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I don't claim to be knollegable here... But in the limited research I did for a race dry sump for 987. I was looking to pull more vacuum (more vacuum reduces windage losses) but too much vacuum and you start pulling seals. Too little and the low tension oil control rings (in the 987 anyway) aren't effective.
No vacuum or even slight positive pressure, just curious if that was addressed.
Truly not asking this rhetorically, but honestly curious...if this is such a cheap part and relatively easy install for the factory, and so beneficial to the health of an engine, then why arent they standard and part of the Porsche OEM design?
"if this is such a cheap part and relatively easy install for the factory, and so beneficial to the health of an engine, then why arent they standard and part of the Porsche OEM design?"
because in the USA and the countries we bullied into making it law, its the law to pump that goo back into the intake, this was okay before DI motors because the fuel washed the backsides of the intake valves, not so in a DI motor. So the reason is, its an illegal mod like removing your CATS.
Are there any pics out there actually showing excessive carbon on 981 engines? I know that is the case for many DI cars, but it is not uniform (see V8 RS4, which was horrible about it, versus B8.5 S4, which was not that bad). I don't recall seeing buildup pics on 981's.
Do what you want, the point here was to try and help. I get that most of you don't work on your own cars and wont keep your 981 more than a few years. For me, this spyder will likely be the only new and likely the last Porsche I ever own. So I work on it myself. So I want it to last till I die. I bought my 914 in 1987 and kept it until 2015. (28 years) so...
Wouldn't a quick dyno run on a Porsche with a bunch of miles give an indication of the buildup having become an issue or not? Horsepower drop-off would be severe I would think if there's buildup no?
I'm familiar with the BG 44K referenced in that link; it was quite popular in the VW/Audi world. Like someone in that thread said, you can add it to your intake tract, let it sit, then start your car and watch all the dissolved carbon blow out the back. I don't know if it's more or less efficient than walnut shell blasting.
Do what you want, the point here was to try and help. I get that most of you don't work on your own cars and wont keep your 981 more than a few years. For me, this spyder will likely be the only new and likely the last Porsche I ever own. So I work on it myself. So I want it to last till I die. I bought my 914 in 1987 and kept it until 2015. (28 years) so...
Well, let's take a look here. There's a moderately-scary photo of a single 997.2 engine from 2010, taken in 2013. There were a lot of 997.2s, and the first ones are now coming up on 10 years old. We should be hearing more reports.
Then there are several people talking about Audis and Cayennes and whatever. There's a particularly sad story from an A4 owner whose dealer diagnosed carbon buildup after several other attempts to fix a CEL. After cleaning the carbon buildup, the CEL went away came back. Not seeing any smoking guns here.
It appears that valve cleaning costs $400-$600 to deal with, if/when it happens after 50K miles or whenever. It should be trivial for anyone with a $99 eBay borescope to pull a spark plug and have a look, so why don't we have more evidence to go on? Coming from someone who's old enough to remember cars that required periodic valve-lash adjustments, this doesn't exactly sound like the end of the world.
because in the USA and the countries we bullied into making it law, its the law to pump that goo back into the intake, this was okay before DI motors because the fuel washed the backsides of the intake valves, not so in a DI motor. So the reason is, its an illegal mod like removing your CATS.
Used motor oil is nasty $#!+. If you vent your PCV line to the atmosphere, it ultimately goes into your intake. A catch can seems like the right way to go for those concerned with this potential issue, but the factory won't install one because it would presumably have to be maintained (emptied) eventually.
I was considering this mod at the same time I have an ipd plenum/gt3 throttle body and headers installed on my gt4. I asked my local Indy what they thought, and here is their reply, "As far as changing the crankcase vent system, it really isn't necessary. Having the system working in the original design actually helps with ring seal between the cylinder walls, due to the small amount of vacuum that is created in the crankcase. Better ring seal means more power and less blow-by. The small amount of oil that does get recirculated back into the motor will not cause any issues, especially given that the engine does not experience any short trips and that the RPM's will be at higher levels more often." Based on this, I decided to hold off. I'm not personally an expert on the topic, but figured I'd add to the conversation since it's something I recently asked my shop about.
Do what you want, the point here was to try and help. I get that most of you don't work on your own cars and wont keep your 981 more than a few years. For me, this spyder will likely be the only new and likely the last Porsche I ever own. So I work on it myself. So I want it to last till I die. I bought my 914 in 1987 and kept it until 2015. (28 years) so...
Interesting...the last statement in the posted thread from 6speedonline says the 9a1 engines should NOT have an issue. I don't have a horse in this race, just wanted to point that out...below are some photos of my heads with about 17k miles, you folks will probably know more what you are seeing. Definitely dark but they were installing the new ones from the x51 kit so I didn't document more thoroughly. There's two pics comparing the original heads to x51 -Dom
Since pictures always make these threads better, here are some I took of the valves on my '09 Cayman S with ~35K miles on it a couple of months ago when I had the intake off to fix a heat exchanger leak. In my view it is very clear 9A1 engines have a carbon build-up issue. I have an RX catch can to go on mine once I get around to having the walnut blasting done.
Eww that build up looks nasty. So is anyone watching F1 2018? I noticed that there was a regulation change with manufacturers doing the 'oil burning' to get more power out of their cars and they are now venting the oil in to the atmosphere. Most visible is the Ferrari engine F1 cars. There's a fine mist being sprayed out of the back of the car. So basically it's the same principle just in this case instead of venting in to the atmosphere there's a catch tank?
03-29-2018, 09:53 PM
