I will be installing a catch can soon, but need more silicone tubing. Is diameter of the tubing critical or is any size okay as long as it fits on to the fittings?

 

As long as it fits tight it should be ok. Just make sure to hook it up to the high vacuum/PVC line.

 

There have been some reports of silicone tubing collapsing. Perhaps this is no longer an issue, or the experiences were rare and explainable, but why risk it when the regular rubber tubing works perfectly?
Are you using the tubing for color bling in the engine bay?

 

nope, the catch can is used, and the tubing that was supplied has been cut, and is too short for my application. I bought a variety of tubing sizes expecting one size to be correct, but no luck....all 3 sizes were either bigger or smaller than the tubing from Alta. However it seems to be the same material, so I didnt really expect it to be weaker or incapable of supporting its shape.