wabmorgan

YES!!!!!!!!!! The F-body's Areodynamics are well known and quite good.


There is no way the car would be more areodynamic rear to frount than frount to rear. The high rear end of the car would make it have the areodynamic profile of a brick from rear to frount. The corvette would be the same way. It would also have about the same areodyamics considering both F-body and Y-body have similiar profiles.

The key to a good areo shape is a low frount nose, steeply raked windsheild, and high rear end. A shape like the F-body and Y-body. The areo profile in the reverse would have to not a good one.

If you think the car is more arrodynamic runnning backwards.... by all means than drive it that way. FRankly, I think I will drive mine the normal way!!!

300bhp/ton

well I see where you are coming from but IMO your reasoning is flawed.

The most aerodynamic shape is a rain droplet, yet this is big or tall at the front and narrow at the back, so maybe driving in reverse would be better with some cars.

Here's a car that's taller at the front than the back yet it's very very very aerodynamic.

wabmorgan

yeah... but the frount profile is still that of a raked shape in the car you have shown in the picture. If anything, you just made my point. The flater more raked the body and windshield is.... the better the areo C/d is.

If you were to rake the firebird's windsheild back 10 deg or so... it would be even more areo than it is now. Not to mention moving the nose out and lower would help even more.

My point is not that the car is taller in back.... it is that the back end of the F-body is flat vertically, like a wall and the corvette is even more so. SO, running backwards in either you would be pushing a lot of wind... not good for C/d.

Slow Vette

iTrader: (1)

the coefficient of drag for the new c6 is .28 and .29 is the c5. btw is .28 and .29 really that much of a difference, anyone?

wabmorgan

no... not enough to hardly even count.

chirp_fourth

The question was:

The answer is:

There is not much you can do to a 4th gen 1998 fbody that will significantly reduce ET or increase trap speed in the 1/4 mile, even if the car is running 11's.

Here's some examples:

ls1 fbody, 375rwhp/375ft-lbs, 3300lb, 3.73 gears, a4, FA = 20' ^2

air density=.00236

If Cd=.35, ET = 11.65 @ 121.69
If Cd=.30, ET = 11.61 @ 122.49
If Cd=.25, ET = 11.56 @ 123.29

This is based off of my 1/4 mile simulator, in a perfect world, with perfect shifting, and perfect launch and traction... And no, Cd of .25 is not attainable with an air dam.

Since he was talking about having a 4th gen fbody, I answered with specificity to a 4th gen fbody. So before he goes out and hacks up his undercarriage, I want him to know that on HIS car, it isn't going to help much. And if he still decides to do it, I wanted to give him real life expectations. What works for one car doesn't work for all cars, because not all cars are the same.

wabmorgan

He didn't ask about 1/4 mile. Just aerodynamics.

LTSpeed

Most people question it, but it's a fairly well known fact among car designers that many cars are more aerodynamic backwards than forwards. What kills the C6 is how far back the windshield starts. Remember the Corvette Indy? That shows a much more ideal shape.

Mirrors are also a killer; not just because of size, but also their location. BTW, the 4th gen Camaro had the lowest drag conventional mirrors ever produced.

wabmorgan

I could understand that statemet with some cars... but not the vette nor the F-body.

Louie83

iTrader: (3)

I remember that from one of my first engineering classes. If you notice, it is very similar in shape to that of a wing and follows the same principle as an airplane wing does. Which explains why someone was stating earlier, that downforce is needed at very high speeds, otherwise, you might really be flyin'.

wabmorgan

I don't think the pictured car was going very fast. MAybe that is why it is shaped that way. They were looking to cut C/d and were not worried about lift!!!!!!!!!

Gearhead1

Back in the day (late '60's early'70's) guys uesed to put spacers or washers between the hoods hinges and the hood itself which raised the rear of the hood approx 1/2 inch or so. This helped to vent the underhood air out of the engine compartment and kept it from stacking up under the hood. This worked on the older cars because they had the aerodynamics of a brick. Would this same "trick" work on a newer vehicle or would it disrupt the airflow and create more drag. It would seem to me that the air entering the engine compartment on a newer car has nowhere to exit but down and under the vehicle If you could vent it out the top (the rear of the hood) how would this affect the aerodynamics??

wabmorgan

The Corvette Indy is slick....



but to me that is not much differant than the Banshee


And the Banshee was what the 4th generation Firebird was based upon. Pontiac said, "The 4th gereration Firebird is based upon the 3rd generation Firebird and the Banshee prototype car."

chuntington101

i think you guys are gettting carried away with just reducing drag! some drag can be goood! its juts how you make it thats the key!!!

big wings are not i a idea as they a very inefficent! now a rear diffucer can be very effective at making downforce and dont dissturb the air at all!

Chris.

DONAIMIAN

iTrader: (18)

I think the reason for the washers was to make homeade cowl induction. The base of the windshield is known for being a high preasure zone. GM put a piece of weather strip there to stop air from entering there and giving the car a light front end/floaty feel at higher speeds. A good example(personal opinion) that we can somewhat compare our cars to is the C5-R and C6-R GM didnt cut any corners on these cars aero wise.

Note where the hood vents are and how the cowl area is completely flush and sealed.

Also you can see where the air that comes in from the radiator never makes it under the hood.

DONAIMIAN

iTrader: (18)

I think the reason for the washers was to make homeade cowl induction. The base of the windshield is known for being a high preasure zone. GM put a piece of weather strip there to stop air from entering there and giving the car a light front end/floaty feel at higher speeds. A good example(personal opinion) that we can somewhat compare our cars to is the C5-R and C6-R GM didnt cut any corners on these cars aero wise.

Note where the hood vents are and how the cowl area is completely flush and sealed.

Also you can see where the air that comes in from the radiator never makes it under the hood.

SSCamaro99_3

iTrader: (1)

Just because a car looks aerodynamic doesn't mean it is. I doubt windshield angle is highly important. They are probably only 4-8* more layed back than a 3rd gen. They are also around 2 inches taller than a 3rd gen.

lt1camaro95

You want to feel the different of drag? Drive a F-body to 150mph full throttle, the try the same with a vette. Ours seem to hit a brick wall about 120, while the vette keeps pulling hard. BTW, I am referring to stock cars, not 500 camaro's that have no problem pushing through the air.

v7guy

iTrader: (1)

There is very little you can do to help the car without ALOT of work.

Removing side mirrors as already stated is the easiest. Taping up the body gaps is the next easiest.

The base of the windshield is a high pressure area. This is fact.
Opening the hood at the rear only lets air under the hood, increasing lift, unless you have a wicker bill.
If you want to reduce underhood pressure a vent needs to be installed in the front 1/3 to 1/2 of the hood, past that you start to see high pressure build up and air would more than likely enter the hood. Louvers, or a big hole is the only type of vent I'm aware of that will do the job. Louvers would have to fabricated. A lip at the front of the "vent" would be needed to make it more effective.

A front air dam, already mentioned, can help significantly. As mentioned by Nata SS a conversion to a front breather is needed.

A rear diffuser, as already mentioned, can help as well. It straighten the air under the car and removes the parachute that is the rear bumper.


These are the "easiest" gains to be had. If you do some research you'll realize that these projects aren't all that easy. If your a drag racer I would say that none of this is going to make much of any difference as most of this stuff doesn't begin to show up until 100mph, improvements and stability are noticed by 150mph or so.

If you want to check out sites that will cater more to high speed motorsports/touring etc check out the following.

http://www.frrax.com
http://www.openroadracing.com/forum/
http://www.pro-touring.com/forum_main.htm
http://www.corner-carvers.com/


Doing searches and reading on these sites should keep you busy for weeks.

FastKat

iTrader: (10)

[QUOTE=v7guy]
The base of the windshield is a high pressure area. This is fact.
Opening the hood at the rear only lets air under the hood, increasing lift, unless you have a wicker bill.
QUOTE]

True that - opening the back of the hood up will get more air to the engine compartment, and eat away at the low pressure under your chasis.