Ford Mustang Forum - View Single Post - Is the "red-line" real or conservative?
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post #10 of (permalink) Old 02-19-2011
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AMChrisRose's Avatar
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Location: Malvern
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Originally Posted by Radioguy View Post
Being an engineer, I probably have a little different perspective on "stressing mechanical things" then some others. If you want to hear what the Ford engineers say about high RPM, this is what they said about extending the BOSS 302 engine red-line to 7500 RPM:

""What most people don't realize is that engine stresses increase exponentially as engine speeds rise," explains Harrison. "So moving up from GT's 7,000 rpm redline required significant re-engineering of many different parts. Sacrificing reliability and usability over the GT engine was never an option.""

The message is that the "reliability" will be effected by running over the red-line. May not fail the day you stress it, but it might fail the next day when you start it or maybe not ever. Reliability is all about "probabilities." The whole article is at:
2012 Boss 302 Mustang Engine Overview
Absolutely, the higher you spin it, the smaller your tolerances get. With the new 4V, there's no issue with bumping up the factory redline a little. We typically set shifts at 7000-7300 depending on which tune you're running. 7500 is where I'd put my foot down. We don't send any 7500RPM tunes out, because we don't feel that last few hundred RPM are doing anything for you (and dyno results back that up). We run 10.93 with a baby shot of nitrous (100 shot), CAI, 4.10 gears and exhaust with our 2011 automatic, shifting at 7300 RPM.

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