[SkyKing]

Kevin, Bob, et al.,

Okay, maybe the following chart will help in the discussion, which shows recommended cruise-climb as well as normal cruise power settings.

Bob, your oil temps don't sound right... we very rarely see them approach 180 degrees unless it's a ++ISA day, and the rear engine always runs slightly cooler than the front with everything buttoned up. Maybe the Riley type intercoolers don't offer the same amount of "inter" cooling - ha! I've not seen the Riley up close, but from pictures it appears the radiator surface is somewhat smaller than the American Aviation units.

Another chart I attempted to scan wouldn't go, but basically the MAX POWER limitation is 35.3" MAP @ 2800 RPM for NORMAL takeoffs. For Density Altitudes above ISA, the chart reflects the correct MAP for a given condition, but in any event max is 37". Today, for instance, our OAT is 90 degrees at sea-level and the chart shows a MAP for takeoff of 36.3".

We normally cruise at 27" & 2300 RPM, and as you can see by the chart, that equates to approximately 55% power with a fuel flow of 57PPH each end using peak EGT for Best Economy, or 64PPH each end for Best Power. At this low cruise power setting, we opt for peak EGT or right in the middle, around 60PPH each end, so Kevin... you're burning more fuel than you need to -- if you have the AA intercoolers. We have the standard Cessna gauges and the dual Economy Mixture Indicator (EGT), which because of the probe placement in the exhaust stream is actually reading TIT. And note what the POH says... "Continuous operation at peak EGT is authorized only at 65% power or less."

SkyKing