C7 factory speed limiter
Thread Starter
Racer
Joined: Mar 2004
Posts: 469
Likes: 190
From: Garland Tx
C7 factory speed limiter
My friend had his 2014 base convertible tuned by an experienced Corvette tuner that he has used for years. He had more than 500 miles on the car. The tuner told him there was a factory installed speed limit of 135 mph in the factory setup. He changed the limit to a much higher number.
Three months later the first car was rear ended and totaled. He bought another 2014 base convertible. The tuner found the same speed limiter in the tuning for the second car.
I have never heard of this limit before. I am expecting to take delivery on a 2015 Z51 in a few weeks. After break in I will be running way over 135 mph in HPDE and open road events. I do not want to get to the race and find out I can't go over 135 mph.
Has anyone else experienced a limit setting like this?
Three months later the first car was rear ended and totaled. He bought another 2014 base convertible. The tuner found the same speed limiter in the tuning for the second car.
I have never heard of this limit before. I am expecting to take delivery on a 2015 Z51 in a few weeks. After break in I will be running way over 135 mph in HPDE and open road events. I do not want to get to the race and find out I can't go over 135 mph.
Has anyone else experienced a limit setting like this?
Race Director
Joined: Jul 2007
Posts: 10,961
Likes: 2,643
From: Texas Hill Country
There are parameters that can limit the speed to 135 but I believe there are also controls in the BCM or CCM that tuners do not have access to.
Under normal operating circumstances, it appears these limiters do not affect top speed. However, they can still be disabled in the tune.
Under normal operating circumstances, it appears these limiters do not affect top speed. However, they can still be disabled in the tune.
Instructor
Joined: Apr 2019
Posts: 227
Likes: 184
From: Pasadena
There are parameters that can limit the speed to 135 but I believe there are also controls in the BCM or CCM that tuners do not have access to.
Under normal operating circumstances, it appears these limiters do not affect top speed. However, they can still be disabled in the tune.
Under normal operating circumstances, it appears these limiters do not affect top speed. However, they can still be disabled in the tune.
Not sure what to do. Definitely not trying to take it to dealership for service.
Moderator emeritus
Joined: Jun 2001
Posts: 18,599
Likes: 3,954
From: Jacksonville Florida BWO Dayton, Cincinnati, Bloomsbury NJ, Cincinnati
2015 C7 of the Year Finalist
Are you saying you can't run the car at a speed higher than 85 MPH? What messages are you getting on your DIC? Do you have an aftermarket tune on your car? What the hell did you do to your car?
Elmer
Instructor
Joined: Apr 2019
Posts: 227
Likes: 184
From: Pasadena
After lowering the car on coilovers and mag delete kit. I (sometimes) get a error message on the dash saying “service suspension”. It’s only at that time my speed limiter enables to 85mph and nothing above that.
Moderator emeritus
Joined: Jun 2001
Posts: 18,599
Likes: 3,954
From: Jacksonville Florida BWO Dayton, Cincinnati, Bloomsbury NJ, Cincinnati
2015 C7 of the Year Finalist
So let me clear it up a little bit so it doesn’t sound as dramatic as it sounds.
After lowering the car on coilovers and mag delete kit. I (sometimes) get a error message on the dash saying “service suspension”. It’s only at that time my speed limiter enables to 85mph and nothing above that.
After lowering the car on coilovers and mag delete kit. I (sometimes) get a error message on the dash saying “service suspension”. It’s only at that time my speed limiter enables to 85mph and nothing above that.
Sounds like some tuning action might be needed to have your ECM disregard the lack of information NOT coming from the parts you replaced. The car thinks the suspension is broken and is trying to save your life and it's fenders by speed limiting the situation.
Elmer
Last edited by eboggs_jkvl; Oct 8, 2019 at 09:00 AM.
Instructor
Joined: Apr 2019
Posts: 227
Likes: 184
From: Pasadena
Mot isn’t really a big deal but sometimes when it happens, it feels real stupid
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Advanced
Joined: May 2015
Posts: 81
Likes: 20
From: Houston Texas
The c7 does have a speed limit set to it but it’s set to around 190MPH tell me how I know 
I have hit it on the autobahn here in Germany
2015 C7 Z51 US spec for reference
I have hit it on the autobahn here in Germany
2015 C7 Z51 US spec for reference
Last edited by Jhanpa4; Oct 10, 2019 at 04:18 PM.
Melting Slicks
Joined: Mar 2007
Posts: 2,240
Likes: 288
From: San Bruno CA
I think GM purposely set a lower speed limit on the car because its a convertible and not a coupe. I know on the Camaro rag tops a couple of generations back, the factory had a lot lower top speed on them even on the Z28 rag tops. Probably because there's not as much protection on a rag top on a roll over accident than on a coupe.
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From: Charlotte, NC (formerly Endicott, NY)
Bill
