AlfaRomeo 159 Windsheild wiper&arm redesign for noise cancel & aerodynamic.

[emre2blue]

Hi,

I'm going to do this changes, because, I think who designed those arms has no idea about aerodynamics of the car. Even at 90km/h wipers vibrate and there is a noise inside the car.Also I will cover the arms and when they are not working . The cover will be under the bonnet, so it would be perfect I think. and hope will work as I thought. After long time It would pay itself, by quality & MPG

[NeilBlanchard]

You should test the aero (with tufts) before doing anything. I doubt there is very much moving air in that area? This is is almost never an actual cause of drag, on most cars.

[aerohead]

I removed my wipers and covered the entire cowl area on both my CRX and T-100 and saw absolutely no difference in performance at top speed at Bonneville.

[emre2blue]

I will go with aero test with tufts because, the bonnet if like flat near the window. And the flow meets first with arms & wipers then window itself. I know that Flow may jump directly to window & tabulate the wipers are. But I will test it and lets see if it can help.

[NeilBlanchard]

Can you post a picture of the car, please? I think the wiper arms are not causing any appreciable drag.

[Arragonis]

No need to tuft and I think you need to check the bonnet first.

Clean the bonnet with normal wash. Apply normal car wax (cheapo will do) in swirls and take off in straight lines. Repeat. Then use a fine hose to spray water onto the area in small drops - the drops should form into small groups due to the wax.

Then drive and observe how the drops move.

I suspect you might find at lower speeds that no drops move, and then the drops at the leading edge of the bonnet bunch up first. Eventually I think the drops at the rear, side edges of the bonnet will move before the ones at the centre where the wipers park.

If you do windscreen with Rain-X (or just wax) at the same time you might find that the drops at the bottom do not move at all as well.

Obviously make sure you drive safe and can see anyone / anything around you.

[emre2blue]

Sorry I'm late. I'm at work & customers don't let me Those are the pictures.

[NeilBlanchard]

What happens when you drive in a light mist? Do the water drops at the bottom of the windshield stay put (more or less)? On my car, which has a sloped hood, the drops above about 1/3rd the way up the windshield move, and below that they stay put. I suspect that with a more level hood (like on your car) that the "pocket" of still air is larger than it is on my car.

[cfd_guy]

Doing this most likely won't make any difference. There is a dead zone in that area of the hood. Not same car but can be seen in this figure. The high pressure would be low velocity. This is also why you should try to vent the engine bay here which is a very common mistake.

[emre2blue]

Hi, again. Sorry I was very busy, I record a video from inside the car when its raining. And I saw the water is moving slowly near the wipers. But wipers is blocking the water, make them stay below the wipers. And if I move the wipers water slowly moves up like a line shape. Now in the area where I live, wind is getting stronger, and side wind is very fast and dens. I saw the wiper blades makes noise when side wind is stronger. So I will only hide them for the noise issue. Thank you for now.