DIY Miata hood vents?
Here are the dimentions:
About that time Ben cut the extractor in his hood just behind the rad and had great results- that convinced me. The best solution IMO is reducing the positive pressure under the hood- it works well at speed and at a stop.
This was my second option for something over the turbo, an 80s trans-am fender extractor:
Nice hood! It looks like it would work well. I have been thinking of doing something similar with a vent on both sides, like Autonixion's hood
Both of those look intended to deal with heat from the turbo, not to help with flow through the heat exchangers. That Nissan vent with the Naca in front will vent turbo heat but the Naca will be adding to the pressure under hood I'd think.
Here's the pic I've been looking for. Looking at the pressure differentials the optimal spot for flow out of the engine bay looks like it would be further forward.
Here's the pic I've been looking for. Looking at the pressure differentials the optimal spot for flow out of the engine bay looks like it would be further forward.
Do you have a similar grid for an NA? It looks like the shape of the headlights might be causing the low pressures so an NA may have different different low pressure areas.
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I have a second hole in the hood with a carbontrix vent, but the hole is cut in a way that the vent can be shifted forward/backward about 2 inches. Its not riveted in yet since I'm going to strip and polish the hood.
Last edited by chpmnsws6; May 30, 2010 at 01:41 PM.
I think you'd be safe referencing the pattern of pressure on the NB hood. Pressure is definitely relative to the coordinates on the hood. Based on that assumption, the further forward the extractor the better it will reduce pressure. Hustler's is just about in that location. You need also consider that too far forward is going to put the scoop over top the radiator. My cooper scooper sits with the tail end just in front of the hood bubble.
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A little air foil or raised portion in front of the vent will also dramatically decrease pressure over the vent. I taped yarn to the inside of the vent in my new hood and the yarn stood straight up and flew off after a few miles thanks to scotch tape...the FM just let the yarn dance around a bit although it did effectively pull air out.










