AOS Delete - 986 Forum - The Community for Porsche Boxster & Cayman Owners

As anyone deleted there AOS, ie blanked off the throttle body and run a pipe from the top of the AOS to a catchment tank/can. l replaced my startermotor a few weeks ago and found a fair bit of oil in the pipe between the throttle body and AOS, but i wasn't getting any smoke bombs while running just the odd puff of blue smoke if reved hard at standstill and when the wife followed me it did smoke a little but nothing major Anyway clean out the pipework fitted a new AOS done 300 miles just checked the pipe and there oil in there again. Have seen posts on here where a guy had 3 duff one's straight from the box think it was one of jake's post. So has anyone deleted theres, if so has there been any performance loss with the crankcase not being under vacuum

What year is your car?

Quotes source post: 450869

1998 with a 3.4 996 motor

What year is the motor?

I have stuff to do. Check this if it corresponds to your engine. Crankcase Ventilation Valve In some cases the ventilation valve on the valve cover that connects the crankcase to the oil seperator becomes clogged, and may cause problems for the oil seperator. If your newly replaced oil seperator is starting to fail, or you are about to install a new seperator, you might consider replaceing the ventilation valve. Pelican Parts - Product Information: 996-107-047-51-M100

I've seen that valve its on bank 4 to 6 AOS pipe did wonder what it was, can it be cleaned

Piston ring tension is affected IIRC. You don't want that

Quotes source post: 450866

The low tension piston rings rely on the crankcase vacuum to help seal the rings, eliminating that vacuum increases blow-by. If the AOS is disconnected from the vacuum source no oil will come out the top of the AOS.

Quotes source post: 450888

Along with blow by and he loss of effectiveness for the low tension rings used in these engines, not having vacuum in the case sump will lead to increased water and fuel level build up in the oil as the low vacuum level created by the AOS helps to flash them off at lower temperatures. This will very quickly degrade any oil.

Cheers for the replys lads, looks like I'll give that one a miss

^^^ + 1 Very interesting comments from BY and JFP

Quotes source post: 450899

A catch can needs to be plumbed inline between intake plenum & AOS.

Something like this then. BRUSHED ALUMINIUM OIL CATCH CAN BREATHER TANK RESERVOIR WITH 19mm 3/4" OD BARB | eBay Should be enough room near the side intake fan to install

Or something like this OK, here's where everyone tells me I'm killing my engine. I've run this for 3-4 years now and 25,000+ miles. So far so good. I think I did it as much to try an alternative solution as I did for a cheap easy fix. But it's just a race car, so what the hey. I would not do this to my everyday driver.

Quotes source post: 451014

Can you elaborate on how you've plumbed this in? I am looking to delete the AOS on my 986 racer (which is getting ITBs, so no real good source to hook up the AOS vaccuum line).

My "piggyback" AOS is plumbed in between the facatory AOS and the intake. I removed the plastic tube, threaded the AOS and the intake "T", adding brass hose fittings. I then mounted the piggyback AOS in the trunk and ran fuel line to connect it to both brass hose fittings.

Resurrecting this post from a fellow 986 track driver, who gets the occasional blue puff of death. Add $1000, the motor sports AOS solution seems to be overkill. Looking for a more pragmatic solution. Is your truck solution still working well? How often do you have to drain the oil from the bowl? Much appreciated!!

I run a 1 qt nuke performance catch can after disabling the stock AOS. I've added a vW regulator further down the line. This seems to work well and would cost you about $350. That said, I've deleted both my SAI and engine compartment fan to get space, so ymmv.

I plumbed a $25 catch can between the AOS and intake. I wanted to leave the AOS as a regulator valve because redoing all the connections would be a pain to do. However, a good adjustable valve would only run another $25 (that way you can dial in the exact pressure you want). I've run mine 5hie way for over a thousand miles. No issues. I've looked in there recently and have very little kerosene like residue. Sent from my SM-G970U1 using Tapatalk