Drag coef on RT's VS. GTS's?

[Russ M]

Drag coef on RT\'s VS. GTS\'s?

Guys I am curious as to how the numbers on the RT are so much higher than on the GTS? Seems like all the info I have seen on the subject states that RT with hard top on is .45 and a GTS is .35?

How is this possible? An RT is identical to the GTS upto the back of the windshield, and is actualy lower even with the hard top on. Agreed that the back is different but, the wing on the GTS should generate even more drag. What gives?

Is it possible that all the info shown is for Gen 1 RT's? And that the Gen 2 RT has just not been tested?

 

[MES]

Re: Drag coef on RT\'s VS. GTS\'s?

RT/10 Drag Coefficient 0.495 (top off)
0.46 (soft top)
0.45 (hard top)

The RT/10 top speed it right around 178-180 MPH while the GTS is 190-192 MPH so there is quite a bit of difference between the cars. These are both Gen II cars BTW. The Gen I had a top speed in the high 160's. Below 100 MPH there is not much difference between the RT/10 and GTS as the drag is less important at lower speeds.

It's the turbulence caused by the straight drop off of the RT/10 rear window that's the problem. The GTS has a nice smooth rear window and creates less turbulence. The small wing (if you can call it that) on the GTS probably does very little, but may clean up the airflow at the rear of the car compared to the RT/10. My uneducated opinion.

 

[Tom F&L GoR]

Re: Drag coef on RT\'s VS. GTS\'s?

Another way to think of it is that the front of the car moves air out the way, the rear end has to put it back. It the air is not "put back" behind the car, there is a big "hole" (that the NASCAR guys use for drafting.) Without the rear glass, the RT leaves a big hole, the GTS a smaller hole.

This description obviously has no relation to the driver or owner...

 

[Gavin]

Re: Drag coef on RT\'s VS. GTS\'s?

Put a GTS next to an RT/10 and I believe you would be hard pressed to find a common body panel - The body shapes looks the same (front end of the car) but is isn't.
Evidence of this is in the numbers.

 

[Russ M]

Re: Drag coef on RT\'s VS. GTS\'s?

Gavin, I tend to disagree.

On Gen 2's the front is identical, not sure anywhere past that. But I believe that front clip/hood/side sills/wind shield/doors?/rear bumper are all identical.

But I did not know that the back of the car had so much to do with the drag #'s. Always assumed that only the front facia really made the biggest difference.