Prez721 Posted April 25, 2021 Report Posted April 25, 2021 I have a 1978 M20J that had the Turbo Bullet STC installed in 1990. About 6 months ago we lost the turbo. I had it rebuilt and believe it on not ... it failed again. Long story, but the oil line to the turbo was the problem. I've decided to remove the turbo and restore it back to the original design. I've bought the original exhaust that came on the M20J but need help with what the original design looks like ... and what we need or don't need. Not everything was included!!! If anyone has done this, i would appreciate any help you can offer. We have questions about the air induction pipe. The one I have now has a venturi inside it and wasn't sure if that's normal or built specifically for the turbo. Also not sure if I need the air cooler or should it be removed. The motor has the high compression pistons. Any original design plans or pictures would help. Thank you, Lee
ArtVandelay Posted April 25, 2021 Report Posted April 25, 2021 You’ve got cowling changes you’ll need to fix, and fuel system changes as well. There is no heat exchanger (air cooler), just an oil cooler behind the #4 cylinder. 1
Guest Posted April 26, 2021 Report Posted April 26, 2021 8 hours ago, Prez721 said: I have a 1978 M20J that had the Turbo Bullet STC installed in 1990. About 6 months ago we lost the turbo. I had it rebuilt and believe it on not ... it failed again. Long story, but the oil line to the turbo was the problem. I've decided to remove the turbo and restore it back to the original design. I've bought the original exhaust that came on the M20J but need help with what the original design looks like ... and what we need or don't need. Not everything was included!!! If anyone has done this, i would appreciate any help you can offer. We have questions about the air induction pipe. The one I have now has a venturi inside it and wasn't sure if that's normal or built specifically for the turbo. Also not sure if I need the air cooler or should it be removed. The motor has the high compression pistons. Any original design plans or pictures would help. Thank you, Lee I have a complete set of baffles, including the air induction pipe and air filter. Clarence
carusoam Posted April 26, 2021 Report Posted April 26, 2021 Hmmmmm.... Knowledge is going to be key... (sell side) Getting the turbo, exhaust and related parts and the STC paperwork boxed together... the system has the greatest value... (Buy side) Getting a copy of the Mooney Maintenance manual and Parts Manual is going to be super helpful for finding the parts you want to have and getting them installed... Buying parts from reliable resource like Clarence (above) adds a lot of value... We have a turbo parts dealer around here as well... that could be helpful... @Tomgo2 (not lit until needed) Best regards, -a- 1
LANCECASPER Posted April 26, 2021 Report Posted April 26, 2021 9 hours ago, Prez721 said: I have a 1978 M20J that had the Turbo Bullet STC installed in 1990. About 6 months ago we lost the turbo. I had it rebuilt and believe it on not ... it failed again. Long story, but the oil line to the turbo was the problem. I've decided to remove the turbo and restore it back to the original design. I've bought the original exhaust that came on the M20J but need help with what the original design looks like ... and what we need or don't need. Not everything was included!!! If anyone has done this, i would appreciate any help you can offer. We have questions about the air induction pipe. The one I have now has a venturi inside it and wasn't sure if that's normal or built specifically for the turbo. Also not sure if I need the air cooler or should it be removed. The motor has the high compression pistons. Any original design plans or pictures would help. Thank you, Lee Now that you've figured out what the problem is, if it was me I would definitely stick with the turbo. Once you've flown a turbo there's no going back. 5
Will.iam Posted April 26, 2021 Report Posted April 26, 2021 1 hour ago, LANCECASPER said: Now that you've figured out what the problem is, if it was me I would definitely stick with the turbo. Once you've flown a turbo there's no going back. Isn’t the turbo bullet one of those TN where the pilot controls the boost via another control lever a.k.a. The “second throttle” he could just fly around without ever adding any boost and see the effect before removing the turbo but i agree i would rather have the boost especially if it’s already on the plane than to spend money removing it also because since nobody can add a turbo to other Js now. He has a unique J that is worth extra when he goes to sell it. 4
aviatoreb Posted April 26, 2021 Report Posted April 26, 2021 What is the compression on the turbo bullet cylinders ? 1
aviatoreb Posted April 26, 2021 Report Posted April 26, 2021 10 hours ago, aviatoreb said: What is the compression on the turbo bullet cylinders ? I meant to ask - what is the compression ratio - I.e., a standard normally aspirated Lycoming IO360 has a higher compression 8.5 which is good for efficiency, but a typical turbo charged engine like my Continental TSIO520nb has a compression ratio of 7.5 which is not as good for efficiency but is really good for high altitude detonation margins. I wonder if the turbo bullet conversion since it is just turbo normalizing just went with the cylinders already on there or the stc included conversion of the cylinders to the lower compression typical of turbo boosted engines?
Prez721 Posted April 26, 2021 Author Report Posted April 26, 2021 Answer The Turbo has a fixed waste gate so you cant turn it off or on. Answer I've thought about fixing the turbo again and changing out the oil line ... that probably the best solution ... but I've trashed 2 of them and would hate to trash #3 in case it was more than just the oil line. Answer Tom ... Thanks Answer Clarence ... any chance of getting a picture of that air induction pipe ... inside and out? Answer I line in North Carolina and very rarely fly above 8,000 ft ... these Turbo Bullets are better above 8K but are a little doggie on takeoff and climb to 8K
gsxrpilot Posted April 26, 2021 Report Posted April 26, 2021 11 hours ago, Will.iam said: He has a unique J that is worth extra when he goes to sell it. That actually doesn't seem to be the case. This J would be worth more if the turbo is removed and it's put back to its original configuration. This is further evidenced by the fact that M20J's are bringing higher prices than comparable 231's and some even out price 252's. 2
Guest Posted April 26, 2021 Report Posted April 26, 2021 1 hour ago, aviatoreb said: I meant to ask - what is the compression ratio - I.e., a standard normally aspirated Lycoming IO360 has a higher compression 8.5 which is good for efficiency, but a typical turbo charged engine like my Continental TSIO520nb has a compression ratio of 7.5 which is not as good for efficiency but is really good for high altitude detonation margins. I wonder if the turbo bullet conversion since it is just turbo normalizing just went with the cylinders already on there or the stc included conversion of the cylinders to the lower compression typical of turbo boosted engines? I believe that the Turbo Bullet conversion installed lower compression pistons and boosted the manifold pressure, and the Rajay turbo normalizer limit manifold pressure to 30”. Removing the Turbo Bullet system means removing the cylinders and replacing the pistons with standard ones. Clarence
aviatoreb Posted April 26, 2021 Report Posted April 26, 2021 36 minutes ago, M20Doc said: I believe that the Turbo Bullet conversion installed lower compression pistons and boosted the manifold pressure, and the Rajay turbo normalizer limit manifold pressure to 30”. Removing the Turbo Bullet system means removing the cylinders and replacing the pistons with standard ones. Clarence That's what I had a foggy memory of what might be necessary - I didn't remember which was which I but turns out I did correctly understand that this may well be very expensive to convert if new original high compression cylinders would also be necessary. I could maybe see doing this at overhaul time but what a nuisance to do mid-time. 1
Shadrach Posted April 26, 2021 Report Posted April 26, 2021 On 4/25/2021 at 12:22 PM, Prez721 said: I have a 1978 M20J that had the Turbo Bullet STC installed in 1990. About 6 months ago we lost the turbo. I had it rebuilt and believe it on not ... it failed again. Long story, but the oil line to the turbo was the problem. I've decided to remove the turbo and restore it back to the original design. I've bought the original exhaust that came on the M20J but need help with what the original design looks like ... and what we need or don't need. Not everything was included!!! If anyone has done this, i would appreciate any help you can offer. We have questions about the air induction pipe. The one I have now has a venturi inside it and wasn't sure if that's normal or built specifically for the turbo. Also not sure if I need the air cooler or should it be removed. The motor has the high compression pistons. Any original design plans or pictures would help. Thank you, Lee I'm pretty sure the Bullett STC called for low compression pistons given the fact that the engine is boosted (38" initially and then reduced to 33" per AD in 1993). If your plane has standard 8.7/1 pistons the plane has not been operated in accordance with the STC. If it does have the correct pistons per the STC, they will need to be changed in order to conform to the TCDS and also as a practical matter. 2
Guest Posted April 26, 2021 Report Posted April 26, 2021 7 hours ago, Prez721 said: Answer The Turbo has a fixed waste gate so you cant turn it off or on. Answer I've thought about fixing the turbo again and changing out the oil line ... that probably the best solution ... but I've trashed 2 of them and would hate to trash #3 in case it was more than just the oil line. Answer Tom ... Thanks Answer Clarence ... any chance of getting a picture of that air induction pipe ... inside and out? Answer I line in North Carolina and very rarely fly above 8,000 ft ... these Turbo Bullets are better above 8K but are a little doggie on takeoff and climb to 8K Here are some pictures of the forward left baffle with the intake pipe and air filter mounting. Clarence
Prez721 Posted April 27, 2021 Author Report Posted April 27, 2021 Thank you all for your post. I think thew easiest and less expensive option would be to put the turbo back in. I'm getting with my mechanic in the morning and let him read all of your thought. Thank you all and i'll let you know what the outcome when its finished. Lee 1
ArtVandelay Posted April 27, 2021 Report Posted April 27, 2021 Thank you all for your post. I think thew easiest and less expensive option would be to put the turbo back in. I'm getting with my mechanic in the morning and let him read all of your thought. Thank you all and i'll let you know what the outcome when its finished. LeeHere’s an article on your engine:https://aeroresourcesinc.com/proj98-ci/WebContent/uploads/199010-1988%20Mooney%20M20J%20201SE%20Turbo%20Conversion.pdf 3
LANCECASPER Posted April 27, 2021 Report Posted April 27, 2021 10 hours ago, Prez721 said: Thank you all for your post. I think thew easiest and less expensive option would be to put the turbo back in. I'm getting with my mechanic in the morning and let him read all of your thought. Thank you all and i'll let you know what the outcome when its finished. Lee I would search out a Mooney Service Center that has some experience withe these installations to get it dialed in right.
carusoam Posted April 30, 2021 Report Posted April 30, 2021 Interesting technical challenge... I’m sure it was a challenge putting that system together... Reversing it will magically take about the same amount of effort... right down to every nut and bolt... So... if it looks easier to remove all the hardware and start over... Expect that is a higher cost than you planned... The Turbo bullet article supplied by Tom above... indicates the modified engine operates at 2575rpm, in place of the usual 2700 rpm... Another person in the recent past had come a cross a similar challenge... he bought a Mooney with a turbo system that wasn’t working... He had an incredibly difficult time ascertaining what was technically wrong with the intake system... A few discussions, a few hours in the shop, it all comes together... If you keep moving the goal posts... you will never score in this game... Pick a direction and follow it through... If you bought the plane because it is a TC’d plane capable of flying in the FLs... it would be best to find out why it is killing off turbos... there are only so many systems to review... follow the oil... If you are thinking about turning it back into the NA M20J... picture how much work is involved when changing out the pistons... It helps to have all of the manuals... Go read the article to determine what engine you have, and what it needs, to do what you want... PP thoughts only, not a mechanic... Best regards, -a- 1
carusoam Posted April 30, 2021 Report Posted April 30, 2021 There was a time... When people with extra Money... Took their expensive Mooney... And made it more expensiver... Swapping out pistons, changing compression, adding a turbo... Even getting a different cowl.... costs as much as a brand new car... Don’t be surprised by what it costs to add or subtract major devices... Keeping them running as designed can be expensive enough... PP thoughts only, not a finance guy... Best regards, -a- 1
Prez721 Posted May 6, 2021 Author Report Posted May 6, 2021 On 4/26/2021 at 11:37 PM, ArtVandelay said: Here’s an article on your engine:https://aeroresourcesinc.com/proj98-ci/WebContent/uploads/199010-1988%20Mooney%20M20J%20201SE%20Turbo%20Conversion.pdf Great article Tom ... Thanks
Prez721 Posted May 6, 2021 Author Report Posted May 6, 2021 On 4/30/2021 at 1:24 AM, carusoam said: Interesting technical challenge... I’m sure it was a challenge putting that system together... Reversing it will magically take about the same amount of effort... right down to every nut and bolt... So... if it looks easier to remove all the hardware and start over... Expect that is a higher cost than you planned... The Turbo bullet article supplied by Tom above... indicates the modified engine operates at 2575rpm, in place of the usual 2700 rpm... Another person in the recent past had come a cross a similar challenge... he bought a Mooney with a turbo system that wasn’t working... He had an incredibly difficult time ascertaining what was technically wrong with the intake system... A few discussions, a few hours in the shop, it all comes together... If you keep moving the goal posts... you will never score in this game... Pick a direction and follow it through... If you bought the plane because it is a TC’d plane capable of flying in the FLs... it would be best to find out why it is killing off turbos... there are only so many systems to review... follow the oil... If you are thinking about turning it back into the NA M20J... picture how much work is involved when changing out the pistons... It helps to have all of the manuals... Go read the article to determine what engine you have, and what it needs, to do what you want... PP thoughts only, not a mechanic... Best regards, -a- Thanks carusoam, You make some really good points. I thought it would be as easy as removing the turbo with a few adjustments, but thats definitely not the case. I've decided to keep it and find the oil problem. Thanks again! 2
KSMooniac Posted May 7, 2021 Report Posted May 7, 2021 I agree that you should fix what you have and get it running well. If you want to reverse it eventually, then start collecting the stock parts and make a plan to do the work when it is convenient, such as overhaul time, or if you need a top overhaul.If you don't have a modern engine monitor, consider adding one and learning how to use it well. Do that, and you'll get a lot better performance and longevity from your plane!If you remove the kit, there might be interest in your removed components for spares to support other installations. Sent from my LM-V405 using Tapatalk 1
KSMooniac Posted May 7, 2021 Report Posted May 7, 2021 I've been absent for a while! Too much work in a phone-free environment...Looking forward to the Caravan and OSH and reconnecting with this world. Sent from my LM-V405 using Tapatalk 1
Recommended Posts