocked vct feed, enlarged oil drains, decent vented catch can. tomei oil pump. all up with the oil cooler and accusump it holds around 9.5L. the only time ive ever had quite an oil puke was when I over filled the sump, other than that, its usually pretty clean apart from the ethanol. has quite a high oil pressure too, sits around 80psi once warm at 2000rpm hits relief spring pressure (110psi) around 4000rpm. haven't had any issues.