Need help on manual testing chart

[ivantoar]

Automation Launcher 2013-05-29 13-59-49-91.jpg (37.34 KiB) Viewed 2058 times

Noob question but I need to know:
1. What is number 1, 3, and 4?
2. On bigger/higher performance engine, number 2 will turn red unless I enlarge the exhaust diameter. What does it mean and how do I properly make it "green" again?
3. Number 5 looks like radiator to me. Am I correct? In what case it will stressed out?

[WizzyThaMan]

1: Airfilter/Airintake
2: Muffler
3: Intercooler
4: Fuel/air valve
5: Crankshaft

The reason the exhaust turns red is that the airflow is too low for the amount of air and gasses trying to get out, thus limiting the car power.

Killrob Edit: Corrected.

[ivantoar]

Got it! Thanks Wizzy and Killrob!

[T16]

The "fuel/air valve" is typically called a throttle