Engine air intake locations Options

[Charles Freeborn]

My car has a downdraft fan and lowered roofline that AJRS was building in the 9o's.
When I installed a CHT I realized that it needed more airflow to the cooling fan. Methinks I'll add some scoop(s) to the equation to see if I can get the head temps down.
So, location, location, location. Three images below. Where will the optimum pickup location be? I've seen a webpage done by a professor who used his AX 914 as a model and did some computer and water tank tests, but I can't read the squiggly lines well enough to tell where the best place to locate scoop(s) is. What I've come up with so far:
Store bought scoops - of the kind one sees on hoods. Kinda cute, fiberglasss, would punch 4" holes through the sail panels, move other stuff out of the way and plumb to a plenum that seals to the top of the fan housing.


Build a lexan scoop / plenum (clear so I can see through it with rearview) and catch the airflow at the trailing edge of the roof. Opening would be roughly 2.5" x 12" to match fan opening (11" round fan)


Build a lexan scoop / plenum that catches air at the leading edge of the roof, would probably run through the interior of the car and out through the rear window opening. This seems the most obtrusive to the driver ergonomics, distraction, etc.



I suppose one more option would be to do a sort of hybrid of the two roof top collectors and have it punch down through the roof just in front of the rear hoop. I've seen one (also an AJRS car) done that way. It too had the raked windshield and lowered roofline as mine does.

What say ye? where is the optimal pressure on a 914?

BTW, I've worked with plenty of Lexan, have all the tools, so fab isn't an issue.

Thanks.

[Charles Freeborn]

Many thanks all. The #13 pics are heartbreaking. Hopefully it was resurrected. That is a different car than the one I saw - and the over-the-roof scoop would be fine for my local club racing (ICSCC) and maybe the local vintage (SOVREN) but probably not the others (SCCA & SVRA). I'm not terribly worried about that just yet - this and probably next year will primarily be ICSCC.
The yellow car I was referring to is this one:
(IMG:http://www.914world.com/bbs2/uploads/post-47-1517426922.jpg)

This arrangement would probably get past the vintage tech purists (?) and in a pinch could be arranged such that the car could still be run with the roof off. I should probably say right here I have no delusions of podium glory. I'm strictly in this for fun so chasing hundredths of a second are not my goal.

The current headlight buckets are removed and have intakes for cabin air. I'm not crazy about that install so I'd gladly re-work. Ducting would be interesting, but do-able. I'm more inclined to stick to some sort of roof or sail panel scoops. I'll continue to ponder and when I do mock something up I'll post here for comments.

My last thought is that the current Spal fan is rated at around 1000CFM. There is another fan of the same diameter that pulls 1300 so that could net a 30% increase right there. Not sure if it would fit the housing, but as I said, I'm not afraid of fab work.
Many thanks again.