I am pulling my motor from the project I picked up a little while ago to clean out the coolant passages due to rust because it has been sitting for 2+ years. While I have the motor out and apart I was thinking about going ahead and porting it. I was wondering how large(if at all) would I be able to port my housing while still running the stock ecu? I am well aware that going stand alone would be better but I just want to get the car running and drive it before going stand alone. I am planning on going stand alone when all the problems are fixed with this car.

I don’t know if this would contribute anything, but it is the stock 12a and has a beehive delete and all emissions deleted(apart from omp) and it has a full exhaust.

 

12A is carbureted, and has no ecu, just an emissions control box

 

Thank you. Sorry for my still small knowledge of these cars. Does that mean it doesn’t matter the port size I go with while still running the stock carb?

 

the carb does better with big ports, although at some point its the bottleneck

 

Is there anything else I need to do after I port it or can I just rebuild and put it back in the car.

 

Depends on what your goals for power and use are. A mild street port will work with a modified nikki carb. Anything more and you will be into some serious carb and/or intake work. If you intend to go above 7K rpm there are mods needed to keep the engine from self destructing but going above 7K will normally mean larger porting and various intake and exhaust mods etc. So what do you intend to do when its ported?

 

It’s going to be a drift car, rarely used on the street. So in turn above 7k would most likely happen. Power numbers, it’s hard to say since I’m still not too familiar with power output of certain mods/changes. Like I was thinking about doing a bridgeport with ITB’s(not sure how much power that would output). So I don’t know if that answers your questions, but maybe it might lead into more?

 

You should start by going to RacingBeat.com and Mazdatrix.com and reading all the articles about mods for high rpm and power output. Then maybe read the book "How to Modify Your Rx-7" and the Mazda Comp Manual\, both can be found at Foxed.ca for free download. Also figure out whats needed for drifting. You are talking $$$$ to do what you think you want to do. So be prepared.

 

Thank you I really appreciate the information. How it be feasible to just do a bridgeport now and then upgrade later? Or alternatively would a street port be possible and then get a bridgeport later?