By now its no longer a secret that the VR-4 is getting a wing.  Not just a “ricer” looking wing but a real-deal if you have to ask you can’t afford it type of wing.  The deal was too good to pass up so we went for it.  What does a rear wing do?  In simplest terms it pushes down on the back of the car.  The faster you go the harder it pushes.  The angle of the wing can be adjusted to “dial” in the amount of down force.  So why the wing?  Having a rear wing helps keep the rear of the car planted and adds overall to the amount of grip the car has.  It also lets you set the car up to over steer at low speeds when the wing has a smaller amount of down force and when you go faster the car becomes neutral so you can take transitions at higher speeds.  The problem is that whenever you push on the back of the car you end up slightly lifting the front.  That’s important because when you want the car to turn you need all the weight you can get on the front tires.

This is where the front splitter comes in.  A splitter is noting more then a big flat piece of something attached to the area under the front bumper which directs air under the car.  Since the air under the car has a shorter distance to travel then the air going over the car it moves faster..  Bernoullis’ principal says faster moving air has a lower pressure and that lower pressure is what causes front down force.   It’s that down force that we are after to help balance out the added down force of the rear wing.

For a splitter to work it has to be flat, parallel to the ground, and be able to hold together at high speeds.  The benefit of the splitter gets better the further back under the car it goes and in

real race cars is part of an under tray that includes a flat middle and a diffuser at the rear.  With very little time to build a splitter we are only going to bring ours as far back as the front of the front tires.  To help the fact that we are not going very far back under the car we are going to extend the lip of the splitter almost 5 inches beyond the lower lip of the fascia.

To build the splitter I chose a product called alumalite which is a sandwich of aluminum-plastic honeycomb-aluminum.  Its used for signs and the sides of tractor trailers.   I was able to get a 4′ x 8′ sheet of 1/4″ alumalite for $90 locally.  Working with it is pretty easy.  You can drill it, cut it in a table saw, use a grinder, or pretty much any other power tool you have.  Lightweight and strong it’s a pretty versatile material for race cars.

A splitter has to be strong.  It has to be able to withstand high loads without bending.  If it bends you loose some of the benefit and some of the down force.  So to make this as strong as I could I decided to build a frame for it out of 1″ aluminum tube.  The frame would be then bolted to 1/2″ nuts that I will weld to the bottom of the.  I used two on the engine cross member with a third on the radiator core support.  I’ve jacked the car up on the engine cross member so I know its strong enough to handle the loads of the splitter.

I am using 1/2″ bolts to attach it to the car so I welded up some 1″ tube risers to the frame to set the height of the splitter.  The lower the splitter the better it works but the lower you build it the better chance you have of having it rip off when you get a little to aggressive over a set of rumble strips.  I decided to build it with 5″ of ground clearance which is just enough to get in and out of my driveway and low enough, I think, to work.

Once in place there is a large gap between the bottom of the fascia and the splitter that must be filled.  After looking for materials to fill that gap I settled on the alumalite.  By cutting relief cuts on the back side I was able to form it around a Map gas bottle so I knew it would conform to the larger curves of the fascia.

Here are some of the first shots of it one the car.  It takes some getting used to messing up the classic lines of a VR-4 but in the never ending hunt for more speed and more grip it was something we had to try.

With the splitter and the air dam built it was now time to turn to a support system.  I need to build a set of turnbuckles to support the leading edge of the splitter and to allow some up-down adjustment to fine tune the amount of down force.  I found a set of turnbuckles at my local hardware store that along with some threaded rod and clevis pins would give me what I needed.

To get a way to use a clevis pin I welded in some washers into the looped end of the stock turnbuckles and then drilled them to size.

I welded up some mounts to attach to the bumper brace and used some angle aluminum to make the lower mounts.  To attach the lower portion of the turnbuckles I drilled a threaded rod union to accept the clevis pin.

Once all together I painted the lip satin black to help hide it’s ridiculous proportions and did the final install on the car.

Finally once fitted it was time a test drive.  Notice how much clearance I have getting out of my own driveway!  This thing is nuts.  After a couple of days of driving it’s been easy to live with and the looks are growing on me.    I’ve only taken a few hot corners with it and so far it feels like it has more grip.  I think there is a side benefit to the splitter under braking.  As the nose of the car dives down the splitter turns into a big air scoop which I think is going to help.

As with any new part there needs to be some testing and adjustment to see the full benefit and I will have an update once I get this on a race track.