tmiked

In most designs a 5-bladed are not symmetric, so they pulse much less. I have not examined my 7 specifically.

Trexthe3rd

The question is have you tried it?? Everyone who has done the conversion including myself did not hear any increase in the noise nor any harmonics that is suppose to be there. Don't remark on other people's EXPERIENCED recommendations unless you have experiences that proves otherwise.
But just to point out the "obvious" that evryone who insist on the noise theory seems to take at face value. In order to generate a hamonic distortion (what you call pulse", the two fans have to be identical in all physical charateristics (weight, shape, size etc), and the 2 motors have to be spinning at the same exact speed, AND the fan blades have to be at the same exact orientation to achieve harmonic distortion.
There are no two motors that can produce identical outputs, therefor once in a while, when the orientation of two IDENTICAL fans come into phase (same orientation) there will be a brief harmonic distortion generated and then disappears. But if you look at the 4 blade fan on you car and the new 4 blade fan ordered from the dealer, you'll notice that the new fan have a small arched notch in each blade making it NOT identical to the original fan, therefor you will NOT get a harmonic distortion and cause the noise you fear so much over the 200 db exhaust noise and the 500W stereo.

Trexthe3rd

Thats true when the cooling system uses a single fan. Our 5 blade fan is symmetrical.

spurvo

I might throw in here that the water pump housing can come away from the block as you are removing the water pump itself. If this happens, you MUST pull the whole housing or you will have a coolant leak. That gasket tears real easy. Anyway, I'd get the water pump housing gasket to be safe.

Part No N386-15-162

jspecracer7

lmfao...YES. When I bought my 7, the 5 blade fan with motor was blown, so I had just the 4 blade running. I got a junk set of fans with a bad shroud but good motor/fan from jesselau2 and decided that it would be "cool" to use the same blade on the other side...guess what...sounded like a damn helicopter under the hood....

Now someone provide me with a CFM chart showing that the 4 blade "flow more air" than the 5 blade

Trexthe3rd

A "junk set of fans" did it ever occur to you the noise is from the condition of the junk fan/motor you got?

You are welcome to put your head under the hood of my car any time and have a listen. As for the flow rate ask anyone with both fans to put their hands in front of the two fans (5 blade and 4 blade). The 4 blade pulls so much more air than the 5 blade it's blatenly obvious. Go ahead and prove it to your self.

duboisr

Garfinkle has done the 4 blade fan on his car and several others with no thumping noise . Maybe luck but the benefit of more air flow is worth doing . If the noise is to loud in some cars then that is to bad for the people that tryed it . They will go back to stock. So far Gar has not heard one car that thumps . So how loud is it ?