akirk wrote:stefan einz wrote:A couple of small points on what you have said.
The Mezger engine was used in GT2s and GT3s in both 996 and 997 Generations. For Turbos, the engine was changed to a DFI engine in the Gen2 997 cars. All 991 GT cars now use the DFI engine, which will also be used in Cup cars from 2016.
The ECU data on over-revs has become more sophisticated over time, and that has allowed Porsche to designate different actions depending on the scale of any over-revs. Minor infractions are fine and require no investigation. More serious infractions may require an engine inspection to assess whether any damage was caused. Warranty claims (or issuing new warranties) would be judged only after such inspection - not necessarily dismissed out of hand.
The Mezger GT3 engine has a red line of 7,800 in the Mk1 996, rising to 8,400 in the final incarnations of the 997. From the Mk2 996 onwards (when titanium con rods were installed) it is capable of taking over 9,000 rpm (for short periods) without any damage at all - the issue at this level is usually with the clutch and flywheel. In reality, the over-rev issue is far more of a concern on the "bog standard" engines, but I think it is an excellent innovation by Porsche for this information to be accessible for anyone looking to buy second hand.
Cheers
interesting to read... but it doesn't answer the underlying logical question:
- if taking the revs over a certain level is not good for the car / is logged / is 'over-revving' / is likely to lose value / may need an engine rebuild / is not the fault of Porsche / etc.
- why don't they simply electronically limit the revs to a level which is okay
the only reason I can see for not limiting the engine to a level at which it can't be damaged is because they feel they would lose credibility
either the engine is not built well enough or you should be able to use the full rev range...
which other manufacturer has this issue with their cars?
I can understand selling a car with an engine which allows you to play on the edge, aware that abuse may lead to a rebuild - but that has its place in specialist engineering / racing / etc. - not showroom cars bought by the general public...
to my mind this is a huge marque failure - I am looking at what car I might buy in a few years, 911s / Astons / bentleys / masers / lots of options - but this totally puts me off porsche, I don't want a car where if I drive it within the capabilities it allows it could cause mechanical issues - that to me is extremely bad design...
Alasdair
Apologies if my post was not clear.
As I understand it, the only reason Porsche have introduced rev range monitoring is to give customers piece of mind when buying a second hand car from their network, AND to give Porsche hard data to work from when deciding whether to a) honour a warranty claim and / or b) renew a warranty. (For completeness I should add the extended warranty is underwritten by a third party insurer, but clearly Porsche had input into the terms.)
Porsches, perhaps more than any other car, are used by owners on track and road. Porsche is essentially unique in encouraging owners to use their cars on track. There are parts of the handbook that talk to track use. Porsche will honour a warranty claim even if the car has been used on track (which typically adds 10x wear per mile driven). Their only stipulation is that the car must not have been abused - and of course they won't cover wear and tear items.
The rev range monitoring gives Porsche valuable data in this regard. Whilst you can
only enter the dangerous over-rev ranges by a mis-shift in manual car (or potentially in a spin), if you see that the driver is constantly banging off the rev limiter it does tell you something about their driving style!
Indeed, actually hitting the rev limiter repeatedly and for long periods can cause damage. When I was racing the GT3 Cup car, our technicians would point out that holding the car on the limiter caused a set of vibrations that could - over time - damage the engine. This not an engineering failure, it's just common sense - the engine is not designed for that sort of use, and nor should it be.
Porsche's Mezger engines are some of the finest ever engineered. In three years of racing using this engine (identical to the road car engine), it never had a problem - and rebuilds involved taking it apart, finding nothing worn and putting it back together again!
Porsche's issue is with the first generation of water cooled engines in the Boxster, Cayman and 911 (designated M96). As noted earlier, these did have design flaws, and I would not own a car with this engine without the benefit of a full warranty. They fail at the rate of about 1 in 20.
The new DFI engines (used in Gen 2 987 Boxters, 997s etc.) and all current cars are extremely robust. At the Porsche Experience Centre at Silverstone, the fleet of cars is used (and probably abused by some less talented drivers!) every day and they have yet to have an engine problem of any sort - that's after four years. I know this because I spent an enjoyable weekend at Le Mans with Porsche, and we were accompanied by the Silverstone master technician - Dave - who services all those cars.
The only recent embarrassment was with the new DFI engine in the GT3 (which is a different design to the engine used in the standard cars). They under-specced the conrod bolts, and on some cars they failed early on, causing catastrophic engine failure. As a result, Porsche replaced every single engine with a new engine during 2014 - an expensive mistake but they absolutely did the right thing by their customers. Before anyone gets too critical, however, it must be remembered these engines are pushing the boundaries of performance and light weight design and on this occasion they sailed too close to the wind.
In any event, I say all this because in my very long and extensive experience with Porsches, I still believe they are
by far the best engineered sports car on the planet. They are one of the very few cars you can drive to a track day, use it as its maker intended, and drive it home.
If buying a Porsche, you just have to be aware that buying a car with the M96 engine needs a bit more care - other than that, all the other engines are great (from the oil cooled through to the Cayenne / Panamera V8s, through to the new generation of DFI engines).
Cheers