I'm still waiting for the SHR lower grille inserts!

 

Me too....

Seriously, they are right on schedule, resin is ordered, we're still looking like end of November / beginning December delivery so long as no real issues crop up.

We're working on adding the fiber optics to the A/C ***** today, hoping to get them up on our website by the end of this week !!!

 

Thread hijack in progress...

So the fiber optics are for the 2007+ ***** or also for 2005/2006? Marcello, my credit card is crying in pain yet you keep tempting me...

 

Ok, after this we'll return you to our normal thread now in progress...


The fiber optic lighting is for all of our *****, 05-08. The difference in the design is on the backside attachment of the part, the front side is identical, no matter what year car you have. Satin anodized, black anodize, and polished / anodized are the first three finishes available, chrome is going to be about another 4 weeks I think at the moment. Also, believe it or not the 07's will be available first, then the 05-06 parts in a few weeks, as it doesn't look like they will make it back from anodizing prior to most of us leaving for SEMA....

Anything else, let's move it back over to the **** thread in interiors to keep from mucking this up.

/thread hijack off/

 

For the GT500, the splitter serves a definite aerodynamic purpose. Here's an excerpt from an article written regarding the front end design (I don't remember the mag, I just saved the article).

"..... once the concept car's front end was redesigned to achieve upper and lower grille openings, it was discovered that the more aggressive design actually created a negative effect on aerodynamics. So engineers who had faced similar design versus air management issues during the development of the Ford GT simply went back to their lessons learned from that program and applied some of the same science to fix the problem without compromising a beautiful design. So the GT500's front splitter was designed quickly and efficiently to improve airflow while adding that desired purposeful look."

So, at least for folks with the GT500 front facia, if you don't have the splitter, you're not getting any aerodynamic advantage; and I wouldn't doubt that this also applies to the GT front end as well.

---John

 

I think the splitter is very efficient at creating an airflow boundary so that less air gets under the car (less lift), and more is forced to go around or over the hood (more down force). A spoiler does similarly, but not as decisively.

 

I'm curious, what is to say that ,for example , the CDC classic chin spoiler does not have the same attributes as a splitter?
Is it that spoilers help direct air up into the engine compartment for cooling, thus no improvement on MPG or do they also direct air away from underneath the car also improving MPG?

I'd like to know your opinions...

 

One of the differences is that when the air hits the front of the car, it spills off on all edges (think what happens when you hit the front of a car with a water hose). A spoiler "spoils" the flow (hence why you can have a spoiler on the rear as well), where a splitter doesn't allow the air to bleed off the nose to the bottom because it projects forward (hence splitting) the air, and keeping the nose air above. The spoiler's only "job" (other than appearance on the front) is to try and deflect some of the air to the sides and away from under the vehicle. A splitter pretty much came about as racers learned that adding the forward projection onto the airdam / spoiler caused its effectiveness to increase.

The height of the splitter then becomes a function of its effectiveness at keeping air from under the car - obviously the lower it sits, the less air can get under it. Also, on most race set ups, you will find that not only does it project forward beyond the nose of the car, but it also helps to form a undertray in the forward section of the car, helping to smooth the bottom of the car and reduce laminar losses underneath.

Finally, one of the "toys" we're working on is going to be offering turnbuckles to adjust the splitter forward height. Adjustment of the splitter's angle / height changes the aero at the front of the car, and while on mild street cars there is no difference, on a race setup at 130+, the difference can definitely be felt.

 

Just plain awesome info. Thank you for the knowledge and well now my head hurts. Imagine opening a thread to see pictures and reading this....I feel smarter and that isn't always a good thing.

In essence the chin spoiler does add some of the splitters benefits and look good too? Do you get lifting effect for a splitter more than a spoiler? And say at, drag speeds does this offer any benefit?

 

No problem, always wiling to discuss what I can to those that want to listen. Heck, I had to pay 12.00 for 24 hours of Internet here in Vegas, so this is all I'll have to say on it until after SEMA

On the spoiler, yes you will gain some benefit, but it also pushes air up, where a splitter just keeps from running under - semantics maybe, but at sufficient speed this could cause downforce or other issues you're not expecting / wanting.

Lifting effect - no, you're cancelling lift. Wings (what a car is when viewed from the side basically) cause lift by making the air take the long route over the top, and the "short" route under - if you ever saw a Porsche or other prototype race car do a "blow over" you saw this happening. By using a spoiler or splitter correctly, you normally are cancelling the lift by reducing the amount of air that can get under the car, hence the force lifting on the vehicle at sufficient speed is reduced. (It's also one reason a race car is low - less room for air to get under it and make a mess of things).

At drag race speeds, there would be a difference, but I don't know if the weight / difference ratio would be enough for you to justify its use on a street type car. Like I mentioned earlier, I saw a fuel economy increase, meaning that it was basically taking less horsepower to do the same job = better aerodynamic efficiency. Remember, horsepower required to move an object through air multiplies at the square of the speed, so anything you can do at 65+ mph to reduce drag or cancel unwanted other effects will increase efficiency = more top speed or more excess Hp to move the vehicle with a lower E.T.

HTH.

 

Marcello thank you for the insight and answers. Another reason you are one of the top companies out there help us Stangers out. I hope you enjoy/enjoyed SEMA....

 

Well I would add to what HTH said, by saying that lift is not canceled. The under car contribution is reduced by spoiler / splitter, but air still has to speed up to get over the car, that causes low pressure (Burnoulli effect) and lift. Ever notice the rear roof flaps on a NASCAR sedan. When the car gets backwards two things start to happen really fast, more air gets under the car and the top of the car is still generating lift. When the flaps on the roof pull up, then lift over the top of the care is substantially disturbed, keeping the car from flying. Now there is some down force component on the body due to the rake of the hood and transition over the whinshield, but after that its lift unless the air flow is separating over the roof.

Formula cars are masters at creating down force by devising ways to make the air flow under the body faster (faster air means lower pressure) causing it to suck down rather than push up. Cars with belly pans have the same benefit, but not necessarily as efficent.

Also as speed increases, drag increases with the square of velocity. But Horsepower goes up by the velocity cubed!

HP = DRAG (lbs) x V (Ft/sec) / 550

I thought the former myself until just a few months ago when I was researching some of this and refreshed my aerodynamic knowledge.

 

You are correct, the semantics I used were incorrect - a splitter or front spoiler helps reduce the Bernoulli effect by reducing the amount of air available underneath the car that causes lift of the car's body as an aerodynamic wing "spoiling" the airflow. It does this by helping eliminate the lower flow / half of the system, and without the lower half of the equation, the lift is "effectively" cancelled, which was what I was attempting to explain in my original post. Even though the air rushing over the top of the body accelerates to try and keep up with what air that does get under the vehicle (hence meeting back up with the same air at the back of the vehicle with a velocity / pressure differential) the rest of the air is hopefully channeled around the sides, therefore the lifting effect isn't noticed because it is reduced to the point where it is a non-factor if the spoiler / splitter / airdam is placed sufficiently low in the airstream. Of course, this is also dependent upon the side ground effects doing their job, otherwise the air will just rush back under from the side, negating much of the benefit as the body / greenhouse will continue to produce lift...

I would disagree on the belly pan, it is more of a drag reducer. Your equation on the drag increasing at the square of the velocity is correct, and hence reducing drag is paramount to speed, thus the belly pan comes into being. Technically, a smooth belly pan will increase lift on the body, because it helps by not reducing the velocity of the air under the car like a normal bottom would. This is part of what I was describing earlier, talking about the "blowover" of the older prototype race cars from the front when air is allowed to get under it - although I'm not quite sure how much of it is due to the lifting effect of the body vs. the simple pressure on the front bottom of the vehicle once it goes beyond a certain angle of attack - in fact there are a lot of factors that play into a blowover incident, the lift of the physical body being just one of them. Back in the days of unlimited cars, "active" ground effects were tried with varying degrees of success as well. Of course, the reduction in drag where it is not desired (under the car) outweighs the lift created by the body, because with sufficient drag reduction where you don't want it, you can install wings and ground effects where you do want them (front and rear) and make them adjustable to control the downforce produced on the car, and where it is applied vs. unadjustable (for the most part) drag under the body.

Ground aerodynamics / vehicle design always interested me, because it is the exact opposite goal of aircraft design. Instead of trying to lift the vehicle off the ground, you're trying to push it into the ground, all the while reducing drag to an absolute minimum. The problem comes in when you add the ground and the physical requirements of the car to hold the driver and drivetrain, and mix it all together into a package that people will want to drive... all a pretty daunting task. I always thought that an inverted body would make the best race car design, but the problems it raises make it worse than the standard alternative, at least in my limited knowledge of the physics involved.

On edit - a lot of what we're talking about here has no effect on a street car, and doesn't come into play until somewhere north of 80+ MPH, depending upon the vehicle's design. If I'm still not articulating what I'm trying to say correctly, please add in what you think I'm not explaining correctly, as in the end, I'd like this discussion to have some technically correct reference for anyone following it / reading it later.