EFIDynoTuning Forum

You will need to plumb back into inlet of compressor if you're setup on a draw thru maf to be closed system pcv.

You will need to see if your definition has that access to unmetered air scalar, and adjust to accommodate the fuel trim. I'm not 100% sure if it can be done with your setup so you'll have to play with the tune.

But I ran a turbo SN95 for years with an old Univer MAF in blow thru configuration with a filtered cap. I just played with the MAF curve and Hi slope to get my fuel there.

Only issue I had was every now and then it would get real fat on AFR if I pulled a ricer move and allowed it to blow off really hard.

Decipha recommended putting a check valve on the fresh air vent to prevent unmetered air from entering the engine. This also will put the crankcase under a slight vacuum.

dleach1407 wrote: ↑2021 May 28, 00:24 Decipha recommended putting a check valve on the fresh air vent to prevent unmetered air from entering the engine. This also will put the crankcase under a slight vacuum.

Check valve to disallow boost from entering the valve cover I assume? That's perfectly fine and works as well.

As with a properly sealed PCV in the back of the intake, you should achieve slight vacuum on the oil nipple as is.

Oil separator would for sure be needed on the line from the plenum to lower PCV.

dleach1407 wrote: ↑2021 May 28, 00:24 Decipha recommended putting a check valve on the fresh air vent to prevent unmetered air from entering the engine. This also will put the crankcase under a slight vacuum.

That's what I thought. So I'm assuming that the check valve would allow flow from oil fill tube to the turbo inlet and not vice versa?

Sorry didn't mean to post that yet.

Anyways if you ask me everything before the turbo is always vacuum so you would want the fresh air inlet (VC vents) there with both vents going to a catch can and then to the manifold or inlet one?
Then the pcv valve could route from the back of the block/crankcase vent to a catch can and then back to the inlet before the turbo since it will see both negative (vacuum) and positive (boost) pressures. During vaccum it could pull crankcase fumes from the bottom end and during boost the valve would shut and cut off flow to not pressurize the crankcase more than what is happening already from blow-by.

I'm probably not explaining it well and probably dont understand it completely but look on Radium Engineerings website and check out there drawings and maybe it will make sense.