I am currently building a 12a half bridge using a nikki, with a s5 stock turbo, and Y plates. I'm not sure about a few things that are unanswered in the forums. First is how far down is too far for a bridgeport turbo application, I made the bridge the entire length of the port. I also port matched the exhaust. Second is turbo size/response to the half bridge. I know a stock turbo would be too small for a 13b but what about a 12a, my hopes are it spools a little fast to help with the loss on the low end but still makes power to 7500-8000 rpm. I intend on sending it to bnr to upgrade it later on. The goal for this project is to see how far factory mazda parts can go with a 12a reliably. I'm not looking for a how to, or a how much power can I make. That has been repeated over and over in the forums. I want some civil suggestions to improve on the 12a to make it last maybe some things that are looked over and not mentioned that would be a good addion to the info we have now.

 

Are you balancing the rotating assembly? Using hardened stationary gear? Pinning those stationary gears? Modifying the oil pressure regulator and using bigger jets on the eshaft for the oil squirters? Are you adding any extra dowels to the housings? All these things and probably more are done to increase life on high end builds like this.

That bridge will want to run at pretty high revs to make the best power and a stock 12A is really only designed to go to about 8K without these extras to increase strength and oiling for cooling and lubrication.

 

well, bolting on something that will increase heat and stress on the engine aint it.

 

Planning on gslse oil pump, higher pressure regulator, and studding the engine. Are changinge oil jets needed with higher oil pressure? I am going to get it balanced and clearanced. Not planning on turning the engine 10000 rpm so no hardend stat gears or pinned ring gears. Maybe external oil mod?

 

If done right and treated with respect I am sure it can last.