I’m installing brake ducting on the E46 and have a question on duct size.
I’m using Corvette Z06 brake ducting from the front bumper to the wheel well, which makes a 90° turn with a 2.5 inch outlet at the end. This is a good solution in the wheel well, because it’s flat and thin and somewhat durable compared to brake ducting.
My brake duct backer has a 3 inch inlet.
Provided everything fits either way, would it be better to run 2 1/2 inch duct to the brake backer or run 3 inch duct to the brake backer? If I run the 2 1/2 inch duct, I’ll have to use my transition to 3 inch there.
I don’t know if the Corvette uses 2 1/2 inch duct all the way, but if they do, it seems like that’s the answer and would keep the airflow at the same rate after the 90°.
Thoughts?
