Looking for a shop that has good turbo experience

[skyfarer]

Can anyone recommend a shop in the midwest that is familiar with our Bravo turbo setups? Mine has an issue that I need looked at. As I increase the throttle, normally the turbo would kick in smoothly at around 27" or so. But recently it hangs at 27 even as I'm twisting the throttle higher. It eventually kicks in all the sudden to red line and then comes back. At that point I can smoothly push the throttle in and MP follows normally to red line.  I replaced the waste gate last year when I discovered that it was leaking oil. I see some oil around one of the controllers (I'm not sure if it's the density or the differential one) so I think one or both of these could use a cleaning/inspection/test. I'd really like the whole system checked over and properly rigged by someone with experience on these systems.

Thanks!

Jeremy

[skyfarer]

I should add that I'm on Don Maxwell's schedule to deliver it to his shop last week of February for it's annual. So I'm trying to decide if I get the turbo system looked at now or just wait for Don to look at it.

[Rick Junkin]

@skyfarer There are two MSCs near us (I'm in Gatlinburg TN). Cole Aviation (706) 271-0222 at KDNN in Dalton Georgia and AGL Aviation (828) 391-8645 at KMRN in Morganton NC. You might give them both a call and see what they have to say about fitting your need. 

AGL has changed ownership since my last annual there but I've heard good things about the new owner. Lynn Mace, the previous owner, is a solid guy and now works at Maxwell's.

Cole Aviation has a good rep but I don't know how versed they are with our Bravo turbo system.

Both are within an hour and a half of Louisville by Mooney.

[Fritz1]

Don is probably your best bet, end of Feb is just around the corner, to work correctly the controllers need about 180 dF oil temp, are you sure it is not just the gauge that is erratic? my density controller was not kicking in enough boost at high IAT and overboosting at low IAT, instead of trying to fix it I installed an IAT probe that feeds to the EDM700. There is a table in the service manual, typically you want at least 35" at low temp and at the most 37" at high ambient temp, the IAT probe is easy to install, intake plenum has a thread for it, with that probe you can fine tune takeoff power boost, I have never seen boost over 37" in my engine though, that is how I have set my density controller after a fair amount of tweaking

[skyfarer]

@Fritz1  I think you’re on to something here because this problem has become worse as it’s become colder here. I think I remember this happening last winter, sporadically. Then the problem disappeared in the summer. Yesterday it was the coldest I’ve flown, -4C on the ground. The engine oil was about 40F, and the cylinders about 40F too before I rolled her out to start. I didn’t run up until the oil hit the green arc, 100F. The POH say 75F min oil temp for run up and 100F for take off.  Looks like Lycoming says 165F minimum is ideal.

Anybody else fly the Bravo in really cold weather and have some tips or similar experiences?

 

[Z W]

Lubricating automatic wastegates with Mouse Milk seems to prevent or fix many issues with erratic boost. No experience with your engine but mine gets lubricated at every oil change and annual.

[LANCECASPER]

14 hours ago, skyfarer said:

@Fritz1  I think you’re on to something here because this problem has become worse as it’s become colder here. I think I remember this happening last winter, sporadically. Then the problem disappeared in the summer. Yesterday it was the coldest I’ve flown, -4C on the ground. The engine oil was about 40F, and the cylinders about 40F too before I rolled her out to start. I didn’t run up until the oil hit the green arc, 100F. The POH say 75F min oil temp for run up and 100F for take off.  Looks like Lycoming says 165F minimum is ideal.

Anybody else fly the Bravo in really cold weather and have some tips or similar experiences?

 

What weight of oil are you running?

[PilotX]

From recent experience you will know when the turbo stops turbroing. Need to lube mine as well.

[Fritz1]

second the mouse milk, causes reproductive harm in California though, preheating helps a lot, Reiff heater gets engine to 120 dF, running 1500W cabin heater in hangar prevents windows from freezing over during taxi, Phillips XC 20W50 appears to do well in the Bravo engine

[Fly Boomer]

Great picture.  I'm saving that one.

[skyfarer]

On 1/17/2025 at 8:50 AM, LANCECASPER said:

What weight of oil are you running?

Phillips X/C 20w50

[skyfarer]

Chalk this one up to “always learning”. It was warmer today, but still below freezing at 3000’. 

I closed the cowl flaps while taxiing and watched the CHT’s carefully They all stayed about 280-300. The Oil temp came up much faster, I opened the cowl flaps 50% once the oil was at 150dF. The turbo started to kick in on run up, which is what I normally expect. Then for take off, cowl flaps full open, no issues with the turbo kicking in on command!

So lesson learned, when it’s really cold I need to pay attention to keeping the engine and oil warm.

[Fritz1]

Maxwell will set it perfectly if needed, you want to see at least 34.5" pretty much under all normal circumstances, you will have alt least 70 dF IAT even when it is very cold, lets say ambient below -20C, the defining moment comes when there is a hot and high takeoff your IAT may go to 140 dF at slow speed before the intercooler start pushing, you want all the power you can get and may need 37" boost, you can adjust the density controller by turning the square piece after removing the safety wire, if memory serves me 11 degrees clockwise increases max boost by 1", very sensitive, be very careful, in order to be able to go to the upper limit when you need it you may have to back off manually at low ambient temp, in order to do that you need an IAT probe installed, JPI makes them, the JPI700 and probably all other monitors are set up to receive the input from that probe, with that probe you can monitor the function of the density controller

[philiplane]

Turbocharging systems require warm oil, at least 160 dF for proper operation. An engine heater can keep the entire engine at 90-120 degrees, to minimize the warm up time once running.