Art20c

Does anyone concern about high RPM engine? 7400 is kinda high for endurance car. Will it become a version of those Italian toys, where 20K is the end of life.

Edgy01

I've watched Porsche redlines moving up over the decades. However, optimal power and torque is around 6600 so much time spent in the upper reaches is a bit of a waste of rpm.

Art20c

Agreed, red line moved up over the years, but hike of almost 1000 RPM? 911, 993 thru 997 all share about the same rev limit as well as optimal operational RPMs in range of 3000-5500. My concern is if those high revs of 991 engine would affect the life span of this engine.

Edgy01

When Porsche raised the redline they did many things to adjust for an consider those issues. The valve springs are much stiffer (to avoid valve float), amongst other things. I think we can assume that when Porsche revives the redline on their cars they are doing it with the full backing of their engineering department. Ironically, there is little need to go deep into the upper end of these rpm ranges today because of the increased displacement of today's engines. Years ago I had to do a lot of gear shifting in order to extract as much power from those engines as I could, but now with the increased displacement and higher torque values, you can really broaden the useful rpm of the engine considerably. Twenty years ago I had to really look to 1st and 2nd a lot for certain steep roadways, yet now I can carry speed and power on steep inclines without the need to downshift much. Even, a bit below 2000 rpm I can get useful power. That was unheard of in the 1960s and 1970s--and even to an extent in the 1980s. You had to look to coming ' on the cam' at 4000 rpm in order to get power. Today--complete overkill. If you're an old time 911 driver you have really had to change your style of driving as the engines have changed.

911dev

No need to play above 7000 rpms as power falls off in the mid to upper 6s; as someone else pointed out. However, even if one revved to 7400 all the time I still doubt it would affect the engine's life by more than 5% over another well exercised 911. And, I am sure one would get well over 100k miles of use out of a well exercised 991 911. Sure if Ms. Daisy owned one and Mr Walter R owned the other the delta would be larger.

I wouldn't consider 7400 high these days. Consider the 2001 E46 M3 had a 8300+ or so redline amongst many others.

10 GT3

Everything you posted above is wrong. You need to look at the basic design of the engine which determines the cruise range, the powerband and rev limit. There is not a one set of numbers fits all. Powerband and peak rpms have moved up as engine efficiency has improved from generation to generation.

A mid-80's stock L98 Corvette would easily burn up the engine if regularly revved to 5500 rpms. While this is in the meat of the powerband (between torque and hp peaks) of a 964 and not even in the powerband of a late GT3.

Here is a comparison of Porsche 3.6l engines (plus the 996 3.4l) that might help explain this:

964: 250 hp @ 6100 rpms, 228 lb-ft @ 4800 rpms, 6700 redline
993: 282 hp @ 6300 rpms, 250 lb-ft @ 5250 rpms, 6700 redline
996.1: 300 hp @ 6800 rpms, 258 lb-ft @ 4600 rpms, 7200 redline
996.2: 320 hp @ 6800 rpms, 273 lb-ft @ 4250 rpms, 7200 redline
997.1: 325 hp @ 6800 rpms, 273 lb-ft @ 4250 rpms, 7200 redline
996.1 GT3: 360 hp @ 7200 rpms, 273 lb-ft @ 5000 rpms, 7800 redline
996.2 GT3: 380 hp @ 7400 rpms, 284 lb-ft @ 5000 rpms, 8200 redline
997.1 GT3: 415 hp @ 7600 rpms, 300 lb-ft @ 5500 rpms, 8400 redline

As the engine is tuned to produce more power due to higher efficiency, the powerband moves up the rpm range. There are also plenty of well built race engines that rev to 9000+ rpms without requiring any special maintenance. Higher revving engines come with improved bearings, oiling systems, high-speed cams, valvetrain, followers and chains/belts. In fact, a higher revving engine is actually more reliable at the upper end of its rev band than a lower revving engine due to the better components. 7400 rpms would be low for an endurance car. Porsche RSRs today rev to 9k and an M3 GT doesn't even make peak power until 9k.

Edgy01

Some of that you posted, 10 GT3, is incorrect. The 996 3.4 and 3.6 engines are redlined at 7300. The base 997.1 engine (3.6) redlines to 7300. The 997.1 (S) also goes to 7300. The X51 package on the 997.1S takes it up a small notch to 7400.

Quadcammer

7400rpm is not really what I'd consider high nowadays. Porsches engines have always been fairly low revving compared to their european counterparts. Hell even my 4v mustang cobra revved to about 7k rpm.

triode

The GT1 Mezger motor has won countless endurance races, and the street version of the 3.8 revs to 8500 RPM. So no, 7400 is not high for an "endurance car".

Carrara

7400rpm isn't the redline. 7400 is where peak power is made. I believe the redline is around 8300.

10 GT3

Redline or limiter? The limiter is 7300, 100 rpms above the redline. Redline is indicated on the tach, while the limiter is where the computer shuts off the fun. The post above is correct. The Redline represents the maximum recommended engine speed. The limiter is at the maximum safe engine speed. Both the 997.1 GT3 and 997.2 GT3 redline at 8400 rpms, but the limiter on the 997.1 kicks in at 8400 while the 997.2 it is 8500. Limiter quite often does not equal redline.

Pics of 996 and 997 Carrera tachs showing redlines:

Art20c

Im not saying that 7400 is not reliable revs range. Of course, modern engines are capable of high RPM, I mean these 7400 is nothing compare to F 1 engines with 18000 rpm mandatory limit (used to be much higher). My concern is the life span of this new engine, wear of piston rings, cylinders and such. When I was around race engines (very long time ago though) we had to tear the engine apart after every race. Rings, main seals, and very often bearings had to go. Valves, valve seats and guides, I had seen wear on all them. But, you dont expect your race engine to last for very long. Another story with regular DD, 100k is nothing for street Porsche. I still have 87 928 with 135k on it and it burns even less oil than 2008 911 turbo engine with 50k. Oil pressure 1.5 at idle and all the way up running at operating temperature. Way back, I dealt with 93 Lambo Diablo with 25K kilometers, power plant was disaster. Clutch was slipping, rough idle, oil leaks, list could go on. I think that engine's power curve was at 7100. I understand, there are could be some other factors contributing to that car's problem, but revs could be one of them. Anyways, I see that most of Porsche enthusiasts here believe that it wont present a problem, so I might be over analyzing it.