ABOVE THE REDLINE for just a second...
12-11-2004, 10:23 PM
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ABOVE THE REDLINE for just a second...
I jumped on it and ran above the redline for just a second or so in second gear - does a 2001 E430 have a rev limiter? Have you heard of anyone doing engine damage running up past the redline before upshifting?
12-12-2004, 12:15 AM
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The redline is NOT the maximum possible engine speed just before the valves flutter and hit the piston crown, the connecting rods break and the crankshaft bends intself into a pretzel. It's an engineer's estimate (read: "guess") as to the speed at which wear increases to an unacceptable level, reliabilty starts to decline excessively and the risk of catastophic events becomes too high. So exceeding the redline by a small amount for a few seconds is very unlikely to do any serious damage. A few illustrations:
1. An engine used in the 24 hours of leMans race is customarily redlined somewhat lower than if the same engine were being used in a race of an hour or two. The concept is that prolonged running at the higher RPM creates too much wear and risk of engine failure, but doing it for shorter times is no big deal.
2. The engines in an airplane I owned several years ago were redlined at 2900 RPM. It turns out that the engines were limited to this low speed partially because the manufacturer had run them for several hundred hours at that speed and nothing adverse happened. I have to admit that that fact made me feel pretty comfortable running the engines at redline for 15 or 20 minutes continuously during climb-out.
3. About two years ago I entered a freeway in a Ferrari 550 by gunning it in first to the redline, shifting into second and gunning it to the redline, and then missing the next shift by putting it back into first (instead of third, which was next door) and popping the clutch. The engine screamed to about 750 rpm over redline, the rear wheels jumped off the pavement, I hit the seatbelt (hard) and then punched the clutch pedal to a position somwhere close to the front radiator. End result: one very shaken-up driver and an engine that ran for another 10,000 miles (when I sold it) with no trouble.
Finally, if you did any real damage to the engine by over-revving it, you would very likely know about it now. You haven't started some chain of events that will result in the engine going up in smoke next week.
1. An engine used in the 24 hours of leMans race is customarily redlined somewhat lower than if the same engine were being used in a race of an hour or two. The concept is that prolonged running at the higher RPM creates too much wear and risk of engine failure, but doing it for shorter times is no big deal.
2. The engines in an airplane I owned several years ago were redlined at 2900 RPM. It turns out that the engines were limited to this low speed partially because the manufacturer had run them for several hundred hours at that speed and nothing adverse happened. I have to admit that that fact made me feel pretty comfortable running the engines at redline for 15 or 20 minutes continuously during climb-out.
3. About two years ago I entered a freeway in a Ferrari 550 by gunning it in first to the redline, shifting into second and gunning it to the redline, and then missing the next shift by putting it back into first (instead of third, which was next door) and popping the clutch. The engine screamed to about 750 rpm over redline, the rear wheels jumped off the pavement, I hit the seatbelt (hard) and then punched the clutch pedal to a position somwhere close to the front radiator. End result: one very shaken-up driver and an engine that ran for another 10,000 miles (when I sold it) with no trouble.
Finally, if you did any real damage to the engine by over-revving it, you would very likely know about it now. You haven't started some chain of events that will result in the engine going up in smoke next week.
Last edited by White Knight II; 12-12-2004 at 09:49 AM.
