So This morning, I was on the highway, and I got on it, and was doing basically WOT in 4th, and I went to change up to 5th, and missed, and slammed the gas on accident, while on neutral, and it shot up to like 6k or maybe higher, couldn't really see, but it was just fir like .5 seconds. It didn't hit the limiter, I dont think, because it didn't start bouncing at all. I have never hit the limiter, and I dint usually go past 5800 rpms. So, my point is, if you skim like 6750-6800 rpms, for like 1/2 second, will this do damage?
Rev-limiter...
- Thread starter bigdaddy
- Start date
Not to worry. We have a rev limiter. It is a "soft" limiter in the sense that it does not kill the ignition or shut off fuel supply abruptly.
I flat shift when tracking or performance testing. I start the shift at 5,500 rpm, knowing that the reaction time will actually put the shift at about 5,800 rpm. With the go pedal flat on the floor during the shift, the rpms spike up toward redline and return. It is safe for the engine. (maybe not safe for the clutch, lol, to do this too often.
Here is what flat shifting looks like on an accelerometer chart. Disregard the far right, because electrical interference produces artifact when you let up completely on the accelerator at the end of the run. Notice the short spikes at the end of second, third and fourth gears. This is the quick run up in rpms during the shift. I've been doing this pretty frequently for two years with no problem.
That is not to say that I would recommend standing on the gas pedal in neutral just for fun. The the rev limiter is there, it's soft, it works, and it should prevent you from damaging your engine.
I flat shift when tracking or performance testing. I start the shift at 5,500 rpm, knowing that the reaction time will actually put the shift at about 5,800 rpm. With the go pedal flat on the floor during the shift, the rpms spike up toward redline and return. It is safe for the engine. (maybe not safe for the clutch, lol, to do this too often.
Here is what flat shifting looks like on an accelerometer chart. Disregard the far right, because electrical interference produces artifact when you let up completely on the accelerator at the end of the run. Notice the short spikes at the end of second, third and fourth gears. This is the quick run up in rpms during the shift. I've been doing this pretty frequently for two years with no problem.
That is not to say that I would recommend standing on the gas pedal in neutral just for fun. The the rev limiter is there, it's soft, it works, and it should prevent you from damaging your engine.
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Darth Vader
Member
Ringing off the limiter can indeed damage your engine. Sometimes catastrophically, sometimes not. I've taken apart engines that had their rods stretched like taffy from this, or broke them, or dropped valves, with "limiters" installed and functioning.
That said, a ring off the limiter every once in a while is unlikely to be fatal. There is an engineering margin in all things and I doubt you tested the limit through one bounce off the limiter.
That said, a ring off the limiter every once in a while is unlikely to be fatal. There is an engineering margin in all things and I doubt you tested the limit through one bounce off the limiter.
The thing is, it didn't even bounce, it just shot up super fast, and I let off the gas immediately, in time before it bounced
Lol. Reminds me of a bumper sticker I saw on the back of an Audi: "Audis are like strippers - they only work when you throw money at them."
lmao !!!
Darth Vader
Member
Like I said, very unlikely there is a problem and yep, don't make it a habit.(boom01)
Another mistake I see people make showing off on Youtube, for example, is free-revving the engine from idle to redline to show off their exhaust sound. I cringe and am glad I'm not the second owner of that vehicle :'(
Here's a classic ring story: I take out my old supercharged 5.0 for a test run, get on the highway, nail it and get a Toyota-floor-mat accelerator catch, rev limiter, full boost, 6250 rpm for, oh, a good 2-3 seconds before I hammer the key and shut it off. Pop the hood, oil all over from the hyper-pressure in the PCV but, I cleaned it up and all was well. 13 years I beat on that engine with every power adder in the book. It woudn't die, it just got faster. I wish this car was that tough.
Another mistake I see people make showing off on Youtube, for example, is free-revving the engine from idle to redline to show off their exhaust sound. I cringe and am glad I'm not the second owner of that vehicle :'(
Here's a classic ring story: I take out my old supercharged 5.0 for a test run, get on the highway, nail it and get a Toyota-floor-mat accelerator catch, rev limiter, full boost, 6250 rpm for, oh, a good 2-3 seconds before I hammer the key and shut it off. Pop the hood, oil all over from the hyper-pressure in the PCV but, I cleaned it up and all was well. 13 years I beat on that engine with every power adder in the book. It woudn't die, it just got faster. I wish this car was that tough.
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- 2007 MS3
I think the real danger here isn't from having the gas pedal down and running the rpms up, it is from the sheer momentum of the vehicle forcing the engine to turn faster than it was designed to. Like how the rpm jumps up when you engine brake, except that because the revs are already high, they try to jump up into a range that is beyond what the engine is designed for. Valves can float and get impacted by pistons, all sorts of bad things can happen.
This is much different than stepping on the gas too long and making the rev limiter protect the engine. I've done this also and it scared the crap out of me. For days I was petrified that I had done some serious damage and the thing was going to blow up any minute. It's been months now with no problem (fingers crossed).
This is much different than stepping on the gas too long and making the rev limiter protect the engine. I've done this also and it scared the crap out of me. For days I was petrified that I had done some serious damage and the thing was going to blow up any minute. It's been months now with no problem (fingers crossed).
MLC: Truth. The downshift at too high rpm, or the accidental missing of a gear on upshift in third that ends up in second rather than fourth, etc. is a real serious danger, IMHO. The rev limiter is not going to keep you from mechanically over-reving the engine due to gearing. And yes, that often means bent valves, broken valve train parts, possible damaged pistions or bent rods.
bykeryder4life
Member
A downshift or missed shift is another story, your ****** then, but theres a rev limiter for a reason. If the engine is in good working order you wont mess it up hitting the limiter. I flat shift my car pretty often and plenty of times bounce it off the limiter, nothing bad happens but a fireball out the exhaust. My car has been fully bolted for 30k doing this...
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- 2007 MS3
We're talking about downshifting when the engine rpm is too high to do it safely, or downshifting when you meant to upshift (ouch!). As long as the engine rpm in the gear you are shifting to is reasonable for the speed you are traveling, no worries. But as an extreme example, if the car is doing 60 and you try to put it into second...
bykeryder4life
Member
yeah kinda like when you mean to shift into fourth at WOT and somehow drop it into 2nd,...thats bad. lol
Darth Vader
Member
Easy to do on this car is going for 6th and hitting 4th instead. That isn't cool if you don't figure it out pretty quick. (drive2)
The rev limiter on this car is by no mean close to all other one i've seen. Usually it just cuts the ignition thus making everything in the engine rock and flutter. This is giving a hard time to the drivetrain. On the MS3 its a different story. I hit the Rev-limiter at an autocross event with a friend of mine as a passsenger and he didnt noticed it since its a soft limiter and it just prevent the rev to go higher. Personally i think that hitting it once in while(read here don't do this for fun or as stated before, by revving to the limiter out of load) will hurt the engine.
