Does anybody know of a difference between the generations of fans? I know there is 2 difference motor setups. 500 and 700 watt I think it is.

But the GMT900 are PWM controlled where GMT800 are a single speed but controlled by a Series/Parallel relay setup.

Setting up a couple turbo trucks and going to try the Dorman 902-310 SSR on them and ive got a set of 2006 fans to test them on.

Wondering if they changed the motors for PWM or are they the same?

 

Other than blade differences I do not know any difference.

 

The GMT 900 fans are pwm? I didn't know that. Well, I don't much about the 900s. 🫣

So since they are pwm, are they like variable speed then? I'm thinking of how the alternators that are pwm controlled from the ECU...

 

Yep. Same concept.
they are PWM by coolant temp and ac pressure.