252 with TSIO 360mb1 & Garrett Turbocharger

[Rick7576]

I have a 252 with TSIO360mb1 and a Garrett Turbo Charger. At max power every thing is well M.P. = about 36" rpm 2680  FF 23.5

when on climbout I will reduse  rpm to 2600.  the problem seems to be that as the airplane continues to climb the M.P. slowely falls off.

I have not gone above 15000msl and at that altitude the M.P. has dropped off to about 22" , this is with throttle full forword . I think the waste gate opens a bit on takeoff for overboost protection and fails to close as altitude increases.  Just wondering what anyones thoughts are on this problem and any suggestions or recommendations or any A&P that may be able to help. 

    Cheers Rick

[Fly Boomer]

17 minutes ago, Rick7576 said:

I think the waste gate opens a bit on takeoff for overboost protection and fails to close as altitude increases.

Could be any number of things.  Wastegate, wastegate controller, or the turbocharger itself.  What do your temperatures look like during climb?

[exM20K]

Start with the easy stuff. Pressurize the induction system and spray with soapy water to look for leaks. Ambient pressure drops about 12” from SL to 15,000

 

-dan

[N201MKTurbo]

It is almost always the pressure controller or the wastegate. Have you Mouse Milked the wastegate lately? It should be done every 100 hours.

[Will.iam]

What is your fuel flow doing on climb out? Make sure it’s not your fuel flow reducing that is then lowering your MP. And why are you going back to 2600rpm? This will not only slow your climb rate but will increase your cht’s due to less cooling and as you are effectively advancing the timing when you slow the RPM’s thus rising the cht’s even more. 

[Will.iam]

If your fuel flow is indeed lowering in the climb, you can check if this is causing your MP to drop by having your mechanic set your full mixture to like 27 gallons. Then on takeoff you just lean out the mixture to 23-24 like you have now but as you climb up into the teens and the MP starts to drop off with the fuel flow drop you can now add that extra fuel you have my increasing your mixture and onxe you bring the fuel flow back to 23-24 you will see that the MP comes back to 36” as well then you know you have a leak in your upperdeck pressure line to your fuel pump that needs to be fixed. 

[Pinecone]

Something is definitely wrong.

However, I climb my 252 (Encore converted to -SB) at full throttle, max RPM and full rich.  MP stays with 1/2 of max all the way to 17,000.