12a to 13b twin turbo swap

[sickVR6]

hi i have an 82 rx7 with the original 12a in it. I am looking to swap engines to a 13b wondering what is my best bet, to stay single turbo or twin to get most power and what year i should get the engine, tranny ecu and full works from? please feel free to give any input.

[BoostedFC]

Well you have project ahead of you. First what is the car's purpose, what is your power goals, what is your budget & who will be doing the work? A S4 (1987-1988) 13BT or a S5 13BT (1989 - 1991) which are both single turbo & should provide a good platform to build on. The 13B-RE (1990-1995) from the 2 rotor Cosmo have the largest ports from the factory, the 13B-REW from the S6 up (1992-2002). The RE & REW are both twin turbo from the factory. When talking about power we would really know your goals, that way we can better direct you. Things like stand alone ECU, Turbo upgrade, fuel system & many other aspects will come to play. BTW there was a factory turbo 12A offered from 1982-1989 in the HB Cosmo or from 1984-1985 in the RX7. You could always spend the money build & turbo the motor you have now.

[sickVR6]

I seen a guy from puerto rico on youtube under "pewee rx7 turbo" having a first gen with a 13b pushing 457 hp at 31 psi. I would really love to get up close to that. I want atleast 325 to 350 at least. I havent really set a budget yet, really just exploring my options to see what kind of money i need to get where i want to be. I definetly want to get big boost even enough so i have to use methenol injection. I was gonna to stay and play with the 12a but a buddy of mine is building a 93 single turbo 13b with like over 500hp and he recommended it would probably be cheaper to switch to 13b and build off that since i would probably have alot of money into it to get the hp i want. what do you think? I plan on tackling the work myself along with a friend that has built a rotary motor! Really quite excited to get so i can start building my dream car! There is nothing like the sound of those rotors spinning and making boost. I like you display pic. lol pistons got nothing on rotary.

[BoostedFC]

Well I have seen more than a few 12A's making upwards of 500 whp, but I would consider them street cars. I'm not saying you can't make power on the stock ports, but a good port job will most likely be in your best interest. Look here for some porting options. http://www.rx7forums.com/forum/showthread.php?p=7080#post7080.

325-350 shouldn't be a problem to reach. Remember to pay attention to other aspects of the car as well as the motor. Making power is good, but if you have crappy suspension, tires & no attention to driveline mods you are just hurting yourself.

I don't recall you mentioning what the purpose of this car is. Street or track?

A good all around turbo would be a GT35r, you could make the power you want & still have room to move up. On a S4 or S5 you could get away with using a modified stock turbo like one of the BNR staged upgrades, if going with the REW I know of a guy that make 405 rwhp on the stock sequential turbos. You are going to need to bump the fuel system in favor of some better flowing items (pump, injectors, ect.) Add in a good ECU with a good tune & you should be fine

[sickVR6]

Im wanting to make the car for street! I dont care if it gets little to no gas milage. I am really leaning towards the REW twin turbo

[BoostedFC]

Well the REW, a good ECU & uprgaded fuel sys. Then you should be on your way to your goal.

[BoostedFC]

I forgot to ask, but you said you & a friend will be doing the work right. If you or him have any welding skills you can definitely save on fabrication & exhaust. Obviously the more you can do yourself the more out of pocket you can save.