Fit Compression Ratio
4 Answers
The compression ratio of the Fit's engine is 11.5. Below is an introduction to the Fit's compression ratio: 1. The compression ratio refers to the degree to which the engine's air-fuel mixture is compressed. 2. It is expressed as the ratio of the total cylinder volume before compression to the cylinder volume after compression. 3. The compression ratio has a significant impact on engine performance; the higher the compression ratio, the greater the engine's power output. Below is some related information about compression ratio: 1. (V swept volume by piston + V combustion chamber volume) / V combustion chamber volume. 2. An engine with a compression ratio of 10 compresses the combustible mixture to 1/10 of its original volume. 3. An excessively high compression ratio can lead to reduced stability and a shortened engine lifespan.
Last time I went for maintenance, I specifically studied the Fit's engine data. The Honda Fit's L15B engine has a compression ratio of 11.5:1, and the new hybrid version even achieves 13.5:1. The high compression ratio design allows gasoline to burn more completely, so the Fit's 1.5L naturally aspirated engine can deliver 131 horsepower. It's particularly noticeable in daily driving—just a light press on the accelerator at a traffic light, and it takes off. However, it's important to use 95-octane gasoline and regularly clean carbon deposits, as this high-compression engine is quite sensitive to fuel quality. Avoid filling up at small gas stations, or the engine light might come on.
The compression ratio of the third-generation Fit has been tested. The older gasoline version was 10.4:1, while the current 1.5L Earth Dreams models are all 11.5:1, with the hybrid version being even more extreme. Many people buy the Fit specifically for this reason – the high compression ratio combined with i-VTEC provides exceptional low-end torque, making overtaking in city driving effortless without needing to floor the throttle. However, this design also has drawbacks. In summer, when climbing hills with the AC on, it's prone to knocking – I've personally heard the 'ticking' sound of engine knock. It's recommended to take the car on the highway once a month to rev the engine higher, which helps clean carbon deposits from the combustion chamber and can also reduce fuel consumption.
When researching Fit modifications, I looked into compression ratio data. The Fit's 11.5:1 compression ratio is considered high among naturally aspirated cars. Combined with direct fuel injection technology, it can achieve fuel consumption of just over 5 liters. However, a high compression ratio means a more compact combustion chamber, requiring special attention during modifications: for example, installing high-angle camshafts can easily cause piston-to-valve contact. Previously, a car enthusiast tuned the ECU to increase the ignition advance angle, resulting in frequent knock sensor alarms. For modifications, it's recommended to maintain the factory settings, at most replacing it with a low-resistance air filter.
