Warren Posted October 14, 2018 Report Share Posted October 14, 2018 The intercooloer should resolve any issues with the inlet charge temperature. Ultimately the CDT will be reduced across the intercooler to a much lower inlet charge temperature. In my 231, the intercooler reduces the temperature 70-90 C. My intercooler STC reuires a temperature sensor that measures the CDT and Inlet Charge Temperture as well as the difference between the two. This decrease in temperature is used to adjust the maximum manifold pressure. Detonation can be caused by high inlet temperatures but with your intercooler this should not be the issue. General guidance for remaining clear of detonation are the following: More fuel - under full power, make sure there is plenty of fuel. In our engines, 23-25 gph gives good margin. If you aren’t seeing this much fuel, have it adjusted. Excess fuel is important for cooling and slowing the combustion burn rate under full power. Higher rpm - moves the peak cylinder pressure later in the cycle. Lower risk at 2700 rpm. Not too much MP - make sure you are accounting for the intercooler and reducing the MP appropriately. You can’t run 40” with this setup because the intercooler increases the density of the air and at 40” you are making more than rated power. Good luck. Quote Link to comment Share on other sites More sharing options...
N231BN Posted October 14, 2018 Report Share Posted October 14, 2018 I bought my M20K 231 without both TIT an CDT with cutted cables and only a JPI 700 to bad track both parameters. Just in the firs hot day my engine went into detonation, and I can tell you won't like to experience this situation since it was sounding that the engine was going to get all apart. After that I decided not to fly before the restitution of the old indications. Now I have TIT indication working perfectly after installing new cables that insane where cutted at time of installation of the JPI engine monitor. Still I have to restitute the CDT indication, but since my 231 have a Turbo-Plus intercooler. Can anyone can tell me how reliable would be this CDT indication to avoid future detonation in my GB engine?. Can you further describe the situation where you experienced detonation? Power settings, temps, fuel flow... Quote Link to comment Share on other sites More sharing options...
carusoam Posted October 14, 2018 Report Share Posted October 14, 2018 Avoiding detonation is done in two ways... automatically or manually... if left to the third method... randomly... undesired results can occur... Some equipment like an inter cooler, improves operations... but, requires proper instrumentation to avoid operating in a red zone... Fortunately, there is a set of instructions that comes with an STC’d intercooler. It will include all the instrumentation that is needed and the details of how to get the proper power settings. Turbo-plus is under new ownership and has done a good job of communicating where they are at with their equipment. Look for the STC. Confirm the proper installation. Use the proper charts to set the power... if using the old charts, missing instrumentation, or don’t have the STC... this is likely to cause a random error of too much pressure, or too much heat entering the engine’s intake resulting in detonation, melted pistons, and engine failure during high power operations like Take-off... We have a Turbo-Plus guy around here... find him. Note on thermistors... they can fail. Slowly, over time. Magically indicating a lower temperature than actual... See if we can find our TP guy... @Turboplus see if this rings a proper bell... for finding the STC details? PP thoughts only, not a mechanic... Best regards, -a- Quote Link to comment Share on other sites More sharing options...
Miguel Fisac Posted October 14, 2018 Report Share Posted October 14, 2018 Thank you al for all the comments, gave me good advises to operate well my GB engine, that is not easy. Of course I am following the Turbo-Plus STC and adjust the MP by the chart they provide, looking at the temperature decrease by the intercooler. One new questión would be if the CDT probe should be moved to the intercooler air exaut, so I really get the real temperature that the cilinders are getting in. Quote Link to comment Share on other sites More sharing options...
Awful_Charlie Posted October 15, 2018 Report Share Posted October 15, 2018 14 hours ago, Miguel Fisac said: Tne new questión would be if the CDT probe should be moved to the intercooler air exaut, so I really get the real temperature that the cilinders are getting in. No, if you want to know the temperature coming out of the intercooler, you should add the IAT (Induction Air Temperature). This will be another probe between the intercooler and fuel injector assembly - on a JPI it is just another probe, maybe like the EGT probes but other styles are available. I used a https://www.jpinstruments.com/shop/tit-716-20-screw-type-probe/ as this screwed into an existing boss on my induction system Quote Link to comment Share on other sites More sharing options...
carusoam Posted October 15, 2018 Report Share Posted October 15, 2018 More data is better... 1) You want temp before and after the intercooler. To know the inter cooler is still working... you want to know if something is blocking the airflow for some reason... 2) If the CDT is low, that is a sign of the turbo not working... 3) air temp entering the engine is important because that is the thing that causes pre-ignition... 4) TIT for the health and safety of your turbo blades... 5) if you get a chance to add another oil temp sensor, one exiting the turbo would be cool... this would help identify if the oil flow is getting blocked... a turbo health issue that is normally harder to sense. PP thoughts only, not a mechanic... Best regards, -a- Quote Link to comment Share on other sites More sharing options...
NicoN Posted October 15, 2018 Author Report Share Posted October 15, 2018 Thank you for all posters. I am not sure, I understood the correct type of CDT-sensor, which is originally installed in Mooneys driving the combined TIT/CDT-gauge. If it is a sensor like oil-temp, then I should be able to measure the resistence with an ohm-meter and see a difference in resistance if put in hot water -right ? Next question is about detonation: I may never have experienced this phenomen, or it is not that impressive. How does "detonation" sound or "feel" like? Is it a clearly audible effect? Are they any sudden changes in EGT/CHT/MAP or something like that ? Quote Link to comment Share on other sites More sharing options...
carusoam Posted October 15, 2018 Report Share Posted October 15, 2018 Lasar is really good at helping with what sensor you have in which location... If it is a thermistor the boiling water and resistance measuring will work... Detonation isn’t something that is detectable by the pilot until after the damage is done... unless you have a sense for where the ignition timing is actually happening? This is why the STCs and PoHs have charts to follow... Similar experience is shared for running LOP to avoid the red box... Best regards, -a- Quote Link to comment Share on other sites More sharing options...
Q The Engineer Posted November 16, 2022 Report Share Posted November 16, 2022 On 9/2/2018 at 12:07 AM, vance.k said: I had the same problem and found the wrong probe and a miswire. The replacement part was 880006-501 and I got it from Lasar, as an earlier poster mentioned. I’m also attaching a copy of the gauge spec sheet / drawing that helped me sort out the wiring and troubleshoot the readings. Good luck! 880000.pdf Thanks Vance, that's very helpful. Quote Link to comment Share on other sites More sharing options...
Q The Engineer Posted November 16, 2022 Report Share Posted November 16, 2022 On 10/14/2018 at 11:26 AM, Miguel Fisac said: Thank you al for all the comments, gave me good advises to operate well my GB engine, that is not easy. Of course I am following the Turbo-Plus STC and adjust the MP by the chart they provide, looking at the temperature decrease by the intercooler. One new questión would be if the CDT probe should be moved to the intercooler air exaut, so I really get the real temperature that the cilinders are getting in. No, leave it where it is. The compressor discharge temp is used to keep you out of high cycle fatigue problems on the compressor wheel. The compressor wheel is aluminum and loses fatigue strength significantly as compressor discharge temperature rises. It's so you keep the temps out of the problem range when flying. If not, you can fail a compressor blade, send the failed parts into the engine and have significant problems. If you want to run your settings tighter for detonation control, I'd install a separate intake manifold temperature sensor if you have an aftercooler on the engine. Quote Link to comment Share on other sites More sharing options...
Fly Boomer Posted December 5, 2022 Report Share Posted December 5, 2022 On 11/16/2022 at 10:15 AM, Q The Engineer said: No, leave it where it is. The compressor discharge temp is used to keep you out of high cycle fatigue problems on the compressor wheel. The compressor wheel is aluminum and loses fatigue strength significantly as compressor discharge temperature rises. It's so you keep the temps out of the problem range when flying. If not, you can fail a compressor blade, send the failed parts into the engine and have significant problems. If you want to run your settings tighter for detonation control, I'd install a separate intake manifold temperature sensor if you have an aftercooler on the engine. These posts you are responding to are 4 years old. Not sure these people are still on MooneySpace with any regularity. 1 Quote Link to comment Share on other sites More sharing options...
jlunseth Posted December 13, 2022 Report Share Posted December 13, 2022 Also it is just not accurate. TIT protects the turbo not CDT. TIT protects the turbo from fan blade deterioration. CDT protects the engine from detonation because of overly hot intake air. 1 Quote Link to comment Share on other sites More sharing options...
Dlummy Posted December 14, 2022 Report Share Posted December 14, 2022 I just removed working CDT and TIT probes and gauges from my M20K and have them if you're interested. I'm installing the EI and it's certified as a primary instrument so I don't need them anymore. Dave Quote Link to comment Share on other sites More sharing options...
Chuck Posted July 26, 2023 Report Share Posted July 26, 2023 On 12/14/2022 at 3:12 PM, Dlummy said: I just removed working CDT and TIT probes and gauges from my M20K and have them if you're interested. I'm installing the EI and it's certified as a primary instrument so I don't need them anymore. Dave Dave I have the original dual CDT-TIT gauge for my 20k but it no longer works. Curious what models you got because I didn't see on the EI website any gauge at all for CDT. Charles Quote Link to comment Share on other sites More sharing options...
LANCECASPER Posted July 26, 2023 Report Share Posted July 26, 2023 2 hours ago, Chuck said: Dave I have the original dual CDT-TIT gauge for my 20k but it no longer works. Curious what models you got because I didn't see on the EI website any gauge at all for CDT. Charles The EI certified units contain all of the instruments in one (MVP-50, CGR30P?). I believe they program CDT in there. Quote Link to comment Share on other sites More sharing options...
kortopates Posted July 26, 2023 Report Share Posted July 26, 2023 CDT is an optional add on with most monitors. If you have an aftercooler then what you want is IAT (unless you want the difference between CDT and IAT to determine the adjustment value for Map - but Turboplus sells a better gauge that just gives you the difference).Sent from my iPhone using Tapatalk 1 Quote Link to comment Share on other sites More sharing options...
glbtrottr Posted July 28, 2023 Report Share Posted July 28, 2023 I believe the issue revolves around primary gauges and airworthiness…which jpi loves as they want you to upgrade to their 900 series. They ne er STC’d the 830 as primary as they used to with the 700/711 precisely for that reason.Even if the sourced sensor primary / non primary is the same, it Carries a different part number.Many people at jpi are awesome. Sales? Hmmmm not so much. They also like to intercept support calls.Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
M20F Posted July 28, 2023 Report Share Posted July 28, 2023 CDT and TIT are an option on MVP-50. There are 4 quasi self setting options to display on it. Quote Link to comment Share on other sites More sharing options...
glbtrottr Posted July 28, 2023 Report Share Posted July 28, 2023 10 minutes ago, M20F said: CDT and TIT are an option on MVP-50. There are 4 quasi self setting options to display on it. Very much a fan of EI and I would have suggested it - except for… ”Several years ago a JPI830 was installed with tons of sensors - but not CDT!” and OP was asking about if it was worth it to hook it up to the 830. i believe some sticklers would say that the airplane is not airworthy without it, necessitating either the original gauge or extra money in an upgrade either for a dedicated gauge or a primary version of an engine monitor Quote Link to comment Share on other sites More sharing options...
M20F Posted July 29, 2023 Report Share Posted July 29, 2023 2 hours ago, glbtrottr said: Very much a fan of EI and I would have suggested it - except for… ”Several years ago a JPI830 was installed with tons of sensors - but not CDT!” and OP was asking about if it was worth it to hook it up to the 830. i believe some sticklers would say that the airplane is not airworthy without it, necessitating either the original gauge or extra money in an upgrade either for a dedicated gauge or a primary version of an engine monitor I have no idea what your point is. Quote Link to comment Share on other sites More sharing options...
Chuck Posted August 3, 2023 Report Share Posted August 3, 2023 On 7/28/2023 at 7:05 PM, glbtrottr said: Very much a fan of EI and I would have suggested it - except for… ”Several years ago a JPI830 was installed with tons of sensors - but not CDT!” and OP was asking about if it was worth it to hook it up to the 830. i believe some sticklers would say that the airplane is not airworthy without it, necessitating either the original gauge or extra money in an upgrade either for a dedicated gauge or a primary version of an engine monitor The situation with me is that I have a JPI 730 which does display TIT (not CDT) but in any case is not primary. With the loss of my original primary gauge - a dual TIT/CDT - I'm in "legal land" where I'm either replacing CDT/TIT with individual gauges or replacing my JPI, a far more expensive proposition. What is interesting is that JPI doesn't have a trade-in program. EI will take a trade-in but you only save about $1000 - so its a lot cheaper to go with individual gauges. I saw that EI has a standalone TIT gauge but I didn't see a CDT gauge on their website. I do have a TurboPlus intercooler (with gauges) which greatly reduces concerns about CDT temperature. But that doesn't make it legal. So I think I'm agreeing with what you are saying above (which is why I was looking into it). Thanks Quote Link to comment Share on other sites More sharing options...
kortopates Posted August 3, 2023 Report Share Posted August 3, 2023 13 minutes ago, Chuck said: The situation with me is that I have a JPI 730 which does display TIT (not CDT) but in any case is not primary. With the loss of my original primary gauge - a dual TIT/CDT - I'm in "legal land" where I'm either replacing CDT/TIT with individual gauges or replacing my JPI, a far more expensive proposition. What is interesting is that JPI doesn't have a trade-in program. EI will take a trade-in but you only save about $1000 - so its a lot cheaper to go with individual gauges. I saw that EI has a standalone TIT gauge but I didn't see a CDT gauge on their website. I do have a TurboPlus intercooler (with gauges) which greatly reduces concerns about CDT temperature. But that doesn't make it legal. So I think I'm agreeing with what you are saying above (which is why I was looking into it). Thanks Its at this junction between deciding to spend money on fixing your CDT/TIT or buying additional primary replacement gauges that most people make the decision to upgrade to modern primary monitor like the EDM-900. The modern monitor will provide for full data logging, greatly increasing your logged parameters beyond EGT & CHT to include FF and all other power parameters as well as eliminate future need to replace the next primary gauge that goes bad like MAP or RPM. And its an investment that actually increases the resale value of your Mooney. If your EDM 730 is decades old, you really want to replace the old EGT and CHT probes and harness anyway with a new monitor. Personally I would still keep the turbo plus differential gauge just because of it's convenience to you. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.