Wind tunnel testing, Charger Daytona, '69 Charger and modern Hellcat Charger

[funknut]

Interesting stuff.  I wouldn't have guessed the Hellcat and the Daytona were so close.


https://www.youtube.com/watch?v=fkwgiiemZ_I

[odcics2]

They're not.
A street Daytona and 'race' Daytona are 2 different animals.
Example: it takes under 600 HP for the race version to go over 202.

How much HP does it take a Hellcat Charger?   (report back with the answer!)

[JB400]

For street cars, it shows how much better in understanding aerodynamics we've come in the last 45+ years.

[odcics2]

For street cars, it shows how much better in understanding aerodynamics we've come in the last 45+ years.

And overcoming the lack of aero on the Hellcat with raw horsepower!   

[alfaitalia]

Sort of....

CODs as follows.

1969 Charger     0.485 (not great ...even compared to other cars of the era).

1969 Daytona street version     0.28 (impressive and not really equalled buy most regular street cars until the late 80s or early 90s.....but those cars did it with body shape rather than wings and noses). Drag is rather less without the wing.....but its not all about drag when racing....you need downforce which of course creates drag.

2017 Charger (Non Hellcat)     0.29. Pretty good by modern standards for a car with a pretty blunt front end....and not that far away from a Daytona

Hellcat     0.335. Hmm......hence the need for big power to go fast. The extra drag is caused purely by the extra vents and quite a lot of extra downforce....which of course is needed at those sorts of speeds. A HC engine on a stock Charger body would be measurable faster.....if you could hold it on the road!

....and just for comparison. Current Challenger     0.38     .....a real brick by todays standards. One of the worst in class.


This car is a Vauxhall Omega....an upper mid sized sedan and a favourite with the police in the UK and built in 1986....no wings or long nose......but a COD of 0.28....exactly the same as a street 69 Daytona....so yes a lot has been learnt about drag in the intervening years !



....and this gives you an idea of the drag of various shapes to compare to the above figures.

[odcics2]

Frontal area has a lot to do with drag numbers, too.  The Omega is narrow!

The .28 "Daytona" number is for the race version.  The street car was never tested. (per Gary Romberg)

Remember the Renault Premier in the 80s?  Slicker than a Taurus from the same time period, although it looks like a brick! 

The Daytona package was a 'zero lift' concept.  Front spoiler size and angle could get a little downforce, along with using the wing to balance the car.  Balance is key.  Petty said the 1974 Charger race car had good balance and was one of the reasons he was very successful with it.

[alfaitalia]

The 0.28 result I found on line was for a street version that was being tested by University folks along with about a dozen other cars...old and new....so cant be much different to the race car. Will try and find the site I found the info on!

Frontal area has NO effect of Co-efficient of Drag numbers at all....but does affect performance. A ten foot wide sphere has the same COD as a one inch one (0.47)....but would still take a lot more energy to push it through the air.

Oh and the Omega is 3.5 inched WIDER than the Daytona....so not that narrow.  

[Ghoste]

It would be interesting to see a test comparing the old race Daytona and street Daytona if such a thing could ever be set up.

[odcics2]

The 0.28 result I found on line was for a street version that was being tested by University folks along with about a dozen other cars...old and new....so cant be much different to the race car. Will try and find the site I found the info on!

Frontal area has NO effect of Co-efficient of Drag numbers at all....but does affect performance. A ten foot wide sphere has the same COD as a one inch one (0.47)....but would still take a lot more energy to push it through the air.

Oh and the Omega is 3.5 inched WIDER than the Daytona....so not that narrow.  

Hmm, looked up the numbers: 1986 Omega is 69" wide, 1969 Charger is 76".    HUGE difference in width. 

Also - Omega has a 107 wheelbase and weights only 2500 pounds!   A shrimp of a car!   

[alfaitalia]

Apologies...I managed to look up the Omega specs on a site where just about every fact was wrong...lol. But the point is size does not affect Coefficient of drag. (Neither does weight...and interestingly weight has no effect on top speed either). So for that car to have the same COD as the Daytona without looking very aerodynamic at all showed how much progress was made.

[odcics2]

Apologies...I managed to look up the Omega specs on a site where just about every fact was wrong...lol. But the point is size does not affect Coefficient of drag. (Neither does weight...and interestingly weight has no effect on top speed either). So for that car to have the same COD as the Daytona without looking very aerodynamic at all showed how much progress was made.

I agree that progress has been made!   Europeans were ahead of the US automakers in aero development because gas over here was, and is, cheaper. 

There are so many details designing a car, or truck for better aerodynamics!   Finally, care is being taken with the bottom!