<VV> CHT data

[AeroNed@aol.com]

I've heard about lowering the cylinder head temps 50 degrees by removing  the 
lower shrouds. I wanted to see for myself. I have two VDO gauges. The  left 
sender is attached where the thermister goes. The right one is located  under 
the snap switch. With all the shrouds installed, the left temp hangs  around 
300 and the right around 250. These temps change a little, maybe 20  degrees, 
with outside temp.
 
Today, I replaced a failed t-stat (repo failed - ULTRA installed) so I  
decided to remove the other lower shroud to do this experiment. After both  shrouds 
were removed, I went for a spirited ride (what other kind is there?) to  get 
the CHT to reach a stabilized value. Sure enough, the left side dropped  50-60 
degrees, just like everyone said it would. The real interesting thing was  
that the right side temp didn't change at all from the 250 degrees it read with  
the shrouds installed.
 
I crawled under the car to see what I could see. I'd say that the airflow  
over the heads was the same on both sides. The airflow over the oil cooler on  
the left side seemed very low. I went for another ride to get more data (the  
fact the it was a beautiful day and driving the Corsa is lots of fun was NOT a  
factor <G>). The second ride had the same results.
 
I'm thinking that removing the lower shrouds on the right side had little  or 
no effect. The "restriction" on that side is minimal. The 50 degree decrease  
in CHT on the left side is due to reduced airflow through the oil cooler. I  
don't have an oil temp gauge, so this is just a guess. With the lower shroud  
removed, the air flows in the direction of least resistance, over the heads.  
When the lower shrouds are installed more of the air flows over the oil cooler 
 and less over the heads which is the reason for the higher CHT.
 
That's just my opinion, I could be wrong....
Ned