Quote:
Originally Posted by ajsalida
Yes you are correct, but I think the volume and flow remarks vs 7" apply to it also. Stepped core is the way to go if you want max volume but don't want to trim anything. The VRSF has the advantage of non OEM couplers and smooth cast end tanks also. I do not think you get near the same volume as a 7" with a VRSF stepped core but I may be wrong.
I think if someone were to test it they might find 7" > 5" stepped core > 5", but I have not seen data to that effect. The main possible issue I have with stepped core, aside from volume, is flow up to the the upper part. I can't see how the air makes it up there and out efficiently, or if it does how it does it as well as a 7" with a more or less straight shot through, even if volume were identical.
edit: wanted to add that tests have shown pretty much any decent aftermarket FMIC is so much better than stock it isn't even funny. Comparing good quality aftermarket FMIC to each other, same sizes and form factors it is nearly a wash, or at least to me, not clear why one that cost 2-3 times more than another is worth it. Lot of what I am citing above like end tanks etc may be noise in an actual test. In my case as I have said I am messing around with fixing high altitude heat issues that cropped up with a already very high quality 5" FMIC. And so if an experiment of moving from a great 5" to a great 7" FMIC doesn't pan out I'd rather it be on a $400-ish FMIC than a $1k (or more) one 
Furthermore if/when I move on to hybrids or a big single I want the FMIC meth and so forth well sorted and prepped for much higher airflow. I do not think the 5" will handle it, no matter who makes it, not if the current one is already pooping out on 91 stage 2+ cobb. |
In defense to most higher priced options like ETS and ER they are made and built in the US, which will by no accident have a large labor rate difference compared to ones made overseas. This is largely where the cost differences comes in.
I wanted to clarify that since people don't always think 360 on why things cost as much as they do or as to why they cost as little as they do, depending.
In the case of Cobb, it's just over priced and made overseas and they like dumb profit margins, to be blunt.