single piston caliper to four piston caliper swap
 

just picked up some 4 pistons i see they bolt on what do i need to complete it i wanna keep the 4 lug whats a bigger rotor i can run i figure theres gotta be one from a other car plus i see the 4 pistons use metal brake lines are the hose fittings the same size i haven't tried to see

plus were can i get these rotors or whats a measurement im gunna need

The 4 pot appears to be made for a bigger diameter and taller rotor found on 5-lug hubs. The single pot rotor will not work. If you don't want/are too broke to upgrade to 5 -lug, I see only one possibility; get 5-lug rotors and drill for 4. That's ASS-U-MEing the 4-lug/5-lug hubs and rotors have the same offsets. don't even think about without confirming.

Aaron Cake has done this on his car Tina (because he is fanatically attached to his 4 lug wheels) and you can read what's involved in his build thread.

He hardly ever posts, so you'll have to do some digging to find it.

I have a set of the Aaron,s spacer on my car,you have 2 get 5 lug rotors and get them machined 2 accept the 4 lug bolt pattern,install spacer,trim a little bit the dust shields,bolt on the calipers(i have fd calipers on mine)install aftermarket na 4 lug brake lines and done.I still have my 4 lug setup but with the upgraded caliper and rotors cause i drag race my car and i have a set of custom weld draglite wheels with the stock 4 lug bolt pattern and custom backspacing to fit.

This will probably have all the information you need:
http://www.aaroncake.net/rx-7/4lug4potbrakes.htm

thanks aaron, the main idea is because i love my 3 peice wheels im pretty sure im gunna need hub extenders to be able to run them there 14s im gunna post pics with cast marks to see if anyone can identify them in the future im pretty sure there not axis og's

I did the conversion many years ago and made a few common mistakes in the process. Many people make the exact same mistakes. If you are switching from single piston to the 4 piston calipers, you must swap out the brake booster too as the 4 piston cars have larger ones. The soft lines are also different between those cars as the 4 piston cars had very slightly larger diameter soft lines. You can't just tell by looking at them. If you do the swap without addressing these steps, your car will still stop. However it will not be at their full potential and isn't that really the whole point?