Bob_pipedream
Active Member
Now here is a thought... (also used speed in title to get Bob to read this)
When the air goes through the cabin heatbox it picks up heat from the exhaust and also cools the exhaust. Could that cooling action have the effect of increasing back pressure and thus increasing EGT on the cylinders on that pipe?
I have my carb heat box and cabin heat box on the same exhaust that deals with Cyl 3&4 - both 3&4 have high EGT and high CHT and very clean pipe, whilst 1&2 have low CHT and EGT and soot in the pipe. This is partly due to airflow, but I am beginning to wonder if having the boxes on the same exhaust is not overcooling it in two patches to create back pressure...
By the way, I know this may be due to other issues such as fuel distribution etc. I have also realised that I did not seal the end of the cowl ramps too - But just thinking on other lines now...
Now if I go and wrap the exhausts, not only do I decrease cowl temperature, but also I speed up the passage of gas through the exhaust which aides cylinder scavenging.
If cowl and CHT temps go down, then perhaps I can decrease cowl intake size and even exit points which could aide performance?
Or is everything I said wrong and the result of too much piccililly in my sandwich?
When the air goes through the cabin heatbox it picks up heat from the exhaust and also cools the exhaust. Could that cooling action have the effect of increasing back pressure and thus increasing EGT on the cylinders on that pipe?
I have my carb heat box and cabin heat box on the same exhaust that deals with Cyl 3&4 - both 3&4 have high EGT and high CHT and very clean pipe, whilst 1&2 have low CHT and EGT and soot in the pipe. This is partly due to airflow, but I am beginning to wonder if having the boxes on the same exhaust is not overcooling it in two patches to create back pressure...
By the way, I know this may be due to other issues such as fuel distribution etc. I have also realised that I did not seal the end of the cowl ramps too - But just thinking on other lines now...
Now if I go and wrap the exhausts, not only do I decrease cowl temperature, but also I speed up the passage of gas through the exhaust which aides cylinder scavenging.
If cowl and CHT temps go down, then perhaps I can decrease cowl intake size and even exit points which could aide performance?
Or is everything I said wrong and the result of too much piccililly in my sandwich?