The ’86-’91 rendition isn’t the quintessential RX-7 that you consider when considering Mazda’s three-generation-spanning sports car. But it must be. With the final three years’ models available with a 200hp turbocharged engine and RWD architecture, it’s never been easier to pounce on boy racers in Civics-all for around four thousand bucks.
A 1988 model in which much time and cash continues to be apportioned to, the most obvious which has gone toward the car’s 13B-RE engine transplant, despite the fact that brian Treffeisen knows this, which is precisely what led to his extensively modifying not the better predictable sequentially turbocharged third-generation version. Sourced from the ’90-’95 Eunos Cosmo-Mazda’s overseas-only, luxury line flagship car-the 235hp 1.3-liter marks the automotive world’s first sequentially turbocharged rotary engine boasting what are arguably the largest side ports among Mazda’s entire 13B engine family. All of this means that the 13B-RE can do very good things. Treffeisen knows this, too, and has gone on to eek out exactly 405hp from yourstarts with a single-turbo conversion based upon Garrett’s GT35R, which mounts up by means of a custom-built, equal-length exhaust manifold. Usually the one-off parts story doesn’t end there, though. I fabricated virtually any part for this vehicle, Brian says. Most aftermarket support for the RX-7 [lacks] quality, and there are a lot of individuals whose practices and theories disagree with my own. A couple of TiAL MV-S wastegates that really work alongside a MoTeC M800’s built-in boost control capabilities allow consistent and repeatable power, which was dialed in on his own. Brian didn’t just fabricate nearly everything on his RX-7, he tuned it, too, teaching himself how to do so as his build progressed, mainly because it turns out.
Little expense was spared with all of this, such as the MoTeC standalone that retails for more than most used cars. According to Treffeisen, he stopped counting after nearly $25,000 worth of mods. You would, too. The damage wasn’t as painful as you might expect it would be, especially since the longtime Mazda fan’s owned the car since 1997, smattering its upgrades out over the course of over a decade along with a half. Enough time spent making his RX-7 the car he knew it needs to be yielded lessons more valuable than whatever was used on doubling its horsepower. He could be the first to share with you how magical the internal combustion process free from pistons and connecting rods can be, brian chose the RX-7 because of what he says is his undying adoration for those spinning triangles. Often scowled at by piston purists or by those people who are easily shied away by the inner workings of rotary engines: The rotary engine is incredibly durable when operated within its mechanical and thermal limits. Operating within its limitations is about as important as not cheaping out on quality parts, which is partially why Treffeisen’s spent as much as he has. Don’t buy cheap parts, and spend your money where appropriate, he warns. Quality OEM engine parts where appropriate, good aftermarket apex seals, and the best, most accurate ECU you can afford. Ignition timing and solid fuel delivery are crucial to get aHave a look at the car’s fuel system and you won’t be able to accuse Brian of not taking his very own advice. Injector Dynamics 1,000cc/min. and two,000cc/min. injectors line up against a set of Guru and CJ Motorsports rails while an Aeromotive 340lph pump draws alongside an already impressive Denso unit. Running lean because of a scant fuel system isn’t very likely to do. The engine itself was also strengthened accordingly. Here, its rotors and plates were cryo-treated and more durable apex seals-the Achilles heel of rotary engines-were sourced from RX-7 Specialties and added. The 13B-RE’s air conditioning was also updated with a customized Griffin aluminum radiator, steel-braided radiator lines, and the later-model RX-7’s water pump and housing. He addressed potential driveline woes with a modified and re-worked six-speed RX-8 gearbox mated to a 4.3: 1 Torsen-style rear differential. An Exedy twin-disc clutch and Driveshaft Shop aluminum driveshaft complete the lion’s share of the RX-7’s under-hood mods. Brian’s affection for customizing his own parts doesn’t stop with what’s underneath the hood. One-off adjustable end links reside behind the 17-inch BBS rims and beskpoke bracing sit along each strut tower where pairs of Stance GR Pro coilovers can be obtained.
Mazda’s second-generation RX-7 isn’t necessarily probably the most sought-after in the nameplate’s two-and-a-half-decade lifespan, but it should be, and Brian Treffeisen’s 405hp example is here to know you as much.