Mr Footlong

I would be changing the oil every 5k miles max. 20k miles on an high performance lump is madness imo.

You guys are great thanks. I have had a good trawl through Rennlist and read the 8 pages of that thread. My concerns have been settled pretty well. I still like the look of that Tubby on Pistonheads, just a shame that I don't think I could trust it based on the valve failure/work.

Thanks again for the reply. So, just to confirm, it is your belief that the 955 TURBO blocks all come with piston oil squirters as standard? I saw this comment among your posts on Rennlist "The 957s and I believe the 958s all of the V8s have oil spray piston cooling". Still struggling to understand then why the NA blocks seem to fail far more if that are made from the same material. I see that the compression is higher on the NA and that the Turbo lumps use forged pistons but other than that..... Thanks again, this is putting my mind at ease a little and that is great as the other half was contemplating me getting another RS6 just for her and having to of those would be boring ;)

Thanks for your reply, any others also gratefully received. I was also concerned about what caused the burnt valve in the first place and what had been changed in order to sort it but he didn't seem to know why. I wonder why other forums seem convinced that the Turbo/S blocks have a different cylinder coating to the standard S lump? If they are the same lump then why would there seem to be a consensus on those forums that the problem is only seen on what I would expect to be the less strained engine? I am in no rush so I think I will scratch that one as I would have to go up to the other end of the country, put a deposit on it subject to it passing a bore scope and compression test on all eight cylinders, then go all the way back up there again.

Hi there. Coming from a few years of happy modified RS6 ownership and XJR ownership before that, I have a good idea of running costs on big forced induction V8 lumps. I have been doing my research on the Cayenne Turbo/Turbo S and test drove a turbo recently to make sure that it was the right car for my other half. She loved it and really wants one but the more I read about engine knocking the more I want to steer clear! I had three Imprezas before I got in to high end machinery so I know engine knock only too well. On other forums I read people saying that due to different bore liner coatings between the S and the turbo/turbo S, the forced induction blocks were tougher and didn't suffer from knock? This forum, which seems to know what it is talking about, contradicts everything else I have read. Been there, done that with the Nikasil lottery on the XJR. I am in the UK, will be buying a Turbo/S with under 85k miles on it if at all possible, will be running it on 99 Octane fuel (Shell V-Power/Tesco 99) and will be looking to remap it as soon as possible along with swapping out the exhaust system for a full Milltek one. As an example of the sort of car I am after, I was considering this example and had talked to the owner - http://www.pistonheads.com/classifieds/used-cars/porsche/cayenne/500-bhp-porsche-cayenne-turbo-v8-4-5l------------------2005/1967747 He explained to me that it had burnt out a valve after "not running right" one day. He then linked me to pictures of the head work carried out, including shots of the burnt (exhaust?) valve - http://www.pistonheads.com/classifieds/used-cars/porsche/cayenne/500-bhp-porsche-cayenne-turbo-v8-4-5l------------------2005/1967747 He only had the valves that appeared to be worn, replaced. This seems like cost cutting to me that makes no sense while the tops were off? Should I be right to want to steer clear of this one? I did ask for before/after compression test results of each cylinder but he doesn't know if this was carried out or not. I do personally think that it is overpriced. If any of you wonderful chaps could give me your input on whether I am right to be steering clear of a Cayenne Turbo/S or if it really is a much rarer case for the blocks to fail I would really appreciate it. Last year I made a "chemo brain" purchase of another Impreza and I lost 11k in 6 months getting that right! With that and the 7k slushbox fund for when the RS6 ZF slushbox finally fails, I have to try to be a little sensible! Thanks, Nick :).