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Chris Hill 05-28-2018 12:20 PM

Real World Aerodynamics
 
Just curious how much aerodynamics help/hurt in drag racing?

Great example is A/SA class final between Larry Hill and Leonard Mattingly.

Hill has 70 cuda and Mattingly has 2000 Firebird. Both cars at same weight, so it's a great comparison.

Hill is 0.8 mph faster in 1/8 ,but Mattingly is 0.7 mph faster in 1/4. Mattingly increases 1.5 mph last half of track. I think that's a lot to make up last 1/2 of the track.

Hill 10.07 at 129.7 to Mattingly's 10.08 at 130.4 mph.

My gut says Hill makes slightly more hp by 1/8 mph, but the aerodynamics of newer and smaller car takes over after 100 mph.

Any SS guys have experience going from old school car to new jellybean car with same combo and weight?

Estimated coefficent of drag for 2000 camero is 0.34
Estimated coefficent of drag for 1979 mustang is 0.46

Kevin Panzino 05-28-2018 12:29 PM

Re: Real World Aerodynamics
 
The Zaskowski's have a great video of father and son side by side heads up for class. The camera is in the camaro looking over at the Chevy II. The cars are extremely close together with the deuce actually gaining a tad on each gear change. Then around 800 ft ish, you watch the camaro begin to get ahead. I think its a great example of exactly what you are talking about. (Plus its an incredibly cool video anyway!!!!)

Kevin

SSDiv6 05-28-2018 01:15 PM

Re: Real World Aerodynamics
 
Chris,
I have posted on this subject in the past.

In addition to poor frontal area Cd, after the launch until the 1/8, most cars are dealing with the ground effects. Due to poor Cd, some cars are more susceptible to ground effects than others.

After the 1/8, as speed increases, if your vehicle has a good Cd, the ground effects start to cancel and aerodynamics plays a major role to stabilize the vehicle and reducing drag while accelerating.

It is one of the reasons why you may have seen some cars porpoising down the track. The cause is ground effects not canceling while the car is accelerating due to both, poor aerodynamics and also the suspension not being properly adjusted. Porpoising also increases drag on the vehicle.

junior barns 05-29-2018 11:30 PM

Re: Real World Aerodynamics
 
Hi Chris. Back when top stock first came I remember Mat Morgan showing wind tunnel numbers between the new firebird and a 69 Camaro and a 69 corvette. His conclusion ( the best I remember) were that as long as no big head wind, the cars would not notice any difference on drag until they approached 130 mph. At that time he was driving a 69 Camaro. I'm sure he got the wind tunnel numbers from the manufacture . He also had numbers for the 69 mustang for the comparison. Wish I would have saved it!!

Greenlight 05-30-2018 12:34 AM

Re: Real World Aerodynamics
 
Here are some drag coefficient values:

http://www.mayfco.com/tbls.htm

Myron Piatek 05-30-2018 11:55 AM

Re: Real World Aerodynamics
 
A Dodge Viper has a worse Cd than a Dodge p/u truck?!?

nickh 05-30-2018 12:44 PM

Re: Real World Aerodynamics
 
Always been interested in aero myself, my 73 nova bracket car must be in the .60's LOL

Randall Klein 05-30-2018 03:10 PM

Re: Real World Aerodynamics
 
FWIW
When Warren Johnson was racing the Cutlass he wrote an artice in ND about aero, if I recall correctly he said it didn't make much difference until tje very end at 200mph

Of course he was representing Oldsmobile (and the Cutlass)....those Cutlass's were very smooth

Myron Piatek 05-30-2018 04:09 PM

Re: Real World Aerodynamics
 
Quote:

Originally Posted by Randall Klein (Post 564207)
FWIW
When Warren Johnson was racing the Cutlass he wrote an artice in ND about aero, if I recall correctly he said it didn't make much difference until tje very end at 200mph

Of course he was representing Oldsmobile (and the Cutlass)....those Cutlass's were very smooth

A few paragraphs down, Warren talks about how inferior the Firebird was compared to the Cutless it replaced......by 1.5 MPH!

http://www.hotrod.com/articles/drag-...hnson-profile/

nickh 05-30-2018 04:09 PM

Re: Real World Aerodynamics
 
WJ also said a while back that the forward facing hoodscoops took away about 60 hp with the drag it created.

Hacksaw 05-30-2018 05:33 PM

Re: Real World Aerodynamics
 
Quote:

Originally Posted by nickh (Post 564214)
WJ also said a while back that the forward facing hoodscoops took away about 60 hp with the drag it created.

I thought he said 80hp.

nickh 05-31-2018 08:02 AM

Re: Real World Aerodynamics
 
Your probably right that was a while ago, I now can recognize a train 2 out of 3 times...LOL

Darrin Christen 06-06-2018 10:06 PM

Re: Real World Aerodynamics
 
Does the Firebird trip the mph clocks with the tire or the nose?

Frank Bialas 06-06-2018 10:22 PM

Re: Real World Aerodynamics
 
1 Attachment(s)
Quote:

Originally Posted by darrin christen (Post 564677)
does the firebird trip the mph clocks with the tire or the nose?

You figure it out. I lost this round.

Attachment 45423

FED 387 06-06-2018 10:45 PM

Re: Real World Aerodynamics
 
looks like the chin spoiler tripped the light BUT it also looks like the driver "tapped" the brakes causing the car nose to dip helping trip the light-- so much for the 3 inches-- FED 387

Larry Hill 06-07-2018 09:02 AM

Re: Real World Aerodynamics
 
finish line is six inches I think.

Dan Fahey 06-07-2018 10:42 AM

Re: Real World Aerodynamics
 
Quote:

Originally Posted by Frank Bialas (Post 564679)
You figure it out. I lost this round.

Attachment 45423

DAMN finished by the(a) NOSE...!!

D

FED 387 06-07-2018 11:30 AM

Re: Real World Aerodynamics
 
6 inches is the correct answer ----all others are all supposed to be at 6 inches--however some 60 foot lights may be set between 6 and 13 inches for cars that wheel stand long distances- I was thinking about static height of the vehicle of 3 inches--actually the starting line lights height I believe is closer to just over 2 inches--regardless looking at the picture the red car tripped the finish line light with something other than the wheel-- how he did it is for future discussion

Adger Smith 06-10-2018 01:12 PM

Re: Real World Aerodynamics
 
Yep, finish line light tripped by the nose is very common.

Myron Piatek Yep, the CD for the pickup is better, but look at the last column. The CD X sq ft of frontal area is the real deal.

Dan Fahey 06-10-2018 10:18 PM

Re: Real World Aerodynamics
 
This was an issue with long nose ProStockers of the 80s.
Especially the Camaros!

Ed Wright 06-11-2018 04:06 PM

Re: Real World Aerodynamics
 
Difference is, unless you are in a heads-up race, dipping the nose to trip the lights with the air dam/chin spoiler, makes your ET look quicker, causing break-out issues.


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