Using just some low-cost tools, you can easily measure the flow restriction of your car’s intake and exhaust. It’s like having a huge flow-bench always available. By making some simple on-road measurements, you can plot the shape of the engine’s power and torque curves – no dyno needed. This allows you to not only see if performance Modifications s to the engine are improving power, but also see where in the rev range those changes are occurring. Assess the worth of cams, a larger turbo, changed boost control or altered engine management mapping. 
But the book doesn’t stop there – it also shows you how to measure your car’s aerodynamics, seeing if at speed your car is developing lift or downforce. Want to make a rear wing work well? Test the angle at which downforce is greatest. You can also test the aerodynamic airflow through oil coolers, intercoolers and radiators.
Interested in improving your suspension? By using a low-cost app and a smartphone, you can accurately measure suspension behaviour. 
If you want a practical, hands-on book that will immediately save you money, show where Modifications s are most needed, and can be used to assess performance outcomes, this is the book for you.

Additional Information
Modifying cars is about achieving results. This book allows people to achieve better results by testing the effectiveness of their performance Modifications s, at low cost and on the road.

This book puts practical and effective performance measuring techniques into the hands of the home modifier.

I woould like further information on Optimising Car Performance Modifications Julian Edgar