Tunnel Motor Question

[brad_in_omaha]

Probably a stupid question, but why do they not make tunnel motors anymore? There are still tunnels all over the country...

 

[kenw]

because part of the theory behind them (the lowered intakes) didn't prove as big a benefit as originally thought, and what did work about them (much larger radiator intakes) was incorporated into newer designs. You will notice that most newer engines have much, much larger radiators, this has the same (and even more) cooling effect as moving more air over smaller radiators.

 

[brad_in_omaha]

Ok. Thanks Ken!

 

[Pat]

I've read there was a difference in radiator life. The fans blowing through the radiator like a tunnel motor gave particulate a higher velocity at the blade tips than fans that pulled through radiators. The article said tunnel motors had a shorter radiator life as a result.

 

[kenw]

I've read there was a difference in radiator life. The fans blowing through the radiator like a tunnel motor gave particulate a higher velocity at the blade tips than fans that pulled through radiators. The article said tunnel motors had a shorter radiator life as a result.

Generally speaking, and with lots of caveats, pull thru gives a better distribution of air over the coils than push thru. Lots of things impact that, like inlet/outlet geometries, air paths, coil-blower spacing, etc, but all being equal pull thru is more efficient.