one600

wow thread back from the dead, seeing its alive does that mean the FEED bonnet will also have an negative effect? Seeing the vents are near the windshield.

Wozza

What about this idea for extra venting. Go easy on me if this is a daft idea.

One of the lads was interested in doing this mod. In the first pic what are the implications in drilling holes in the structure and venting out to the side air vent beside drivers door (pics attached). I know by drilling holes or cutting in the structure etc will weaken it but can it then be re-inforced etc... Just an idea so go easy if it's a daft one.

CrispyRX7

iTrader: (139)

The meshed fender liners is a great, IMHO, to engine bay cooling but you will absolutely destroy your engine bay (with dirt) with so much a drop of moisture on the road surface. This also calls into question electrical connectors and components in the vicinity also. Personally I'd never do it...not that I matter

FWIW I meshed cutouts in my liners using the same approach to let the oil coolers breath.

my 2 cents,
Crispy

RaceDriver7

iTrader: (9)

I believe the FEED hood has vents at the rear corners of the hood, correct? The air pressure is high (positive) at the center of the windshield, but decreases as you move towards the sides where airflow is higher as some of the air is flowing around the windshield instead of over it.

Take a look at this diagram for example:



The colors here actually indicate air velocity, but since air speed is related to pressure (Bernoulli affect) it gives you a general idea of the air pressure contours. Blue areas are areas of low airspeed (hence positive air pressure) and the red areas are low (or negative) air pressure. Notice that at the base and center of the windshield, you have hardly any air movement at all. In fact, in this area the air is actually moving backwards into the A/C intake vents that are at the base of the windshield. This is why the A/C vents are placed at this location, and that's why at high speeds, even with the air off, you can feel air flowing out of your A/C vents. The air is being forced into the vents at the windshield because the pressure there is higher than the pressure inside the cabin (which is close to atmospheric with the windows open).

Anyway, the point is that as you can see from the diagram, there is probably some negative pressure in the rear corners of the hood, though I think it's probably not very much. It won't be as high as the area just behind the nose of the car (where the radiator air exit duct is in the diagram). I would imagine FEED measured pressure differentials across the hood before they decided where to place the vents. I wouldn't risk putting air vents in those locations without measuring the pressures first. I'd probably avoid the FEED hood to be safe. The important thing is that there be a vent near the front of the hood, just after the radiator. That's the best way to optimize cooling.

one600

no the feed hood has two vents running along the back of the hood, looking at that diagram the FEED bonnet looks like it will have a negative effect on cooling? Hope someone disagrees with me..

NissanConvert

iTrader: (1)

The feed bonnet has vents closer to the middle. It's the windshield that causes the high pressure area. Since the feed vents are closer to the middle of the hood it has an extractor affect. Also, since it has a bit of a lift in front of the vents it creates a low pressure area behind it.



If i'm not mistaken howard has louvered his hood to replicate this affect.

7racer

https://www.rx7club.com/forum/showth...tuft+feed+hood