The interesting thing about GT race cars compared to their street car brethren is the race car is sometimes less high-tech or racy compared to the street cars. Gone are the carbon brakes on the street car, replaced by two-piece brake rotors with cast iron rings on aluminum hats. As the street GT is going to make over 600hp, I think it’s a safe bet to say the race car will have less power much like the C7.R Corvette race car has less power than the Z06 street car. It is truly amazing that street cars have more power than race cars nowadays. Anyway, back to the Ford GT, the race car has converted from 5-lugs holding the wheel on to a single center locking nut. Another race car mod where the A-pillar meets the fender is the air-line hook-up for the onboard jacks.
There are no speed bumps on race tracks, so the Ford GT race car has side skirts very low to the ground compared to the street car. Being as close to the ground as possible should help the side skirts minimize any high pressure air above from curling into the low pressure area under the car and screwing up the underbody airflow reducing downforce. A major mechanical change from street car to race car is where the exhaust dumps. On the street car, the exhaust dumps out the two melon shooters in the middle of the rear of the car. On the race car, the exhaust dumps out the sides of the car at the rear of the side skirts. Why did they do this? We’ll get to that in a bit.
A closer look at the exhaust dumps shows two tubes. One should be for the flow out of the turbine wheel of the turbo while the smaller tube is for the wastegate flow. Remember, you want minimum back pressure on the turbine wheel (Check out this turbo tech article on why), so keeping the flows separate is ideal.
Where the street car has the exhaust dumping out the twin cannons in the middle of the bodywork, the race car just has vents for getting hot air out of the engine bay area. The vents are into a low pressure area at the rear of the car which should help pull the air out too. Remember, race cars need lots of cooling! Those small side vents on each side of the engine bay also lose the plastic insert on the race car to minimize the resistance to the hot airflow to be vented out. The air dumps for the intercoolers are through the middle of the rear brake lights on the street car and I imagine it’s the same on the race car. The race car does appear to have wider bodywork to fit wider race rubber. The other huge difference between street and race cars at the rear is the hacking of the rear bumper and addition of the massive rear diffuser for more downforce.