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It’s a fuel cutoff. More than one person has missed a shift, gone into the wrong (lower) gear, and grenaded the engine. Not a limiter in the world that can beat physics.
You can't over rev the engine unless you have a manual trans and drop it into a low gear at high speed. The automatic will not allow you to do that. Under normal acceleration the rev limiter will prevent over reving the engine
Is it possible to blow the engine on a 2019 Grand Sport when you hit redline or is there a limiter to prevent that from happening?
Have to try it, at least once! There is a fuel cut-off that stops you instantly and limits the RPM to 6600! Not hard to do in 1st and 2nd in an M7! No harm done.
Now if you have an M7 and were shifting 3rd to 4th at 6500 rpm but by mistaken instead of pulling straight back pulled the shift lever toward yourself you would be in 2nd gear. The instant the clutch was engaged you would be set to have the engine turn 9400 rpm. The tires would loose traction and you would not reach that but be well over 6600 rpm and bend some push rods as a minimum if not worse! Not covered under warranty as the rpm excess would be recorded!
If speed shifting that is only 103 mph so at a drag strip easier to do that one would think! The good news is you'll only do that once!
I have a manual and in fourth gear I hit 152 at redline. Car was still accelerating but I backed off because I didn’t want to blow the engine. I still had about 1500 of straight before turn one. I was on a track. So basically what I was asking is that if I kept my foot on the gas a few more seconds to get it up to 155 or 160 is there anything on the car to prevent the engine from blowing up? I heard there was a rev limiter but don’t know if it would help in this situation. Thanks again.
^^^
Regardless of gear when it hits 6600 rpm the fuel shuts off, you'll feel it Comes back on quickly when you get below. My math says you were at all you'll get. May feel like it was pulling but you'd never get to 155 without shifting.
Heck I don't track but live in a rural area with no traffic or homes between long straight roads with cotton fields on both sides. I've hit redline a few times in 1st and 2nd and occasionally 3rd! That is a fast as I'll go! You should try in a lower gear so you know what it feels like. Could try to shift to 5th at 152 mph but with the excitement of a turn coming just be sure you're going into 5th NOT 3rd!
Yea thanks for the reply. I tried shifting into fifth a few times but as soon as I step on the clutch I loose 10 MPH. Shifting at redline without taking my foot off the gas wasn’t an option I wanted to try either. Not enough time or straight track to get back up to speed before the turn. I should have gotten automatic. I was able to hit 160 on the same track (Pocono Raceway) many times with my 2013 Grand Sport even though that car had 30 less horsepower. The difference was that car was automatic and my 19 is manual. Oh well, I still love driving my new car.
I know the C5 has a computer controlled limit, but I also know it does not always work. (Its a long story - suffice to say GM bought a new motor for my C5 when the limiter failed to do what it was supposed to do when it was supposed to do it.)
Given there is a limiter on the C5, I would venture there is also one on the 7.
I have a manual and in fourth gear I hit 152 at redline. Car was still accelerating but I backed off because I didn’t want to blow the engine. I still had about 1500 of straight before turn one. I was on a track. So basically what I was asking is that if I kept my foot on the gas a few more seconds to get it up to 155 or 160 is there anything on the car to prevent the engine from blowing up? I heard there was a rev limiter but don’t know if it would help in this situation. Thanks again.
You won’t get to 155 unless you have one hell of a tailwind to overcome the aero drag or a longer straight and no way will you see 160. In my C6 GS in 4th gear holding at 6500 was 152mph at Auto Club Speedway. Same gearing as a C7 GS which I have now. The only thing more power affects is how quickly you get to a given speed and rpm.
I know the C5 has a computer controlled limit, but I also know it does not always work. (Its a long story - suffice to say GM bought a new motor for my C5 when the limiter failed to do what it was supposed to do when it was supposed to do it.)
Given there is a limiter on the C5, I would venture there is also one on the 7.
Older Vettes used an ignition interrupt as a rev limiter. Couldn't just shut it all off or fuel would build in the cylinder and when ignition would be reconnected a big bang (recall doing that with the ignition key as a teenager!) So they alternately shut off some cylinders. With DI they just shut off the fuel. Easy to do. Car slows very fast.
Suggest all who drive aggressively try it in 1st or 2nd to feel what it does. No harm as the engine won't explode at 6800 rpm, which you'll never reach! Easy to do with an M7 but not sure if with an automatic in manual mode the trans won't shift.
Suggest all who drive aggressively try it in 1st or 2nd to feel what it does. No harm as the engine won't explode at 6800 rpm, which you'll never reach! Easy to do with an M7 but not sure if with an automatic in manual mode the trans won't shift.
The automatic in manual mode won't automatically upshift either and will just run at the limiter like the M7. The only time the auto will shift automatically in manual mode is when slowing down it will downshift in manual mode. But it won't upshift automatically at redline in manual nor will it force a downshift if you go to full throttle while the engine is running at 1,500 RPM on the interstate.
I am not sure how the transmission will respond in manual mode if you are heading down a sufficiently steep slope which will force the engine above redline if brakes aren't applied and I am definitely not going to experiment with this scenario.
I've hit the rev limiter twice now in my A8 GS, first time I was in Drive and downshifted using the paddle to do a 50 mph roll-on and it didn't up shift automatically. Lesson learned when in Drive and you start using paddles it switches to M mode. Second time I just didn't shift fast enough from 2nd to 3rd in M mode. So the rev limiter did what it was designed to do.
The automatic in manual mode won't automatically upshift either and will just run at the limiter like the M7. The only time the auto will shift automatically in manual mode is when slowing down it will downshift in manual mode. But it won't upshift automatically at redline in manual nor will it force a downshift if you go to full throttle while the engine is running at 1,500 RPM on the interstate.
I am not sure how the transmission will respond in manual mode if you are heading down a sufficiently steep slope which will force the engine above redline if brakes aren't applied and I am definitely not going to experiment with this scenario.
Thanks for the Auto info.
Would have to be a very steep hill! In the lower gears it is accelerating rapidly pushing you back in the seat and then suddenly zero acceleration!
Yea thanks for the reply. I tried shifting into fifth a few times but as soon as I step on the clutch I loose 10 MPH. Shifting at redline without taking my foot off the gas wasn’t an option I wanted to try either. Not enough time or straight track to get back up to speed before the turn. I should have gotten automatic. I was able to hit 160 on the same track (Pocono Raceway) many times with my 2013 Grand Sport even though that car had 30 less horsepower. The difference was that car was automatic and my 19 is manual. Oh well, I still love driving my new car.
The C7 has no lift shifting ability in Track mode. You could have left your foot on the gas with the pedal to the floor and then shifted into 5th. The cars ECU would have limited the car from over revving.
10-22-2018, 01:27 PM
Blown engine
