Squish VS Compression In A 500HP Hayabusa V8 Engine | Radical Sportscars [TECH TALK]

The RPV8, a 400-500HP Suzuki Hayabusa based V8 engine, is used as an example to help explain compression ratios and squish with James Pinkerton of Radical Performance Engines.

The N/A Hayabusa V8 used in some Radical Sportscars models runs a 12.5:1 to 13.5:1 ratio on 98 RON pump gas, with only the higher ratio becoming prone to knock, aka detonation, before minimum timing for best torque (MBT) is reached. In this interview James explains why he would choose more ‘squish’ over a higher compression ratio along with exactly what squish is and why it is so important for a complete fuel burn not just to make as much power as efficiently possible, but also to reduce the chance of detonation which can cause terminal damage to your engine very quickly in some circumstances.

Interestingly even with the knock limitation the change of compression from 12.5:1 to 13.5:1 can see an increase of 10-15HP which is getting down to some of the last small percentages of power increases from the potentially 500HP power plant depending on variant.

TIMESTAMPS:
0:00 - Intro: What Compression Ratio Should You Run?
0:19 - RPE V8 Compression Ratios: 12.5:1 To 13.5:1
0:38 - Fuel Requirements: 98 RON Minimum
1:00 - Knock Limit At 13:1 On Pump Fuel
1:18 - What Does "Knock Limited" Mean?
1:48 - Power Difference Across The Compression Range
2:11 - Effect On Fuel Efficiency
2:30 - What Is Squish?
2:52 - Squish Vs Compression Ratio Trade-Off
3:09 - Compression Ratio And Flame Front Travel
3:45 - How Squish Reduces Detonation Risk
4:15 - Thanks James and RPE!