By on June 18, 2013

Picture courtesy Matt Johnston

I needed something cheap, fuel efficient, and at least as powerful as the rotary it would replace… What I came across was something that didn’t excite me much but fit the bill fairly well, a 3.8 liter V6 and T5 transmission out of a 98 Camaro complete with ECU and harness, the price, $600… Turns out GM had their stuff together on this little bastard. It’s a little heavy due to being all cast iron and the heads don’t flow well but it’s rock solid reliable and gets great mileage. Plus it’s power numbers are not far from the 5.0/T5 I was originally looking for. Time to get transplanting.

And that’s how a fellow in an Ohio garage wound up building a race-winning RX-7 that happens to be powered by a Series II 3800 V6.

Picture courtesy Matt Johnston

Johnstown, Ohio’s Matt “Tinman” Johnston has acquired a fair bit of rep in the Midwestern racing community for fabricating all sorts of things from scratch. Your humble author directly credits him with his continued existence on this planet: a few years ago I hit the Armco at Mid-Ohio nose-first at a very high speed and kept my legs thanks to a Tinman-built cage.

Several years ago, Tinman put an actual NASCAR V-8 in an FC RX-7. The resulting car was great for midnight street racing but a little difficult to operate on a road course. So he did what you’d expect: bought another RX-7 and put a V-6 in it. The full build of the car, along with all sorts of drool-inducing shots of rollcages and whatnot, can be read at NoRotors.

Without the NASA-required ballast, the Mazda weighs 2,470 pounds dry and puts 199 horsepower to the rear wheels. It’s capable of running with 370Zs and the like on-track. Tinman’s won a few NASA races with it, but he’s now building himself some sort of tube-framed ASC road-race stock car powered by a NASCAR V-8. Therefore, the RX-7 is for sale.

What’s next for Tinman, after the stock car? I’m glad you asked. It’s a 2.4L Plymouth Voyager engine swap into a certain Lapis Blue Neon… that’s right, after three years away from NASA Performance Touring, I’m returning. With a vengeance. Well, strictly speaking, there’s no real vengeance involved. But it sounded cool when I thought about writing it. The big-block Neon might well find itself lined up against the RX-7 at Mid-Ohio next spring, so if you think you have what it takes to show your tailpipes to my Mopar, you know where to send the check, right?

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41 Comments on “What the FC RX-7 Always Needed Was… A General Motors V-6...”


  • avatar
    danio3834

    Our similarly powered big-block Stratus might have something to say about that. What it gains in weight, it makes up for in having a real suspension.

    Overall, it’s probably held back most by the lack of real driving talent. It would be cool to get your impressions of the rare on a road course Stratus vs. the ever popular Neon though. Mid-Ohio ain’t far.

  • avatar

    We could make the stakes somewhat more fair by having a girl drive the Neon? :)

  • avatar
    Trend-Shifter

    I am really surprised we are not seeing more late model light-weight V-6 transplants into many imported classics. Volvo 1800’s, Alfa’s, BMW, Mazda RX7&8, Miata, etc…

    As an example the Ford 3.7 NA V-6 or the Ford 3.5 Eco-Boost V6 can be found in wrecking yards everywhere from low mileage crashed Mustangs and pick-ups. They are 305 to 365 hp and many are stickshifts! They are generally unwanted and can be had a good price.

    The pan shape lends itself to be set back just right if replacing a 4-pot. The engine is light.

    Even think green! In a small light weight car with good aerodynamics it could probably get over 40 miles per gallon. Keep the Cat and improve the air quality to boot.

    • 0 avatar
      Featherston

      @ Trend-Shifter – Don’t forget that 3800 is a pushrod engine. Pushrod engines are smaller than overhead cam engines of similar displacement. More recent OHC V6s would be tougher to swap into small engine bays. (I’m ignoring discussion of bank angles.)

      Here’s a 3800 swap into an older Corolla: http://www.youtube.com/watch?v=HLgHguU2rSQ

      • 0 avatar
        DeadWeight

        Here’s what I don’t understand about this inexpensive 3800 II swap –

        1) The 3800 II is NOT a transverse V6? I know JB said it came from a Camaro, implying rwd, and I was so removed from GM’s products in the 90s that I didn’t know they made such an animal.

        (Wouldn’t this also then be the successor to the 3800 in the Buick Grand National?)

        2) Is the 199 horsepower figure that’s quoted from a normally aspirated 3800? And is that true “at the wheel” figure as measured on a dyno?*

        My understanding is that if this 3800 is from a ’98 Camaro, it has to necessarily be a L36 which is spec’d at 200 horsepower at the flywheel.

        • 0 avatar
          danio3834

          The 3800 was available in the F-body cars from ’95 through the end in ’02 with either a 5 speed maual or 4 speed auto. A far far better engine than the 60* 3.4L it replaced.

          I knew a guy who had a ’97 that he grafted a ported eaton blower onto. With a smaller pulley, cam swap and supporting mods to the engine, he was beating up on LS1 cars with his single tail-piped ugly wheeled F-body. It sounded terrible.

  • avatar
    Redshift

    Yes, I’m a rotary guy, but, I don’t get this swap for a race car. A heavier engine that makes less power than an NA rotary can make. (Never mind a turbo.)
    T5 trans is a nice upgrade though.

    Better fuel mileage does lower operating cost a bit, but usually not a big deal on a race car unless you are doing endurance races. Interesting swap for a daily driver though. Also, I will give credit where it’s due on the fabrication work.

    • 0 avatar
      danio3834

      Torque.

      • 0 avatar
        Redshift

        Fair point, actually. Depending on the track, that difference in torque could be a significant advantage.

        Still need to overcome the more weight in the nose, less HP and less revs to play with issues.

        I suppose the 38000 Supercharged would make things interesting.
        (But I’ll stick with my spinning Doritos)

      • 0 avatar
        Athos Nobile

        “Torque.”

        In spades. I drive a 3800 everyday.

        3800SC would be interesting… with some of the toys they have down here. 350+ HP anyone?

        Or one of the nice turbo kits available.

    • 0 avatar
      patman

      Those 3800s are surprisingly compact. The 3800 Series II doesn’t appear to be that much heavier than an N/A rotary – not as much as you might think, maybe 50 or 60 lbs – and they may weigh possibly less than a turbo. Not bad for iron block & heads. It’s mostly behind the front axle so it’s probably not the end of the world for handling – not like dropping a 700 lbs big block where a 450 lbs small block used to reside. He’s having to add a good bit of ballast to get it up to minimum weight anyway.

      Probably worth the modest tradeoff in mass for stone cold reliability and much improved fuel efficiency.

    • 0 avatar
      N21923

      S5 NA was 160hp and 140ft/lbs to the crank, stock 3800 SII is 205hp 225ft/lbs to he crank. That’s before intake/exhaust, DIY porting, or swapping in any of the readily available and affordable cam packages. 220 wheel hp is realistic.

    • 0 avatar
      DeadWeight

      My 8 has been tied as the most reliable car I’ve ever owned, and I drive it year round, in summer and in snow.

      The failure of Renesis motors predominately occurs for the following reasons:

      1) The owner is not staying on top of oil levels, which is very easy to do, as it only requires a quick check once every 1000 miles or so. We’re talking a 2 minute glance at the dipstick while the motor is warm, not hot and not cold. In any event, keeping the oil at the full mark or slightly above it on the dipstick has been a sure fire way of dramatically reducing the chance of premature failure due to improper lubrication and compression issues.

      2) The predominate majority of premature failures have happened to the 4 port motors that are paired with the automatic transmissions (which should never have been made an option with the rotary). The 6 port Renesis motors not only have higher tach limits, but are equipped with two, rather than one, oil coolers (which is also critical since many premature failures happen to automatic paired rotaries in HOT climates).

      3) Staying on top of the cooling system is critical given the aluminum intense fabrication of the Renesis. As with the Cadillac Northstar, even one overheating event can spell a death sentence for the motor. 30k coolant change intervals and fastidious attention paid to the condition of the radiator hoses is cheap insurance against such overheating events, and can go a long way to extending the life of the Renesis.

      Thankfully, the Renesis is an extremely easy motor to DIY on, and coolant flush and fills are a piece of cake.

      If anyone cares to check out some of the rotary forums, there are MANY people running long and strong on their original motors well into the 6 digits on the odomoter (and many even at 200k+, though Tigger just a failure EXACTLY at the 200,000 mile marker – bummer).

      I wouldn’t be opposed to a swap necessarily, but given the very compact size and low weight of the Renesis, there is bound to be some adverse handling effects introduced by even a relatively lightweight V6 the likes of which JB speaks of.

  • avatar
    OneAlpha

    Conceptually, a V6 seems a like perfect match for this chassis.

    A V8 is too much, a straight-6 is too long, and fours just don’t seem right for some reason – probably the exhaust note.

  • avatar

    I can tell you from experience of riding in this car, its a blast! Aside from being a little warm, Tinman is a great driver and built a solid car!

  • avatar
    geozinger

    I would have thought a LS motor of some stripe would fit in there just fine. There’s a reason why they’re called mouse motors…

    Or get one of the longitudinal 3.6 OHC V6’s out of a CTS. Well, that might be too tall…

    • 0 avatar
      28-Cars-Later

      I’m with you on an LSx but I wouldn’t even both trying to find a 3.6 with stick, the 3800 he used fits the bill well.

    • 0 avatar

      I dunno about a 3.6 DOHC being worth the effort for this swap; they’re a lot larger dimensionally than a 231ci Buick (height, width), they’re more complex, more trouble-prone… and they wouldn’t haul any more ass than a blown 3800 with a t5.

      Speaking of which, didn’t they sell the Holden Monaro with a s/c 3800 and a 5-speed down in the land of crazy murder-bugs and backwards toilets? I really think a blower addition would only do great things to this car.

    • 0 avatar
      patman

      LS(X) swaps are pretty popular but they’re not exactly cheap compared to a complete 3800 with trans, ECU and harness at $600! When I was researching parts for project trucks a couple of months ago, halfway decent iron block truck motors by themselves were going for twice that – I’m scared to see what an aluminum motor is going for.

      • 0 avatar
        wumpus

        A quick check of ebay said to expect to add another zero to that $600, and maybe even double that ($12k). I don’t think that includes the transmission, either.

        I’m certain the real reason has to do with the class rules, as the swap will take an extreme amount of fabrication work (the first kit I saw for the LS2 was $3k, I suspect Tinman trusts his own work more than an oddball “v6 kit”). If you have to go through that I’d expect to pay the extra money and 50lbs and double the power.

      • 0 avatar
        ajla

        “I’m scared to see what an aluminum motor is going for.”

        The Cadillac and Rover V8s seem to be pretty cheap.

        • 0 avatar
          patman

          Well, I meant aluminum GM LS engines – Corvette, Camaro/Firebird, GTO, etc.

          You can find Lincoln MKVIII 32V Mod motors for next to nothing too.

        • 0 avatar
          wumpus

          Aren’t both of them DOHC? I’d think that even the 6L pushrod would be smaller. Might want to keep the GM transmission (I don’t think those caddys had a manual option, and I’m less confident about Rover transmissions (or am I thinking Jaguar?)).

          • 0 avatar
            ajla

            The Northstar family was a DOHC, the Rover V8 was OHV.

            The Cadillac 4.1, 4.5, 4.9 line was aluminum block/iron head and OHV. However, the 4.1L is nearly worthless.

          • 0 avatar
            patman

            Not only is the Rover V8 a pushrod V8, it began life as the Buick aluminum V8 that gave birth to the Buick V6 that, after a detour through Jeep and AMC before coming back to GM again, eventually ended up in the RX7 featured here.

  • avatar
    redav

    I have an RX-8, and I’ve thought that if the rotary ever goes bad, I’d like to drop a V6 in it. I know there are LSx swap kits, but the V8 is too long & necessitates extra work (IIRC, steering rack, radiator etc.). I like the idea of a shorter V6 to keep it simpler; plus a V6 should weigh less & keep more of the weight close to the center of the car.

    I’ve thought the Duratec 37 from the V6 Mustang would be a great option and an impressive upgrade in power & torque, and hopefully with the plethora of V6 Mustangs, a good engine shouldn’t be too hard to find at a decent price. But that’s just pie-in-the-sky thinking. I have no idea if/how it’d fit, what the weight penalty would be, much less all the other gremlins that are sure to elbow their way in.

  • avatar

    You’re getting a custom-engine Neon? That’s cool, Jack.

    Is that what you’re saying?

  • avatar

    I’m sure that the 3800 II is more common in junkyards, but the Buick/Rover aluminum V8 weighs about 75 lbs less. It even came in turbocharged version from Oldsmobile. Brabham won the 1966 F1 constructors championship with an engine based on the Oldsmobile version.

  • avatar
    raph

    How do forced induction engines fair in road racing? My car with its puny heat exchanger gets heat soaked rather quickly (then again it has an overdriven HEaton on it) as an example, 3 pulls on a dyno and the car is already snatching timing.

    Given this it seems like a naturally aspirated engine would be the ticket since power remains fairly constant.

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