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im curious as to what you guys think about reving or mod engines up to redline, or slightly lower. say your on the highway and you decide to floor it and rap the motor up to 5700 rpms, what affects does it have on the motor? everlasting affects? is it especialy damaging to high milage cars?
 

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When I race i run it up to 6000rpm and so far no problems. I hear that the valves begin to float around 6500 though
 

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I think the valves will float long before 6500rpm, and if you have stock cams there is no reason to shift above 5800rpm, that's where power starts dropping off, if you shift higher it will actually slow you down. As to the effects, high rpms expose the engine to a lot more stress and can cause a lot of problems: the valve springs can break, the locks can break and drop a valve, anything in the bottom end (at 6000rpm the rotating assembly is experiencing THOUSANDS of g's) can let go. For most 4.6's in good condition there shouldn't be much harm in running high as long as you stay below the redline, assuming its well maintained (proper weight and amount of oil is crucial here), but there are no guarrantees. I'm not trying to scare you from running your car hard, the opposite actually, but it helps to understand what's going on in there. One thing that makes a well machined engine far better, in addition to the better materials used, is the machining is done to closer tolerance, so there is less of the bad things like being off balance, binding between mains, out of round journals, etc. As the rpms go up, the stress increases exponentially, that's why its hard to find a V8 that can run 10,000rpm, at those stress levels most rotating assemblies would come apart like they were hit with a cruise missle.
For most street motors 5700rpm shouldn't hurt anything if its in good shape. It could cause a spring to break, drop a valve, blow the head gasket, or break something in the bottom, but I've seen "good" engines let go violently at 2000rpm. Will it cause more wear, sure, but it should hold together fine, and running an engine hard from time-to-time is good for it. Besides, we have Mustangs for a reason: If we wanted to go slow we'd drive hondas.
Damn... I talk-type too much, must like the sound of my own keys.
 

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im curious as to what you guys think about reving or mod engines up to redline, or slightly lower. say your on the highway and you decide to floor it and rap the motor up to 5700 rpms, what affects does it have on the motor? everlasting affects? is it especialy damaging to high milage cars?
Don't be stupid. Don't rev your car that high. There is no need for it. They call it redline for a reason you know. Why wait til it blows your motor before you stop doing it?
 

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i have found that having my autos shiftpoints set at 5600 and the rev limiter set at 5700 my car was faster at the track than letting it shift at 5700 you will get better times if you shift before the power starts to drop off
 

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Yeah i agree i have an auto that has a custom tune that will allow me to shift at 6500 but i dont cause i know its hard on it but i also agree on shiftin earlier cause when i shift right before redline it pulls alot harder so yea...:bigthumbsup
 

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Yeah i agree i have an auto that has a custom tune that will allow me to shift at 6500 but i dont cause i know its hard on it but i also agree on shiftin earlier cause when i shift right before redline it pulls alot harder so yea...:bigthumbsup
+1
The higher the rpm's when you shift doesn't mean you're getting the most power out of the motor. Don't shift too early, but don't shift too late either.:nono:
 
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