Surface area question

Hay Fred, Ken, StrokerSS HELP:)
Riddle me this please...
Four bores of 1.75 inches equal a surface area of?
One 90MM bore= a surface area of?
Thanks for your help. I think I have the correct answer.

An easy area formula is:

diameter squared x .7854

(real formula is dia. squared times PI divided by 4. PI/4 = .7854 which just happen to be the 4 numbers in a clockwise square on the upper left corner of a keypad)

25.4 mm = 1 inch

1.75 x 1.75 x .7854 = 2.405 in.^2

4 x 2.405 = 9.62 in^2

90/25.4 = 3.5433

3.5433 x 3.5433 x .7854 = 9.86 in.^2 or about 2.5%more area.

Look at the total circumference or wetted area:

C= PI x Dia or:

4 x 1.75 x PI = 21.99 in.

1 x 3.5433 x PI = 11.13 in.

So, if you were talking throttle bodies (wild-a** guess :) ), the 90 mm would probably flow quite a bit more than the 4 x 1.75 in.

How much? Engine Analyzer PRO software estimated about 13% more.

Originally posted by OldSStroker

So, if you were talking throttle bodies (wild-a** guess :) ), the 90 mm would probably flow quite a bit more than the 4 x 1.75 in.

How much? Engine Analyzer PRO software estimated about 13% more.

;);)
Yep
So what would your feelings be on the effect of adding one of those Precison turbo cast 100 degree elbows on top of the nitrous plate of my setup be? Would the added Plenum area of this help or hurt, and boy I'm I holding a gun to my head thinking about try'n this out ;)
I would be hanging my 4 inch mass air meter up stream of the 90 MM.

Thanks for your input!
Jeff

If you are running it into a single plane manifold like a SuperVic, I like the idea. Bret is working on a similar intake for a 4th Gen. I think the elbow allows better clearance on the cowl than does the 4-bbl with air inlet on top of it.

Look at a Wilson 461101 (100 degree) elbow which goes from 90 mm to a 4150 carb base. I believe Wilson and Precision might use the same castings, except for names on them.

Add on:
I just visited your website. I think the elbow and 90 mm TB might help you. You've already worked on turning the air 90 degrees into the 4-bbl. As nice as those toppers are, I think the Wilson elbow, or the ported one if money isn't a problem, might be the next logical step. Can't tell what your intake is, but if it's shorter than a S-Vic, you might find more power in the intake.