I have just pulled my engine and I’m planning on street porting it as well as removing the emissions and getting a new standalone ECU as well as a full exhaust. I’m trying to gauge how much horsepower I would be able to make with the stock AC and power steering. I plan on keeping it NA and want to keep the streetability but also want to have some fun with it. does anyone know what a reasonable horsepower expectation would be for this set up?

 

I will give you a bump, I am curious too. There are many threads here on this, many are older posts though. Many variables to consider too, s4 or s5 intake and others. Older posts suggest maybe +10hp with an aftermarket ECU? Some say the squeeze isn't worth the juice there, I disagree.

Also HP is one thing, better gearing is another. A lower HP build with a RX8 six speed, different drive shaft, something for the speedometer, supporting mods like a custom mount, a shifter relocation and a 3.9 rear gear is great mod suggested by @peejay . With a '99 Miata fourth gear(if possible), that setup gives a very even and quicker acceleration with a higher top speed. With the sixth gear, highway driving is possible too.

This is the direction that I am headed in anyway along with your engine mods. Still debating exhaust, the porting though and keeping emissions, HP dependent decision. Aiming for 170hp at the flywheel.

Don't forget about custom suspension with comp mounts and air handling mods across the body of the car, the intake setup and a possible different throttle body, those increase the fun factor, too.

 

Going from all I've read on here 200rwhp is the max on a stock S5 intake setup. It just doesn't flow enough for any more than that. The other thing is most comments by knowledgeable people say 200rwhp is about the max on a street ported 6-port regardless of the intake. Keep in mind I'm just regurgitating what I've read over the years. I have yet to install my standalone on my car which has a street ported 6-port and attempt to find these things out for myself. The few cars that hit or got close to that 200whp had a lot of exhaust tuning and time spent on the dyno. A more realistic number is probably 160 to 180rwhp.

On another note if your pockets are deep enough you'd be much better off to start with a 13B-REW from a FD or a 13B-RE from a Japanese Cosmo. There was a FC with a street ported13B-RE on here that made 230rwhp with a modified 13B-RE intake. 13B-REW should be capable of similar numbers n/a. Even a 13BT from an FC paired with the right intake should have better power potential n/a than the 6-port.

The N/A performance section has a wealth of knowledge. https://www.rx7club.com/naturally-as...nce-forum-220/

 

Made about 175whp on a safe tune, streetport, standalone, T2 irons, S5 NA rotors, T2 intake with gredde elbow to 3" pipe and filter, headers, 3" exhaust. No AC or powersteering tho. (But who measures hp with ac On and PS uses maby 5hp?)

 

Thanks for the post @Pettersen! You give me more hope that I can get this done, too.

What standalone, if I may ask? Some of these with the autotune? features via different software? have me seriously interested. The power FC with added software?, I think.

 

At that time i had power fc. But this was back in 2013 ish, so would not go with that ecu today. For my current build i'm using a Maxxecu Sport that has autotune, but any modern ecu should do fine. Autotune is one thing, but modern ecu's are generally so much nicer to work with than the 10-20 year old ecu's and software.