[luke33]

My plastic engine cover has foam on the underneath, will it be much louder if i just pull it off?

 

[jon applespeed]

Just pull it off. If you are really that worried about noise, drive around with the entire cover off and see if it's that much louder. I can't even tell the difference.

 

[gino5]

You could put some kind of heat resistant foam there. I woudn't put styrofoam there because it could melt or some other foam could catch on fire. Just take it off and be done with it.