As I was taught at Sheffield University, 1985, burning diesel oil does nuclear fusion.
1 C12H23+pO2+TU->(12CO2+(12-r)H2O-E)+r(He+O+E3)+H+X-ray TU=turbulence
So we would rather avoid hydrocarbons – as oxidising the carbon radical takes in heat. This requires 8 atmospheres. But at 10, water will diesel
2 H2O+TU->He+O+E3+X-ray data source Sheffield on my PhD 2000
The simplet way to enhance car performance is to change the fuel injection systems to economy burn. You can also Ti plate the emgine cylinders and head. This requires no modifications – other than turn the fuel injection system to an economy burn cycle. 2 times the power, for the fuel you use.
The Ti plate doubles the energy power – as the Face Centred Cubic metal catalyses the Molecular Nuclear Fusion. Berilium also works. But we need to increase the diesel pressure.
If you want to do a cone head modification to increase car engine pressure, read http://www.demon-tweeks.co.uk/blog/performance/need-more-power-our-top-5-ways-to-increase-your-bhp/
Once you have 10 atmospheres, we inject water, rather than dusel fuel. We get more power out – from regular tap water.
Stop at the service station, to refuel using a water jug in the tolets. And now the exhaust is He, O and steam. Like today – with no CO2. And you may have notice, water is nearly free. Filter out river water – and it is totally free.