[E90ice]

Forced Induction Engines vs NA Engines....

Which are affected most by altitude and heat?

Can someone explain?

[Driver72]

Altitude affects NA motors more than heat.
Heat affects FI motors more than altitude

[wj4]

Originally Posted by Driver72

Altitude affects NA motors more than heat.
Heat affects FI motors more than altitude

Altitude affects FI'd cars tremendously as well. For instance, here where I live, I had no problem boosting 25psi in my old car. When going to a track like LACR where it's 1000 feet above sea level, you're lucky if you hit 20psi.

I think both factors are about 50/50 for our cars. Temperature is the reason why I only WOT my car at night, during the hot sunny day, it feels so slow.

[SoCal335i]

LACR is more like 2700 feet above.

[Driver72]

Originally Posted by wj4

Altitude affects FI'd cars tremendously as well. For instance, here where I live, I had no problem boosting 25psi in my old car. When going to a track like LACR where it's 1000 feet above sea level, you're lucky if you hit 20psi.

I think both factors are about 50/50 for our cars. Temperature is the reason why I only WOT my car at night, during the hot sunny day, it feels so slow.

Altitude affects FI cars 1/2 as much as NA cars. An example:
A 335i and E46 M3 run nearly side by side at sea level, with a slight advantage to the M3.
At 2000 feet the cars will be side by side with a slight advantage to the 335i.
At 8000 feet the 335i will walk away from the M3

Heat on the other hand affects FI cars much more than NA cars (it takes a lot to "heat soak" a NA car, but a heat soaked FI car loses lots of power).