Can anybody offer me some advice. I use the super chargers at about FL13 or FL15 depending on when the engines start struggling.
I am using the AFE still, and I have followed Robs tutorial on the pmdg YouTube channel.
I take off with about 10k lbs of fuel and half load cargo.
I’ve tried a few times, different flights. I just can’t get above FL120 if I get to about FL160 I can’t even keep 130knts.
What am I doing wrong?
You’re probably better off using the “Abort” button on the AFE screen.
Should get about 165 KIAS out of that setup.
Cheers! 
Have you checked if your engines need repair ?
Or sometimes people have issues with control mappings preventing the levers moving correctly or such.
Gust Lock unlocked ?
FSUIPC has caused issue with plane performance for some people I have read, not sure if that’s still the case though.
But be assured: You can easily use the AFE and climb above FL120. I works here with my DC-6, so not sure what is the issue you are experiencing, wished I could be of more help.
I had no issue at 16000 feet for 5 hours, without super chargers (AFE controlled).
Full main tanks and 2000lbs (?) of load. Around 250 knots ground speed (210 or so indicated).
I agree: have a look if the engines are still functioning properly. Also, your climb speed needs to be quite low in some situations. Else you start to lose speed rapidly (say 500 feet per minute max).
(The thing also seems to lose oil all over the place… you need to keep topping it up…)
Thanks all for the help and replies… will try these suggestions
I’ve read these engines use about 1 gallon of oil per hour… no wonder there’s a 26 gallon auxiliary tank for oil! 
I wonder why it was so difficult to keep it in a closed system?
Hey guys, the superchargers are always ON. They do have two speed gearing so you can select LO/HI but never ON/OFF.
As you climb and the air gets thinner, the throttle needs to be opened further. If you use the AFE it should do that for you, if you do not use AFE then you must do it yourself.
It’s not a close system. Oil is used to lubricate the pistons, 18 of them, and some of that leaves the engine with the exhaust. Automobiles in the 1950s used a lot of oil too, but seldom had that much power or number of cylinders. Then there are always the leaks, that why there are drip pans that should be used when ever parked.
Well, that explains…
May also have something to do with forced induction. Oil control rings don’t stand a chance against 1.6 or 1.7 times atmosphere! 
Also better not stand behind them when they’re running… filthy things will spit all over you…
130kts sounds like you have an engine out. The gyro pilot (if engaged) with AFE cruise settings will usually pitch you up significantly and this is usually where the airspeed ends up.
A fairly common problem I’ve run into, if you use the mouse to look around the cockpit, is unwittingly hitting the left co2 release handle. This will knock out an engine without much fuss, the only indicator is the manifold pressure guage.
Keep an eye out for this next time.
^this. It’s important to reduce Manifold pressure before engaging the high gear supercharger or it won’t engage properly, thus reducing your overall power output.
I use 79% RPM myself, but mostly the same or similar settings as Seven7Tango here and I think my max altitude was around 27k ft (but barely, 25, 26 are much more attainable, 15-20 is a good cruise altitude.
ps; I don’t use AFE, it’s a cool feature but for my kind of control, it just complicates my end of things, I like to be in control.
Watch the tutorial video on climbs. You will need the superchargers. Don’t just click them on without following the proper procedures or you’ll ruin your engines.
Here’s the link to proper procedure for engaging “high blower.” Keeping MP at or below 38" and RPM at or above 2400 will keep the overboost warning on the Stress Monitor from turning orange.
VERY true ^^ There is a “funny” video, well actually a totally normal video, by Kermit Weeks flying his Wildcat (I think) and I think he does it in the T-6 too… When he opens the Canopy for landing he takes a rag and cleans the windshield from oil
That, sir, is radial engine blood and how you know someone works on a radial engined aircraft! 
(Actually it really is. I used to work with a flying museum and we had white shirts (bad idea) for our crew. We would have little black oil spots all over them in very short order.)
Many thanks.
I am currently at FL200 at 236KTS Ground Speed just about to go over the alps and the weather is bad!
Many thanks 
Such a fun aircraft, and quite a challenge to learn. The reward is worth it, yes?