I did not have room for an extra oil cooler or one larger oil cooler on the firewall. So elected to use the Revmaster oil cooler. The Revmaster oil pump flows 50% more oil; perhaps that does the trick, don't know for sure. The Revmaster spring temperature regulator does work as advertised keeping the oil temperature at 170 degrees F.
The air inlets for the engine cylinders are approximately 2-1/4 x 6 inches each. Fiberglass ducts direct air to VW metal shrouds ($26 for a pair) which in turn direct the cooling air down onto the cylinders just like the Beetle car installation. Definitely use the cool tins too. The single inlet for the oil cooler, is 2-1/4 x 10 inches. The ratio of the total areas of inlet area for both the cylinder head cooling ducts and the oil cooler inlet on the front of the cowl compared to the single outlet at the bottom rear of the cowl is 1 to 1.45. The oil cooler inlet is on a flat face square into the wind stream just below the prop; seemed like a high pressure location to me. The outlet has a ramp at the bottom of the cowl to get the warm air out into the low pressure location behind the cowl (inspired by Mark L.). The four exhaust pipes terminate in two ramps at the bottom edge of the cowl to provide augmentation of the outlet air flow (similar to the T-34B). I was definitely avoiding the kind of outlet found on the bottom of Cessna type cowls; these seem to have a huge hole on the bottom and hope the air gets out some how. Conventional wisdom says the outlet ratio should be 2.5 to 1. This is not a pressure cowl, conventional installation. My goal was to minimize cooling drag. Cylinder head temperatures vary from one cylinder to another about 10 degrees F. After about a 5 minute warm up, the head temperatures stabilize from 340 to 355 degrees F depending on throttle setting. Steve Bennett recommended 350 degrees F. Sid Wood Tri-gear KR-2 N6242 Mechanicsville, MD, USA -----Original Message----- > https://s3.amazonaws.com/expercraft/sidwood/164594493535aecddd7537.jpg Hi Sid I just look at your photo of your cowling, I just wonder whats the area on the front opening for the inlet of air, compare to the area back of the cowling? Regard Leif NORWAY -------------------------------- Hello Sid,I was wondering the same question as Leif?Is there a ratio of the areas?Thanks,Bill Jacobs Daytona Beach, Fl. -------------------------------- Sid,Had same issues with the 7500BTU cooler from GPAS so I bought another 7500BTU cooler and put them in series.Worked much better.They have a 15000BTU unit that would have done the trick but I was able to stack the 2 and may have saved a little space.Tommy W.
