I have been trying to optimise the CHTs on a carbed 0-320 for several years, changing baffles and routing, using light to test for possible leakages, adding lower cowl vents and covering a third and half of them, modifying the lower cowling for better extraction, every time I make a change I get different results. The hottest cylinder has been 1,2 and 4, to complicate matters I have Lasor Electronic ignition with the CHT been taken from the hottest cylinder so I have moved this three times. The main aim is to be able to keep full throttle from take-off to 10k feet, and keep all CHTs below 400F, I’ve make good improvements but the changes have meant #1 was hottest and then #3.
Savvy offer a paid for service to analyse your engine after carry out in flight tests: http://content.savvyanalysis.com/static/pdf/SavvyAnalysisFlightTestProfiles.pdf
Anybody used Savvy for this is, was it beneficial?
Many thanks
Those are tests you can perform yourself and absolutely do not need Savvy for.
The goal of the GAMI test is to compute the difference in fuel flow between richest and cleanest cylinder to evaluate the power balance between cylinders. The Savvy Analysis tool can automatically compute the GAMI spread once you understand how to use it, but you need to carry out the test itself.
The LOP mag test tests the state of your ignition system and can give you early warning about problems with mags, harness, plugs, timing.
It is unlikely that any of these tests addresses your baffling issue.
CHTs are very sensitive to the detailed airflow. For example if you have a 3-4mm gap here
that is enough to increase the CHT by some 30F. Same with a gap between the baffle seal and the cowling. The air just shoots into the gap. See other threads on reworking the baffle seals; one needs two different materials for the lower and upper seals.
I would strongly recommend an EDM-type multi-cylinder engine monitor. Without that, you are just poking about in the dark. They are cheap to buy and the installation is just tedious labour, running the 12-13 thermocouple wires through and crimping them into terminals (they can’t really be soldered, not with normal solder anyway).
You should be able to climb full throttle all the way to the operating ceiling, just by leaning the mixture enough to maintain the EGT (of any particular chosen cylinder) which was seen just after departure.
GAMI injectors may be needed, but you won’t know until you have collected the EGT data versus the fuel flow.
The LOP mag test needs to be done with great care: if any cylinder cuts out totally or misfires, the throttle must be full closed before switching to BOTH, to avoid exhaust damage.
I’ve usually found the cure for front cylinders being hotter than the rear ones on climb is to replace the inlet gaskets. On my O-360-C1F we seem to do that every year or two. YMMV.
