How to Improve LXi Engine Cooling Performance

[cmillsap]

David,

BirdPilot made several good suggestions above. It makes me think that we may find a better solution to improve the cooling in our busses than installing the louvers. As it stands presently; our cooling systems can be described as adequate but having the ability to climb steep grades at a 10% or 15% higher road speed would be nice. I don’t like traveling in the truck lane on steep grades. That is not a good representation of the quality of a Wanderlodge but maybe I’m asking too much out of a 500 HP DDS60 to push a 50,000# behemoth up a long 6% grade at any higher speeds that it is presently capable of doing. It certainly has the power to do so if we could keep it a little cooler.

As previously mentioned, I believe the cooling system is more than adequate to allow better cooling if we could get more air cfm capacity through the radiator. I remember years ago when I owned a rear radiated Safari coach; I had the same condition. I complained to the factory and they sent me a nine bladed fan to replace my seven bladed original equipped fan. I don’t remember if the blade pitch was changed or not. I do know that it improved my ability to climb steep grades at a higher road speed.

The question now is: What is limiting the air volume (cfm) radiator throughput. Is it the static head pressure developed in the engine bay? Is it the fan’s capacity to move air against an ever increasing static head? Could it be that the slip stream effect of the air passing the side radiator limits the fan’s ability to draw from that slipstream? Or is it that the air being pulled through the radiator is limited due to its turbulence?

Several years ago there was a side radiated coach parked next to me. I noticed the owner had made a “scoop” and attached it to the trailing side of his radiator grill. He claimed it solved his overheating problem. I’m not suggesting we attach scoops to our radiator grill, just mentioning it to make a point of the slipstream’s potential effect on limiting available air for radiator throughput.

You manometer readings suggest that our present fan may not have the capacity to generate a static head of more than 0.80 in. of H2O. At its maximum head, the cfm volume becomes static also. Perhaps we should consider a fan replacement that is capable of more cfm at a higher static head. I think the fan generated air volume increase is substantial when I open the rear engine access door, especially if the fan is on override and running at maximum rpm.

Just some thoughts,

Chuck