FC high speed stability
#1
613nn
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FC high speed stability
I have an '87 with coilovers set mid way on firmness. 8k springs front, and 10k springs inthe rear. Wingless warrior, but do have a front air dam. Previously I ran 245/40-18's, and with this set up it would get "light" in the rear above 130 MPH. I have changed to 245-17 front, 275-17 rear to bandaid the problem till fixed properly.
I thoroughly enjoy my speed, but not to fond of the puckered pooper when things get iffy. I am a minimalist, don't care for body kits, obtrusive wings and such. They mostly just add weight, and have very little overall effect on handling. Most actually have a bad outcome to them, to much rear downforce unsettling the front, ect..
What should I be looking into for the stability I want? Was actually thinking of a drag type wing, commingle strait off the deck, with four adjustable struts.. Comments? Thanks in advance. And I searched many diffrent ways to no avail.
I thoroughly enjoy my speed, but not to fond of the puckered pooper when things get iffy. I am a minimalist, don't care for body kits, obtrusive wings and such. They mostly just add weight, and have very little overall effect on handling. Most actually have a bad outcome to them, to much rear downforce unsettling the front, ect..
What should I be looking into for the stability I want? Was actually thinking of a drag type wing, commingle strait off the deck, with four adjustable struts.. Comments? Thanks in advance. And I searched many diffrent ways to no avail.
#2
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A properly designed wing doesn't add much weight, but does add downforce at speed. An inverted airfoil is a tried and true design.
My rear feels a lot more stable (and less puckered) with the stock wing than without. Not to mention it looks more like an FC than a Poopra.
I'm not a fan of the drag-type wings, they just don't make much sense to me.
1. They don't spoil the airflow (spoiler on NASCAR) creating a high pressure pocket on top of the trunk forcing the rear down.
2. They're not an inverted airfoil (upside down airplane wing) using lift (though upside down) to push the rear down.
3. All that metal is just increasing slipstream-drag
Look at race cars. They all have wings or spoilers.
Top fuel dragster - airfoil
NASCAR - spoiler
Formula cars - airfoil
A WING IS NOT A SPOILER!
A spoiler spoils the airflow creating a high pressure pocket in front of it, above the rear wheels.
A wing is mounted above the bodywork of the car. Usually this is an airfoil designed to push the rear of the car downward using the same physics that create lift in an airplane.
Jim Hall was a pioneer in adding wings to race cars for downforce with his Chaparral 2E race car. His rear wing actually mountedto the wheel hubs (iirc) so as not to compress the cars suspension at speed. Read up on him.
If you don't want a wing/spoiler but want more downforce (weight at speed), then put some dumb bells in the rear, cause that's the only way you'll get it.
My rear feels a lot more stable (and less puckered) with the stock wing than without. Not to mention it looks more like an FC than a Poopra.
I'm not a fan of the drag-type wings, they just don't make much sense to me.
1. They don't spoil the airflow (spoiler on NASCAR) creating a high pressure pocket on top of the trunk forcing the rear down.
2. They're not an inverted airfoil (upside down airplane wing) using lift (though upside down) to push the rear down.
3. All that metal is just increasing slipstream-drag
Look at race cars. They all have wings or spoilers.
Top fuel dragster - airfoil
NASCAR - spoiler
Formula cars - airfoil
A WING IS NOT A SPOILER!
A spoiler spoils the airflow creating a high pressure pocket in front of it, above the rear wheels.
A wing is mounted above the bodywork of the car. Usually this is an airfoil designed to push the rear of the car downward using the same physics that create lift in an airplane.
Jim Hall was a pioneer in adding wings to race cars for downforce with his Chaparral 2E race car. His rear wing actually mountedto the wheel hubs (iirc) so as not to compress the cars suspension at speed. Read up on him.
If you don't want a wing/spoiler but want more downforce (weight at speed), then put some dumb bells in the rear, cause that's the only way you'll get it.
Last edited by Jet-Lee; 06-07-12 at 03:03 PM.
#4
Rotary Freak
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wing (wng)
n.
1. One of a pair of movable organs for flying, as the feather-covered modified forelimb of a bird or the skin-covered modified digits of the forelimb of a bat.
2. Any of usually four membranous organs for flying that extend from the thorax of an insect.
3. A winglike organ or structure used for flying, as the folds of skin of a flying squirrel or the enlarged pectoral fin of a flying fish.
4. Botany
a. A thin or membranous extension, such as of the fruit of the elm, maple, or ash or of the seed of the pine.
b. One of the lateral petals of the flower of a pea or of most plants in the pea family.
5. Informal An arm of a human.
6. An airfoil whose principal function is providing lift, especially either of two such airfoils symmetrically positioned on each side of the fuselage of an aircraft.
7. Something that resembles a wing in appearance, function, or position relative to a main body.
8.
a. The act or manner of flying.
b. A means of flight or rapid movement: Fear lent wings to his feet.
9.
a. Something, such as a weathervane, that is moved by or moves against the air.
b. The sail of a ship.
10. Chiefly British The fender of a motor vehicle.
11. A folding section, as of a double door or of a movable partition.
12. Either of the two side projections on the back of a wing chair.
13.
a. A flat of theatrical scenery projecting onto the stage from the side.
b. wings The unseen backstage area on either side of the stage of a proscenium theater.
14. A structure attached to and connected internally with the side of a main building.
15. A section of a large building devoted to a specific purpose: the children's wing of the hospital.
16. A group affiliated with or subordinate to an older or larger organization.
17.
a. Either of two groups with opposing views within a larger group; a faction.
b. A section of a party, legislature, or community holding distinct, especially dissenting, political views: the conservative wing.
18.
a. Either the left or right flank of an army or a naval fleet.
b. An air force unit larger than a group but smaller than a division.
19. Sports
a. Either of the forward positions played near the sideline, especially in hockey.
b. A player who plays such a position.
20. wings An outspread pair of stylized bird's wings worn as insignia by qualified pilots or air crew members.
spoil·er (spoilr)
n.
1. One who seizes spoils or booty.
2. Something that causes spoilage.
3.
a. A long, narrow hinged plate on the upper surface of an airplane wing that reduces lift and increases drag when raised.
b. An air deflector mounted usually at the rear of an automobile to reduce lift at high speeds.
4. A candidate for office whose chances of winning are slight but who may get enough votes to prevent one of the leading candidates from winning.
5. A published piece of information that divulges a surprise, such as a plot twist in a movie.
air·foil (ârfoil)
n.
A part or surface, such as a wing, propeller blade, or rudder, whose shape and orientation control stability, direction, lift, thrust, or propulsion.
n.
1. One of a pair of movable organs for flying, as the feather-covered modified forelimb of a bird or the skin-covered modified digits of the forelimb of a bat.
2. Any of usually four membranous organs for flying that extend from the thorax of an insect.
3. A winglike organ or structure used for flying, as the folds of skin of a flying squirrel or the enlarged pectoral fin of a flying fish.
4. Botany
a. A thin or membranous extension, such as of the fruit of the elm, maple, or ash or of the seed of the pine.
b. One of the lateral petals of the flower of a pea or of most plants in the pea family.
5. Informal An arm of a human.
6. An airfoil whose principal function is providing lift, especially either of two such airfoils symmetrically positioned on each side of the fuselage of an aircraft.
7. Something that resembles a wing in appearance, function, or position relative to a main body.
8.
a. The act or manner of flying.
b. A means of flight or rapid movement: Fear lent wings to his feet.
9.
a. Something, such as a weathervane, that is moved by or moves against the air.
b. The sail of a ship.
10. Chiefly British The fender of a motor vehicle.
11. A folding section, as of a double door or of a movable partition.
12. Either of the two side projections on the back of a wing chair.
13.
a. A flat of theatrical scenery projecting onto the stage from the side.
b. wings The unseen backstage area on either side of the stage of a proscenium theater.
14. A structure attached to and connected internally with the side of a main building.
15. A section of a large building devoted to a specific purpose: the children's wing of the hospital.
16. A group affiliated with or subordinate to an older or larger organization.
17.
a. Either of two groups with opposing views within a larger group; a faction.
b. A section of a party, legislature, or community holding distinct, especially dissenting, political views: the conservative wing.
18.
a. Either the left or right flank of an army or a naval fleet.
b. An air force unit larger than a group but smaller than a division.
19. Sports
a. Either of the forward positions played near the sideline, especially in hockey.
b. A player who plays such a position.
20. wings An outspread pair of stylized bird's wings worn as insignia by qualified pilots or air crew members.
spoil·er (spoilr)
n.
1. One who seizes spoils or booty.
2. Something that causes spoilage.
3.
a. A long, narrow hinged plate on the upper surface of an airplane wing that reduces lift and increases drag when raised.
b. An air deflector mounted usually at the rear of an automobile to reduce lift at high speeds.
4. A candidate for office whose chances of winning are slight but who may get enough votes to prevent one of the leading candidates from winning.
5. A published piece of information that divulges a surprise, such as a plot twist in a movie.
air·foil (ârfoil)
n.
A part or surface, such as a wing, propeller blade, or rudder, whose shape and orientation control stability, direction, lift, thrust, or propulsion.
#5
Unconventional
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wing (wng)
n.
7. Something that resembles a wing in appearance, function, or position relative to a main body.
spoil·er (spoilr)
n.
3.
a. A long, narrow hinged plate on the upper surface of an airplane wing that reduces lift and increases drag when raised.
b. An air deflector mounted usually at the rear of an automobile to reduce lift at high speeds.
air·foil (ârfoil)
n.
A part or surface, such as a wing, propeller blade, or rudder, whose shape and orientation control stability, direction, lift, thrust, or propulsion.
n.
7. Something that resembles a wing in appearance, function, or position relative to a main body.
spoil·er (spoilr)
n.
3.
a. A long, narrow hinged plate on the upper surface of an airplane wing that reduces lift and increases drag when raised.
b. An air deflector mounted usually at the rear of an automobile to reduce lift at high speeds.
air·foil (ârfoil)
n.
A part or surface, such as a wing, propeller blade, or rudder, whose shape and orientation control stability, direction, lift, thrust, or propulsion.
air·foil : a body (as an airplane wing or propeller blade) designed to provide a desired reaction force when in motion relative to the surrounding air
http://en.wikipedia.org/wiki/Spoiler_(automotive)
A spoiler is an automotive aerodynamic device whose intended design function is to 'spoil' unfavorable air movement across a body of a vehicle in motion, usually described as drag. Spoilers on the front of a vehicle are often called air dams, because in addition to directing air flow they also reduce the amount of air flowing underneath the vehicle which generally reduces aerodynamic lift and drag. Spoilers are often fitted to race and high-performance sports cars, although they have become common on passenger vehicles as well. Some spoilers are added to cars primarily for styling purposes and have either little aerodynamic benefit or even make the aerodynamics worse.
Spoilers for cars are often incorrectly confused with, or the term used interchangeably with, wings. Automotive wings are devices whose intended design is to generate downforce as air passes around them, not simply disrupt existing airflow patterns.
Spoilers for cars are often incorrectly confused with, or the term used interchangeably with, wings. Automotive wings are devices whose intended design is to generate downforce as air passes around them, not simply disrupt existing airflow patterns.
A wing in this context is an aerodynamic device intended to generate downforce on an automobile. The first production car to feature a rear wing was the 1969 Mercury Cyclone spoiler, soon followed by the drastically larger Superbird and Daytona wings. The angle of attack of the wing on some cars can be adjusted to increase downward force over the rear wheels, but drag is also increased. The simulation and testing of wings can be very expensive.
Spoilers are often confused with wings, and the terms are frequently (yet incorrectly) used interchangeably. Spoilers increase grip by reducing the lift created by a car's shape, and also reduce drag by eliminating the induced drag associated with that lift. Wings increase grip by producing downforce, at the expense of additional induced drag. Although identical in form to the wing of an aircraft, wings used in automotive applications are usually inverted (oriented upside-down) and sometimes reversed (oriented backwards) by comparison.
Spoilers are often confused with wings, and the terms are frequently (yet incorrectly) used interchangeably. Spoilers increase grip by reducing the lift created by a car's shape, and also reduce drag by eliminating the induced drag associated with that lift. Wings increase grip by producing downforce, at the expense of additional induced drag. Although identical in form to the wing of an aircraft, wings used in automotive applications are usually inverted (oriented upside-down) and sometimes reversed (oriented backwards) by comparison.
The 2E established the paradigm for virtually all racing cars built since.[2] It startling in appearance, with its radiators moved from the traditional location in the nose to two ducted pods on either side of the cockpit and a large wing mounted several feet above the rear of the car on struts. The wing was the opposite of an aircraft wing in that it generated down-force instead of lift and was attached directly to the rear hubs, loading the tires, for extra adhesion while cornering. A ducted nose channeled air from the front of the car up, creating extra down-force as well. By depressing a floor pedal that was in the position of a clutch pedal in other cars. Hall was able to feather, or flatten out, the negative angle of the wing when down-force was not needed, such as on a straight section of the track, to reduce drag and increase top speed. In addition, an interconnected air dam closed off the nose ducting for streamlining as well. When the pedal was released, the front ducting and wing returned to their full down-force position. It was a brilliant design. Until they were banned, many sports racing cars, as well as Formula One cars, had wings on tall struts. Many were not as well executed as Hall's. The resulting accidents from their failures caused movable wings mounted on the suspension (as movable aerodynamic devices) to be outlawed.
Last edited by Jet-Lee; 06-07-12 at 03:45 PM.
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#8
Rotary Revolutionary
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^^^...wheres the wing? j/k
OP, if you are so opposed to things that have been scientifically proven to provide the downforce you claim to seek , would you at least consider installing your coilovers correctly? It might not solve your problem but it would certainly be a step in the right direction.
OP, if you are so opposed to things that have been scientifically proven to provide the downforce you claim to seek , would you at least consider installing your coilovers correctly? It might not solve your problem but it would certainly be a step in the right direction.
#9
Rotary Motoring
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The Mazda factory aero kit that was produced in the Miyoshi wind tunnel with the development of the FC halved the rear coefficient of lift (bringing it in balance with the front) while decreasing the coefficient of drag from .30 to .29.
It has 3 piece front lip with wheel spoilers, flat alum tray under the oil pan, rear wheel spoilers and a small rear spoiler.
Someone recently has made a CF reproduction of the factory foam and rubber aero spoiler at a very reasonable cost. Get this.
It has 3 piece front lip with wheel spoilers, flat alum tray under the oil pan, rear wheel spoilers and a small rear spoiler.
Someone recently has made a CF reproduction of the factory foam and rubber aero spoiler at a very reasonable cost. Get this.
#10
Unconventional
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That pic is in my private collection.
Pic?
OP, if you are so opposed to things that have been scientifically proven to provide the downforce you claim to seek , would you at least consider installing your coilovers correctly? It might not solve your problem but it would certainly be a step in the right direction.
The Mazda factory aero kit that was produced in the Miyoshi wind tunnel with the development of the FC halved the rear coefficient of lift (bringing it in balance with the front) while decreasing the coefficient of drag from .30 to .29.
It has 3 piece front lip with wheel spoilers, flat alum tray under the oil pan, rear wheel spoilers and a small rear spoiler.
Someone recently has made a CF reproduction of the factory foam and rubber aero spoiler at a very reasonable cost. Get this.
It has 3 piece front lip with wheel spoilers, flat alum tray under the oil pan, rear wheel spoilers and a small rear spoiler.
Someone recently has made a CF reproduction of the factory foam and rubber aero spoiler at a very reasonable cost. Get this.
Last edited by Jet-Lee; 06-07-12 at 05:37 PM.
#11
Sideways is the only way
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ya, OP your coilovrs are on backwards. they should be 10 in the front and 8 in the back. might be your problem a little right there. are you also opposed to the stock spoilers? even the small duckbill from the sport models?
#12
F**K THE SYSTEM!!
OP, your spring rates are a big reason to your issue
If you dont want to mess with that..( i know it can take long as fyork to get the right suspension setup.) I would suggest stiffening the front shocks 100% and do 100% soft in the rear.. see if it even works. try it. Next would be to do custom rear diffuser. This would eliminate lift and drag. in the rear.
Also. what air dam do you have? Things like front lips can create a good bit of front down force. SO now you have added downforce in front and no wing on back..
I would also suggest removing the front airdam for factory front bumper.
If you dont want to mess with that..( i know it can take long as fyork to get the right suspension setup.) I would suggest stiffening the front shocks 100% and do 100% soft in the rear.. see if it even works. try it. Next would be to do custom rear diffuser. This would eliminate lift and drag. in the rear.
Also. what air dam do you have? Things like front lips can create a good bit of front down force. SO now you have added downforce in front and no wing on back..
I would also suggest removing the front airdam for factory front bumper.
#13
613nn
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Lol, that was a typo. They are on right, just that my head isn't. Where can I find that carbon repro kit at? Who's making it?
Thank all of you for teaching me about spoilers, air foils, and wings. All without helping with anything! Really is impressive.
Thank all of you for teaching me about spoilers, air foils, and wings. All without helping with anything! Really is impressive.
#16
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Sell your car or put a block under your gas pedal. If you can't understand how these simple things work, you don't need to be going that fast.
Also, if your front air dam is dragging the nose of the car down, it's leveraging the rear end up; more need for a wing/spoiler to help keep it settled down.
#18
613nn
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^^ Really.
I understand how these things work. What I'm asking isn't for a debate on terminology, but for advise from some who know about the dynamics of these cars. So don't take offence to my remark, take offence to the fact that you had no answer Wikipedia couldn't spit out in half a second, but still had to remark to feel knowledgeable. You are that Guy. All your teachings in mechanical engineering sure as hell didn't give you any couth.
I understand how these things work. What I'm asking isn't for a debate on terminology, but for advise from some who know about the dynamics of these cars. So don't take offence to my remark, take offence to the fact that you had no answer Wikipedia couldn't spit out in half a second, but still had to remark to feel knowledgeable. You are that Guy. All your teachings in mechanical engineering sure as hell didn't give you any couth.
#19
Airframe & Powerplant
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...
lets keep it simple then:
u need downforce in the rear end, look into oem pieces [ducktail or S5 type] if you dont like aftermarket. they are proven and functional and dont unsettle the front end.
problem solved...
lets keep it simple then:
u need downforce in the rear end, look into oem pieces [ducktail or S5 type] if you dont like aftermarket. they are proven and functional and dont unsettle the front end.
problem solved...
Last edited by 1st_gen7; 06-08-12 at 12:28 AM.
#20
Rotary Revolutionary
iTrader: (16)
Just so that we're all clear....
You start this thread asking for a solution, a solution is provided. You express your dislike for said solution and express your (apparently I'll-informed) doubts as to its effectiveness. You are them provided with the evidence to educate yourself, retract your fool hardy assertions and correct your problem, yet you do not.
If you had all the answers, you wouldn't be asking for help now would you? Just because you don't like the answer you get, doesn't mean its wrong.
https://www.rx7club.com/2nd-generation-rx-7-1986-1992-parts-194/carbon-fiber-duckbill-spoiler-oem-style-999204/
Buy this, install it and report back. Or....don't buy it, run backwards spring rates (the level of intelligence you have shown in this thread makes me doubt the mistake is just in your head) and crash. Do what you like.
"you can only lead a horse to water, you can't make him drink it"
You start this thread asking for a solution, a solution is provided. You express your dislike for said solution and express your (apparently I'll-informed) doubts as to its effectiveness. You are them provided with the evidence to educate yourself, retract your fool hardy assertions and correct your problem, yet you do not.
If you had all the answers, you wouldn't be asking for help now would you? Just because you don't like the answer you get, doesn't mean its wrong.
https://www.rx7club.com/2nd-generation-rx-7-1986-1992-parts-194/carbon-fiber-duckbill-spoiler-oem-style-999204/
Buy this, install it and report back. Or....don't buy it, run backwards spring rates (the level of intelligence you have shown in this thread makes me doubt the mistake is just in your head) and crash. Do what you like.
"you can only lead a horse to water, you can't make him drink it"
#21
Unconventional
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I would love to buy ^^that^^ CF ducktail! Just don't got the $$ right now.
I'm an ******* and I don't give a **** what you think of me. Last I checked, couth didn't have any effect on any of the physics associate with a car.
I didn't ask for debate either. I stated facts, someone challenged them, I verified them. There was no debate, it's verification of facts.
However, you said you don't care for wings and spoilers but are asking about downforce so I took the time to explain how they work and how they are/have been used.
If you read the second sentence of my first post, I did directly answer your question.
Here, I'll quote it for you so your lazy *** doesn't have to scroll up
There's also the last sentence in the same post:
I'm sure others that have read this thread have actually absorbed the information that's been posted to make better decisions on their cars or maybe just expanded their knowledge a little.
Now quit your woe-is-me bullshit, go fix your coilovers and slap an APC wing on your car and claim how you gained 20hp at the front wheels...or go snort some bath salts and add to that Florida zombie statistic, I really don't care.
^^ Really.
I understand how these things work. What I'm asking isn't for a debate on terminology, but for advise from some who know about the dynamics of these cars. So don't take offence to my remark, take offence to the fact that you had no answer Wikipedia couldn't spit out in half a second, but still had to remark to feel knowledgeable. You are that Guy. All your teachings in mechanical engineering sure as hell didn't give you any couth.
I understand how these things work. What I'm asking isn't for a debate on terminology, but for advise from some who know about the dynamics of these cars. So don't take offence to my remark, take offence to the fact that you had no answer Wikipedia couldn't spit out in half a second, but still had to remark to feel knowledgeable. You are that Guy. All your teachings in mechanical engineering sure as hell didn't give you any couth.
I didn't ask for debate either. I stated facts, someone challenged them, I verified them. There was no debate, it's verification of facts.
However, you said you don't care for wings and spoilers but are asking about downforce so I took the time to explain how they work and how they are/have been used.
If you read the second sentence of my first post, I did directly answer your question.
Here, I'll quote it for you so your lazy *** doesn't have to scroll up
There's also the last sentence in the same post:
I'm sure others that have read this thread have actually absorbed the information that's been posted to make better decisions on their cars or maybe just expanded their knowledge a little.
Now quit your woe-is-me bullshit, go fix your coilovers and slap an APC wing on your car and claim how you gained 20hp at the front wheels...or go snort some bath salts and add to that Florida zombie statistic, I really don't care.
Last edited by Jet-Lee; 06-08-12 at 09:58 AM.
#24
613nn
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Lol, guess you had the ability to miss type also.. :p
I do apologize for my quick retort. I do like low profile, like the last wing pictured. Anyone know where I can find that reproduction Mazda aero kit?
And I do appreciate everyone's input, just took offence when I shouldn't have. New to the car, not the game.
I do apologize for my quick retort. I do like low profile, like the last wing pictured. Anyone know where I can find that reproduction Mazda aero kit?
And I do appreciate everyone's input, just took offence when I shouldn't have. New to the car, not the game.