This is a design I have been working on for some time this year but I had a few things in the way so I wasn't really able to get much work with it. However, when I found out about this site (A friend told me about it), I decided to work more on this pie design and see how it would look here. It has 6 colors (Light blue being the background) and it references that 3.14 backwards spells something that looks like Pi.
Any thoughts about this T-Shirt? :)
However, if you really want to go with this I've not seen that many designs that play on the 3.14 backwards looking like Pie. Chewie's advice is good, go for a better font.
I think 4 colors for a simple design like this is too many. On the technical side of selecting designs the number of ink colors is sometimes a factor and printing in 4 inks is obviously more expensive and labor intensive than printing 1 or 2.
see http://en.wikipedia.org/wiki/Screen-printing#Printing_technique
My advice would be to reduce this down to one or two colors but make it more interesting with halftoning or cross hatching adding more detail to the pie crust. Remember the shirt is a color in your design, so use it as thru-color.
see http://en.wikipedia.org/wiki/Halftoning
or
http://en.wikipedia.org/wiki/Cross-hatching
Whichever way you decide to go, try to add more visual interest to the Pie. It's a bit too simplistic to catch the eye, whereas a really nicely detailed pie might do the trick. Hope this helps. :)