[CJZ-SS1LE]

Ok so for xmas my lady got me a darton sleeved, diamond piston, 12 to 1 cr, callies rods, callies crank, coated king bearings, arp main studs 427 shortblock. We reused my prc ltx heads, msd intake, 103 katech tb, 1 7/8 headers, 3 in custom exhaust with x pipe to the stock npp muffler, with rotofab intake. Now i just put a dry filter on brand new 4 months ago its not dirty but on the dyno it gained 24 rwhp taking the filter off. Rotofab is amazing stepped up an are sending me a new oiled saying it flows more. Even went on to say so much so that on their big gulp they dont even offer a dry filter. Dont see how a newish filter could be such a restriction. ..... thoughts?

[ctrlz]

Originally Posted by CJZ-SS1LE

..... thoughts?

I think you may be changing the flow around your MAF when going from filter to no filter. The filter likely provides a diffuser function for the airflow. You could check fuel trims and MAF readings to compare the effects of filter vs. no filter.

[Mark114]

Didn’t Pray find similar results with a Roto-Fab bellmouth?

https://www.camaro6.com/forums/showthread.php?t=603015

https://www.camaro6.com/forums/showthread.php?t=616005

[Megahurtz]

Taking the filter off moves the airmass around so your fuel and timing values were likely different. Also, the oiled filter does flow more than the paper filter.

A data log would have told the whole story but it sounds like you COULD have some power to gain by more tuning.