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Old 05-08-2011, 01:09 PM
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Jac Mac Jac Mac is offline
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Join Date: Feb 2006
Location: Gore. New Zealand., SI
Cobra Make, Engine: DIY Coupe, F/T ,MkIV.
Posts: 808
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Quote:
Originally Posted by Caprimaniac View Post
Great, Jac.

Thanks alot. Did you write & sketch that note?

It's interesting. As you can see from the photos, the angeled rear face of the hood scoop have been removed. And me & my pals have been trying to figure wether this is a low or high pressure are. - Suitable for wenting or intake. We, maybe, solved this question with 3 inch of wool thread. While driving, the thread clearly made is way out of the opening. Which, made us conlude it is a low pressure area. - The oposite to the connclusion in your note. Even more, our thery was that the high pressure zone was above the ventilating plenum- exactly as the note says.


Impressive you could see it was a early Capri from the engine bay pics. Although, if you've stared into a Capri enginebay earlier in life- it's been etched onto your retina.... And what's funny is that I've asked for info on airstream/ windtunnel/ high-low pressure zones on Capri fora without anyone coming up with anything.

Once again; CC has alot of great resources - even Capri related! I have come across other people with Capri knowledge at CC before. I have also stated (somewhere) that I have no Cobra, but a Capri and use (& maybe contribute?) the weber & small block ++ resources.
Yep, the note was sketched up on the 'paint' program of the PC, Have been involved with several ''OSCA'' Capris here in NZ,[ Open Saloon Car Association]', Built another 351c powered one only 5 years ago for a local guy who wanted to relive his youth. They were a very popular car in the class in the early 70's/80's.
We used the 'tuft' test on the TVR I work on to establish the 'zone', also if you have a close look at some of the original 'Daytona Coupe' pics you will see the intake opening is about 10" wide by 3" high on a reverse slope area right at the back of the hood and about 8" to 10" in front of the w/screen base, works fine for them as well. Nothing much will happen with the tuft until you get up around 40/50 mph, but from there onward its all good, the better you seal the airbox to the hood or plenum area the better it gets..

With regard to the mistaken indication that it was better as an outward vent, this comes from too much air being rammed in around the radiator etc, to cure this use a front airdam to create a low pressure area under the car and add vent holes to the inner guards behind the front axle line, the front wheels create another low pressure area behind them to assist in evacuation under the hood. Once you get the intake air from outside and realise that most radiators only require an intake/grill area approx one third of the radiators core area you will start to get on top of the issues your having.... its not really a matter of getting more air in, its more a case of getting the heated air out.
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Last edited by Jac Mac; 05-08-2011 at 01:19 PM..
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