Honda B20A engine

Partially unrelated to the Honda B-series engines are the B20A and B21A. By some, these are not considered (by tuners) to be part of the B-series group of engines because they are not compatible with most of the other B-series parts and all of the other B series chassis.

There were 2 versions of the B20A

  • The first generation of B20A engines was available in the 86-87 Prelude 2.0SI in Japan and Europe, the 86-89 Honda Vigor and Accord . It leaned towards the front of the car just like the A20A engine found in the same cars. This B20A produces and torque in Japan. In Europe this called B20A1, produces and 172 Nm.
    • There was also a similar engine named B18A for the 86-89 Accords. It was a destroked B20A powered by 2 Sidedraft Keihin carbs.
  • The second generation of B20A was found in the 88-91 Prelude. The 88-91 Prelude B20A and B21A blocks are cast so they lay at an 18-degree angle leaning towards the firewall. This was done to please the exterior specifications for the 1988-1991 3rd Generation Prelude due to its ultra-low hoodline which Honda dubs the "engineless design" and also for handling reasons due to placing the engine at an angle gives it a lower center of gravity (similar to straight 6 designs in older BMW's).

The B20A, B20A3, and B20A5 engines consisted of closed-deck aluminum blocks with thicker-than-average iron sleeves where as the B21A1 had FRM (fiber reinforced metal) cylinder liners.

The B21A1 was basically a re-worked B20A5 with an increase in bore to . The external block dimensions had to stay identical (although there was increased external strengthening and webbing on the B21) to the B20A5 block so Honda called upon Saffil to create a thin but strong cylinder liner called FRM (fiber reinforced metal) which basically consisted of a carbon fiber matrix, aluminum alloy, and aluminum oxide to make a very strong cylinder sleeve. But, the 2.1L engine is notorious for burning oil. A lot of B21A1 engines burn oil and have low cylinder compression numbers. The original 2.0L (USDM B20A5 and JDM B20A) engine did not suffer the same problem. Good news though, you can usually replace the piston rings without any honing to the sleeves and go another + without any sleeve wear .


(16-Valve, 4 Cylinder, DOHC, PGM-FI)

  • "Honda" logo in center of valve cover - Filler cap on left side of cover.
  • Found in:
  • Displacement: 1958 cc
    • bore:
    • stroke:
  • Compression: 9.4:1; 9.5:1
  • Power:
    • (JDM GOLD TOP B20A 1986-1987) @ 6300 rpm & 186 N·m @ 4000 rpm, using PH3 ECU
    • (JDM BLACKTOP B20A 1988-1989) @ 6300 rpm & 186 N·m @ 4000 rpm, using PH3 ECU
    • (EDM, B20A1 Gold Top) @ 6000 rpm & 172 N·m @ 4000 rpm, using PJ5(602,603,752),PJ7,PH3 ECU w vac. advance
  • Transmission: B2K5, F2K5


This is for the B20a that came in 88-91 Preludes, not the same motor as listed above. (16-Valve, 4 Cylinder, DOHC, PGM-FI)

  • Found in:
  • Power: @ 6000 rpm
  • Torque: 128tq @ 4500 rpm
  • Compression ratio: 9.4:1


(16-Valve, 4 Cylinder, DOHC, PGM-FI)


(12-valve, SOHC, dual side-draft carburetors)

  • Found in:
  • Power: @ 5800 rpm (MT)With cata, @ 5800 rpm without cata
  • Torque: @ 4000 rpm
  • It was PGM-CARB microprocesor controlled (pk-1)


(12-Valve, SOHC, dual side-draft carburetors)


(16-valve, DOHC, PGM-FI)

  • Found in:
  • Power: @ 6200 rpm
  • Torque: @ 4000 rpm
  • Engine cc: 1958.14
  • Cylinder cc: 489.535
  • Deck cc: 13.885
  • Head cc: 47.3
  • Compression Ratio: 9.0:1


(16-Valve, DOHC, PGM-FI)

  • Found in:
    • 1988-1991 Honda Prelude Non-U.S. New Zealand, and Australian Domestic Market
@6000 rpm 174 nm@4500 rpm KY model is one of them


(16-Valve, DOHC, PGM-FI)

  • Found in:
    • 1988-1991 Honda Prelude Non-U.S. UK, France, Holland, Norway, South Africa
  • Power @6000 rpm
    • 132tq (180nm) @ 5500rpm
      • Compression ratio 10.5:1


(16-Valve, DOHC, PGM-FI)


(16-Valve, DOHC, PGM-FI)

  • Found in:
    • 1990-1991 Honda Prelude Non-U.S. Finland, German, Norway, Netherlands, Russia, Argentina
  • Power @6000 rpm
    • Torque 129tq (175Nm) @ 4500rpm
      • Compression ratio 10.5:1


(16-valve, DOHC, PGM-FI)

  • Found in:
  • Very rare, it was only produced for the "Si States" models in Japan
  • Power:
  • Torque: 186 N·m (137 lbf·ft)
  • Compression Ratio: 10.5:1

engine using a pk-3 honda ECU


(16-valve, DOHC, PGM-FI)

  • Found in:
  • Power:  @5800 rpm
  • Torque:  @5000 rpm
  • Engine cc: 2056.03
  • Cylinder cc: 514.0075
  • Deck cc: 10.191
  • Head cc: 51.0
  • Compression Ratio: 9.4:1

See also


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