From 1989 until 1998, a Japanese company produced the 2.5-liter Honda G25A engine, which was used in the company’s large models, including the Inspire, Rafaga, Ascot, Vigor, and Saber. This engine was developed from the power unit of a Formula 1 car, according to a well-known legend.

Another internal combustion engine in the G-series is the G20A.
The engine was mounted on:
- Acura TL 1 (UA) in 1995 – 1998;
- Honda Ascot 2 (CE) in 1993 – 1997;
- Honda Inspire 1 (CC) in 1989 – 1995;
- Honda Inspire 2 (UA) in 1995 – 1998;
- Honda Rafaga 1 (CE) in 1993 – 1997;
- Honda Saber 1 (UA) in 1995 – 1998;
- Honda Vigor 3 (CB) in 1989 – 1995.
Specifications
| Production years | 1989-1998 |
| Displacement, cc | 2451 |
| Fuel system | injector |
| Power output, hp | 180 – 190 |
| Torque output, Nm | 225 – 235 |
| Cylinder block | aluminum R5 |
| Block head | aluminum 20v |
| Cylinder bore, mm | 85 |
| Piston stroke, mm | 86.4 |
| Compression ratio | 9.0 – 10 |
| Features | SOHC |
| Hydraulic lifters | no |
| Timing drive | belt |
| Phase regulator | no |
| Turbocharging | no |
| Recommended engine oil | 5W-30 |
| Engine oil capacity, liter | 4.3 |
| Fuel type | petrol |
| Euro standards | EURO 1/2 |
| Fuel consumption, L/100 km (for Honda Inspire 1996) — city — highway — combined |
12.6 7.8 9.7 |
| Engine lifespan, km | ~350 000 |
| Weight, kg | 170 |
Disadvantages of the Honda G25A engine
The motor’s dependability is undeniable, but there are issues with spare parts and maintenance;
Frequent oil leaks from gaskets and seals annoy the majority of owners;
The timing belt travels approximately 100,000 kilometers, and in 100% of cases, the valve bends when it breaks;
A dirty throttle or idle valve is typically the cause of the floating engine speed; hydraulic lifters are absent, and valve clearances must be changed every 40,000 kilometers.
