The Best K Series Engine

The Best K Series Engine

The 2.4L K24 engine is the best starting point for any K series engine swap. They are relatively easy to find, modify, and are capable of making 220-230whp and 180+wtq with proper supporting upgrades. Specifically, the JDM K24A engine with head code RBB-3 and / or RBB-4 are the best k series engines you can buy for your k-swap. 

Photograph of K24A engine on engine house in enthusiast garage K-SERIES

How do you tell if a K24A is High Compression? Check the head code (located underneath cam angle sensors) for "RBB-" followed by either 1, 2, 3 or 4. If the engine you are looking at has a head code of RBB-3 or RBB-4, you are looking at the most potent K24 on the market. 

Photograph of HONDA ACURA 2.4L K24A RBB-3 HEAD - 3 LOBE VTEC ENGINE MOTOR K-SERIES

Why is the K24 the best and not the K20? The K24 is a big block. It produces more torque, and is more reliable. The K24 features more durable connecting rods and superior counter-weighted crankshafts Compared to the K20, the K24 engines have less problems. One example being the improved timing chain design of the K24.

 

Photograph of K24A2 vs K20A2 Dyno Chart Graph Comparison

Why is the JDM K24A with head code RBB-3 or RBB-4 the best K-Series Engine? Don't get me wrong, the RBB-1 and RBB-2 head code 2.4L K24A engines are not bad, they are still based on an aluminum cylinder block with:

  • cast iron cylinder wall liners
  • 231.7 mm deck height
  • 99 mm stroke crankshaft
  • 87 mm pistons
  • 157 mm length connecting rods
  • compression ratio of 10.5
  • 6,000 rpm VTEC engagement
  • 60 mm throttle body
  • output of 187-200 hp 
Photograph of HONDA ACURA ENGINE 2.4L K24A RBB-2 HEAD - 3 LOBE VTEC 4 CYLINDER MOTOR K-SERIES

The RBB-3 and RBB-4 head code K24A engines are much better. The engine was revised with:

  • cast iron cylinder wall liners
  • 231.7 mm deck height
  • 99 mm stroke forged crankshaft (with more counterbalance weight)
  • 87 mm lightweight pistons (with a height of 30 mm; increasing valve-piston clearance)
  • 157 mm length reinforced connecting rods
  • compression ratio of 11.1
  • 4,500 rpm VTEC engagement
  • 36 mm intake valve heads
  • 64 mm throttle body
  • output of 201-205 hp
Photograph of HONDA ACURA JDM ENGINE 2.4L K24A RBB-3 205HP - 3 LOBE VTEC 4 CYLINDER MOTOR K-SERIES

The K24A is the "best bang-per-buck" (or value-per-dollar) K-Series engine of the lineage. The K24A is a high displacement torque monster of an engine. With simple bolt-on upgrades and E85, these engines will make over 240HP Naturally aspirated. The biggest downsides of the K24A are the limited VTC gear and balance shaft oil pump. However, both can be upgraded for a couple hundred dollars, making it a small hurdle to jump for an engine with extreme upside potential. We offer both the 50 degree VTC cam gear, and the K24 oil pump upgrade kit here at Liken Motorsports.

Photograph of RSX Type-S K20 PRB Oil Pump (left) vs TSX K24 RBB Oil Pump (right)

Where can you find the JDM K24A with head code RBB-3 or RBB-4? Contact your local engine depot or check online. Here is an example of where you can secure a HIGH COMPRESSION RBB-3 JDM K24A ENGINE. More often then not, you will be allowed to go in-person (if they are local to you) and hand select the engine you want to purchase. So be sure to exercise your right as an educated consumer / enthusiast, and check those head codes. 

Photograph of K-Series Engines at JDM ENGINE DEPOT IMPORTER
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