what size can?

[pureboiracer 0]

what size oil catch can do i need for a m20b25 turbo?? and how would you go plumbing it in? as i here its not done the standard pipe into the can and block off the throttle body way???

[williams 0]

all depends on the wear in the engine and how hard you want to boost-found it best to blockoff the breather between the intake and block(m3 shim fits perfectly in block)-when the boost was pushed up oil was forced out of the seals,you could even plumbit back into the air cleaner as this would suck the oil fumes and burn them

[kerrynzl 3]

what size oil catch can do i need for a m20b25 turbo?? and how would you go plumbing it in? as i here its not done the standard pipe into the can and block off the throttle body way???

you MUST run a breather or the engine will breathe through the front and rear crank seals [ or any orrifice it can find ]

crankcase pressure is caused by ring blowby [ no rings can get 100% seal ]

Remember all pressure in the crankcase equalizes [ the valve covers have the same pressure as the sump ] the higher the cylinder pressure , the more blowby.

The best way is to run a catch can with a breather in the top [ it must have an oil separator like a gauze in it ]

gravity fed oil returns to the sump dont work with the engine running [ unless you have a bilge pump with pressure greater than crankcase pressure ]

use a tank with a minimum capacity of 1 litre [ more if you're gonna boost it crazy ] dont plumb it back into the intake,just let it breathe through a pod filter

I once test drove a diesel that had so much blowby plumbed into the intake that the motor couldn't be switched off [ it ran on it's own crankcase fumes ]

[Boost Junky 1]

I was going to run a catch can that returned to the sump but somebody mentioned to me the other day about moisture etc which you would not want to drain back into your sump?

On another note, the ICV lines... one runs before the throttle body from the ICV and one runs to the intake manifold after the throttle body from the ICV on the M50. Is it the same on a M20? Either way should i be plumbing any of the two hoses under boost? Or leave the one before the throttle body venting to the catch can? And the other one left in the Intake manifold?

This may apply to you also sydwayz e30.

[pureboiracer 0]

yeh that was the plan. wasnt going to waste my time trying to plumb it back in. just wasnt sure if it would mess with the engine running having the crank case venting to air.

just one other thing. will my oil return line be ok plumbed into top of sump?

[CamB 48]

just one other thing. will my oil return line be ok plumbed into top of sump?

Huh? Do you mean on the passenger side of the car? How could you get the line around there without it going upwards?

[pureboiracer 0]

no i meant the top of the sump on the driver side. just below where the oil filter usualy sits???? would it drain properly or would i need a scavange pump?

[Mike 1]

hang on, are you now talking oil return for turbo, or are you trying to drain your catch can. if its the later I wouldn't bother. just empty it every so often. put a glass sight on it and you should be all good

[pureboiracer 0]

sorry to confuse. i will just drain my catch can every now and then. no point in returning it. i was talking about the oil line for the turbo in the top of the sump

[ecko_complex 3]

Would you like a picture of my setup for the catch can?

[CamB 48]

no i meant the top of the sump on the driver side. just below where the oil filter usualy sits???? would it drain properly or would i need a scavange pump?

It should be fine as long as the drain on the turbo points straight down (or close enough - like within 15 deg of straight down), only slopes downwards (no upwards bits), and joins the pan above the normal oil level.