Hello All,

I KNOW that many out there have to have seen this same piece of info, but it seems like every time it's discussed during "hood vent" installs or "High speed instability" threads, nobody mentions it. I thought I'd chime in with this ACTUAL piece of info on front end lift in the Fiero and put it in an easy searched for thread name. This piece comes from the "PONTIAC FIERO Technical Analysis" that appeared in Road & Track in 1983 (note the ALL CAPS SECOND PARAGRAPH):

"Aerodynamics may not have been a high priority consideration in the original Fiero design. With a relatively low weight and small frontal area (by American standards), good EPA mileage figures were possible without going for the ultimate in low drag coefficient. The reported Cx is 0.377, which is not bad for such a short car, but not too strong an advertising point either. The obvious problem is the notchback rear window, which is almost a necessary evil in a mid-engine car. Although it allows easy engine access
and ventilation, it really disturbs the upper air flow and increases drag while reducing potential down force from any rear spoiler.

THE FIERO'S OTHER PROBLEM IS THE NOSE-UP LEADING EDGE OF THE FRONT BUMPER. THIS DESIGN ALLOWS A GOOD OPEN ANGLE AND RADIATOR INLET, BUT IT ALSO RAMS A LOT OF AIR DOWN UNDER THE NOSE. NOT ONLY DOES THIS USUALLY INCREASE DRAG, BUT IT ALSO GENERATES A LOT OF LIFT, IN SPITE OF THE BOTTOM-BREATHER RADIATOR INLET. REPORTED FRONT LIFT FIGURES WERE ABOUT 120 LB AT 100 MPH, WHICH CAN BE SIGNIFICANT WHEN THE STATIC FRONT WEIGHT IS JUST OVER 1100 LB.

It also appears that the opened headlight buckets were not as well researched in the wind tunnel as the Corvette's, as they raise the Cx to 0.417. Be that as it may, the pop-off plastic body panel concept means that better aerodynamics can be incorporated easily in the future.

-Gary

They are talking about the base coupe body style. The Indy, GT, and SE aero-nose is a little better and in 87 they re-designed the base nose but this was mostly for drag. All Fiero's have the front lift problem and a vented hood does reduce the lift a lot.

Oreif,

I know what you're saying about the article and it being the early, non aero model. But at least it's a real number being reported and not so much just "seat of the pants" conjecture. Gives us a base to start with and we can at least assume that the "aero" nose cars and 87-88 base noses as you mentioned are not any worse than that base, right?

-Gary

I wonder how much lift can be taken away by jacking up the rear an inch or two with coilovers? (or larger diameter wheels in the rear)

Would lifting the rear actually reduce lift at the front?

quote Originally posted by FieroFanatic13: Would lifting the rear actually reduce lift at the front?

yes.
first, it swings the nose just a hair lower, and creates slightly less angle. yes - this is minor - but better
next - and the more important part - it creates a place for the air that does go under the nose to go. the wedge shape of the underside will pull more air to the rear.

but - air damn. side skirts. hood vent. thats the real answer. the hood vent not only lets the air out to reduce the "lifting bubble", but, when done right actually produce downforce on the nose. you'll see hood vents on just about every car that has a windshield & races on a race track.

Pyrthian,

I've seen very few "side skirt" projects on the forum in my searching. Do you know of any that look good and are useful? And has anyone created any kind of functional (not just for looks) rear diffusers? With the lack of a belly pan/cover and an open engine bay underneath I'd expect not? And what about a true front splitter possibly as opposed to just extended air dams?

-Gary

well, to the degree we lower our cars anymore, side skirts is almost moot anymore anyways.
and, you only want to use them if the slope of the underneath is lower in the front, and higher in the rear - like the larger wheels example. this creates a vacuum underneath, sucking down the car, or, sucking the front air bubble out.

and, yes, there was a guy a few years ago - smooooothGT I think it was - who did MUCH fiberglassing. tho, I think it was and abandoned project. and, there was another guy who tried to do a belly pan - again - abandoned.

but, overall - most of this is silly anyways. if you got the $$$ to actually race & use this kind of stuff - you got the $$$ to hire someone to do it right. otherwise, it is just a learning experience or a waste of time - depending on who you are.

thanks for the real numbers. 100+ lbs is quite a chunk.

Along this line I fabricated hood vents and installed the Kris Munson flush mounts.

I recently swapped back to a plain hood and I have the vented hood in storage.

The reason I did this is that I want to experiment with internal ventilation for the headlight cavity.

The air pressure builds up at the top of the radiator and pressurized air looks for the easiest route out. That is without a doubt, a large hood vent.

I also think that using pipe of some type, you can vent into the forward wall of the wheel well. You wouldn't simply cut a hole, but you would try to channel the air to the negative pressure area of the wheel well. You might also use this as a brake cooling device.

The question is, has anybody actually tried doing this?

Arn

quote Originally posted by Arns85GT: .... I also think that using pipe of some type, you can vent into the forward wall of the wheel well. You wouldn't simply cut a hole, but you would try to channel the air to the negative pressure area of the wheel well. You might also use this as a brake cooling device. The question is, has anybody actually tried doing this? Arn

yes, there was someone, I think Skitime, who vented the underhood air to the wheel wells. no pipes, just little grills mounted on the inside wheel well. but, I think the hood vent is a much better way to go. it can also provide downforce, on top of reduceing the air bubble, when done right.
tho, going the extra step to vent to the brake calipers would be pretty dang sweet.

I've only seen the brakes provided cooling air through the front fascia openings and using tubes of some sort as far as I can remember. I also know there WAS a thread somewhere about turing the headlight covers themselves into the vents to let air out. I don't think the thread ever finished beyond some test fitting of one side. He was using a cut up rear vent if I remember correctly?

In the end, I'm REALLY only trying to improve (for me) the look of the GT front fascia. I'm a fan off the 87-88 standard nose truth be told- but they don't mesh well with the GT aero package in my opinion. If someone would make a simple add on air dam for the 87-88 base fascia that integrated well with the aero package I would be elated!

-Gary