Vented hood thread

[wstar]

Originally Posted by DIGItonium

I'm not sure I even need a thermal camera since it's easy to test with the cooling fans running. The front most vent doesn't flow much air at all, but the one in the middle vents lots of air. That should give you guys a ball park.

Yeah but I assume you mean you're looking at the coolant fan flow with the car sitting at a stop. Everything can change pretty dramatically once the aero effects come into play at speed (80mph wind hitting the front grill, flowing over the car in some unknown shape, bouncing off the windshield, etc).

Ideally we'd wind-tunnel this stuff, but that's pretty unlikely to happen given the costs. The yarn thing is really the way to go for at least understanding the airflow on the outside skin of the hood. Differential pressure gauges can tell us for sure where the pressure buildups happen both under and over the hood. Between those two we can probably make some pretty good approximate design choices.

To me, the real tragedy is that the community will have to eventually do this itself instead of some manufacturer doing it with their own resources and time. The ratio of vented hoods being sold by vendors to vendors actually doing research to make sure they're effective is sad.