Was just reading a MotorTrend First Drive review of the Lotus Exige S 240 and they mention that the Exige has a "suspension designed to break away/collapse in the event of a crash"

They mention that this is because its more of a track car and is there to help minimize the damage done to the aluminum chassis.

Is this a normal feature on real race cars? Hows it work, do the struts just disconnect from the body when a certain amount of force is exceeded?

 

Yes, it is a common feature. Races cars have done this for years as a way to dissipate energy in a crash. The designer I know has talked about this exact thing when doing suspension design. When you see an Indy car hit a wall and lots of parts start flying off just remember that it takes effort (energy) to tear all those bits off. That means there is less energy to harm the driver.

Also, racecar repair is different than roadcar repair. It generally isn't a big deal to replace a suspension arm. It's actually not even that big a deal to have to replace a suspension arm mount. Again, these parts generally tear away in a wreck.

I would also mention one other thing, compared to a race car, a road car is always way over built. A little bit of extra beef in a part may cost Honda almost nothing. A little bit of extra beef in a Lola or VanDiemen part could men the difference between being competitive and too heavy. Generally they don't want to add anything more than they have to get the job done, or feel that the car is safe (even in racecars, safety sells).

 

If I damaged the chassis on my elise, I'd total the car. If I break a suspension bit, it's a few grand and a couple days. I'll choose the latter.

 

I suspect this is actually a common thing for all cars, not just race cars. When a car crashes into something, energy is dissipated by deliberately having parts between the impact site and the passenger compartment collapse or displace.

I sort of parked a Skip Barber formula car at a 45 degree angle into the wall at Laguna Seca once. The right front suspension basically broke off at its mounting points, but that was all the visible damage to the car.