Question to those whom have gone mafless:

I am in the process of a mafless build and have haphazardly embarked on removing the Y pipe, intake, F Pipe + DV's, Air Pump, ect. I have found the supply of information on which lines you need to keep, which lines you need to block off and which lines you can toss, sparse to say the least.

I was hoping that someone could help direct me as to "How to go Mafless: A lesson in vacuum lines" that could walk me though which are mission critical and which are for the birds.

Car will be running a FabWorx Y pipe with BOV and filters off the turbos thus replacing any need for DV's or the stock setup...

Any help is appreciated.

Depends what your plan is for the secondary air pump?? If your not using that you can remove all the lines and just have one vacuum/boost line to the BOV and one to the fuel pressure reg.

If your still using the secondary air, than that complicates things. You don't want boost, so a one way valve (the black and white ones) is needed. You only want vacuum, so set the valve up that way.

All 3 lines will come of the plenum.

Thanks for the quick response, and excellent follow on question - To be honest I am not sure what the benefit would be of keeping the secondary air pump while going mafless? My gut tells me to scrap the entire SAP and keep things in the bay clean and less muddied.

Is there a direct pro/con of removing the SAP?

What type of boost control?

Stock n75, or I can switch to an AVCR that I have laying around the house. Unless there is a newer recommended EBC that people seem to have good luck with.

There is a 3/4 vent line off the oil tank you will need to put a filter on. Hope the red line drawing is understandable.

Much cleaner without. If your engine is out and your intake is off, you can make simple blockoff plates and remove it all. If it's not, just remove the SAP and cap the line (you don't have to cap it as it wont operate without vacuum)

Make sure you tell your tuner to give you ROW tune.

If the engine is out you can also remove the vacuum canister of the manifold. Only have to run 2 lines then one to BOV other to fuel pressure and no one way valves. Much simpler

You sir, are a god amongst men.

I appreciate it. Will start removing and follow up if any additional questions.

No problem. Other than the n75 valve and lines to the wastegate, it's possible to get rid of basically everything in your second picture.

If you have any questions let me know.

Craig

what do you plan to do about the kali visual?

Subbed! Details on the Y-pipe? I'm headed down this path and honestly didn't realize it could get this complicated. If you keep the SAP, can the oil tank vent remain as-is? In my case I really just want to dump the MAF and restrictive intake piping while leaving most everything else alone if possible?

The SAP has nothing to do with the oil tank. Going to filters on the turbo or fendor intakes is the reason for the filter on oil tank. I ended up running a longer hose to the fendor intake, so the oil tank is under vacuum like oem instead of the filter.

That's the info I was looking for, thank you! I too think putting it under vac is a good idea and pushing the fumes through the engine is fine. I've got a different vehicle, a Subaru, that just has a vent on the AOS and it stinks! I'll be fixing that too, no sense just venting the fumes IMO and yeah I know it can lower octane if it vents enough. Prefer to keep as many of the engineered systems together as possible

rather than burn it or vent to the atmosphere you can vent it to a catch can and drain it keeping the messy oil fumes out of the t/b

As I've found with my other car, draining that thing is a PITA and the vac ought to pull more out and perhaps assist the ring seal. I've seen some use the exhaust system to draw a vacuum and burn the fumes too but don't think I want to go there. I'd like to do this car as close to stock, regarding this, as possible. Other car will get a heated AOS that drains to the crankcase and has vac applied come Spring I think, sick of smelling it