I am looking at an 84 SE that has a 13B from a 1991 Rx7. According to a tech article I read somewhere, the 91 NA was rated at 200 hp. Is that correct? Seemed a bit high to me. The seller says the engine was "street ported." How much hp might that add to the engine? Curious to find out what this engine puts out. Thanks.

I checked many posts/information cites on this question before posting and could come up with no consensus. Since no one answered, I did more research and still have no answer. Now I understand why the question would be difficult to answer. Too many variables. I need to find out what the factory's base hp claim was for a 1991 13B (the motor is now in an FB) and come up with my own estimate. Sorry to have bothered anyone with this.

 

91 NA rated at 160, turbo was 202-215. Source: wikipedia

 

Also depends a lot on what intake and fuel system is on it. If he used the stock -SE intake manifold and Bosche fuel injection system using the Air Flow Meter, then its unlikely to be pushing over 145hp-155hp with a streetport, as the stock -SE 13b was 135hp on two high flowing injectors.

If he also swapped in the 91 intake, thats good for a few horses, but would need the later Mass Air Sensor to reduce intake restrictions, and would also need the 91 ECU to run it. This would get you closer to the stock 91 output numbers, maybe more given the streetport.

Very hard to determine u less you know what you're looking at,

 

true. those are the numbers for the stock S5 motor

 

I am going to email the seller and ask him these questions today. I was wondering if the 91 motor came with the 91 externals or those that would have been on an 84 13B. From what I read here, it makes a significant difference. Also, if I read the other threads correctly, what makes the real difference in performance is the exhaust system (header, exhaust pipes etc), and intake systems including injectors and even going to a turbo. My goal is like everyone else, to get the most out of the motor and car without going too crazy.