This is actually what I fully intend to do, when it eventually gets to the top of my list. I plan to make a deeper splitter than Beejay, or potentially an additional length that can be attached at the track, to try and get some useful force from it. I will also add another pair of stays further to the sides of the car, as I don't think Beejays design would transfer a lot of the force from the splitter to the chassis with only the two central stays - but nor was it intended to, he built it mainly to protect his pace car spoiler from bumps, something that I need also. I do have thoughts to build a diffuser for the rear also, but I doubt that it will be very effective at creating any downforce due to how turbulent the air under the car is - I have looked into how I might add some flat undertrays to try and improve it. All of this will happen at some point, but likely not terribly soon.

Adam, it may interest you that I have done quite a bit of reading on splitter materials in planning for this, and plastic is not regarded as a good choice - too heavy and not stiff enough. Plywood or various composite materials are the most common/popular choices for stiffness against weight, with plywood winning for most due to its wear properties (won't splinter into a million pieces on bumping a curb etc.) and cost. I was surprised too, but plywood seems to be a good choice. Some people are using plastic as a thin layer underneath as a wear surface.

 

I have been considering a splitter for my PC spoiler also. I thought about spraying plywood with pickup box liner. That stuff is tuff and would probably make the plywood stiffer and far less susceptible to damage.

Mike

 

I'm shocked. This is great info. I figured plywood would be FAR too heavy.

For any underbody/belly trays, plastic aluminum is still preferred as the rigidity isn't as important there, though; right?


Adam

 

Birch plywood is often made from thinner laminates and is both light and strong. They use it quite a bit to make lightweight guitar and bass amplifier and speaker enclosures. You may have to find it at a real lumber supply rather than the big box stores like HD or Lowes.

 

Guys, I certainly think a splitter or a spoiler is a good idea, but ya can't combine them ***** nilly. In a previous post there's a picture of a splitter (which works by allowing fast moving air to create a low pressure zone) with a spoiler (which works by slowing/stopping air to create a high pressure zone ahead of it) mounted down downstream. There seems to be some serious negation/inefficiency with this combination.
​​​​​​​ It seems the choice should be made whether to keep air out, via a low spoiler, or allowing any air going under the car to remain in a high velocity state. Letting it under the car, and purposely slowing it down seems counter productive, both from an aero perspective and from a componentweight perspective.

 

I found these pictures on social media a while back the car belongs to Garrett Randall and it the sharpest looking rear diffuser I've seen to this day on a c3

 

Agreed, the model that Beejay had with the extra flap at the back of the splitter did not make sense aerodynamically. I don't think he retained that flap for long from memory.

 

Looks nice, but I'd be surprised if it does much - air would be too turbulent. I don't think it extends far enough forward and/or not enough has been done to smooth the airflow underneath for me to think that it would do much to improve the aerodynamics. It may reduce a little drag at the rear, but I'm doubtful that it creates any downforce.

 

​​​​​​​I agree.

 

I have read it here that removing the rear window makes it much more quiet.
That being said, would that act as a diffuser?

Second: I just saw the beautiful Green Mamba Pro Tourer.
Very nice splitter in front.
In most shots the rear has a full wing.
I did see a video where a flat plate acts as a bolt on spoiler.
There seems to be a gap at the bottom.
That could also act as a diffuser of sorts?

I do like the idea of bolting on as much spoiler as needed!

JMHO

R

 

Check out Dynamic Corvettes. com. I saw their display at Carlisle and they had some cool stuff for our cars. They had f-glass bumpers and splitters and such.