I never noticed that one fan has two more blades than the other. Would that be the high speed fan?

 

I'll trade you, your 7 blade for my 5 blade, then you'll have a matching set

 

I got LT1 fans. I was just asking because I saw a picture.

 

yes they are different, I'm sure airflow is involved, no Idea which is for what.

Would be interesting though to find out, one: how a 100% stock 05 efan setup is actuated (i.e. conditions/speeds). two: which fan of the two is the high speed fan or any combination thereof. three: some cfm ratings.

 

those fans are the same as putting an fbody fan in these trucks... like as far as needing a nelson harness and what not?

 

I would expect that the two fans have different blade counts not for airflow reasons but for noise.

Two fans running with the same number of blades at close to the same speed (but not quite) will make a racket. Kinda like the drone of a twin engine boat (or prop type airplane) with the engines not quite "synch'd" up. Causes some interesting resonance and disharmony.

I'd bet that GM engineers use a 5 blade & 7 blade fan to eliminate NVH issues.

'Dreamin'