Thread: Functional Fender Vent Kit
View Single Post
Old Sep 1, 2011 | 08:43 PM
  #25 (permalink)  
onehundred80's Avatar
onehundred80
Senior Member
Joined: Apr 2006
Posts: 25,432
Likes: 648
From: Ontario
Default Re: Functional Fender Vent Kit
Originally Posted by Franc Rauscher
Please do. And I am serious about the CAI adaption. Having tested for a negative pressure last summer during the infamaous ram Air tests I did not find a pressure difference between the fake vents and the current site of my CAI intake.
Since Eurpocharged has me at almost 200HP at the wheel, I imagine there are no issues with "negative air presure' and would not be so from this new position.

Any improvements would be from removing the CAI away from the hot valve cover of the engine causing a loss of power when idling at the stop light. I could stop burping my engine which seems to invite unwanted challenges from neighboring ricers, Mustangs and Cobalts

Frankly the low performance of Squirrelcrusher's open side vents suggest that the natural outward airflow would not be that great. And my vacuum tests affirm that theory. There simply is not that much negative AP at the side wall of the car.

Look;
We have guys here that actually wrench on their cars, like Waldig and Boiler Up. Then we have armchair engineers who suppose what would happen but don't really apply these mystical concepts as serious mods to their Crossies.

Unless others have tried and proven them.

I like Wally's hood vents for simpliscity and actual function. In point of fact, he proves his theories before he proposes them here. One has to respect that.

But. that said, most of us would prefer more aestheticaly pleasing mods like what you have suggested.

Go for it.


roadster with a stick
The reason air comes out of Squirrels side vent so little is because it is much easier for the air to go out a bigger hole, and the air that comes out of those vents is only being sucked out in an effort to balance air pressure. Air that is going into the engine bay will come out all exits from under the hood, but most of that will go out the largest gap, down the tunnel if the pan is on.

To test the venturi effect on a blind cavity stick your head out the window of a moving car and open your mouth while facing at right angles to the direction of travel, you will find the air sucked out of your mouth and nose. Face rearward and it is worse. You could not expect a CAI to operate well in such conditions. Face the direction of travel and you have too much air. The faster you go the more evident are the effects.
Do not do this while driving.

Burping your engine at the lights would do very little to cool the CAI as air is very poor as a coolant when it passes over a smooth surface, that's why a multitude of fins are used in actual cooling practice. Turbulent air is much better, lamina flowing air as in a CAI tube is poor. Turbulent air causes all or most of the air to be used not just some. The slower moving boundary layer of air in the tube gets hot and the air above that remains the same. Turbulence in a CAI is prejudicial to the cause and minimizing the thickness of the boundary layer gives more efficient air flow. The inside of the boundary layer causes turbulence at the edge of the lamina flowing air and that is not wanted either as this turbulence cools nothing. The boundary layer is caused by friction and the more polished or slippery the surface the thinner the boundary layer will be, it will also reduce the cooling effect as well as it will depend on radiant heat loss more.
It is a quite complex area and I know little about it. Although I have been involved somewhat with water cooling and the principles are similar.
That's my take on it anyway.
 
Reply
0