Dbro172
Well Known Member
I officially stand in the camp of folks who thought their cowl seal baffles were fine and then experienced great results from improving them. Previously I had the standard Vans material, cut into 3 segments along the sides and a couple in the rear. Seemed to seal fine, due to the markings on the top of the cowl but had a few puckers as well as the the front seals never really tucked behind the outboard sides of the inlets (i think a lot of air getting in through the outboard edges of the inlets).
I reworked them with better material and was able to do so with only a few cuts, as well as extend them forward a scoche to tuck behind the outboard side of the inlets. They seal very well, following the top contour of the cowl. Climbed to 10,000' yielded hottest Cyl #4 at about 370 and cooles #3 in the 330's. Leaned out in cruise in the 350's. A good 20 degree improvement. Now I'm playing with front dams to even things out in cruise and am at about a 10 degree spread.
Also tried a little experiment on the oil cooler to reduce and redirect flow through the fins and it too seemed to have a pretty dramatic effect:
I reworked them with better material and was able to do so with only a few cuts, as well as extend them forward a scoche to tuck behind the outboard side of the inlets. They seal very well, following the top contour of the cowl. Climbed to 10,000' yielded hottest Cyl #4 at about 370 and cooles #3 in the 330's. Leaned out in cruise in the 350's. A good 20 degree improvement. Now I'm playing with front dams to even things out in cruise and am at about a 10 degree spread.
Also tried a little experiment on the oil cooler to reduce and redirect flow through the fins and it too seemed to have a pretty dramatic effect:
