Speed limiter

[zbzo6]

There are many high performance cars that have a speed limiter from the factory. Does the Z28 have such a limiter from the factory. If not what is the top speed of the Z28.

[Bhobbs]

My understanding is the Z/28 is drag limited, not computer limited, at around 175 mph.

[A12vguy]

I have been 165mph in mine, just had shifted into 5th and it was pulling very hard. No doubt it would have punched well past 175, for sure not drag limited...the car has Aero for days...I don't think it is top speed limited...I ran out of road or I am sure it would have buried the speedo..

[Norm Peterson]

Unless it's been modified for more power or a lot less drag, I think aero is going to put a halt to things at 180 or maybe a mph or two more. Top speed that is drag-limited is a wall that you can't see from 15 mph back. For a car that's drag-limited to about 170 mph, each of the last 4 mph takes about 900', 1200', 2000', and over a mile to tack on. You can't see that coming at 155, where each added mph comes in every couple hundred feet.


Norm

[Bhobbs]

Originally Posted by A12vguy

I have been 165mph in mine, just had shifted into 5th and it was pulling very hard. No doubt it would have punched well past 175, for sure not drag limited...the car has Aero for days...I don't think it is top speed limited...I ran out of road or I am sure it would have buried the speedo..

If the car isn't limited by the computer than it is aerodynamically limited, if the tires can handle the top speed. There isn't enough power to push the car through the drag created by the airflow.

[backtotintops]

around here between exit 3 and 4 north on 684 you can find the top...I suspect exactly what they said it was @177 and then with wickerbill maybe a bit less. I suggest spotters, a few radios and a good scanner...and remember video or it didn't happen...now get to work.

[Zslash28]

Standing 1.5, I wonder if you can get close?

[Norm Peterson]

My guess - you'd be about 5 mph shy.

I'd have a better answer if I knew the Cd (instead of estimating it) and knew the gearing and the HP and torque figures with rpms for both. Then I could run a little sim.


Norm

[DGthe3]

Originally Posted by Bhobbs

If the car isn't limited by the computer than it is aerodynamically limited, if the tires can handle the top speed. There isn't enough power to push the car through the drag created by the airflow.

There is a 3rd option, though it tends not to be a factor in most modern cars: mechanically limited. If you redline in the top gear, the car cannot go any faster no matter how powerful or streamlined it is. But I think for the Z/28 that won't occur until about 220 mph.

However, what does sometimes happen is a car will be either aero or mechanically limited, depending on which gear its in. When you shift to a higher gear, the RPMs can drop so far that the engine is no longer making enough power to overcome the drag at that speed. It is possible that this is the case with the Z/28. I know it happened with the C6 Z06.

[Norm Peterson]

Found a few of those numbers and ran it through a sim that can recognize all three of the above mentioned limits . . . and I'm still thinking 182, maybe 183. On the way I got 12.3 @ 116 vs Road & Track's 12.4 @ 115.9 for quarter mile data, so the sim can't be too far off.

I'm not sure where R&T got their top speed from (I think they could have used another mile and a half of straight and level road) or 172 in 5th @ 6925 rpm (I get 168 @ 7000) unless the tires are actually stretching the steel belts and expanding.


Norm