jairbne1725

does anyone know if it is possible to put a 3 rotor motor in a 85 rx7

Aaron Cake

iTrader: (1)

Yes, it is. Bring the car to a trusted fabricator, write a $50,000 cheque and pick it up in 6 months when it's done.

Evil Aviator

Anything can be done with enough money.

jairbne1725

Is this yours and if so who did the work and about how much did it cost can you put me in a ball park figure. Not trying to be in your financial business just wanted to know

Aaron Cake

iTrader: (1)

That's not his.

I already gave you an estimate on a 20B install. It's about $50,000 if you pay someone else to do it.

If you do the work (and I'm assuming because you are asking whether it can be done, you won't be), then the budget will depend entirely on what you are capable of doing. Figure $20,000 if you can fabricate everything.

And that's the issue. Everything needs to be fabricated. Engine mounts, turbo setup, intercooler stuff, exhaust, oil/water cooling, etc. All the systems in the car need to be upgraded to support the 20B. Bigger rad and oil cooler. Replumbing the fuel system for EFI with an appropriately sized pump. A stronger transmission (Mazda R type typically, from the TII or FD) needs to be installed but is not a bolt-in (tailshaft housing needs to be swapped to relocated shifter).

You'll need an aftermarket EMS to support it all, which needs to be tuned. There are so many little things like gauges, fittings, wiring, etc.

Best bet is to head over to the 1st gen subforum and search "20B".

Evil Aviator

The car was owned by "The Hitman", who used to be a Haltech EMS tuner. Aaron's estimate of $50K is about right for the high end, and maybe around $35K at the low end. I would check with Defined Autoworks to get an estimate if you are serious about bankrolling this project.

Here is a breakdown of The Hitman's car:

Chassis 1982 Mazda RX-7 Series 2, Freedom Bodystyling kit, 2-part Honda NSX Indy Yellow Pearl paint
Engine Custom made 3-rotor based on RX4/5 13B components, Custom made two-piece Crankshaft, 12A RX7 centreplates with one modified to take a stationary gear, RX-5 end-plates and rotor housings. Custom parts made by Jeff Bruce except apex seals. Series 6 stationary gears, bearings, and seals. 3mm Chromoly Apex Seals.
Inlet Custom-made 6-runner lower section , machined injector mount spacer and fuel rail, Mazda 20B upper Inlet and Throttle Thanks George
Exhaust 3-into-1 Tubular Header , 3.5" mandrel bent exhaust system with hand-built mufflers
Turbo Garrett TA45 with 76mm compressor wheel in an A/R 0.72 cover, unmeasured turbine wheel (large though) in a 1.22 A/R divided housing.
Intercooler Custom made by Plazmaman, hand fabricated aluminium ducting and throttle adapter. Custom alloy radiator supports.
Gearbox Toyota Supra Turbo 5-Speed , Custom "Jeff Bruce" Bellhousing Adapter, 3" Thick-walled Tailshaft
Clutch 6-Puck Brass, Heavy Pressure Plate, Hydraulic Direct-Acting Bearing Caliper
Diff Borg Warner 3.45:1 LSD (ex-Holden Commodore VL)
Radiator Mazda RX-7 FC Series 5 13B Turbo. Needs a bigger one.
Oil Cooler Mazda JC Cosmo 20B Turbo, may need bigger yet.
Fuel System Electronic Fuel Injection , 6x800cc Mazda 12A Turbo "Green" type injectors, Essex 7.0L/min high-pressure pump and filter, 62psi static fuel pressure, Fuel tank modified with sump pickup. Braided fuel lines with Aeroquip screw fittings.
Ignition Direct Fire , 13B Turbo Series 4 Crank Angle Sensor modified to take twin Hall Effect sensors with a 6-window chopper wheel for Main trigger with a single-window chopper for home trigger, 6xBosche HEC715 Coils , 2x M&W "triple dumb" ECU dwell-controlled ignitors, NGK B9EGV plugs, Magnecor Leads.
Computer Haltech custom setup: E6K controlling fuel injection and ignition timing. ECU controlling thermo fans, boost control, launch control, oil cooler fan.
Brakes Front:10.5" Diameter 1" Thick custom discs with Volvo 4-Spot Calipers
Rear: 11" Commodore discs , single-spot calipers
Suspension Koni Adjustable Shocks, Pedders custom heavy and lower springs, Urethane bushes. Soon to have stiffer adjustable coil-overs
Wheels 14" Neale's Wheels. Simmons 17" soon
Interior Standard Interior. Momo steering wheel , Alpine CD and comprehensive stereo. VDO Boost gauge.

Note from Evil Aviator - The turbo is a bit small, and some of the parts are a little outdated because this car was built about 15 years ago.

Aaron Cake

iTrader: (1)

Hitman also went about a weird way of making his 3 rotor. Instead of bolting in a 20B, which were very rare years ago when he built his car, he made his own 3 rotor.

Nowadays you can get a 20B from the eBay for $2000 (if you're lucky) to $6000.

Jesus Eunos Vega

just like everything. it all depends how deep your pockets are and how far down the rabbit hole your willing to.go

ALT2X2

iTrader: (2)

From what I know... Now days you can do a 3 rotor conversion in almost any car... Check out the Australian race tracks... But listen to Aaron cake, a 3 rotor conversion is extremely expensive, not to mention almost silly to throw 20K+ on an 600.00 barn find. It is still an awesome sleeper/dream car, but you will need to pack and move closer to your mechanic, because you will see him very often...

jairbne1725

thanks for all the info guy i have the motor already and it was going to go on my dune buggy but i found a Porsche motor and went that route instead. I do all of my own mechanical and fab work but i just don't have the extensive knowledge on the rotary engines. thanks again for all of the input.

WJM ROTARIES

It can be done I have a 20b in a ser 3 rx7 Hurricane but a bit expensive to bring yours to aust to do it. lol