Project FD RX-7 Restomod: Part 1 – Introduction

FD3S RX7 FD Stock Sequential TurbosThe stock sequential twin-turbo layout is often misunderstood.  The FD RX-7 utilizes two identically-sized turbochargers that deliver 10 pounds of boost. Below ~4,500rpm, all of the exhaust gasses are fed into one turbo, delivering quick response with all of the exhaust gasses spooling up the single turbo.  Around 4,500 rpm, the diverter valve opens and exhaust gasses are sent to both turbos, preventing an exhaust restriction and allowing for more airflow to produce power at higher RPM.  This transition causes the boost pressure to drop from 10 psi to 8psi briefly, before stabilizing back at 10psi to produce a peak of 252hp and 217lb-ft of torque propelling a 2,750lb car.

FD RX7 Front Suspension GeometryThe FD RX-7 features a proper double wishbone front suspension.

FD RX7 Rear SuspensionIt also has a double wishbone rear suspension with a 2-piece lower control arm.

MotoIQ Project FD RX7 RestomodThis project car is a 1993 Mazda RX-7 Touring with less than 70K miles on the clock.  This car remained stock for its entire life until the previous owner started to modify it.  An OEM 1999+ front bumper was installed, which I think looks a lot better but more importantly, the front openings for the radiator and oil cooler are substantially larger.

FD RX7 stock bumperThis is part of the groundwork that needs to be put in place to optimize the cooling and reliability of the RX-7 since the original pre-99 bumper has an insufficient opening for the radiator and especially the oil coolers.  Retaining the original bumper would have made it extremely challenging if not outright impossible to keep the temperatures in check at higher power levels.


    1. I’ve had my 1993 since 1998. I bought it with 12,000 miles and just hit 180,000 yesterday. Best money I ever spent. It is on engine number two fir anyone wondering…

  1. As a fellow rotor head and FD owner, i am very excited for this build. I am currently working on improving my car so that it can better perform at the track and give that OEM + feeling while driving it on the street.

    i also work at Ford and had the pleasure of working on both the Voodoo and GT500 engines. I’m excited to see what this FD can do with Billy behind the wheel.

    1. Way cool! We sort have somewhat worked together on those awesome products! Stay tuned to see the path I am choosing to make this car more reliable faster, and more refined!

    1. Great to hear! Yes, and we will cover all of the things that happened to the car before that video was shot 🙂

  2. Be interested to see your take on things; the car looks like a decent starting point and there’s a lot of really interesting options for drivable, reliable power on these cars nowadays. Not that I’m a Mazda fanboy or anything (OK, I am) but it’s really nice to see an OEM do stuff where so many of the fundamentals are basically right.

    1. It really is a great starting point. Miatas are such good sports cars and the RX-7 takes that to another level in terms of chassis stiffness, power, and torque. Mazda has always been sports-car and driver-focused and the FD RX-7 IMO is one of the best cars they ever made. This is going to be a lot of fun working with this car.

  3. “Series 8 (produced from 1998 to 2002) was the final series, and was only available in the Japanese market. More efficient turbochargers were available on certain models, while improved intercooling and radiator cooling was made possible by a redesigned front fascia with larger openings.”

    Is it possible to get parts from these last models? Seeing how this is a ‘restomod.’

  4. I had and FD for a little over 5 years and the last couple years of ownership I tracked it almost once a month. I loved that car, it was reliable, made decent power and handled really well. I’m actually more paranoid about my current stock engine S2000 blowing than I was about my FD lol. If I had the money, space (and wife’s approval) for a dedicated track car it would 100% be an FD.

    1. Those are both great cars. I’m actually going to do a track comparison of the S2K vs the FD. Stick around!

  5. Love the way you lay things out in your write ups. Very analytical without being too wordy.
    We’ve had a few theories on heat management as well as practical results on these motors after applying both Deep Cryo and WPC to race rotaries . We believe that thermal dispersants and thermal barriers should be tested and applied on internal components in key locations. Of course along with DCT and WPC as major contributors to longevity and performance gains. 😇

    1. Thank you, that’s what I strive for in my articles. What components have you had success with cryo, WPC treating, and coating?

      1. All internals really for the WPC and Cryogenics. The rotors and select areas in the motor for the coatings. We can discuss in person if you like…. Hit up Martin to Mike for our contact info.

  6. Love the FD….. I ended up with Project S2000 because I needed a reliable daily driver. You’ll have to drive it after it’s boosted. I FINALLY have a timeline for dropping it off to get the fab work done. I was talking with my coworker Billy J today and it sounds like he’s got his S2k lined up for the track comparison with you. Gonna be fun to watch!

    1. Can’t wait for the FD vs S2K comparison. Having driven both, the cars’ development goals are obvious from behind the wheel. The S2000 was built for driving pleasure, with maximum performance a secondary consideration, whereas the FD was built as an all-out performance machine to take on the fastest sports cars of the day. On track I think the FD will ultimately be faster due to its superior aerodynamics, lower CoG, and longer wheelbase. The S2000 offers maximum driving enjoyment though with its refined inputs, and the shifter feel and throttle response are immediate in a way that the FD is not.

  7. That radio was pretty decent back in the day. Time alignment, 3-way crossover and the ability to control multiple (!) disc changers. Ok, so maybe the last feature isn’t that great. But it will probably bring a couple hundred bucks on eBay or DIYMobileAudio

    1. Thanks! I’ll look into that when the head unit is replaced. The far bigger issue is what was done to the speakers.

  8. I loved my 93, and I’m anxious to follow your build, as I did with Dave Coleman’s articles in “Sport Compact Car” to guide me through my mods. As you mentioned, I took care of overheating at the track with all front “mouth” air being fully ducted to the upgraded intercooler, and the intake air taken in from a separate side opening. I do feel it’s confusing to liken this engine to a 2 stroke, given the fact that it is a 4 stroke engine that lacks the 2-stroke porting that interrupts the cycles near BDC.

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