Not too sure if this will work
 

i was thinking of buying some subs for my car in the near future and since i would have to build a custom sub box for my car beacuse of the layout of the trunk and i had an interesting idea for the ports but im not too sure if it would work. my car was built with componet speakers but the last owner took them out and replaced them with 2 way speakers so the spot for the tweeters is just an empty hole. and i was thinking i could probably run piping from those holes into the sub box and use that for the ports. is this a good idea?http://s13.photobucket.com/albums/a2...=100_30202.jpg

arent tweeter holes like 1.5 inches big or so?
i dont think this will work on account of there wont be enough air flow for a ported box, you might as well have a sealed box. plus i really dont understand how you would run the piping through your trunk through the door and into the tweeter holes anyway

what kind of music do you really like to listen to? you may just want to go with a sealed box in the first place

its actually right above where the box would be i wouldent have to cut anything since it goes straight through into the trunk anyways, i listen to rap, techno, metal, pretty much anything

You could take out the rear speakers and fire 4 inch ports through them instead

This will only work with a bandpass box as all the energy from the sub is through the port. Still the necessary ports would likely be too long, which would be ok if you only listen to organ music.

im relatively new to car stereos, how long should the ports be?

That depends on the driver you choose.