5.12 Ring and Pinion for 2nd Gen RX-7

[eyedoc]

I had a 5.12 pinion and ring gear fabricated for my 1989 RX-7 and what a difference it made in acceleration. The difference in 2nd and 3rd gear is really something. Also, 4th gear pull like my old 3rd gear. I took my car out to the local Kart track and it is so much faster out of the tight corners. Also, did an autocross event and easily beat my closest competitors. If you want to go faster get this modification. I had help from Bill Hennecy and he can be reached at 843-222-2897. He was a pleasure to work with. :happy204:

[Chris Wire]

I had help from Bill Hennecy and he can be reached at 843-222-2897. He was a pleasure to work with. :happy204:
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Glad to hear it. It's probably the best investment an RX7 racer can make. And it's definitely a small world for people looking to have a machine shop do the work. There aren't many people who will touch it anymore.

And Bill is one of the good guys. RX7 racers, make a note of that number.

[mazda49]

I had Bill, do two for me and was very happy with the nice finish, the pinion looked as if it had never been modified. I've had two done and a friend had one done also. I couldn't find anyone to do this modification and Bill spent considerable time finding a source and staying on top of the work. It seems no one is willing to do one of's because of the time it takes to set up the process and the time it takes to make the run out/straigtening to within a tight tolerance and the welding of something that is going to have stress and high RPM's to deal with. The best value for the dollar for performance that I have bought. I now have an E Production car and I glad he could get this done for me. Leroy Maner EP #33

[Redshift]

Any hints you can give on the approximate costs involved?

[eyedoc]

The modification costs is approximately $500 plus your purchase costs for the 5.12 pinion and ring gear plus the 2nd gen donor pinion gear.

[eyedoc]

I had my first opportunity to try out the new gearing at Thunderhill. It was a huge improvement in my ability to accelerate. I didn't run out of rpm's on the front straight in fourth gear but I could have shifted into 5th gear. If you are serious about improving your ability to go fast consider this modification.