Porsche Enthusiasts Club Forum

I think it's fair to say that certainly on the GTS they are renowned for using oil, even to the extent that in the history file with my their is a letter from Porsche to a previous owner saying that 1 1/2 litres of oil per 1000km is deemed normal! I saw these and wondered if it was worth fitting one - https://www.928gt.com/productspecs/40579.htm . My GTS gives a healthy puff of smoke on occasions, it's not constant it just seems to pass too much into the intake at times as if you shut down after a bit of spirited driving and then get back on the throttle a few seconds later it does it.
Anyone know if these help?

Hi

Umm the answer is maybe lol....

Mine uses a lot of oil so I have a catch can for the breather system...so none goes to exhaust...works for me

All the best Brett

try searching the rennlist 928 forum.

Thanks for that stunning piece of advice I'll get my coat and save my £40.00 next year.

Except in this case it is fairly good advice - as it comes from the USA there are probably more people on Rennlist who'll have one fitted, most of the new 928 developments are introduced/advertised by a posting on Rennlist and the discussion there is often a lot more technical (and argumentative ).

How often do you need to top up the oil in your car, if you just get a little bit of burnt oil now and again it'll be a long time before the system pays for itself - Brett's suggestion of a catch can is probably a more economical route (although not as pretty).

Fair enough I'll stand corrected, I was kind of hoping that somebody over here may have had experience of them, I'm topping up my oil far to often is the answer to the question so anything that can reduce this would be good. It seems to smoke as you shut down, I'm told there is a cure which would involve a complete engine out and some modifications but if one of these would cure it that would save me an awful lot of work.

Hi

I seriously doubt it will CURE it although it MAY cut down the consumption....

From my experience, once you have a 928 which USES oil (like mine) there is little that you can do apart from live with it.... my catch can saves the "smoke from the exhaust" thing... and you can think of adding a reasonable amount of oil as a sort of running oil change lol you will rarely if ever have dirty oil


There is a piston mod that works by drilling the skirts but it involves a complete engine rebuild, and that would cost a fortune.....and its a lot cheaper to add oil lol


All the best Brett

OK, to expand slightly, I believe the two most likely ways your GTS may be using oil are:

1. Common to all 928's there is a tendency for the oil in the sump to get "stirred up", especially if the engine is revved hard, to form an oily mist which then gets breathed-in and burned. The "Sharkvent" you originally asked about is designed to reduce these losses by changing the arrangement of the engine breather hoses and having a separator to remove the oil from the air and return it to the sump. In general, owners in the US have reported a reduction in oil consumption, but I don't remember any hard evidence, so there may be some placebo effect.

2. Only applicable to the GTS, there was a problem of excessive oil consumption noted for many of these cars when new and, although there are several theories as to why, it's generally thought to be due to the oil used to lubricate the cylinder walls getting past the piston rings. Porsche did, in some cases, carry out remedial work (replacement engines/liners?, I can't remember) and if you have a full service history for your car you may find evidence of this. If, however, your GTS was one of these "oil burners" when it left the factory, then fitting the "Sharkvent" is going to have a far smaller effect and the only fix is, as you mentioned, to take the engine apart and modify it internally.

Perhaps you could fit a catch can for a trial period; if you find it's filling with oil regularly then consider investing in a "Sharkvent", if it doesn't seem to be collecting a lot of oil then you're probably losing the oil due to reason 2 (or you've got a leak somewhere!) and the "Sharkvent" probably won't help much.

bmjb, thanks for that it was the sort of answer I was hoping for with a little more detail as to the likely causes and pro's & con's of something like the Shark Vent. To be perfectly honest although it's not ideal to keep topping the oil up it's the embarrasing puff of smoke out the back which usually occurs on shut down rather than acceleration.
Do you know where I would be able to find a catch tank with suitable diameter plumbing to fit my car?
Thanks.

The ingested oil can cause detonation, and this is not uncommon in a GTS engine. Do you here ay "pinking" ?

The SharkVent has been successful when fitted to GTS car in that it stops the detonation. You also need to be clear of oil induced detonation before Sharktuning to get maximum benefit.

Some GTS engines were modified under warranty for oil burning problems, is there any evidence your car is one of them ?

John, no sign of any detonation whatsoever and sadly no sign that the engine has been modified, although I'm sure a Shark tune will get it running sweeter it pulls smoothly with no misfires or hesitation. As stated with no detonation just an embarassing puff of smoke usually when you shut down after a bit of progressive driving.

Has anyone ordered parts from www.928GT.com , I ask because I was going to order one of their Shark Vents as it's probably easier to try than an engine strip and rebuild, but I've had no response from either of the two e mails I've sent them to ask a couple of questions about it. Do I just go ahead and order and hope I'll be alright or just give up?

I've ordered from them a few times and always been very happy - and you get Jeannie's southern belle accent if you phone!

Interesting you couldn't raise them though as someone on Rennlist raised same issue today.

Suggest you phone them before ordering to confirm all's ok.

I did a few years ago when you got almost two dollars for every pound, didn't encounter any problems apart from their website not being able to do international shipping properly.

Also, I believe this weekend is their annual 928 event, so they might be a bit busy with that.

Thanks for the replies.