B-25 exhaust stack question

[wwrw2007]

Can somebody enlighten a novice here? I've always wondered how adding the collector ring on the top cylinders affected performance on the R-2600 compared to having short stacks on all the cylinders (claytons?). I used to race stock cars years ago and the best headers had the same length pipes on each cylinder to keep each cylinder equal. Did the difference in back pressure on the cylinders with the collector ring affect the performance and if so how did they compensate? Just curious.

[51fixer]

Can somebody enlighten a novice here? I've always wondered how adding the collector ring on the top cylinders affected performance on the R-2600 compared to having short stacks on all the cylinders (claytons?). I used to race stock cars years ago and the best headers had the same length pipes on each cylinder to keep each cylinder equal. Did the difference in back pressure on the cylinders with the collector ring affect the performance and if so how did they compensate? Just curious.

I don't believe it affected output much.
It did slightly quiet the noise inside the fus as it pointed the outlet away from the fus..
Usually when the exhaust system was modified the carb was changed and the carb inlet changed as well. At least on the N models.
When an engine gets supercharged it kinda mutes the exhaust pipe length issue as these things have so much horsepower a 30-50 HP difference isn't really noticed on a 1800+ HP engine. The airflow through the induction system is incredible due to the supercharger.

[Chris]

Not sure about the noise factor since they are so d@#m loud anyhow nor the ability to blow out air but if you notice, the semi collector is attached to the upper seven cylinders. I believe this gave more exhaust surface area to give better carb heat should it be needed and also the number 1 Clayton "s" stack had a tendency to crack due to vibration and routing since it was the one that was used for carb heat. When Hays modified the B-25s, they installed Bendix carbs and removed the Holley units. This necessitated the change in carb heat ducting and the shape of the intake. The short stacks also had varying lengths and bends due to cowl ring clearance too. Not all the stacks would fit on every cylinder and still fit in the opening in the cowls. Any B-25 experts out can certainly refute me on this if I'm in the wrong.