Chito's 20B RX7

20B FC3S PROJECT CAR

My name is Chito Solomon, from Northridge, a suburbs of Los Angeles, California. I want to share with you a project I started about five years ago – a 20B conversion of a 1987 second generation Rx7 (FC3S).

It all began when a close friend of mine, Bebot Rodriguez, introduced me to rotary powered vehicles. He asked me, "Have you heard of a three rotor 20B engine?"

The original car was left-hand drive (as most cars are in the United States, except for postal delivery cars & vans). It was converted to right-hand drive (to make it more unique) by using parts from a used Japanese import. The 20B was fitted with a Ford T5 transmission and Tilton’s twin-plate racing clutch (capable of 750ft/lbs torque). The 20B flywheel was replaced with the original TurboII flywheel although using the 20B counterweight. The original TurboII bellhousing as well as the original starter were used.

The original engine crossmember was modified to accommodate the original 20B engine mounts. Also, the drive shafts were modified to accommodate the Ford tranny and the original Mazda rearend.

As the 20B is about seven inches longer than the 13B TurboII engine, the radiator was moved farther forward and replaced by larger one made of aluminum with a cooling fan. The huge Spearco intercooler was also fitted in front. With these space-consuming modifications, air-conditioning was removed and the front sway bar was modified.

Due to the extremely complex layout the sequential twin turbos and no original EFI computer to run it, the original twin turbos were removed and replaced by a single Garret T64 turbo. The original 20B in the Eunos Cosmo generates a stock 280HP, up to around 350-400HP with minor modifications. Running a stock engine with a single T64 turbo produced 457HP on the wheels with 434 ft/lbs torque (see Jackson Racing Dynomometer sheet, page 2). 550cc injectors were used on the primaries and 1100cc injectors on the secondaries. Given that, the 20B should have enough fuel for about 10-12 lbs boost with a little left over in injector capacity so it does not lean out. The exhaust is custom-made from stainless steel with a 3 ½ " downpipe to a 3 ½" Borla stainless steel resonator branching into two 3" stainless steel pipes and two 3" Tri-Flow mufflers. Evidently, it sounds great.

The Electromotive TEC1 engine management system was used with two sets of three coils, three spark plugs goes into one set of coils (the other side is grounded). Two crank angle sensors were used which are 180 degrees apart, (leading and trailing). The TEC unit manages both ignition and fuel.

Additional modifications were also made such as the strut braces, coil overs all around with Tokico Illuminas, and front camber plates. Tri-Point racing body flares and spoilers were installed. Three-piece Panasport wheels (16 x 10) with 265/45vr16 Kumhos were used.

Finally, I would like to thank my good friends who helped me a lot with this project: Bebot Rodriguez, Alan Santos, Chito Cuison, Tony Santiago, Jun Arriola, Louie Depante and specially Fred Miranda, who actually wired, programmed the TEC unit, and made the car roadworthy.

If you have questions, e-mail me at rx720b@aol.com (r-x-7-2-zero-b).