The Honda A Series engines, prominent from the 1980s to the 1990s, represent Honda’s commitment to efficiency and innovation. Known for powering classics like the Accord and Prelude, these engines laid the groundwork for Honda’s reputation in reliability. This guide delves into their history, specs, and enduring impact.

History of the Honda A Series Engines

Milestones:

• 1982: A16A1 debuts in the Honda Civic Shuttle (1.6L SOHC).
• 1985: A18A powers the Honda Vigor and Accord, expanding to 1.8L.
• 1986: A20A becomes the flagship 2.0L engine for the Accord and Prelude.
• 1990s: Phased out in favor of the B and H Series, but remain a cult favorite.

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Technical Specifications and Performance

The A Series featured SOHC designs, carbureted or fuel-injected systems, and cast-iron blocks. Below are key engines in the lineup:

1. Honda A16A1

• Displacement: 1.6L (1,590 cc)
• Valvetrain: SOHC, 8-valve
• Fuel System: Carbureted
• Power: 76–85 hp @ 5,500 RPM
• Torque: 93 lb-ft @ 3,500 RPM
• Applications: 1983–1987 Honda Civic Shuttle

2. Honda A18A

• Displacement: 1.8L (1,829 cc)
• Valvetrain: SOHC, 12-valve
• Fuel System: Carbureted/Fuel-injected (varies by market)
• Power: 90–110 hp @ 5,800 RPM
• Torque: 105 lb-ft @ 3,500 RPM
• Applications: 1985–1989 Honda Accord, Honda Vigor

3. Honda A20A

• Displacement: 2.0L (1,955 cc)
• Valvetrain: SOHC, 12-valve
• Fuel System: Carbureted (A20A1) / Fuel-injected (A20A3/A20A4)
• Power: 98–130 hp @ 6,000 RPM (JDM A20A3: 130 hp)
• Torque: 114–121 lb-ft @ 4,500 RPM
• Applications: 1986–1989 Honda Accord, 1986–1991 Honda Prelude

Performance Table

Engine Code	Displacement	Fuel System	Power (hp)
A16A1	1.6L	Carbureted	76–85
A18A	1.8L	Carb/FI	90–110
A20A1	2.0L	Carbureted	98
A20A3 (JDM)	2.0L	Fuel-injected	130

Cars That Used the Honda A Series Engines

• Honda Accord (1986–1989): A20A1 (USDM), A20A3 (JDM).
• Honda Prelude (1986–1991): A20A3/A20A4 (2.0L FI).
• Honda Civic Shuttle (1983–1987): A16A1.
• Honda Vigor (1985–1989): A18A (1.8L).

The A Series in Motorsport and Tuning Culture

While not as race-oriented as the B Series, the A Series found niche success:

• Rallying: Privateers used A20A-powered Accords in European rally events, leveraging their torque for loose surfaces.
• Drag Racing: In the 1990s, Australian tuners turbocharged A20A engines, pushing them to 200+ hp with forged internals.
• Modern Restomods: Today, restomod shops pair A Series blocks with modern EFI systems for vintage Hondas, blending classic looks with reliable power.

If you are interested you should read about the Honda B-Series Engine

Tuning the Honda A Series Engine

While the A Series engines weren’t designed as performance powerhouses, their robust construction and simplicity make them ripe for tuning. Here’s how enthusiasts squeeze extra power from these vintage gems.

1. Basic Bolt-On Modifications

• Cold Air Intake (CAI):
  • Cost: 100–100–250
  • Gains: 5–8 hp (improved throttle response)
  • Best For: A20A3 fuel-injected engines. A16A1 carbureted models benefit less due to restrictive stock carbs.
• Exhaust Upgrades:
  • 2.25″ Cat-Back System:
    • Cost: 300–300–600
    • Gains: 8–12 hp (frees up backpressure, especially on EFI engines).
  • Headers:
    • Cost: 200–200–400 (used)
    • Note: Rare aftermarket headers exist for A20A engines (e.g., DC Sports), but most are custom-fabricated.
• Ignition Upgrades:
  • MSD Ignition Coil: 80–80–150
  • Performance Spark Plugs (NGK): 20–20–50
  • Gains: Smoother revving, better combustion.

2. Fuel System and ECU Tuning

• Carburetor Upgrades (A16A1/A18A1):
  • Weber 32/36 DGV Conversion:
    • Cost: 400–400–600 (kit)
    • Gains: 10–15 hp (replaces restrictive stock carbs).
  • Jetting Kits: Fine-tune air/fuel ratios for 50–50–100.
• EFI Tuning (A20A3/A20A4):
  • Standalone ECU (Hondata S300 or AEM):
    • Cost: 800–800–1,500 (including tuning)
    • Gains: 20–30 hp with optimized fuel maps and timing.
  • Upgraded Fuel Injectors:
    • Cost: 200–200–400 (compatible Denso or Bosch units).

3. Forced Induction – Turbocharging the A Series

Turbocharging is possible but requires custom work:

• Budget Turbo Kit (eBay): 800–800–1,500
  • Includes: Turbo, manifold, intercooler, piping.
  • Gains: 150–180 hp at 6–8 psi (stock internals).
• Built Engine for Boost:
  • Forged Pistons/Rods: 1,000–1,000–2,000
  • ARP Head Studs: $120
  • Custom Tuning: 500–500–1,000
  • Total Cost: 3,000–3,000–5,000 for 250+ hp.

Risks: Stock A Series engines have low compression (8.8:1–9.3:1), making them turbo-friendly, but weak connecting rods can fail above 12 psi.

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4. Camshafts and Valvetrain Upgrades

• Performance Cams (Delta Camshafts):
  • Cost: 250–250–400 (regrind or custom)
  • Gains: 15–25 hp (aggressive lobes improve mid-to-high RPM power).
• Upgraded Valve Springs: 100–100–200 (prevents valve float).

FAQs About Honda A Series Engines

Q: Are Honda A Series engines reliable?
A: Yes, with proper maintenance, they often surpass 200,000 miles. Common issues include distributor failures and oil leaks.

Q: Can you turbocharge an A20A engine?
A: Yes, but aftermarket support is limited compared to B Series. Custom setups may be needed.

Q: What’s the difference between A20A1 and A20A3?
A: A20A1 is carbureted (98 hp), while A20A3 is fuel-injected (130 hp) and found in JDM models.

Q: Are parts still available?
A: Yes, through Honda specialists and online retailers, though some components are becoming rare.

Q: How does the A Series compare to the B Series?
A: B Series engines have DOHC and higher tuning potential, but A Series are simpler and robust.