IPD Plenum arrived at my Indy and they are suggesting that the inside of the IPD Plenum should get polished to reduce drag since it's not very smooth on the inside as it is right now. I did order this new from SunCoast.

Have you heard of this to be an issue? I don't have pics but can get them to send some And upload here if that helps.

 

Smooth doesn't always translate to efficient airflow. Think golf ball dimples...
Nonetheless I'm not at all suggesting this is the case with the IPD. However if the product has been properly engineered and tested then any changes to the internal surface may have adverse effects and I certainly wouldn't risk it. Just my humble opinion

 

Don't mess with it.

 

Thanks for the feedback guys. I was hoping for the same answer 😊

 

The newer IPD plenums have golf ball style dimpling for better airflow

 

I went over this with Greg Martin at IPD last year and you should DEFINATELY not screw with the surface finish. They have run these through a flow bench and the current surface finish is the most efficient. The old IPD plenums had a smooth orange surface, but that was found to be less efficient.
Lyn

 

'Rough' finish increases turbulence which improves mixture would be my guess. I wondered when I went to Comp plenum why it did not have that nice coated surface inside that original did. I figured they cheeped out