[TenTec] Modifying Centaur air intake to reduce air noise?

[Jerry Volpe]

I wonder if anyone has successfully reduced the Centaur's noisy cooling 
system through modifications to the actual case. It seems to me that the 
slotted 'louver' design itself produces a siren effect due to the high 
velocity of air being sucked past the horizontal slots (a friend 
reminded me of the mechanics of how sirens work and the similarity to 
the Centaur louver air feed). I have been considering removing this 
entire section of top and bottom case and placing a safety round wire 
fan grill over the top.... or even just leaving it open all together.... 
perhaps inserting a chimney (pvc) through the case right up to the fan 
itself to minimize all hard edges. Anyway, before attempting a physical 
mod as dramatic as this I was wondering if anyone else had attempted 
this and what were your results? I think I recall someone 'bending the 
existing slots to minimize their apparent surface area, but I think 
removing them altogether would be a far better approach? Thoughts on this?

Jerry, KG6TT
Fairfield, CA