Okay. I want to see this covered at least once... In a recent top speed thread, somebody mentioned 195mph in a fiero. So my question is, *STRICTLY FROM AN AERODYNAMICS PROSPECTIVE*, what is necessary to obtain those kinds of speeds (safely without an FAA waiver)?

Some things for discussion:
-California kid mentioned the non-aero noses were going airborne near 120mph.
-The back window section of a fiero most likely creates a strong low pressure area, due to the seperation of the air from the 'airfoil' (roofline). Possibly require louvers to prevent this???
-Air rushing underneath the car will experience turbulence as it hits all the various crap underneath. Possible high pressure buildup? Maybe not even worthy of consideration?

[This message has been edited by ryan.hess (edited 03-15-2005).]

Roof wing

quote Originally posted by gusshotrod: Roof wing

Your car first. I'll get the drill.

From a physics perspective the Fiero has to have the nose lowered, body lowered, and the huge wheel wells closed off. The line of the hood and the window is fine. Having a vertical rear window is fine as long as it is not too large... notice it was on the Ford Le Mans racers. Smoothing the bumpy sides especially around the side windows and sail panels is a must. Continuing the laminar flow of the roofline out to the rear of the vehicle would be wise, whether this is done by louvers or by a rearrangment of the rear shape of the vehicle is open to experimentation. Having a wing on the rear with sides to add down force and vertical stability to the rear of the vehicle seems to me to be a must with a Fiero at extreme speed. Just looking at the noses, I think that the non aero '88 nose is the best shape for flow, but who knows without wind tunnel or model tests.

(Physics guy guessing... )

Gary

quote Originally posted by yosemitefieros: ...and the huge wheel wells closed off..... Just looking at the noses, I think that the non aero '88 nose is the best shape for flow...

I'm thinking to keep the car looking as close to stock as possible. As for the nose comment - I thought so too, but apparently they create more front end lift than the gt nose!

Seriously, I think an aero nose, a couple of degrees of body rake, front and rear spoilers of the right size, some kind of vents for the radiator to keep the hood from blowing off, and tape up the seams on the hood.

quote Originally posted by gusshotrod: and tape up the seams on the hood.

Why is that necessary?

Might help to have an underbody pan of some sort, to keep airflow under the car as smooth as possible.

quote Originally posted by ryan.hess: Why is that necessary?

Helps keep turbulence from getting under the hood edge and peeling it up. Also, edges and lips create turbulence, and turbulence is drag and costs power.

JazzMan

downforce, gearing and mucho horsepower ..Something along the lines of Norms front end and a functional rear spoiler ..just look at a F40...a longer wheelbase would help also

[This message has been edited by Erik (edited 03-15-2005).]

quote Originally posted by ryan.hess: I'm thinking to keep the car looking as close to stock as possible. As for the nose comment - I thought so too, but apparently they create more front end lift than the gt nose!

I can only tell you what I heard within GM, the GT aero nose was developed (in the GM Wind Tunnel) primary for the IMSA Race Cars due to known front end lift at high speed. At the time they were testing Fiero's with hotter power plants, was the same time frame that proto noses were being produced for the "first off" race cars, so they changed a mold so a direct bolt on would fit on a stock fiero. GM liked the look and aero performance which resulted with it going into production. The nose changes over the years were not only styling, but performance improvements over the noses produced in 84 and 85. I don't recall the exact speed when front tires became air-borne with early noses, but it was between 120 and 140 mph, of course wind direction/speed with be a factor. This is related to only stock 84,5, and possibly 6 non-GT non-Wedge Nose Fiero's without lowering, or added measures to exhaust front end pressure under the nose. I have yet to ever see anything in print from GM, or Car Mags on this issue, but few people tend to push their car that high, so it was hushed up so to speak. A few brave members here have reported severe front end float with the early noses in the area of 120 mph.

There was extreme "heart burn" over the development of the Aero GT Nose, due to process mold flow issues, but they did over-come the problems encountered. There are a couple places on every Aero Nose that you can actually see where the "feed-runner" were trimmed off, they are so close to the "show surface" that they couldn't be completely removed to a flush condition, without risk of ruining the whole part.

[This message has been edited by California Kid (edited 03-15-2005).]

quote Originally posted by California Kid: The nose changes over the years were not only styling, but performance improvements over the noses produced in 84 and 85. I don't recall the exact speed when front tires became air-borne with early noses, but it was between 120 and 140 mph.... A few brave members here have reported severe front end float with the early noses in the area of 120 mph.

My 88 coupe front end is raked a few degrees with lowering springs no hood vent, no rear spoiler and it just starts to get light feeling at about 143-45 mpg ..I dont know what the earlier front end would feel like at that speed nor would I want to find out...The aero nose would seem to help resolve this just by looking at it. I wonder if the non aero 87-88 nose flows as well as the aero..

edit thats mph not mpg

[This message has been edited by Erik (edited 03-16-2005).]

There is a chin spoiler for the non-aero nose... it's available with the IMSA widebody that Sage sells.

I'd say start with an aero nosed car, add a closed chin spoiler that retains the stock front mouth opening, vent the hood, and add a whale tail spoiler instead of the stock wing. That's it for body mods.

Since aerodynamic force is EXTREMELY dependent on pitch attitude, the front of the car MUST be lowered and the car MUST be set up with rake. Exactly how much is just a matter of experimentation.

A Mk2 MR2 has gone very fast on the salt flats, so there's no reason a Fiero couldn't

I'm no expert, but I think these tactics should help. This is assuming you're starting with an aero body.

To reduce the amount of air flowing under the car:

-- Vent the hood
-- Install a front air dam, make it as low as possible
-- Install side skirts on the rocker panels, make 'em as low as possible
-- Vent the decklid... a BIG vent right behind the rear window
-- Remove the plates in the bottoms of the decklid grates

Some things to smooth airflow:

-- Flush-mount the front turn signals
-- Remove the side mirrors and tape the holes
-- Tape the seams around the hood, front fascia, and headlight doors
-- Shave the side mouldings
-- Install fender skirts in the rear fenders
-- Install a wedge-style spoiler (like the GTP Fieros, but without the "arms" on the ends)

Also note that the decklid vent and spoiler will work together to help smooth the airflow over the rear deck. The air coming out of the engine bay will form a "bubble" between the rear window and rear spoiler. The air coming across the roof will slide over the bubble, instead of getting caught up in turbulence.

And finally, jacking up the rear end and/or lowering the front will increase the frontal area of the car, thereby increasing drag. So the angle of attack (i.e. rake) should be increased as little as possible.

[This message has been edited by Blacktree (edited 03-15-2005).]

quote Originally posted by California Kid: This is related to only stock 84,5, and possibly 6 non-GT non-Wedge Nose Fiero's

Pardon my ignorance, but what is that? The "bumperpad" notchies?

quote Originally posted by ryan.hess: Pardon my ignorance, but what is that? The "bumperpad" notchies?

For lack of a better description, and it's late, that's a good description ! Pictures of all the different noses would help in this case.

quote Originally posted by California Kid: For lack of a better description, and it's late, that's a good description ! Pictures of all the different noses would help in this case.

bumperpad

coupe

GT

afaik, those are the only choices out there......

That would be:

OK

Better

Excellent !

Hey! You guys are talking my language - outrageous performance Here's the MR2 Will referred to. Good info in this write-up from a "been-there, done-that" persepctive.

http://www.bobnorwood.com/The%20Fastest%20Little%20Sports%20Car%20in%20Utah.htm

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Todd Perkins - the member formerly known as "perkidelic"
todd's hot rods

ahh yes, this reminds me that i have this car and driver article on my webpage about aerodynamics. Sorry if bandwith is used up! It is geocities after-all, maybe someone else could host?

Aerodynamics for dummies: http://www.geocities.com/j_depies/aerodynamicspage.html enjoy

Jeff

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REMEMBER: If you cant win the race you loose the argument!!

3.4 DOHC Motor Swap-14.7 in the 1/4 mile with no hook-up, crumby exhaust and automatic chip.
Better exhaust, chip, cam retarding, and driver to come... I'm feeling lucky!
www.geocities.com/j_depies

quote Originally posted by toddshotrods: Hey! You guys are talking my language - outrageous performance Here's the MR2 Will referred to. Good info in this write-up from a "been-there, done-that" persepctive. http://www.bobnorwood.com/The%20Fastest%20Little%20Sports%20Car%20in%20Utah.htm

excellent read..I've always had a love for small displacement oversquare HO engines ...

quote Originally posted by Erik: My 88 coupe front end is raked a few degrees with lowering springs no hood vent, no rear spoiler and it just starts to get light feeling at about 143-45 mpg ..I dont know what the earlier front end would feel like at that speed nor would I want to find out...The aero nose would seem to help resolve this just by looking at it. I wonder if the non aero 87-88 nose flows as well as the aero

Whoa! You need to post in this thread and tell us all how you're getting that kind of mileage!

[This message has been edited by eatoninside (edited 03-16-2005).]

quote Originally posted by eatoninside: Whoa! You need to post in this thread and tell us all how you're getting that kind of mileage!

LOL....ooops ..well er ummm ..concentrated gas?

I wonder what the imsa gtu car did at daytona for speed trap #s
that was a tube frame with the SD motor
but looked like our body with some mods [ w-i-d-e-r ] mostly
they lead at miami in 85 intill it blewup
first daytona run would be 86 I think as miami was first 85 outing

not the later GTp car that didnot look much like a fiero at all

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Question wonder and be wierd
are you kind?

A couple of years ago I had a friend working at a car-research & development center trying to optimize a swedish sportscar (nowadays known as the KoenigsEgg).
I had the opportunity to try my Fiero GT in their windtunnel mostly because the Fiero was such an "odd" car and it looks aerodynamic and the engineers wanted a good laugh
The results weren't that good actually. A few very restrictive parts on the car was: windshield wipers, side mirrors, rear parts of the wheel wells, front blinkers, restrictive radiator, the rubber molding around the windshield, the edge between the roof and the rear windshield, the notch between the side windows and the sailpanels and believe it or not the rear wing! In fact a standard Saab 9000 had just about the same values as the Fiero according to one of the engineers.
The positive thing was that the downforce was pretty high compared to other cars. This because the Fiero is very flat underneath.

I know a few will demand numbers and receipts but this test was made "just for fun" and wasn't planned and I had no intentions of proving anything at the time.

The Fiero I had at the time was all stock except 17" rims, no sunroof.

Edit: And no I wasn't allowed to drive the KoenigsEgg

[This message has been edited by Intel (edited 03-16-2005).]

quote Originally posted by Intel: A couple of years ago I had a friend working at a car-research & development center trying to optimize a swedish sportscar (nowadays known as the KoenigsEgg). I had the opportunity to try my Fiero GT in their windtunnel mostly because the Fiero was such an "odd" car and it looks aerodynamic and the engineers wanted a good laugh The results weren't that good actually. A few very restrictive parts on the car was: windshield wipers, side mirrors, rear parts of the wheel wells, front blinkers, restrictive radiator, the rubber molding around the windshield, the edge between the roof and the rear windshield, the notch between the side windows and the sailpanels and believe it or not the rear wing! In fact a standard Saab 9000 had just about the same values as the Fiero according to one of the engineers. The positive thing was that the downforce was pretty high compared to other cars. This because the Fiero is very flat underneath. I know a few will demand numbers and receipts but this test was made "just for fun" and wasn't planned and I had no intentions of proving anything at the time. The Fiero I had at the time was all stock except 17" rims, no sunroof. Edit: And no I wasn't allowed to drive the KoenigsEgg

I assume by GT you were reffering to a fastback GT..
keep in mind the aero notchies were supposed to have the lowest drag coeficient.. the slope of the rear lights helped - and in their case atleast the wing is not a wing but a spoiler..

sure would be cool to get a group of modded fieros and stock fieros to a windtunnel day to test em all.. wonder if there are any associations that would do that for not TOO much money

I'd love to see a windtunnel smoke stream test of Kameo's fastback with the rear louvers

[This message has been edited by Kohburn (edited 03-16-2005).]

Sorry ... yes it's an 87 Fastback GT.

The pricing of the windtunnel (back then) was around $40000 a day including high speed fotos and film.

[This message has been edited by Intel (edited 03-16-2005).]

quote Originally posted by Blacktree: And finally, jacking up the rear end and/or lowering the front will increase the frontal area of the car, thereby increasing drag. So the angle of attack (i.e. rake) should be increased as little as possible.

Lowering the front will NOT increase the frontal area of the car because of the chin spoiler.
The car MUST be set up with a rake, in the name of stability. That increases front aero loading and keeps the nose on the ground.

I don't know if it's been mentioned but you will need to nail the headlight doors shut.

For any serious run, like for a Bonneville-only race car, I'd say remove the headlights and fiberglass the doors shut. Still need to vent the hood, though, to keep the front from getting light.

quote Will said: The car MUST be set up with a rake, in the name of stability.

You misread my post. I did not say to refrain from changing the angle of attack. I said to keep it as little as possible so as not to create unnecessary drag.

[This message has been edited by Blacktree (edited 03-16-2005).]

In the early 1990s...

Oldsmobile took a 88-89 FWD Cutlass and achieved over 300 mph on the flats with a QUAD4 breaking 17 records previously held by Mercedes Benz.

With enough funding, you can make just about any car go fast.

quote Originally posted by Skybax: In the early 1990s... Oldsmobile took a 88-89 FWD Cutlass and achieved over 300 mph on the flats with a QUAD4 breaking 17 records previously held by Mercedes Benz. With enough funding, you can make just about any car go fast.

The fastest oldmosbile that broke the speed records was the '87 Olds Aerotech with a twin-turbo Quad4, I don't believe I've ever heard of Olds using a W-body to do that.

http://www.fast-autos.net/oldsmobile/oldsmobileaerotech.html

Top speed was 278mph.

There was a concept '89 Cutlass sedan called the Aerotech III, it had a supercharged Quad4 that put out 230hp, but it was never run at the salt flats from my knowledge.

quote Originally posted by Blacktree: I said to keep it as little as possible so as not to create unnecessary drag.

Who cares about drag? That can just be overcome with more HP

quote Originally posted by Intel: Sorry ... yes it's an 87 Fastback GT. The pricing of the windtunnel (back then) was around $40000 a day including high speed fotos and film.

i know some schools in the US have windtunnels also.. maybe get some student to do a senior project of designing a more aerodynamic body for the fiero

im in!!!!!!!