CHT questions

[wjunius]

The GAMI injectors are basically numbered to match the cylinder, I assume based on the air flow to each cylinder of the average IO-360. As I understand it, each cylinder’s intake gets different amounts of air depending on the distance from the main air intake. The injector is supposed to normalize the air/fuel mixture among all the cylinders. There is really not much else that is done. There isn’t any custom tuning. GAMI does, however, guarantee a GAMI spread of lower than 0.3 (I have to double check that figure). GAMI will replace the injector for up to 1 year after install if the GAMI spread is too high.

My spread differs depending on if I hit peak from the rich side or from the lean side while doing a sweep. From the rich side it’s consistently 0.2. From the lean side, it can be as bad as 0.7.

I’m flying home tonight. I will look again at the EGT’s but as far as I remember they are not spread like the CHT’s. I send my info to Savvy but I’m not very impressed with them. A story for another time is when, prior to overhaul, I realized there was a change that both Savvy and my mechanic wrote off since the parameters were still “normal”. Turned out I was right that something was wrong, my cam and lifters were spalled and I had zero compression in a cylinder.

[Rich]

I had a problem that popped up after I installed a Surefly. #3 cylinder was suddenly higher than all the others by a lot. But it wasn't the Surefly. The scat tubing that runs to the battery box somehow got shifted so that it partially blocked the airflow below cylinder #3 in the area where the CHT sensor lives. Taking care to reroute this tubing alleviated the problem. So you might check for something impeding airflow below the cylinders (as well, as above, naturally).

As far as Mr. Busch, I have seen quotes from him that say you should avoid running Lycomings below 350 Deg CHT's for extended periods and others that say you should not run any higher than 350. Kind of a challenge to conform to both