How good is the stock spoiler?

NerdKrusher

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I'm hoping someone can help me out here. I am looking to build my 96 GT convertible for drag and road racing. I would like to know how effective the stock spoiler is at generating down force for my car? For road racing I could see it possible for my car to get near 200mph. Would the stock spoiler handle this? Or be useless?
 
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stormsedge

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It’s for looks...nothing more
Concur. My recommendation is to do a search for SN95s in the road racing scene and study the pictures. A quick look this AM yielded many with large adjustable spoiler surfaces...the one car retaining what looks like a stock spoiler had an additional surface added to the back of it. I recommend picking the aero rigs that interest you and make contact with the race teams through their websites/FB/whatever to ask specific questions. Happy hunting.

Or you can read articles on the internet like this: https://www.sn95forums.com/threads/may-the-downforce-be-with-you-lots-of-reading-but-worth-it.70578/ and wonder if the calculations are correct and "if" the downforce in the calculations are enough or too much for your application.
 
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BlakeusMaximus

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There probably isn't any data on that. I agree with the statements, its for looks only.
 

Mustang5L5

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There probably isn't any data on that.
none accessible to “regular” people at least. Youd need to find someone with a wind tunnel that decides to actually test the car with wing on and off and see what it actually does. If someone like that exists, you’d have to find them and convince them to share their data.

I did some wind tunnel testing in college and wrote a paper on it. The wing probably does do something and adds a little downforce, but you are better off looking at aftermarket wings if you really plan on getting serious
 

Warhorse Racing

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You mentioned that your car is a convertible. You should find out if you are required to have the top down when you road race (most clubs/tracks have rules about convertible tops, but they can vary). Having the top up or down can impact aerodynamics and how effective a wing will be.
 

Mustang5L5

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Also, you really need to decide if this car is going to be. Drag car, or a road course car. It can’t do both without serious compromise. Suspension will be different, gearing will be different.
 
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lemosley1973

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I'm hoping someone can help me out here. I am looking to build my 96 GT convertible for drag and road racing. I would like to know how effective the stock spoiler is at generating down force for my car? For road racing I could see it possible for my car to get near 200mph. Would the stock spoiler handle this? Or be useless?
Not even if you drove it off of a cliff.

(That spoiler is for looks)
 

NerdKrusher

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You mentioned that your car is a convertible. You should find out if you are required to have the top down when you road race (most clubs/tracks have rules about convertible tops, but they can vary). Having the top up or down can impact aerodynamics and how effective a wing will be.
This is a good thought. I will be installing a maximum motor sport 6 point roll cage. It's the right one the rules require. As for the top being down or not. That is a very good point.
I will need to do my own testing with friends to figure that one out.
 

lemosley1973

Doing something with a heavy tranny now
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Mustang aerodynamics are pretty bad - a convertible will be even worse. 200mph on a road race course (which one) would require a ton of power and a lot of work aerodynamically - I'm curious what kind of build you are looking at to be able to do this + be suitable for drag racing.

For that much speed, you're going to need something more than the stock spoiler, which probably would rip off at those speeds anyway!
 

Mustang5L5

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Goal is road racing primarily. Then i will adjust setup to do drag racing for fun.

Unfortunately there is no "one size fits all" setup for road course racing and drag racing. A road setup for a car capable of 150-200MPH is going to be likely far too stiff to be any good at drag racing. The suspension setups are at opposite ends of the spectrums as you'll want a suspension capable of articulation to allow the vehicles weight to plant during a launch. Total opposite of what you want on a road-course setup.

Also, gearing is a factor, as your gearing for a road-course setup will likely be much taller than what you'd want to run in a drag setup.
 
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Hoytster

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As a person that has done a fair amount of HPDE and road racing events with a 95 Cobra.....

The stock spoiler on an SN95 has been measured to delivery ~40 lbs of down force over 100MPH. In other words, it's almost useless and is for looks. Most people add a Gurney flap to the original wing to add additional down force, install a NASCAR style spoiler, or add a full wing to get over 100lbs of downforce on the rear.

I would reduce you're expectation of hitting 200MPH on a road course unless your planning on going down the Mulsanne straight with the chicanes removed and have some serious money into your car. The fastest car I drove at Summit main was a 800+ HP AIX car that was fully setup with aero bits out the ass and a proper suspension, and I think I might have hit 160 down the straight. That car probably cost over 100K to build. You will have to do some serious aerowork on an SN95 to keep it planted above 150. The front end starts to get pretty light around 130-140 even after being lowered and all the normal stuff done. You run into all sorts of durability and cooling issues on a road course when you start making enough steam to even try and hit 200. And then you have to scrub all that speed off before you enter the corner, otherwise you kill yourself.

You can setup a car to do both drag and road racing, but it won't be the best at either. It can be somewhat good at both, but not the best. You're probably going to want to look at a full torque arm with panhard/watts link setup as a base, and then have to swap springs, shocks, and tires out when going between events. You're better off setting it up for one or the other, or have two cars like I'm doing. A car setup for drag is downright scary on a road course.

Just for some perspective. This is a video of Brian Faessler, son of the owner of Paul's Automotive Engineering. He's one of my favorite AIX/unlimited class racers I like to watch as he's a great driver and has some serious money into his car. He says he's making 750-800 HP here and has the car built to support it. I wouldn't want to guess how much money it took to get here.

 
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Hoytster

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If you're on Facebook, a good group to follow would be "79-04 Mustangs Road Race-HPDE-AutoX" if you want to get into road racing. If you've never done it before, start with HPDE or autoX and move up from there. Jack Hindley from Maximum Motorsports is in that group as well as a lot of very knowledgeable people.
 

Mustang5L5

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If you're on Facebook, a good group to follow would be "79-04 Mustangs Road Race-HPDE-AutoX" if you want to get into road racing. If you've never done it before, start with HPDE or autoX and move up from there. Jack Hindley from Maximum Motorsports is in that group as well as a lot of very knowledgeable people.

Very good group. I'm a member of that one and those guys there are extremely knowledgeable. I miss my AutoXing days.
 

Hoytster

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Very good group. I'm a member of that one and those guys there are extremely knowledgeable. I miss my AutoXing days.
If you're like me, once you do it it's hard to get our of your blood . Just like everything else in 2020, most of the road racing this year was either cancelled or had some ridiculous requirements (like face masks under your helmet while in the pits). Drag racing just opened up at Maple Grove in June, but I would need to have a running car to get there......
 
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