One Whiskey Hotel Posted October 14, 2018 Report Share Posted October 14, 2018 (edited) Question I’ve had on my mind for a while: with reduction in manifold pressure due to the presence of a Turboplus intercooler on a 231, would one see the corresponding fuel flow decrease as well? Where the continental regulates fuel flow within the meter plates, it would seem to me this is correct, but would love the opinions of fellow M20K pilots and A&P’s. At 40” (on a below standard day) I see fuel flows that aren’t concerning, 22-23 gph. When I pull back for intercooler air difference, at around 36” I see lower flows around 20 gph. This isn’t quite what I saw when I bought the airplane, but I also was looking at a ship’s gauge that was about to die and be replaced with an EDM-900. TIT on takeoff full rich is about 1475-1490, and CHT’s about 385. I would admittedly like a little more fuel to cool things down, but last annual proved unsuccessful at getting higher flows even with a fuel meter overhaul. What fuel flows are fellow Turboplus equipped 231’s seeing, and at what power setting? A round of beers for your expert advice? Next time I’m in town... Edited October 14, 2018 by One Whiskey Hotel Quote Link to comment Share on other sites More sharing options...
N231BN Posted October 15, 2018 Report Share Posted October 15, 2018 After installing the intercooler the fuel injection system is adjusted so you get the same fuel flow at a lower manifold pressure. That TIT is way too high for takeoff power. Your mechanic needs to setup the fuel system while running 36" instead of 40" like the continental manual says. 1 Quote Link to comment Share on other sites More sharing options...
carusoam Posted October 15, 2018 Report Share Posted October 15, 2018 1WH, Expect the fuel metering to have figured out Temp and pressure changes along the way... Before you added the inter cooler, you weren’t making adjustments for summer vs winter OATs... but something had to... I bet Clarence @M20Doc might know... he has explained fuel set-up and operations on M20Ks before... The K has a very remarkable fuel system. Even the fuel mixture and priming systems are interesting. Best regards, -a- Quote Link to comment Share on other sites More sharing options...
kortopates Posted October 15, 2018 Report Share Posted October 15, 2018 58 minutes ago, N231BN said: After installing the intercooler the fuel injection system is adjusted so you get the same fuel flow at a lower manifold pressure. That TIT is way too high for takeoff power. Your mechanic needs to setup the fuel system while running 36" instead of 40" like the continental manual says. Indeed, a TIT above 1450F is essentially an emergency calling for the boost pump because of the insufficient fuel flow in the more modern POH's where 1450F is called out as a redline limitation for full power TIT. I would get it properly adjusted before further flight. 1 Quote Link to comment Share on other sites More sharing options...
carusoam Posted October 15, 2018 Report Share Posted October 15, 2018 Our @Turboplus guy has some pretty good insight on operations as well... Thats two questions for him today! Best regards, -a- Quote Link to comment Share on other sites More sharing options...
Guest Posted October 15, 2018 Report Share Posted October 15, 2018 The STC for the intercooler installation should/will contain instructions for correct set up of the fuel system. Generally increased air density caused by the intercooler will require more fuel. Clarence Quote Link to comment Share on other sites More sharing options...
One Whiskey Hotel Posted October 15, 2018 Author Report Share Posted October 15, 2018 (edited) 22 minutes ago, carusoam said: Before you added the inter cooler, you weren’t making adjustments for summer vs winter OATs... but something had to... The intercooler was present when I acquired this aircraft a little over two years ago. Fuel flows on the steam gauge were 22-24 gph. That gauge later laid an egg, and an EDM-900 was installed which removed the rest of the original engine instruments. I have heard the TIT gauge on original ship gauges read about 75 degrees low. That is somewhere in line with what I’m seeing (1400 on the steam gauge TIT vs. 1475 now). The only changes made other than the EDM-900 was a different A&P-IA for annuals. I’m right in the middle between Longview and Lakeport, but found an experienced M20 A&P in Wyoming. He reset the fuel flows last annual and I’ve felt they’re a little low since. Admittedly, when I saw 1400 on the original steam gauge prior to the EDM-900 and resetting of fuel flows in Wyoming at last annual, 1400 was achieved with roughly one twist less than full rich. Full rich then was about 1325-1340....but again, that was on a factory gauge alleged to indicate about 75 degrees lower than actual. On that note, I wish I hadn’t adjusted fuel flows at the same time as the 900 went in. I’d like to have had the chance to verify this rumor of steam gage inaccuracy. Quote The K has a very remarkable fuel system. Even the fuel mixture and priming systems are interesting. You can say that again! Edited October 15, 2018 by One Whiskey Hotel 1 Quote Link to comment Share on other sites More sharing options...
One Whiskey Hotel Posted October 15, 2018 Author Report Share Posted October 15, 2018 9 minutes ago, M20Doc said: The STC for the intercooler installation should/will contain instructions for correct set up of the fuel system. Generally increased air density caused by the intercooler will require more fuel. Clarence Has anyone here a copy of the Turboplus STC, specifically procedures for setting fuel flows? Are these substantially different than TCM SID97-3e? Researching this topic on Mooneyspace discussions previous, someone was after the Turboplus STC / SB for setting fuel flows, but hadn’t received it yet from them. Anyone have it now? Or, right to the point, are there are notable differences between SID97-3e and Turboplus procedures for setting up fuel flow? Thanks again, all! Quote Link to comment Share on other sites More sharing options...
carusoam Posted October 15, 2018 Report Share Posted October 15, 2018 Also look into the probe locations for the TIT. The ship’s gauge gets the known key spot. Mostly to protect the turbo vanes from becoming turbo nubs... Some added JPIs may be reading a secondary location. You want to know exactly what thermocouple is mounted in exactly which location... A Jpi 900 should be able to give exact readings for the important job it is doing... The only confusion comes from the location and depth of the thermocouple in the exhaust stream... There isn’t much room to assume a delta in tit is proper... 2 amu for a certified box and you still need to add a delta to have it work safely...? Followed by who is going to give you the delta that you can bet your power plant’s health on...? Or... is the jpi not certified for tit, and you want to use it still...? Call me confused... I remember somebody discussing this detail before... But certified instruments in certified machines shouldn’t be needing deltas... if they were needed, the official document, like the STC would call out a different Temp to go by... eliminating the delta caused by some older less reliable equipment... PP thoughts only, not an instrument guy. We have an instrument guy on MS, but he comes from a different company....EI... Want to ask him? He is pretty good with technical sensor questions... Best regards, -a- Quote Link to comment Share on other sites More sharing options...
Guest Posted October 15, 2018 Report Share Posted October 15, 2018 What model of engine is in your airplane? It should have a fuel injection pump similar to this one. Other things to check while you’re at it. Pressurize the exhaust and intake systems with a clean shop vac discharge, repair any leaks. Also check the the upper deck air system, leaks and loss of pressure here will lean the mixture. Clarence Quote Link to comment Share on other sites More sharing options...
carusoam Posted October 15, 2018 Report Share Posted October 15, 2018 Doc, From the OP/title... TSIO-360 T/O (Turboplus) Fuel Flows Seeing if @One Whiskey Hotel has additional data to add to that... Thanks for hanging around on Sunday evening! Best regards, -a- Quote Link to comment Share on other sites More sharing options...
kortopates Posted October 15, 2018 Report Share Posted October 15, 2018 The Turboplus document could have been summed up with how to adjust the Max MAP down by ~2.5" based on OAT relative to ISA and then says to follow the TCM guidance for setting up the fuel system, subject to the reduced MAP. But here you go: TSIO360 Fuel Setup - NEW 08.pdf But SID-97e is very old. The last revision of SID 97-3 was G which was obsoleted a couple years ago by M-0 Standard Practices & Maintenance which replaced 100's of SB's SID's and SIL's which is therefore very large. But I values you need are: GB & LB: 2700 rpm 40.0" (reduced per above) max FF 23.0-24.7 GPH However, at Savvy we recommend using a target FF of 0.5 to 1.0 GPH above TCM's high number (24.7) which yields a target of 25.2 to 25.7 GPH. Of course, your mechanic will need to ensure all the fuel flow set up parameters are in spec after changing any one. These are the idle unmetered fuel pressure and idle mixture (both at idle rpm of 700) and the metered max redline FF per above. FWIW, their is really nothing complicated about the TCM's fuel system, its actually the simplest between Lyc and TCM since it only meters based on volume unlike Lycomings which is much more complicated. The priming system though is unique to the TSIO-360 which was put on for really cold winter starts. None of the big bore Continentals have such a system. 1 1 Quote Link to comment Share on other sites More sharing options...
One Whiskey Hotel Posted October 28, 2018 Author Report Share Posted October 28, 2018 (edited) Thank you all for your replies, Had the fuel pressure set up at my local engine shop the other day, I think we’re closer but may still have some more to go. A&P at my engine shop was hesitant to go much more for fear of being too rich. In any event, unmetered fuel pressure on this TSIO-360-LB is now at 39 at 38.3” MP (based on a temperature that day of 15C). Takeoff fuel flow is 23.3 gph and TIT is 1400, highest CHT was 365 with mixture all the way in. If I’m understanding correctly though, I’m really looking for a little more still to get to around 25 gph (even if that means leaning a tiny bit to get 1400 TIT?), such that I may have another option to cool things down should anything (TIT/CHT) start to run warm, correct? When warner temperatures arrive (either in spring or in warmer climates in travel), I’m thinking these engine temps may increase some and more fuel pressure would be a friend to me and my engine. May take one more iteration of adjustment to get it right, do you concur? Edited October 28, 2018 by One Whiskey Hotel Quote Link to comment Share on other sites More sharing options...
kortopates Posted October 28, 2018 Report Share Posted October 28, 2018 44 minutes ago, One Whiskey Hotel said: Thank you all for your replies, Had the fuel pressure set up at my local engine shop the other day, I think we’re closer but may still have some more to go. A&P at my engine shop was hesitant to go much more for fear of being too rich. In any event, unmetered fuel pressure on this TSIO-360-LB is now at 39 at 38.3” MP (based on a temperature that day of 15C). Takeoff fuel flow is 23.3 gph and TIT is 1400, highest CHT was 365 with mixture all the way in. If I’m understanding correctly though, I’m really looking for a little more still to get to around 25 gph (even if that means leaning a tiny bit to get 1400 TIT?), such that I may have another option to cool things down should anything (TIT/CHT) start to run warm, correct? When warner temperatures arrive (either in spring or in warmer climates in travel), I’m thinking these engine temps may increase some and more fuel pressure would be a friend to me and my engine. May take one more iteration of adjustment to get it right, do you concur? You're still too low. You are at the bottom of TCM's range (assuming your FF is properly calibrated). Your TIT of 1400F is too high which is proof your FF is too low. To qualify that, in a modern POH a TIT of 1450 is max TIT limitation at full take-off power and you're too close at 1400F. It would be better to see your full power TITs closer to low 1300Fs. Your A&P should be targetting for a couple GPH higher at 25.2 to 25.7 GPH. To get it dialed in, you really need to take it up for a lap in the pattern, check the data and then re-adjust. You can't exactly get it to full MAP until you are accelerating down the runway and giving it a minute to climb at full power to 1000' agl will give you a minute of data for the FF to stabilize. What I do is measure it on the ground as close as I can get to full power without the cowling on and try to adjust by the how much I want to change it based on the actual in flight data, and then cowl it back up and take it for the test flight to check. Remember that unmetered fuel pump pressure for full power is just for reference to be in the ball park, Its metered fuel pressure and Fuel Flow that are primary for full power. And since you do have Fuel Flow that's really all you need for the high setting adjustment (as long as its shown to be accurate). 1 1 Quote Link to comment Share on other sites More sharing options...
N231BN Posted October 29, 2018 Report Share Posted October 29, 2018 16 hours ago, kortopates said: You're still too low. You are at the bottom of TCM's range (assuming your FF is properly calibrated). Your TIT of 1400F is too high which is proof your FF is too low. To qualify that, in a modern POH a TIT of 1450 is max TIT limitation at full take-off power and you're too close at 1400F. It would be better to see your full power TITs closer to low 1300Fs. Your A&P should be targetting for a couple GPH higher at 25.2 to 25.7 GPH. To get it dialed in, you really need to take it up for a lap in the pattern, check the data and then re-adjust. You can't exactly get it to full MAP until you are accelerating down the runway and giving it a minute to climb at full power to 1000' agl will give you a minute of data for the FF to stabilize. What I do is measure it on the ground as close as I can get to full power without the cowling on and try to adjust by the how much I want to change it based on the actual in flight data, and then cowl it back up and take it for the test flight to check. Remember that unmetered fuel pump pressure for full power is just for reference to be in the ball park, Its metered fuel pressure and Fuel Flow that are primary for full power. And since you do have Fuel Flow that's really all you need for the high setting adjustment (as long as its shown to be accurate). This is very sound advice. If you are using the 1400F target number from the MAPA article on how to fly a 231, you need to forget everything you read. That article has to be responsible for many premature top overhauls. If you are getting CHT's of 365 on takeoff with the cowl flaps open, you are clearly not getting enough FF or are climbing at too slow of an airspeed. 1 Quote Link to comment Share on other sites More sharing options...
Phil EF Posted October 29, 2018 Report Share Posted October 29, 2018 The GB limitation is 1650 max continuous TIT. Is the LB that much lower? (1400-1450) Quote Link to comment Share on other sites More sharing options...
N231BN Posted October 29, 2018 Report Share Posted October 29, 2018 The GB limitation is 1650 max continuous TIT. Is the LB that much lower? (1400-1450) Same turbo, same limitation. We are talking about what the TIT should be at takeoff power. 1 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.