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hitting rev limiter (help?)

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Old Jan 3, 2004 | 10:34 PM
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Default hitting rev limiter (help?)

tonight i hit my rev limiter in first gear. as soon as it hit, i let off, and it didn't hit the rev limiter again. only one time, and i guess it's possible it did it twice. but my foot was quick to get off of the gas when i heard it, so i only think i hit it once.

2 things. firstly, i read this, and was concerned i may have damaged something:

https://ls1tech.com/forums/showthrea...v+limiter+6300

of course, he has his limiter set higher than stock, but still, only 100 more rpms is not very much higher, and he seems to have had a lot of damage.

also, i read somewhere that the rev limiter goes by what the tach reads. well, i have also read the tach is slow, especially in first gear. so, when i hit my stock 6200? rev limiter, then it maybe have actually had the motor at 6500 or so?

how bad do you think this is? will i notice any damage right away, or will it take a while to show up?

nothing strange happened after i did this, and i even pulled over to listen to the car. no odd noises, and no sputtering. it ran just like it always had, and ran strong for the rest of the night. should i worry?
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Old Jan 3, 2004 | 10:39 PM
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i dunno, but last night i went drag racing in my truck, and lost traction during midrange 1st gear, and i banged off the limiter a couple times (it was raised to 6000) but no damage has been done. Usually thats what the limiter is there for, preventing damage.

Then I did 6 more passes, and drive 2 hours home. Drives fine.



I think your fine.
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Old Jan 3, 2004 | 10:54 PM
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You are prolly OK.
There is a big difference from just tagging the limiter-to-miss-shifting & over reving the motor.
It depends how the over rev occurs, if you ran 1st up & it bounced the limiter you likely did nothing.
But if you miss-shift into a lower gear at high r's the vehicles speed , high rpm mechanically over rev the motor.
The PCM/ tach have nothing to do with this.
It will turn the motor over fast enough to float the valves at which point the pistons catch & bend the valves & or pushrods.
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Old Jan 3, 2004 | 11:03 PM
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Originally Posted by tuffluck
also, i read somewhere that the rev limiter goes by what the tach reads. well, i have also read the tach is slow, especially in first gear. so, when i hit my stock 6200? rev limiter, then it maybe have actually had the motor at 6500 or so?
FYI ;
the limiter is an internal pcm fuction,it enables the limiter,it is far quicker than any tach it runs the injectors & coils after all.
The tach is a PCM output but in no way contols any engine fuction.
So in other words the PCM's rpm reading is exact , & it is that information/rpm sigal it enables the limiter.
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Old Jan 3, 2004 | 11:29 PM
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Originally Posted by wrencher
FYI ;
the limiter is an internal pcm fuction,it enables the limiter,it is far quicker than any tach it runs the injectors & coils after all.
The tach is a PCM output but in no way contols any engine fuction.
So in other words the PCM's rpm reading is exact , & it is that information/rpm sigal it enables the limiter.
I've bounced off the rev limiter probably 50 times. No damage yet.
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Old Jan 4, 2004 | 12:11 AM
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oh ok, it sounds like i'm ok. thanks a lot for the responses, they were incredibly helpful and reassuring

the other day i accidentally downshifted at about 65 to 2nd gear. of course, 2nd gear doesn't quite run out at 65, but as soon as i went into 2nd gear, my rpms went near 5500. but i quickly upshifted. is that an example of mechanically overreving the engine? how could it be if 2nd gear has yet to run out at that speed though?

i guess i just do not understand the theory of mechanical overrev?

Last edited by tuffluck; Jan 4, 2004 at 03:10 AM.
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Old Jan 5, 2004 | 09:23 AM
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It'd be over reving if you went to first. I know people who downshift to second at 60 mph frequently.

Over reving the engine would be taking it well past redline by downshifting into a gear too low to be in. Say, if you shifted to 2nd at 90 you'd be at like 8000 RPM.
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Old Jan 5, 2004 | 03:12 PM
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I downshift to 2nd from 60 all the time, but I have stock 3.42 gears. Ive also done the dreaded 3-2 shift and over revved...3 times...no damage. I sure was lucky.
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Old Jan 5, 2004 | 03:29 PM
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I have tagged the limiter about 4 times. So far so good. I usually do it if the car breaks traction at about 3500 in first. It shoots up faster than I can react sometimes.
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Old Jan 5, 2004 | 03:39 PM
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I've nailed the rev limiter too much.Probly over 200times with no problems.That's why it's there..The damage ussually happens when you mechanically overrev the motor by backshifting.
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Old Jan 5, 2004 | 04:44 PM
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Originally Posted by SSCamaro99_3
I have tagged the limiter about 4 times. So far so good. I usually do it if the car breaks traction at about 3500 in first. It shoots up faster than I can react sometimes.
i know man. i took the car out last night and that's all i did really - just practiced on shifting the damn car into second when the tires break loose in first. i never hit the limiter once, so i must be getting it down. the hard part is correcting the fishtail at the same time you are watching the tach

my 275 kumho's aren't bad when the weather is above 60, but anything below it and they don't stick any, especially in first.
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Old Jan 5, 2004 | 07:20 PM
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Originally Posted by tuffluck
oh ok, it sounds like i'm ok. thanks a lot for the responses, they were incredibly helpful and reassuring

the other day i accidentally downshifted at about 65 to 2nd gear. of course, 2nd gear doesn't quite run out at 65, but as soon as i went into 2nd gear, my rpms went near 5500. but i quickly upshifted. is that an example of mechanically overreving the engine? how could it be if 2nd gear has yet to run out at that speed though?

i guess i just do not understand the theory of mechanical overrev?
Well a bad miss shift would be something like this I will use my car .. right now I am shifting at about 6900 rpm's and at the top of third gear I am doing close to 101 mph . if I were do downshift to second instead of hitting 4th it would bring the rev's up to about 9700 rpm's even for a split second with the motor reving that high you would do some messed up $hit to the motor ..
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