Chicago Car Life FC RX-7, Next Chapter Begins Posted on 25 Apr 14:18
In the last feature I gave an introduction to the long term project that is my 89 Mazda RX-7. As of that post, the car was running, but not very well. With a slew of aftermarket parts all more robust and powerful than what came from the factory, and an engine computer to match, the car needed a proper tune to make all the new equipment cooperate nicely. The freshly rebuilt engine and turbo were begging for use, and after a long period of limited time to drive it, and several mechanical fits and starts that needed to be sorted, I finally had the mileage necessary to break in the engine. Enter Elite Rotary Shop, and their dyno tuning event with Nelson Siverio.
Elite Rotary is new to the Chicago area, having just set up shop about a year ago. They have, however, come onto the scene with force, offering a gorgeously manufactured intake manifold for the 13b and enlarged throttle bodies, among other components. The owner Sal, is incredibly friendly, helpful and knowledgeable about rotary engines and the cars they power. The real difference maker with Sal and Elite Rotary, is that they have several tuning events throughout the spring and summer where Nelson Siverio performs dyno tuning sessions for customers. Nelson is a proper O.G. when it comes to rotaries, and the wealth of knowledge and experience he has with tuning rotary engines is unmatched. The midwest may never match the west coast for the number of tuners and customer shops, but those with piston engines still have a plethora of choices. If you search for a rotary tuner in Chicagoland, the common refrain of "rotary? Oooh, no we don't tune those" is what you will quickly become accustomed to hearing. So it is with that in mind, that I really want to support Elite Rotary and would encourage any rotary fans to do the same, these are good people and we want them in Chicagoland. I can not stress enough, if you have a rotary powered car in the midwest, go to Elite Rotary Shop!
The day my FC was scheduled to be tuned, I was a bundle of nerves all day. I was the last car of the day scheduled, so I anxiously agonized all day until the afternoon when it was due to go in. When I arrived, the nerves subsided as I was distracted by an absolutely bonkers convertible FC that was built for drag race duty. It was on the dyno when I walked up to the shop, doing it's best to attempt ripping the rollers from the earth. The noise was so deafening it caused genuine ear pain. As it climbed closer to redline, the noise somehow increased and became more a feeling than noise, a feeling of your inner core being shook from your body. As the pull ended, the lift of throttle welcomed an eruption of flames from the fender exiting exhaust. It was like a momentary bonfire emitting from the front of the car. Any attempt to "check out" what was under the hood while it was running, was met with burning watery eyes and shortness of breath as this monster spewed partially burned race fuel and Marvel Mystery oil. It was akin to walking to the edge of a volcano spewing noxious gasses, and nearly as impressive. It put down a horsepower number, a big one. I would have been elated to achieve even half of what it did with my humble build.
Once the monstrous convertible rolled off the dyno, it was my turn, and the butterflies quickly returned. I watched as they strapped the car down, hoping everything would go well, but fearing the worst; a blown engine or some other major catastrophe. It wasn't that I doubted Elite Rotary and Nelson, it was more a matter of self doubt. The engine was my first time rebuilding a rotary, and although I felt I did a good job, there was still much concern on my mind. Watching Nelson work, methodically going through the paces, making adjustments, running through the revs, making adjustments again, put my mind a bit more at ease. When putting down the power pulls I tensed a bit, listening for redline and watching for any signs of imminent disaster. However, there would be no disasters, as Nelson expertly tweaked the engine computer and even recognized a couple of minor issues we were able to address on the dyno.
By the end of the session, there was one insurmountable issue that needed to be hashed out, and it was a lack of strong consistent fuel pressure. Due to this, Nelson was limited to safely tuning only up to 6000rpm, until I was able to sort out the fuel pressure problem in the future. The end result of the tune though, was a car I could now confidently push, going wide open throttle and allowing the turbo to boost as you normally would. Drivability vastly improved, with it no longer stalling at idle and no longer misfiring in partial throttle driving conditions. The FC went from a worrisome driving experience, where I wondered if it would be a one way trip, to being a normal dependable car. The final numbers you ask? It made a peak 276 horsepower to the wheels at 6000rpm with 262 ft./lbs. of torque to match. Not a bad number for a car that started with less than 200 horsepower to the wheels, especially considering it has room for more once the fuel issue is sorted.
The smile never left my face the whole drive back home, the culmination of years of work on the car. It was completely out of commission for 7 years, then only a shadow of what it was for the last two after being rebuilt. Now it was back, and although limited by a lower 6000 rpm redline, feeling better than when I first got it. It pulls strong and smooth, but there is a noticeable 'second level' of power from about 5000 rpm to 6000 rpm. It is this rush of power that has me eager to re-tune after correcting my fuel pressure problem, with 3000 more rpm to play with and potentially more power, this thing could get very interesting! I can not stress enough the gratitude for having guys like Sal and Nelson for helping to make this happen, and their patient guidance in helping me further improve the car. For now, I am truly content having the car back on the road, and being able to get re-acquainted to the new tuned version of my FC, but as of this writing I am working diligently on the fueling issue, more updates to come!
-photos and writing: Robert Sixto