One caveat to this. If you miss a downshift at high revs (the infamous 5-2 mistake), the rev limiter will *not* save you. If you check out cstreit's post of his engine mishap incident, he caught the error really fast but still bent valves.

Keep the revs up, but pay attention when you shift.

Assuming that you aren't just 'pulling our legs', you definitely could be running the car harder. I don't think it's necessary to 'redline' each time you drive but even for daily driving, exercising the engine between 3500-5000rpm is both practical on city streets and fun.

Related to this, I hear lot's of opinions that it is actually bad for the car not to run it all the time at high rpm's. But I wonder how true this is. Anyone have any data that shows the relationship between the condition of a car and how it is driven?

Not pulling legs at all. The last time I owned a car was about 20 years ago before I moved to Manhattan. When I got to the city I lived 1 block from school...no need for a car. Just resigned from my job of 10+ years, bought a house in NJ and finally had a reason to buy my dream car. Actually, the purchase of the house was an excuse to get the car but that rationale only causes concerned looks on the faces of my friends. On a final note, the last car I owned was a '64 Mercury Comet, straight 6, 189 cubic inches, 3 on the tree.

So, if my posts seem insanely rudimentary, that's the reason.

Ahh I understand your fear of revs now! Having exploded a few Ford straight sixes myself! ;) These two engines only have number of cylinders in common. The Porsche is a wonderful high-end performer horsepower engine with a soft lowend while the Ford Six is an excellent lowend torque motor that self destructs when revved above 4k for very long. A 300 Ford six can be shifted at 3k all day long while dragging a house behind it and be perfectly happy the 189 is just it's little brother, these engines have long strokes and small bores, perfectly suited to low rpm grunt while the 911 motors have a short stroke and big bore perfectly suited to 3k+ rpm HP. Short stroke engines need to be revved to get to the power and to keep carbon deposits down since they lack the port velocity of a long-stroke, small runner torque engine. The 911 oiling system is very well setup for extended high rpm usage consisting of parts and circuits only found on "the other guys" race engines. Dry sump oiling, oil sprayers on the valve springs and backside of the pistons, excellent mainbearing layout and overhead cams all aimed at one thing, high rpm durability! Warm up the oil and enjoy that car! :D

So, if my posts seem insanely rudimentary, that's the reason.

my general rule is to keep the tach at 12 o'clock which works out to 3.5K

I shift at about 4-4.5K and it drops back to 3.5K etc...on the freeway I am pegged at 3.5K

I think the sweet spot is 4-5K but for everyday I use my 3.5K...keeps me out of trouble...

but alas...my car is apart getting 964 cams...my rules may change after getting her on the road after the mod...

MJ

MJ, you're gonna like how your car drives with the cams. You'll like 3000 rpm better than before.

No data regarding rpms and longevity, but it is common knowledge that 993s driven at light loads all the time (pampered Tiptronics), have valve guides wearing out long before 993s that are driven like they should be.

Just an observation. My car ALWAYS runs smoother and cleaner after a day of flogging on the track.

Tinker

Why would this be the case? You would think that higher rev's would mean more wear? There must be other factors here. What could they possibly be?

Hey 82SC
 

I see you're in LA. What part? Westside, The Valley, Southbay? I'd like to check out your car when those cams are installed. I'm thinking of the same mods myself in the future.

Thanks.

i am either in the south bay (parent's home/garage) or UCLA (school)

sure when we are done we can do a get together...I know speeder is planning similar stuff but with a full rebuild...tyson and I have talked about getting together sometime to hang out...noah gave me a ride in his carrera with the cams...so I think it is my turn to return the favor...

I am in the midst of midterms, but once I am done (3 weeks ish) we can figure something out

MJ

I know this was silly (the drinking bit) but one night I was as drunk as a skunk and was driving at about 120mph (with the stero blaring so I couldnt hear the engine) thinking the car was going a bit odd, I was up and down on the gas and found the car would slow down but wouldn't go over 120. I looked down and found I had been driving in FOURTH gear at about 7,000rpm plus. Well, that was about five years ago and the cars been fine since.

82SC sounds good
 

Yeah, Tyson and I have talked about the cams several times, though I haven't any real-world gauge on what they're like. Your car will be my only example. I appreciate the opportunity to check yours out. But enough of this. Don't you have some studying to do?:D

Yeah, Bill, but how's your liver?:)