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- Jan 16, 2018
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I own a 1978 Turbo Lance II, with a TIO-540 S1AD engine. I now have 100 hours on the rebuilt engine and Turbo. My issue is the #4 CHT is running much hotter than any other cylinder. At high altitudes I’m having to burn 19-20 GPH to keep the temps in the 420’s. POH states 15.8 GPH at 65% power
Examples: At 15000’, OAT -5c, running 23/2300 my #4 CHT was 428/1310 EGT at 19 GPH. All other CHT’s in the low 390’s. All EGT’s between 1280 and 1310. At 8000’, OAT 1c, running 23/2300 my #4 CHT was 402/1350EGT at 18GPH. At 5000’, OAT 2c, running 23/2300, #4 CHT was 408/ 1480EGT, at 16 GPH.
We have checked the injector and it is fine, switched around CHT probes and no change. I understand that there is less air at high altitude but seems odd that with lower temps I need to increase fuel well beyond what the POH recommends in order to keep the CHT on #4 in the 420’s, well above where I would want it.
Examples: At 15000’, OAT -5c, running 23/2300 my #4 CHT was 428/1310 EGT at 19 GPH. All other CHT’s in the low 390’s. All EGT’s between 1280 and 1310. At 8000’, OAT 1c, running 23/2300 my #4 CHT was 402/1350EGT at 18GPH. At 5000’, OAT 2c, running 23/2300, #4 CHT was 408/ 1480EGT, at 16 GPH.
We have checked the injector and it is fine, switched around CHT probes and no change. I understand that there is less air at high altitude but seems odd that with lower temps I need to increase fuel well beyond what the POH recommends in order to keep the CHT on #4 in the 420’s, well above where I would want it.
