BT Tech Rear Aero Spoiler!!

[BT Tech]

BT Tech Rear Aero Spoiler

After several months of testing and fine-tuning, our newest product is out of the prototype stages!! For those that have already purchased our Prius Stiffening Plate, this makes the perfect addition for increased handling precision and high speed stability.

For information on purchasing and viewing our stiffening plate, please click on this thread:

http://priuschat.com/forums/1-vt9445.html

The Prius is a remarkable achievement in obtaining both economy and performance. One of the engineer’s goals for this vehicle was clear; to make the car as aerodynamic as possible to reduce the coefficient of drag in an effort to increase fuel economy at highway speeds. It is also used as a marketing tool for Toyota and taunting this number puts them in a class by them selves.

Unfortunately, in the imperfect world in which we live there rarely is a “free lunch”. In order to obtain extremely low coefficients of drag for a vehicle, there usually is a tradeoff. This tradeoff in our case takes the form of an aerodynamic phenomenon known as lift.

If one looks at the entire top and bottom profile of a Prius, you will notice something very interesting. Its form resembles that of an airfoil!! Those that are familiar with aviation know all too well where this is going. As your speed increases, the amount of air flowing over the top increases due to the shape of the vehicle. This happens because the air flowing over the top takes a longer path than the air flowing under the bottom of the car. The result is that the faster moving air over the top creates a low-pressure zone and the air moving slower under the vehicle creates positive pressure. This phenomenon results in lift and greatly contributes to the un-easy handling that a lot of us experience at highway speeds.

I have spent a great deal of time with a close friend that is an aerospace engineer and after going over the many different ways to reduce the amount of lift without seriously affecting the coefficient of drag, this is what we have come up with.

We already have seen the aftermarket “spoiler” that is offered in Japan. This device should NOT be called a spoiler as a “true” spoiler has an aerodynamic function. The larger “spoiler that comes out of Japan seems to be merely an aesthetic part and nothing more.

Spoilers generally work by disrupting the airflow going over a car. This disruption has two primary effects:

1. Reducing the amount of lift naturally generated by the shape of the car, and

2. Increasing the amount of positive pressure downward through the vehicle

What we have come up with is an aerodynamic part that will attach to the rear of the vehicle, at the base of the hatch glass. Its purpose is to reduce the amount of lift by altering the air flow. At the same time, this will give the rear of the car more downforce and is easily felt when driving at highway speeds. A byproduct effect that this part has is that it greatly lessens the side wakes of larger vehicles that go by.
For example, when that huge 18 wheeler is doing 80 MPH, the car will be less sensitive to its wake producing effects when it passes by.

We will be offering this part in flat black that is ready to be sanded and painted or already pre-finished in your factory color. The paint job will be done by a professional paint shop using Dupont base coat /clear coat for a factory original type finish.

Prices have not yet been set as I am still negotiating with several shops to get the paint work done.

For those that are interested in this part, please email me privately at bttek@bellsouth.net so I can gauge how many to include in my first production run.

Thanks!!

Brian
BT Tech
305-652-3115

[Godiva]

How does this attach to the car? Is it mechanical or adhesive? Would I be able to do it myself?

If it's not too expensive and is as easy as the plate (yes, I've decided to do it myself on Tuesday afternoon at my Dad's house. As long as the car is going to be jacked up, I'm installing my mudflaps too) then sign me up.

I've got a black Prius and you'll probably hardly notice I've done anything to modify the car. I'll miss a few of those miles but if it reduces shimmy when those big rigs pass me, that will be great.

[efusco]

Have you calculated a new Cd? Any estimate as to the MPG hit?

Let us know a price range estimate when you can

[BT Tech]

Hello Mary.. I just got home from an afternoon on the water and read your email. I must say that I am VERY happy that you are going ahead with the install yourself!! Once under the car, you will see that the stiffening plate is very easy to install. All you need to do is to unbolt the factory one and replace it with your new one using our stainless bolts.

In regard to the spoiler, it will adhere to the base of the glass with powerful 3m adhesive. I have had the prototype on my car for a while now and it has been perfect. You will simply wipe down the area with some rubbing alcohol, dry the area and then place the spoiler in the area that is indicated in the instructions. VERY simple!!

If you have any questions, please let me know.


Thanks!!

Brian
BT Tech
305-652-3115

How does this attach to the car? Is it mechanical or adhesive? Would I be able to do it myself?

If it's not too expensive and is as easy as the plate (yes, I've decided to do it myself on Tuesday afternoon at my Dad's house. As long as the car is going to be jacked up, I'm installing my mudflaps too) then sign me up.

I've got a black Prius and you'll probably hardly notice I've done anything to modify the car. I'll miss a few of those miles but if it reduces shimmy when those big rigs pass me, that will be great.

[BT Tech]

I knew that this question would come up and unfortunately, I do not have any way to caluclate what effect this has on the Cd. I can tell you that I have not seen any decrease in gas milage with the highway driving that I do but I do expect there to be a marginal gas penalty.

It really is amazing that a part such as this can make such a difference when driving on the highway but it truly does.


Thanks!!

Brian
BT Tech
305-652-3115

Have you calculated a new Cd? Any estimate as to the MPG hit?

Let us know a price range estimate when you can

[popoff]

and is as easy as the plate (yes, I've decided to do it myself on Tuesday afternoon at my Dad's house.

I've got 20 years on you and did it without even jacking up the car. I had the ratchet and the 2 sockets cost about 6-7 dollars total. It would make it a little bit easier if you had a second pair of hands available to hold the plate in place while you insert the first bolt.

[popoff]

Brian, if possible would you please post a photo of just the spoiler?

I'm interested and would like to see some more details, when available, about the estimated price and production date.

[Godiva]

Actually, I'm probably better equiped than the average 50 year old woman when it comes to power tools.

Boy, did *that* come out wrong.

I've got both a cord and cordless power drill with complete drill bits for wood, metal and even concrete. I've also got a circular saw, looking to buy a compound miter saw. I also have a jigsaw and some sanders.

Yep, if I ask for power tools...Santa comes through every Christmas.

Auto mechanics is a new field for me. I do have a complete set of socket wrenches. My concern was that the current plate would be so tight I wouldn't have the upper body strength to loosen it. I have been reassured that I will be able to get it off. Turns out I have the Allen wrenches so putting on the new one is not a problem. And the torque is so low I am assured I will be able to tighten it quiet well.

What can I say? My Dad raised us with the idea that if we couldn't afford to pay someone to do something, we better learn how to do it ourselves. I'm a teacher and now have new car payments so money is tight.

I've laid ceramic tile, sweated copper pipe and wired and hung my own ceiling fans. So now I am venturing into the wonderful world of auto mechanics. All thanks to you guys.

I think on the Do-it-yourself scale I can do this. I'm even looking forward to it.

[mehrenst]

Is that what the NASCAR guys call a "wickerbill"? :mrgreen:

I have a white Prius and I was totally surprised by the number of little black dots (bugs) that I found on the roof just ahead of the hatch after an evening drive.

[LuckyP]

Actually, I'm probably better equiped than the average 50 year old woman when it comes to power tools.

Boy, did *that* come out wrong.

That made me spray beer through my nose!