How to Improve LXi Engine Cooling Performance

[Hisham Amaral]

(11-23-2013 19:21)davidbrady Wrote:  Today I ran my usual bus exercise route two times. The first time I had the under-radiator shrouding in place and on the second loop I had it removed.

With the shrouding in place running at 65mph and consuming about 200hp the temps ran a fairly steady 193 deg F. Under the same conditions w/o the shrouding the temps ran at 190.
There are a handful of climbs on my route. With the shrouding in place the fan went to full speed 3 times. With the shrouding removed the fan went to full speed once.
The coolant temperatures climb more slowly at higher horsepower loads, they also drop more rapidly at lower horsepower loads, and they hugged the tstat open temperature of 190 deg F at loads less than 200hp.

This is about the best I can do w/o logging data and crunching numbers. I chose an average temperature day of 65 deg F, dry, and no wind. I was able to run back to back comparisons on the same 50 mile loop with the same ambient conditions.

It definitely cools better w/o the shrouding. It's an incremental improvement. I don't know if I'll get the same results by cutting louvers into the center shroud piece but I'm going to try!

David
Try to run the engine at Idle and see what will be the temps and how long does the cooling fan run. The only reason we used shroud is to disallow re circulation of air into the and around the cooling fan.
I agree that the system will run cooler and fan does not engage as often as it would when there is a shroud. Better airflow path. Be sure you get the engine to temperature before you run the idle test.
Hish