ADias

Porsche 911 Buyer's Guide (2nd edition), by R. Leffingwell.



On pg. 194 in reference to reliability:

" You could have a failure if the previous owner ran low on oil, used the wrong plugs, or consistently shifted below 3,000 rpm.

The improved reliability of 964, 993, and 996 has enticed many individuals to buy their first Porsche. But getting first-time owners to run the engine past 4,500 rpm is difficult. The truth is, it's more harmful if you don't run these engines."

Quadcammer

where is the evidence...?

Doc GTO

If Porsche owners can't bring the rev counter above 3K on a daily basis then they need to buy a diesel truck. That way they can hang out at 1500rpms all the time




I can tell you this being into Italian cars for a long time. The ones that got babied all the time didn't run anywhere near as good as the well maintained, "driven" ones! Owner experience here.

Quadcammer

If I paid for my Porsche, I can do as I damn well please with the rev counter, including revving it to 9000rpm or shifting at 2k. Now that this is out of the way...

How old were your italian vehicles, and did they have carbs or electronic fuel injection (or a relatively decent mechanical fuel injection)?

Palmbeacher

These days it seems anyone can write a book or put up a website and in a short time whatever's written becomes gospel to the masses. True, if you look at the torque curve of these engines (and many other European high-performance cars) you can see they will actually run more efficiently (in the engineering sense of the word, not referring specifically to fuel economy) in the fat band, which is higher up the rev range than most plebian engines. But these engines have enough low-end torque that they can pull strongly even in 4th from 1500, without lugging, and if it's not lugging, there's no damage being done. (I'm putting aside the issue of short-trip driving, long periods of idling, and carbon build-up inherent to cars driven only in urban traffic).

The one exception I can see is the lubrication of the IMS bearing. Since it was designed to be grease-packed and sealed, its placement doesn't allow for copious bathing with engine oil. It makes intuitive sense that running at higher revs will kick up more splash from the cam chains, and the faster rotation of the bearing will impel and expel a greater volume of oil.

w00tPORSCHE

If revving is good for the engine why would the Porsche engineers design a transmission that shifts to 7th gear when we are doing 40 mph with engine revving a 1.5K ? Does not make sense to me Adias that Porsche would do something to hurt their engines just to meet EPA regulations on fuel economy. Does this book apply more to the air-cooled engines ?

Palmbeacher

Porsche is a business. Businesses exist to make maximum profits. Car makers face stiff penalties for not meeting fuel economy standards, which would detract from their profits. The engine warranty goes to 50K miles, so any long-term effects of running at too-slow revs won't detract from profits. Hope this helps it make sense.

Mike in CA

All due respect, but that reasoning seems rather cynical. It assumes that for the sake of short term gain (meeting economy standards) Porsche is willing to sacrifice it's long term reputation and engineering standards built up over 60 years. Also, your theory that because of the 50K mile warranty coverage "long term effects of running at too-slow revs won't detract from profits" is somewhat faulty. If engines fail under warranty, Porsche foots the bill, which has a direct effect on profits. And if they don't fail, then the warranty, and your theory, are irrelevant.

Might another more reasonable explanation be that Porsche has designed an engine with adequate torque and other design attributes that allow it to be driven at low RPM's more safely than before?

w00tPORSCHE

I belong to Mike in CA's camp on this one. Why would Porsche want to plagued by engine reliability issues in the near or distant future which would certainly tarnishing their image after all these (mostly) glorious years.

Quadcammer

Porsche is ok with engines burning a quart of oil every 388 miles.

I don't think they care much about their reputation for excellence.

kosmo

i did a lot of inquiring about 1yr ago when i bot my PDK equipped car. I couldnt believe how early the tranny would upshift is Normal Auto mode. Im still confused by this as the cynic in me says "the Engineers caved in to the accountants and marketers."
Now I mostly drive in manual mode and shift around 4k once the engine is in operating temp.

ADias

Wise fellow!

sin911

Whenever I go to the tracks and drive my car as hard as I can, on the way back I always find my car pulling harder than before I was at the track.

I strongly believe working your car (and I mean working hard for some time 20-30 mins) every once in a while does give the car an edge, keep the engine fresh.

ADias

It is apparent that you do not know the book's author - R. Leffingwell.

w00tPORSCHE

Adias, but what about people like me who stretches a 3 mile commute to a 6 to 7 mile commute everyday just to get the engine to operating temps (by the way there is no stop and go traffic at all and I drive at 40 to 55 miles/hr all backroads during that commute expect for the very last mile). Does that mean I cannot shift around 3.5 to 4K until the engine warms up to 200 degrees. It was my understanding that it is okay to rev up the engine as long as RPM's are under 4K even before engine gets to operating temp. Atleast that is the case with the air-cooled engines.