Fast Car Physics

I was looking for a book to replace the highly dated text I have been using in my Chassis Engineering course. Based on the description here, I thought this might be the one. Having read it, though, I am designing a new course using it as my text. Yes, it's that good!Other reviewers have gone into detail about its strengths. I agree with them. For my purposes, the book only has two weaknesses. 1) it's too short and 2) it doesn't cover brakes except as it relates to cornering strategy. Others may not agree, and that's okay. Neither one is major, and the fact that I'm adopting the book as a text and building a new course around it means that I don't think they're showstoppers, either. All in all, it's a great book, an easy read, and a wealth of knowledge.

Lots of great info, but some is very technical/science. Nice to know the science behind my car and what happens on the track.

I loved how it was about racing and how to relate a lot of what I thought useless things in high school in to reality. some of the subjects were way over my head but still made me think of things in a whole new way

Item was not new as advertised. Has writing in it...

I am an electrical engineer and now appreciate the complexity of car functions. The book is very good in its explanation of theory and practice

Being both an engineer and a car enthusiast, this book is right up my alley. I approached it with much anticipation, and at the end I wasn't disappointed. Though a few points could have been explained better and benefitted from more graphics, overall the book is plenty clear, covers a lot of material, and includes enough derivations of equations to satisfy people with a good physics background. I highly recommend this book to every car enthusiast, since it can greatly deepen your understanding of how cars should be designed and driven, and the challenges involved in both.The following are my notes on the points from the book I personally found most worth remembering:(1) Acceleration equals TG/mR, where T is engine torque (minus drivetrain losses of about 15% to 25%), G is overall gear ratio, m is car mass, and R is wheel radius. This equation shows that acceleration is primarily related to torque rather than horsepower, but acceleration must drop with higher speed as G increases.(2) Since P = Fv and F = ma, a = P/vm, so horsepower is also important, since it can be viewed as the ability to generate acceleration at a given speed, but maximum acceleration is still inversely related to speed, as noted above. This is why cars have higher accelerations (and can spin their wheels) at lower speeds as compared to higher speeds.(3) The maximum grip of street tires is about 1.1 g, so for powerful cars, tire grip, rather than torque or horsepower, is the limiting factor in acceleration at lower speeds. Specialized tires for drag racing can generate a grip of more than 4 g under ideal conditions. And because of the grip limit, AWD cars can achieve up to about 25% better acceleration than 2WD cars. Considering all of this, the best 0-60 time attainable is about 2.5 s (1.1 g acceleration the whole time). Race cars improve traction and stability by using wings and ground effects to produce substantial down force.(4) Large-displacement naturally-aspirated engines typically have more low-rpm torque and higher overall acceleration. By contrast, forced induction (turbocharged or supercharged) engines compress the air entering the cylinders and have a more peaked torque curve.(5) Top speed is the point where acceleration drops to zero, and thus the force generated by the engine equals aerodynamic drag (roughly proportional to speed squared) and rolling resistance. Because of the effect of gearing ratio, this force (and thus top speed) is not always achieved in top gear, but rather in the next lower gear.(6) Maximum overall acceleration is typically achieved by upshifting at redline, or a little below redline.(7) Acceleration can generally be increased by increasing gear ratio, but this is at the expense of lower top speed and lower fuel economy.(8) Power is defined as torque x rpm (analogous to Fv), so the horsepower curve is implicit in the torque curve, the two curves always intersect at 5252 rpm (assuming units of horsepower and lb-ft), and the shape of the horsepower curve can readily be inferred from the shape of the torque curve. Also, peak horsepower will typically occur at higher rpm than peak torque.(9) On the track, the fastest possible lap time is achieved by finding the optimal racing line and keeping the car at its limit along this racing line. The racing line varies somewhat between cars. Because of the banked track, Indy cars lap at an average of 225 mph.(10) The friction circle shows the limits of a car's grip in the longitudinal and lateral directions. For the best lap time, a car should be kept close to this circle as much as possible (though staying strictly on the circle is physically impossible, due to the need to switch from acceleration to braking, and switching direction of turning). For cars which generate significant aerodynamic downforce, the friction circle will vary with speed. Also, tire temperature affects grip, and thus the diameter of the friction circle.(11) Speed achievable through a turn is proportional to the square root of radius (and tire friction), so the radius should generally be maximized. However, when sequential turns are involved, a line must be chosen which is optimal for the group of turns.(12) An implication of the friction circle is that there must be an inverse relationship between braking/acceleration force and turning force. This means trailing off the brakes while turning into a corner, and gradually adding throttle while unwinding the steering while on exiting a corner (after the apex). Exit speed from turns is especially important, especially if followed by long straights, and higher exit speed is achieved by later apexing (slow in, fast out). Later apexing is also generally safer.(13) A non-flat track changes the optimal racing line and acceleration/brake points, since crests decrease grip and sags increase grip ("compression").(14) The CG is one of a car's most important performance parameters, the CG height perhaps being most important, since this directly affects load transfer, and low CG is also needed to ensure slipping before rolling (most passenger cars need 1.3 to 1.5 g of lateral force to roll over, so slipping occurs first if tire grip is less than 1.1 g). A 50/50 weight distribution from front to rear is also desirable.(15) Tires are among the most important and complex factors affecting a car's performance. Tires must be properly inflated to prevent uneven wear, and tire pressure increases as tires become warmer.(16) Tire grip is due to both adhesion and mechanical grip. In wet conditions, adhesion is lost more than mechanical grip. Grip is generally optimal when tires are warm. Grip increases with vertical load up to a point, and then decreases with further vertical load.(17) When turning, the angle of the tires generally doesn't match the direction of the car's movement, and the difference is the slip angle. Slip angle generates both lateral force and induced drag (which slows the car).(18) A car with equal slip angles front and rear is neutral. Higher slip angle for the rear results in oversteer, whereas higher slip angle for the front results in understeer ("pushing"). At low speeds, slip angles are small enough to be neglected. At higher speeds, slip angles increase, and tendency to oversteer or understeer may depend on speed. Nearly all production cars are designed to understeer, since slowing down will tend to restore front grip and thus reduce understeer.

Excellent book. Author gets the physics right and provides insight.

As a text book this is much more readable than dry stuffy more academic books but it does lack a little bit in depth against others. I have found it very usefull though as a resource for my dissertation. and I think anyone trying to understand vehicle dynamics could learn something from this book. the only drawback is that it uses American units so every force is described in foot pounds and Slugs but the equations still work if you want to use metric units

All OK, Thank you all.

This book quickly turns you into a car expert! It explains the physics behind getting a car working in much detail.