Quote:
Originally Posted by mlee
Yes, all that too... 
It is actually pretty good which is probably why HP gains are minimal with aftermarket. Some cut the entire bottom out of the OE box for more air flow and that seems to work very well too. |
I've tried a cut bottom OEM box. Can't say it made a noticeable performance gain. It did give more blower whine but it also caused higher IATS when stopped at a traffic light.
I broke off one of the posts removing the box from the car and was forced to go back to an uncut bottom.
I removed the snow/rain blocker almost a year ago. As another member stated, removal seems to allow the engine to build boost faster. This gives my ZL1 a little more low-end grunt and some ram-air effects above 60 mph. IATs also seem to recover quicker from a stop.