When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
At the moment +400 cars modified without any problems!
only benefits: no more crap in intake, cooler intake temp (+bhp), smoother idle, never hydrolock due to oil dumped in intake, AOS always open (diaphragm never ‘fails’), easy to temporary revert to OEM for inspection.
This system is a good "low cost, temporary down and dirty DIY Mod", but the Type 3 pcv system was abandoned in the US decades ago.
It may be ok to use in other countries, because it will stop the risk of hydrolocking, but not as efficient at removing the blow-by that can cause sludge in the oil or create enough negative crankcase pressure to help stop oil leaks. Would not be a "legal fix" and definitely cross the line in the US, unlike the " Ultimate AOS" which is a slightly better design than the OEM all the way around.
I can agree on your arguments. Legality of it is different for every country or regio. I just wanted to share this modification works very well. Notwithstanding all the hypothetical technical drawbacks posed.
AOS is still in place, evacuated crankcase gases still go to the intake only now before the throttle body instead after. Fresh air get mixed. Would this means it is still a type 3 system?
How It would not be good to remove the blow by gases? Even a throttle body in small open position already creates enough vacuum to evacuate the crankcase gases back into the engine. As the throttle body is closed there is no or very little evacuation of gases in the original situation, just the same as in the modified situation.
As already said I in the US it will not pass any technical inspection I suppose.
I can agree on your arguments. Legality of it is different for every country or regio. I just wanted to share this modification works very well. Notwithstanding all the hypothetical technical drawbacks posed.
AOS is still in place, evacuated crankcase gases still go to the intake only now before the throttle body instead after. Fresh air get mixed. Would this means it is still a type 3 system?
How It would not be good to remove the blow by gases? Even a throttle body in small open position already creates enough vacuum to evacuate the crankcase gases back into the engine. As the throttle body is closed there is no or very little evacuation of gases in the original situation, just the same as in the modified situation.
As already said I in the US it will not pass any technical inspection I suppose.
I hope your ultimate solution works well too!
Yes your system is a typical Type 3 system.
I have used the Type 3 system on my 996 and I know it does work, it's just "messy" with the oil vapor getting on the air filter/MAF sensor, and doesn't produce as much negative crankcase pressure or a constant negative pressure as the original design, therefore is less efficient and hence it was abandoned in the US..My engine was a lot happier and peppier when I went from the Type 3 to the Ultimate AOS design. More negative crankcase pressure means more power.
The original design and the Ultimate AOS keeps a constant negative pressure on the crankcase at all times even during high load or low load due to the balancing of pressures by the flow regulator. The flow regulator uses atmospheric pressure, spring pressure, and blow-by pressures to control the negative crankcase pressure provided by the intake vacuum. More negative pressure on the crankcase is better for emissions, ring seal, and also overall power (windage losses from high piston speeds)..
True. Also it gets a bit more dirty quicker. The dirt stays in the airbox though, so it is a very easy clean. And who does not change is airfilter regularly? It is a fair trade off between safety and workaroundability.
The MAF getting dirty is all within reasonably expectations, cannot complain about that. I relaxed it after 30.000 miles. I consider it anyway as a ‘regular’ wear item. So I don’t mind the extra dirt. Hot film voltage values stay perfectly within the +- 0.03V bracket for a long time.
For what it is worth the MAF design is also highly flawed. Highly sensitive to heat soak. When spoiler is down and low speeds, intake temps rise high fast, but It takes very long for the temperature sensor to read the accurate intake temperature when driving at higher speeds again.
I really admire the engineering behind your mod. Hope it works good in practice with the IR sensor.
True. Also it gets a bit more dirty quicker. The dirt stays in the airbox though, so it is a very easy clean. And who does not change is airfilter regularly? It is a fair trade off between safety and workaroundability.
The MAF getting dirty is all within reasonably expectations, cannot complain about that. I relaxed it after 30.000 miles. I consider it anyway as a ‘regular’ wear item. So I don’t mind the extra dirt. Hot film voltage values stay perfectly within the +- 0.03V bracket for a long time.
For what it is worth the MAF design is also highly flawed. Highly sensitive to heat soak. When spoiler is down and low speeds, intake temps rise high fast, but It takes very long for the temperature sensor to read the accurate intake temperature when driving at higher speeds again.
I really admire the engineering behind your mod. Hope it works good in practice with the IR sensor.
Thanks man,
The infra-red sensor is a really nice piece, very accurate, durable, not effected by ambient light, bubbles ect.
It sends an Infra-red LED light into a prism which reflects the light back to a photosensor. When the liquid level reaches the prism tip, the Infra-red light is refracted into the the liquid and away from the photosensor, causing less reaction of the photosensor which is picked up by the microprocessor and switches the output. It's very fast, accurate, and precise.
I know it's hard for you to go away from the type 3 system since it is a low cost, easy mod, and you are having success, but you may want to think about going to the Ultimate AOS for the efficiency, better ring seal, lower oil leaks, more power, and of course emission friendly.
BTW I like your drain vent hole idea in the lower case, that's makes since, and is easy to do "while your in there"..
The drain hole vent works. Tested on car with a fragged AOS refitted. It will just give you that safety when the diaphragm breaks your engine does not convert into a direct oil injected engine.
Coincidentally after making the vent hole in my car and reverting back the AOS modification to stock the AOS broke after 400miles. Probably it was already terminal. I got none of the usual symptoms. Except the puff of smoke at startup and symptoms of high vacuum under idle when removing the oil filler cap. I got it replaced and all good now
ahhh and for oil consumption ... I have had a stable oil consumption of 1 quart every 1250-1500 miles. I was curious to see if reverting my car to stock AOS setup would make any difference. As I was convinced the non ideal vacuum would influence ring efficiency. In my case no difference.
I would love to try your solution if it gets available.
On the other hand I am one of those that drive their car, hard, no mercy, ... and in those circumstances the AOS cannot cope always well with the amount of oil mist to separate. I really don’t like all that gunk going directly into the intake. I notice it now with my stock setup that I have the occasional smoke on startup. Which I did not have with the mod. So I prefer the extra safety over the little extra power and efficiency.
i will make up the loss of uuumpf by getting rid of 9k unsprung mass and rotational inertia at the wheels and putting finally my recaro seats.
Would excessive hard driving and occasionly overwhelming the AOS trigger your IR sensor?
I'm in the middle of an AOS rebuild right now, replacing the AOS unit with a Provent 200. Everything is put in place but have not yet started the engine due to other works needing done before. In a few weeks.
Something which have not been mentioned is the tubes in the system. Mine where very brittle, basically shattered when trying to bend a bit. They also had beginning cracks in bends and connectors. I think replacing these should be high on the list of to-do when sorting out the AOS. The connectors can be reused if 19mm I.D hose is used.
I'm in the middle of an AOS rebuild right now, replacing the AOS unit with a Provent 200. Everything is put in place but have not yet started the engine due to other works needing done before. In a few weeks.
Something which have not been mentioned is the tubes in the system. Mine where very brittle, basically shattered when trying to bend a bit. They also had beginning cracks in bends and connectors. I think replacing these should be high on the list of to-do when sorting out the AOS. The connectors can be reused if 19mm I.D hose is used.
Please do post photos of your Provent install. I have always thought this would be a great alternative and have a Provent in the office for this exact reason.
AOS vent lines and oil fill tubes are a must on almost every engine we see come in for an IMS bearing. They are all brittle and when they crack, it leads to vacuum leaks that cause enrichment and wash down cylinder bores. Definitely a maintenance item.
AOS vent lines and oil fill tubes are a must on almost every engine we see come in for an IMS bearing. They are all brittle and when they crack, it leads to vacuum leaks that cause enrichment and wash down cylinder bores. Definitely a maintenance item.
Sounds like motor out maintenance is a good idea for these close to 20 something cars. I had the air cooled engine out routine mastered. Now gotta figure out this water cooled lump.
Sounds like motor out maintenance is a good idea for these close to 20 something cars. I had the air cooled engine out routine mastered. Now gotta figure out this water cooled lump.
Lately we've been dropping the engine and trans on most IMS jobs as we're doing so much preventative maintenance, it's faster that way. The engines more or less fall out and in without much fuss. Porsche did a good job making them plug and play.
Sounds like motor out maintenance is a good idea for these close to 20 something cars. I had the air cooled engine out routine mastered. Now gotta figure out this water cooled lump.
While it's not "difficult" to drop the motor, it is a lot of work - especially the first time around. Even though I'm using jack stands, for doing something like the AOS or the oil cooler/heat exchanger, I'd do it again in a heart beat (and I'm sure it would go quicker the second time around). It really makes these jobs so much easier (and safer - there are lots of brittle plastic things to break or knock loose if you're fumbling around blind in there). It also gives you the benefit of being able to look at everything on top of and behind the areas you can see with just the engine lid open, as well as ding a good cleaning while you're in there (99% you've got some rodent nest/droppings on top of your engine).
I have used silicone hoses. But you need to spend time with a catalog to find the best shapes and adapters.I used only the best quality USA made hose and thick wall[ or wire reinforced to prevent it collapsing under vacuum. https://www.siliconehose.com/blog/si...bsolute-best-/ Use black so it looks stock -not Ricer red ! I found some import silicone hoses became stiff after heat cycling. The best connectors imho are barbed brass. Another rabbit hole of hours of nerdy research.They are cheaper online than the official Pcar plastic parts.https://fastfittings.com/
Hope this helps
QUOTE=Nick_L;16389343]I'm in the middle of an AOS rebuild right now, replacing the AOS unit with a Provent 200. Everything is put in place but have not yet started the engine due to other works needing done before. In a few weeks.
Something which have not been mentioned is the tubes in the system. Mine where very brittle, basically shattered when trying to bend a bit. They also had beginning cracks in bends and connectors. I think replacing these should be high on the list of to-do when sorting out the AOS. The connectors can be reused if 19mm I.D hose is used.[/QUOTE]
Dropping the combined engine and transmission is much safer and easier with a scissor lift table on casters .We've discussed this at length with videos in other threads. Some have used a motorcycle lift on casters.
There are some vital concealed connections and obstructions to deal with. Also covered in the past.
Then there is the need for an engine yoke to fit a standard engine stand.....
Originally Posted by dporto
While it's not "difficult" to drop the motor, it is a lot of work - especially the first time around. Even though I'm using jack stands, for doing something like the AOS or the oil cooler/heat exchanger, I'd do it again in a heart beat (and I'm sure it would go quicker the second time around). It really makes these jobs so much easier (and safer - there are lots of brittle plastic things to break or knock loose if you're fumbling around blind in there). It also gives you the benefit of being able to look at everything on top of and behind the areas you can see with just the engine lid open, as well as ding a good cleaning while you're in there (99% you've got some rodent nest/droppings on top of your engine).
01-04-2020, 01:37 AM
