So as I go down the road of my final decisions to add a hood scoop (some more tuft testing to do with pics yet to come), I thought about some of the discussion about the Stelling & Hellings air cleaners and their effectiveness.
The concern expressed by some is that the S&H air cleaners are so small that they are quite restrictive. So I wondered about an alternate, especially if a hood scoop will add some nice cool air.
So I went through this analysis:
1) The S & H air cleaners have a surface area of 33.375 sq in each for a total of 66.75 sq ins. But the perforated metal surround only has a 51% effective open area, taking the total back down to 33 sq in . (let’s assume the S&H foam filter flows about the same as a K&N pleated filter)
2) Air cleaner discussions have said a 14 in air cleaner is better ( a 2 in high 14 in air cleaner has 88 sq in). But a 14 in air cleaner won’t work on a 2 x 4bbl set-up.
So how could I increase the total air filter area of my S&H air cleaners?
It has to be through the top. But how?
I could cut screening or perforated metal and fab a top for the S&H base. Sandwich a piece of foam filter material between two screens and attach it to the S&H base. Pricey and a lot of work.
Looking through a Speedway catalog I found these:
Speedway p/n 550-2085 ($19.99 each) and is 8.75 in dia. And it already has the two screens, filter foam and a nice chrome surround.
So I ordered a couple and got started by trimming the chrome surround from the base:
Then I reassembled them and here’s what they look like installed:
So the tops add 56.75 sq in of area each totaling 113.5 sq in but at 51% effective area due to the perforated metal I’m back to 56 sq in.
But adding the Speedway tops to the S&H sides now yields a total of 89 sq in , equal to that of a 14 in air cleaner.
A big improvement over the S&H stock air cleaners.
But do I like the look of them? I think they will have to grow on me.
And I’ll have to make a couple of S&H decal/medallions to install on top.
Now on to the hood scoop fab and installation.
Cheers
Greg