Welcome to the From Mild to Wild Engine/Power section.  This section will go into recommended stages of upgrades for your FC3S in terms of power/engine upgrades; there is a companion section on suspension mods also.  The stages are broken down into roughly 7 groups; this gives you a feel for how mods can complement and work with each other.  A brief description is typically given for each mod with links (if available) to a much detailed description existing in the TECH | MODS section on this web page.  Enjoy!

Stage I consists of relatively easy bolt-on mods that will give you the most performance for the least amount of money.  Emissions will be kept intact, so this will be the perfect beginning for most street cars.  With Stage I mods, the foundation will be laid for the later stages.  Concentration will be on making the engine operate more efficiently by opening intake and exhaust sections without affecting emissions.
Stage I:
Estimated Boost 8psi (5.5psi stock) Zenki
10psi (7.5psi stock) Kouki
Estimated Power 200hp (182hp stock) Zenki
220hp (200hp stock) Kouki
¼-mile Potential:  mid to high 14's (low 15's stock)
Emissions:  Not affected - will pass smog
  • Rewire fuel pump power
  • Power going to the fuel pump is suspect on these cars due to age and corrosion of the wires and connectors.  A rewire guarantees full voltage to the fuel pump.  [MORE]
    An optional (more expensive) solution is to go with a fuel pump voltage regulator.  Kenne Bell offers their Boost-A-Pump that will ensure proper voltage levels.  Others are made by MSD and B&M.  If you choose this route, a re-wire is not necessary. 
  • F.C.D.
  • The fuel-cut defenser prevents overboost fuel-cut when running higher boost levels.  The stock ECU is programmed to trigger fuel-cut when running approximately 1psi over the stock boost levels. 
  • Air Filter
  • K&N offers a drop in filter replacement of your OEM stock air filter that will flow more air.  K&N part number 33-2017. 
  • Cat-Back Exhaust
  • A cat-back exhaust system will free up your exhaust system by replacing the restrictive Y-pipe and mufflers.  Emissions is still intact.  Although technically not a "cheap" purchase, the (freeing of the) exhaust system is the key to producing power on these vehicles.  [MORE]
  • Porting Stock Turbo Wastegate
  • The stock wastegate will be overwhelmed when exhaust is freed.  This can cause uncontrolled boost creep that can damage your engine.  Although labor intensive, it is a very cheap mod is you have the proper tools.  [MORE]
  • Shimming Eccentric Shaft Thermowax Pellet
  • Not so much as a performance mods, but more for a safety precaution against a failing front eccentric shaft thermowax pellet.  Failure of this part will cause decreased oil pressure inside the engine.  [MORE]

    Stage II goes into an extension of Stage I.  Mods are to stress reliability and efficiency of the engine without impacting emissions; the car should still be able to pass an emissions sniffer test without any problems.  Very strict visual tests would arouse suspicions.
    Stage II:
    Estimated Boost 10psi Zenki
    11psi Kouki
    Estimated Power 220hp Zenki
    230hp Kouki
    ¼-mile Potential:  low 14's
    Emissions:  Will pass smog sniffer tests, but questionable on a visual
  • Fuel Pump Upgrade
  • An upgrade fuel pump guarantees fuel supply for increased power.  It also prevents lean conditions due to the stock fuel pump running out of capacity when getting close to the 250hp level.  [MORE]
  • Downpipe
  • Replacing the stock pre-catalytic converter with a downpipe will increase engine breathing and release more power.  The pre-cat is primarily for cold-start emissions, but this should not affect a sniffer test when the engine is fully warmed up properly.  [MORE]
  • Ignition CDI Box
  • An ignition CDI box will produce a more consistent ignition system.  The stock ignition system has been known to be "weak".  A Crane Cams HI-6 or MSD 6A will give you a little more power (up to 5hp) across the entire RPM band, crisper throttle response, and possibly better gas mileage!  [MORE]
  • Electric Fan
  • The stock viscous fan can fail without warning.  Installation of an electric fan will free up some of the parasitic power loss from the stock viscous fan.  An electric fan is also a much more efficient method of cooling, since the fan is only active when needed. 
  • Cone Air Filter
  • The stock air filter box is very restrictive.  By replacing the air filter box and stock panel air filter with a cone filter, we free up the intake even more.  1986-1988 Zenki models needs to run an airflow meter adapter plate to mount a cone filter.  1989-1991 Kouki models can just clamp an air filter directly to the airflow meter.  [MORE]
  • Fuel Computer
  • The addition of the fuel computer adds to fine-tuning the fuel delivery.  This might or might not add to peak horsepower, but substantial gains are made by leaning out the midrange, as the stock ECU runs rich in these areas.  One of the most popular types of fuel computers if the A'PEXi S-AFC.  [MORE]

    Stage III is the point of no return for emissions.  With these mods, the car not pass an emissions test.  A lot of the mods are to remove emissions components that are not necessary, the key component being the removal of the main catalytic converter.  Power potential takes a large jump due to the removal of the main cat.
    Stage III:
    Estimated Boost:  12psi
    Estimated Power:  250hp
    ¼-mile Potential:  high 13's
    Emissions:  Will not pass emissions
  • Pre-silencer
  • Replacing the main catalytic converter with an in-line muffler ensures a very free flowing exhaust system.  You can even go straight pipe for this section, but a pre-silencer will give you a quieter exhaust note.  With the removal of the main cat, emissions gets thrown out the door.  [MORE]
  • TID Replacement
  • By replacing the stock turbo inlet duct with a straighter pipe section, the intake gains even more efficiency.  [MORE]
  • Air Pump Removal
  • Main cats have been removed, so there's no need for the air pump.  We recommend running a double-sheave alternator pulley and double water pump / alternator belts to prevent water pump pulley slippage after removing the air pump.  [MORE]
  • ACV/EGR Valve Removal
  • Likewise with the air pump, the ACV and EGR valves have no use once the main cat is removed.  After removal, replace with a block-off plate. 
  • Upgrade Fuel Injectors
  • At this level of power, the stock fuel injectors (4 × 550) are getting close to their maximum safe output at 85%.  Larger fuel injectors (coupled with the control of a fuel computer in Stage II) would allow for safer pulsewidths under 85%.  [MORE]
  • Upgrade Radiator
  • The (turbo) rotary engine generates a lot of heat.  The increase in power requires the needs for more cooling capacity.  An upgrade radiator ensures increased cooling over the stock unit.  [MORE]

    Stage III+ is an extension of Stage III.  The foundation for more power through higher boost has already been laid.  With the higher boost levels, more power can be produced.  The stock turbocharger cannot handle more than 14psi of boost consistently; higher boost pressure tend to cause it's oil seals to fail and produce excessive oil leaking.  This causes huge clouds of oil smoke from the exhaust.
    Stage III+:
    Estimated Boost:  14psi
    Estimated Power:  280hp
    ¼-mile Potential:  low 13's
    Emissions:  Don't even bother
  • Electronic Boost Controller
  • An electronic boost controller will give you a more boost and a more aggressive boost curve.  While running such modified boost levels, you'll need to tune for the fuel delivery with the fuel computer mentioned in Stage II. 
  • Gauges
  • Although not a performance enhancement, aftermarket gauges are used to monitor vital areas of your engine.  They can immediately tell you when you're in danger and pinpoint a potential component failure.  This is more of a safety mod at this point, as we are starting to make almost 100hp more than stock!  [MORE]
  • Blow-off Valve
  • With the increased boost, the potential for compressor surge is increased.  By going with an aftermarket blow-off valve, we increase the capacity to vent the increased boost over the stock compressor bypass valve.  Compressor surge will eventually kill turbo bearings and cause the turbo to wobble itself to death.  [MORE]
  • Upgrade Oil Pressure Regulator
  • With the increase of power, higher oil pressure is recommended to keep bearings and internal components libricated properly.  Racing Beat offers an 80psi-85psi upgrade OPR that is easily installed once the oil pan is removed.  [MORE]

    Stage IV will start to go beyond the capacities of the stock components.  This is mainly for the stock turbocharger and intercooler.  The upgrade fuel pump and larger fuel injector should be able to support power levels to the largest compressor upgrade available for the stock Hitachi HT-18; the 60-1 compressor upgrade is the largest compressor upgrade we can go with that will fit with relative ease.  Fine-tuning of fuel delivery is possible with the fuel computer recommended in Stage II.
    Stage IV:
    Estimated Boost:  14psi
    Estimated Power:  Up to 350hp
    ¼-mile Potential:  low to mid 12's
    Emissions:  Don't even bother
  • Compressor Turbo Upgrade
  • The stock turbo is restricting power at this point.  By enlarging the compressor section, we can increase serious power potential!  By keeping the stock turbine, CHRA, and turbine housing (and turbine wheel), we are able to keep the stock turbo exhaust manifold and forego the cost of an expensive (full) turbo upgrade.  [MORE]

    Stage IV+ is for the front-mount intercooler.  It can be argued that an upgrade intercooler is required earlier in the mods stages, but this mod is very expensive for most owners.  We have decided to include it here, prior to the big full turbo upgrade in the upcoming Stage V.  The intercooler doesn't necessarily increases performance, but it does add a margin of safety by ensuring cooler intake charge temperatures reaching the combustion in the engine.  This minimizes the chances of detonation and potential engine damage.
    Stage IV+:
    Estimated Boost:  14psi
    Estimated Power:  Up to 400hp
    1/4-mile Potential:  high 11's
    Emissions:  Don't even bother
  • Front-mount Intercooler
  • The stock-mount intercooler is not very efficient above 10psi of boost.  At higher (turbo) flow rates, it ends up being a restriction.  By going with a front-mount intercooler, we ensure cool air intake temps to ward off detonation.  [MORE]
  • Engine Rebuilt and Porting
  • We are at the stage where an engine rebuild is highly recommended.  Some stock components are weak, and all engine internals should be inspected.  Even the smallest internal parts failure can cause a catastrophic engine failure.  At the same time, you have the luxury of porting the engine for more efficient flow.  A street port / side port / extend port can gain up to 10% more power.  [MORE - intake port]  [MORE - exhaust port]
  • Upgrade Corner Seal Springs
  • If you're planning to do an engine rebuild, use the stock FD3S corner seal springs.  [MORE]

    Stage V is where all the fun begins.  This is a big jump in performance and cost.  The bulk of the performance gains are from the full turbo conversion.  Due to the many types of full turbo (kit) options avaiable, it is very hard to give accurate power potentials.  Depending on turbo size, it can be lower than a compressor turbo upgrade but have the potential to hit 600hp when turning up the boost!  1/4-mile times can easily dip into the 9's if the engine and drivetrain can hold together under such power.  With power potential of this magnitude, we recommend at least a 3" full exhaust system.  Your fuel system needs to be addressed, as you're going to (almost gaurantee) need a larger fuel pump when pushing over 400hp.  With the stock ECU, you'll need to go AIC, as bigger fuel injectors cannot be easily controlled by the stock ECU even with a fuel computer; a stand-alone EMS (i.e. Haltech) is highly recommended and detailed in Stage V+.
    Stage V:
  • Full Turbo Upgrade
  • This is not an easy or cheap upgrade.  Full turbo kits can easily cost a minimum of $3,000.  If you're starting out with a bare turbo, you'll still need to buy a turbo exhaust manifold, intercooler and intake piping, oil (and water) lines, and exhaust discharge piping.  The gains from the full turbo upgrade are huge and almost outside the control of the stock ECU.  It is possible to get a full turbo upgrade running with the stock ECU, but restriction from the stock airflow meter starts to hinder efficient intake air flow with the larger turbos.  [MORE]
  • AIC
  • Additional fuel injectors and an AIC controller is the easiest way to add more fuel if you're still sticking with the stock ECU.
  • Upgrade Rotor Bearings
  • If you're going for extreme power levels like 500hp, there are a number of engine components that should be upgraded.  The rotor bearings are the first of many.  Deeper oil grooves serve as more protection from such high power levels.  [MORE]
  • Upgrade Stationary Gears
  • Another engine part highly recommended to upgrade...  [MORE]
  • Upgrade Stationary Gear Bearings
  • With the upgraded stat gears, we recommend the better stat gear bearings to match.  [MORE]
  • Eccentric Shaft Oil Jets
  • Add another part to increased lubrication...  [MORE]

    Stage V+ complements Stage V by introducing additional components to add to the efficiency of the full turbo upgrade.  Mods center around the stand-alone EMS install that greatly adds to power efficiency.
    Stage V+:
  • Stand-alone EMS
  • With the installation of the EMS, there are several advantages that become apparant.  Most EMS units can control both fuel and ignition, which gives you total power over the engine.  Don't be surprised, as with such flexiblity comes the danger of damaging the engine due to bad tuning!  The elimination of the stock airflow meter adds greatly to the efficiency of the whole engine.  The Haltech EMS is a very popular stand-alone EMS unit for (turbo) rotary engines.
  • Upgrade Fuel Lines
  • The stock 5/16" O.D. had fuel lines can support up to 500hp.  If you are planning to run more power, it is recommended to replace the primary fuel line feed with a -6 or even -8 AN stainless steel braid fuel line.
  • Upgrade Fuel Pressure Regulator
  • With such increased demands on fuel delivery, we recommend installing an aftermarket FPR for proper fuel rail pressure control.  The FPR should have a vacuum fitting for boost, as pressure should rise with turbo boost.  Popular units are made by SX and Aeromotive.  [MORE]
  • Parallel Fuel Rail System
  • The stock fuel flow runs from the primary fuel rail to the secondary fuel rail then the FPR.  Most aftermarket FPR's can handle dual inputs, so it's advantageous to convert the stock fuel flow system to a parallel flow system to take advantage of the aftermarket FPR.  The parallel fuel rail system allows for more consistent fuel delivery to all fuel injectors.  [MORE]

    At Stage VI, engine integrity is in question.  The stock Zenki engine has been known to twist and crack end plates due to extreme power output over 450hp.  We introduce engine doweling to prevent twist and housing flex.
    Stage VI:
  • Doweled Motor
  • By inserting extra dowels within the engine housings, we strengthen the engine from unwanted twisting and flexing.  This is not an easy procedure to do, as it required accurate machining to do properly.  There are rumors that the front housing tension bolt bosses crack on a Zenki motor at anything above 400hp.  Kouki motors have been known to go up to 500hp.  13B-REW engines have been known to go up to 600hp.
  • Bridgeport
  • A bridgeport requires opening and porting the intake ports.  A bridgeport can make great power gain at the top end, but it's typically kills low-end torque due to the increased overlap.  The bridge in the bridgeport also tends to fail due to it's delicate design.  [MORE]

    It is ironic that the last stage ends in 7.  Stage VII is the border where we go past the limits of the 2-rotor 13B engine and go with an engine swap (for more displacement).
    Stage VII:
  • 20B Conversion
  • With the limits reached with the 2-rotor 13B, the 20B is the natural progression for more power.  Add another rotor chamber for 50% more displacement, we're talking an engine that has the potential to break the quadruple digit power mark.  Building a 600hp-700hp 20B engine is trivial - add a big enough turbo with enough boost, and you have the potential to literally twist the stock chassis.
  • Support for the 20B
  • This pushes you back to square one.  You'll need to calculate power potential and install the proper components to support such power levels.  This means a bigger fuel pump, more/larger fuel injectors, reconfigure the stand-alone EMS to fire the 20B correctly, bigger turbo, bigger pipes...  Stronger, bigger, more, more money!

    Questions?  Comments?  Send mail to:  reted@fc3spro.com