FloridaMan Posted May 16, 2019 Report Share Posted May 16, 2019 Was climbing out yesterday and lost manifold pressure in the climb and amended altitude to 160. It wasn't a sudden or catastrophic loss, I just couldn't maintain 35" so I cruised at 2300/29". If I pushed the throttle forward I could get 33", but I wanted to leave some headroom as I believed I was dealing with an intake leak and was concerned my turbo might be running at excessively high RPM. At 10,000ft, I was able to get a full 38" of MP. Previously, I might start seeing a drop from 38" to around 37" at over 20,000 and could get close at 24,000ft. I could maintain a 35/25 climb to 240, but fuel pressure would drop off and I'd have to use the low boost for assist. I haven't tried going that high since getting my engine monitor installed. 1 Quote Link to comment Share on other sites More sharing options...
aviatoreb Posted May 16, 2019 Report Share Posted May 16, 2019 9 minutes ago, FloridaMan said: Was climbing out yesterday and lost manifold pressure in the climb and amended altitude to 160. It wasn't a sudden or catastrophic loss, I just couldn't maintain 35" so I cruised at 2300/29". If I pushed the throttle forward I could get 33", but I wanted to leave some headroom as I believed I was dealing with an intake leak and was concerned my turbo might be running at excessively high RPM. At 10,000ft, I was able to get a full 38" of MP. Previously, I might start seeing a drop from 38" to around 37" at over 20,000 and could get close at 24,000ft. I could maintain a 35/25 climb to 240, but fuel pressure would drop off and I'd have to use the low boost for assist. I haven't tried going that high since getting my engine monitor installed. Yoru symptoms worry me too. Given the fuel pressure is also involved - I don't know what's going on. Until I read the fuel pressure was involved I was guessing your turbo is getting tired and maybe ready for an overhaul - vs what you suggested which is a induction leak that I would guess would not happen rather suddenly. In any case, this change seems important to sort out right away. Your airplane is talking to you, so listen! Which of course is what yoiu are doing and why you are posting here. 1 Quote Link to comment Share on other sites More sharing options...
FloridaMan Posted May 16, 2019 Author Report Share Posted May 16, 2019 11 minutes ago, aviatoreb said: Yoru symptoms worry me too. Given the fuel pressure is also involved - I don't know what's going on. Until I read the fuel pressure was involved I was guessing your turbo is getting tired and maybe ready for an overhaul - vs what you suggested which is a induction leak that I would guess would not happen rather suddenly. In any case, this change seems important to sort out right away. Your airplane is talking to you, so listen! Which of course is what yoiu are doing and why you are posting here. Another thing that happened was I had forgotten to get my pair of keys from my IA and was using the ignition key on my heavy keychain. In the climb, turbulence switch me to one mag. I felt a hiccup and then noticed the rising TIT and rectified it before it went into the red -- first by increasing richness to cool TIT, then backing off on power, noting that the CHTs were down around 300 and then noticed I was on one mag. That's when I first noticed the loss in MP. The engine and turbo have less than around 350 hours SFRM. On the trip up, the plane performed without issue so this was a sudden onset. One other thing is that oil consumption appears to be up a bit on the plane with a quart every 5 hours. On a Lycoming, that would not be a concern, but this is an increase in consumption for this engine. I do run aggressive power settings in climb and cruise at 2400/32". All other instruments were completely normal in cruise as if I'm using standard power settings. Descending resulted in increasing manifold pressure like an NA airplane. Quote Link to comment Share on other sites More sharing options...
aviatoreb Posted May 16, 2019 Report Share Posted May 16, 2019 13 minutes ago, FloridaMan said: Another thing that happened was I had forgotten to get my pair of keys from my IA and was using the ignition key on my heavy keychain. In the climb, turbulence switch me to one mag. I felt a hiccup and then noticed the rising TIT and rectified it before it went into the red -- first by increasing richness to cool TIT, then backing off on power, noting that the CHTs were down around 300 and then noticed I was on one mag. That's when I first noticed the loss in MP. The engine and turbo have less than around 350 hours SFRM. On the trip up, the plane performed without issue so this was a sudden onset. One other thing is that oil consumption appears to be up a bit on the plane with a quart every 5 hours. On a Lycoming, that would not be a concern, but this is an increase in consumption for this engine. I do run aggressive power settings in climb and cruise at 2400/32". All other instruments were completely normal in cruise as if I'm using standard power settings. Descending resulted in increasing manifold pressure like an NA airplane. That is interesting and spooky regarding the heavy key chain!! Quote Link to comment Share on other sites More sharing options...
RLCarter Posted May 16, 2019 Report Share Posted May 16, 2019 I have seen several ign. switches fail and or come apart on motorcycles due to too many keys. Quote Link to comment Share on other sites More sharing options...
N231BN Posted May 16, 2019 Report Share Posted May 16, 2019 Have you had an increase in idle RPM? Quote Link to comment Share on other sites More sharing options...
FloridaMan Posted May 17, 2019 Author Report Share Posted May 17, 2019 1 Quote Link to comment Share on other sites More sharing options...
Yetti Posted May 17, 2019 Report Share Posted May 17, 2019 i'd be mad at whoever worked on the turbo last. Quote Link to comment Share on other sites More sharing options...
carusoam Posted May 18, 2019 Report Share Posted May 18, 2019 Turbos and tubes...... a good conversation to have with the mechanic... V-band clamps on the hot side can be a bit more dangerous... If the hose clamps came off the cold side.... you really want to make sure they aren’t going to come off the hot side too... Now where is the oil going? Is it showing up in the tail pipe? Check the age of the last turbo OH / reseal... seals have a tendency to get used up.... PP thoughts only, not a mechanic. Best regards, -a- Quote Link to comment Share on other sites More sharing options...
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