gjestico

iTrader: (5)

A number of us here have 60's-70's cars which have poor aerodynamics compared to modern cars.
How much does that poor aero hurt your quarter MPH ? Especially when you start getting faster, like 110-120 mph etc.
Looking around a bit at timeslips on this site, For example - Speedtigger has a very potent and consistant car that seems to trap about 5 mph lower than a 4th gen camaro with similar ET.

orange88ls1s-dime

150mph is usually a benchmark for Aero unless your driving a 4*8 sheet of plywood. The next benchmark is 190-200 then again at 250

Gray86hatch

iTrader: (83)

I found noticable gains in mph on my mustang when blocking off openings in the front bumper. This was going mid 120's to 130.

It makes more of a difference than you think.

Tim

The stunningman

iTrader: (47)

I know at 125+ mph the spring loaded wipers on my Dakota would lift off the windshield and do a zombie imitation floating around. The roof of the truck is very tall and the truck in general is very square. Aerodynamics definitely affect ET MPH. This would be a great one for mythbusters to do some back to back testing. I'm just not willing to cut the roof off my truck YET.

ZONES89RS

iTrader: (25)

I was wondering if this was an advantage for my 86 TA over the 89 RS with a sealed front end and no sunk in head lights.

The stunningman

iTrader: (47)

Just want you to remember one thing. Thats the early cars like Tiggers have that huge,HEAVY hunk of steel under them called a FRAME... Some poor fellows even got the BOXED ones. The later model stuff use unibody construction and subframes which are lighter. So don't push it all on aerodynamics. My poor dodge is doublef@cked its unaerodynamic and its got the heavy frame.

wildcamaro

iTrader: (15)

For reference a 1970 chevelle has a coefficient of drag of 0.42 compared to a late model corvette having cd of 0.28, frontal area also has to be considered which I'm sure the chevelle has more of....

I would think this would be negligible because the real killer in the 1320 is weight bc it isnt enough distance for aero to play a huge role I'll take a 3000lb chevelle to a 3200lb vette all day provided they have the same power...now if we are talking standing mile I'll take the vette

gjestico

iTrader: (5)

My Car is a 67 Chevelle. Technically a First generation 'A' Body just like 'Tiggs.
In Fact - I boxed my frame for extra strength (added 22 lbs). Still, my car weighs 3410 wet without driver. Look around and you will see that is right on the average weight for a 4th gen F-Body.
Sooo since I seem to spend more time with the calculator than the 'Tree at the dragstrip, I will keep pondering

HioSSilver

iTrader: (8)

Aero starts coming into play @ about 45 mph. I contribute some of my 130 mph trap speed with a bolt-on ls6 to playing with the aero of the car.

speedtigger

iTrader: (16)

Most of the F-Bodies that are in the mid to low 11s pick up about 24-25 MPH on the 2nd half of the track. My car picks up about 22 to 22.5 on average.

There is another guy on here who has a 70 Chevelle who only picks up 20 to 21.

I have wondered if a chin spoiler would help.

Doug G

There was a lot of testing on the front air dam and rear spoiler on the First Gen. Camaros.... showed a definite improvement....I'll look for the link.
Now this brings another question.... IF bad aerodynamics cause lift, do they effectively make the car lighter which makes the car faster, and thats why they pick up a "set amount" on the second half ????

Edit... here it is......http://www.camaro-untoldsecrets.com/...es/rpo_d80.htm

HOW EFFECTIVE?...

When asked about the effectiveness of this special equipment, Van Valkenburgh emphatically states; "The front valance and rear deck spoiler were more than mere styling gimmicks. They actually made a measurable contribution to cornering and stability at highway speeds and were indispensable on the race track".


THE DYNAMICS OF AIR FLOW AND ITS EFFECTS ON AUTOMOBILES...
What actually causes lift? To some degree, body panel shape and to a larger extent, air that passes through the opening of the grille and under the front end sheet metal. At speed, this massive air stream builds up tremendous pressure under the hood where it is forced to exit rearward, below the chassis, resulting in body lift.
We can effectively counter lift by limiting the amount of air flowing under the front sheet metal with the use of "dams" and by down-sizing the opening in the grille. Furthermore, we can relieve pressure under the hood by incorporating exhaust vents in the fenders such as the ones used on the Trans-Am Firebirds and Corvettes. Any remaining lift may be countered by applying down force using additional aerodynamic "spoiler" devices at the front and rear of the vehicle.

speedtigger

iTrader: (16)

The only problem with this thought process is that it does not reduce mass, which is actually what your motor has to move. It may affect weight in relation to gravity, but this much less significant. Aerodynamics provide lift, they don't reduce mass.

I had a buddy once who said he was going to fill his roll cage with helium. Like the weight of the air inside of his cage was the issue. LOL.

The stunningman

iTrader: (47)

On motor my dakota picked up 22 regularly on the second half. On spray it would pick up 25 (106 to 131 mph).

IMO horsepower to weight has a lot more to do with it. I don't think many people are going to pull 2-3 mph out of small changes in aero.

My Faimont picks up 25 mph (102 to 127mph). IMO its probably as boxy as speedtiggers, just a bit lighter.

HioSSilver

iTrader: (8)

Lift= turbulence. If you've ever noticed manufacturers usually talk about reducing lift because then they reduce turbulence..... and turbulence is bad.

LIL SS

iTrader: (9)

So my old 347 at one point made 430 rwhp. The heads cam came off my buddies 4th gen which also was a 347 and made the same 430. If you put the two graphs over each other, it was like it was traced. Both had 4,500ish stalls, same effective gear ratio (his 28" 4.10 to my 30" 4.56). His 4th gen with driver weighed 3150lbs my 63 pick up weighed 3525lbs with me in it.

He went 10.7x @ 123 with a 1.55 60'
I went 11.4x @ 117 with a 1.59 60'


Can't really compare my back half right now as the last 50-100 feet I and having valve float, so I am no longer accelerating. But it probably is only off 1-2 mph.

speedtigger

iTrader: (16)

What's up with your 1/4 bottle numbers in your signature? Also, how far did your roll out before you hit it and what jet?

LIL SS

iTrader: (9)

Left on a na tune, sprayed at the 60' (pulling 4* timing). Out of gear by 800 feet coasting through the traps.

I have to double check but I believe I have a 52n jet in the first stage right now. And that is all I sprayed on it. Got to get the valve float issue/gearing figured out before the 2nd stage gets turned on.

speedtigger

iTrader: (16)

That is encouraging. You picked up almost 9 MPH in the 1/8th with a 52 jet. I am starting out with a 51 jet this he weekend. If I pickup that kind of MPH in the 1/8th, I will be thrilled.

Doug G

Could you imagine all those bottles floating around full of helium ?.....LOL

I can only guess the weight off-set is counter-acted by the wind resistance.

Looking back to NASCAR and the Daytona or Superbird and the "aero-car wars" can really explain a lot.

LIL SS

iTrader: (9)

Might have been 10 if I sprayed out of the hole. Details for you..

13-1cr 418
PRC heads
254/260 cam
Super Vic intake
Nx 2stage plate
4150 to dominator adapter
Dominator tb
1 3/4 stepped to 1 7/8 with 3 1/2 hvmc
18" dumps
Power glide with a 1.78 first
Verter flashes to 4600 off the 2-step/tbrake
4.56 gear
315/60/15 drag radial
E48 for both motor and n20 passes

NGK 8 looked perfect on motor and the 9 looked perfect with the 52n jet.

Truck weighed 3175 with me in it.