Aerodynamic lift- A real problem

[Hermie]

Originally Posted by Frank Lee

Tempos weigh about 2500 lbs empty. Add two guys in the front seats at 200+ lbs each and 15 gallons of gas at about 90 pounds and you have a 3000 lb unit for a typical load. Then know that 2/3 the weight of Tempos is on the front wheels and you have 1000 lbs on each front wheel, and 500 lbs on each back wheel.


I've been a gearhead since before you were swimming around in your Dad's shorts, ya punk. Put your car on a scale and get back to us.

I weigh 150, and drive solo. Try again, jackass.


Neil: Explain your fixation on drag.

Madison: An Audi TT has enough rear lift to kill someone from spinning out of control at about 120 MPH. Your exaggerations either show a lack of maturity or IQ.

[Christ]

The language was brought up in the other thread that you created this one from... I think it's probably in our best interests to relax a bit, guys.

[Hermie]

If Frank would stop being so immature and jumping to insults, we wouldn't have this problem. But apparently, he has nothing intellegent to say, so he resorts to the only thing he knows.

I merely act as a mirror and return what is given. Remember the golden rule?

[MetroMPG]

Correct me if I'm wrong, but from the examples posted so far, I'm only seeing lift becoming an issue at vehicle speeds that none of us who really care about fuel economy ever drive at. Speeds like 120, 110, 100 mph.

Hucho has a quote about design choices vs. lift in ordinary passenger cars, but I loaned my copy to Ben so can't look it up.

[MetroMPG]

Also, yes everyone please: at least be civil.

[user removed]

I am not Frank and have no real care about lift, or super wide tires, or driving at speeds where lift becomes any issue.

Where do you drive for best mileage where you have to worry about your car becoming airborne?

Seems like you just don't like to see someone post a different opinion from your own.

Since lift manifests itself in the vehicle rising up above it's normal ride height, maybe you could rig a camera that would show me that your car is in danger of becoming airborne at posted national speed limits.

Does lift exist? Certainly.

Do aerodynamic improvements, with measurable increases in mileage exacerbate the effects of lift?

Good question----my opinion is if the total aero drag is reduced then the increase in mileage would be mitigated by any increase in lift.

regards
Mech

[Hermie]

Here's some more info:

"But why is lift so bad? You'd be right in assuming that no car produces such a dramatic amount of lift to be dangerous to drive. But lift does negatively affect performance in two ways. First, lift reduces the load acting on the tires. Since the maximum amount of traction available from each tire is a function of the load acting upon it, a reduced load means less available traction. Lift also causes extra drag called "induced drag," which is a good percentage of the overall drag on the car."

Car Aerodynamics Diagrams - Sport Compact Car Magazine




I didn't join here because I want to squeeze every drop of gas I can. I came here because it seemed like a wealth of information for DIY modifications. My interests lie in eliminating lift and reducing drag at the same time, so when I'm going 70 down the freeway, I know I have all the control I need to avoid accidents, and less drag so I'm paying less at the pump.

[user removed]

If there is sufficient lift to affect traction then it would also reduce rolling resistance and improve gas mileage.

Answer me one question?

What speeds are we talking about?

I seldom if ever go over 65 MPH. Most cars have down force on the front and lift on the rear. You can also get lift if the bottom of the front of your car has a valence panel like the early Z cars which was a major contributor to the front end lift on that model.

Many cars had lower front valences that created lift, and air dams cured that poor design a long time ago.

regards
Mech

[Hermie]

Actually, almost all cars have a degree of front-end lift, unless they're well-designed high-end sports cars. As ncs posted on page 2, even the Mitsubishi Lancer Evolution and Subaru Impreza WRX STI have front-end lift.

I'm talking about speeds of 65-80 MPH, the common speed of highways and freeways, which I drive on daily.

[Frank Lee]

Michael has been all over the internets with this **** for at least 4 months now... not finding too many buyers either.

So... where's the data? Where's the figures? Where's anything that adds up to anything- in your posts that is?