Ram-Air Revelations

[Izso]

http://farm7.static.flickr.com/6062/6081505835_4c8407d0fc.jpg​

I'm preparing my few upcoming DIYs and some of them will be done over the long holiday break. But until then please enjoy something everyone seems to be fond of : Ram air intakes or Cold air intakes. It's not an exact science but Autospeed (whom I've been following for years) is pretty damn good at turning it into a R&D!

Michael Knowling who did the DIY essentially ripped out his old snorkel and measured where had the best positive pressure using a manometer and installed his ram air snorkel there. And he did it in his original VR4!

To achieve the greatest ram-air effect, you need to perform aerodynamic pressure measurement on the bodywork while driving on the road or racetrack. For this you’ll need a sensitive positive pressure gauge (or manometer) and a length of tube to probe aero pressures at various locations across the front of the car. (The frontal surface of the car is where you’ll find the greatest aerodynamic pressure.)

The ideal location for the air pick-up is where there’s the greatest build-up of aerodynamic pressure. This pressure can be harnessed to force-feed the airbox.


In the case of the Galant VR4, we tested aerodynamic pressure in the frontal cooling aperture (which feeds the radiator), the fog light area, and immediately below the bottom edge of the front bumper. At a road speed of 100 km/h, we measured 2.1 inches of water (0.5 kPa) positive pressure in the cooling aperture and fog light area. In contrast, the area immediately below the bottom edge of the bumper had negative pressure.

You sure as hell don’t want to mount your air intake there!

In this case, we decided to remove the driver’s side fog light and use the cut-out as our air pick-up. Why? Well, it’s in a high pressure area, it’s relatively easy to access and the pick-up can be made to look entirely factory.

Results :

With our new ram-air snorkel installed, we took to the bitumen with a couple of pressure gauges to check the results.

The first pressure tapping was in the new snorkel near the airbox. When cruising at 100 km/h, this showed a ram-air effect of 4 inches of water (1.0 kPa). This positive pressure build-up gave a noticeable improvement in throttle response.

And what about intake restriction at maximum power?

Well, the ram-air intake certainly gave an improvement – albeit not huge. Compared to standard, we saw a reduction from 27 inches of water (6.7 kPa) pressure drop to around 23 inches of water (5.7 kPa). Note that reduced restriction is from the combined effect of the ram-air pick-up and the oh-so slightly larger diameter snorkel.

Granted, these gains are relatively modest but they do highlight the effect that a ram-air induction system can create.

The most important lesson we’ve learnt is that a ram-air system can provide positive pressure inside the airbox at cruise. This gives a distinct advantage in terms of throttle response compared to a big diameter snorkel mounted in a low pressure area. But when it comes to making power, our old saying still applies – bigger really is better when it comes to snorkel diameter.

Still, if you’re up against space limitations or you’re reluctant to chop up the standard airbox you can find gains with this approach. We’ve proven it!

Source : http://www.autospeed.com/cms/A_110824/article.html

 

[D7zul]

positive pressure = force induction..

looks like ZTH people will get a Naturally "Forced Induction" Aspirated car

 

[amrancharger]

i use pvc pipes for my CAI...hahaha!

The journey begins: CAI using PVC Pipe- DIY Style!

 

[arturo]

autospeed contributer's DIY damn power. the things they do just simply impressive. The other guy who used water in tubes to measure pressure for his intercooler ducts super DIY!

 

[Izso]

autospeed contributer's DIY damn power. the things they do just simply impressive. The other guy who used water in tubes to measure pressure for his intercooler ducts super DIY!

Check out how they increased the performance on their Toyota Prius! Not only do they get better FC, they get more power too!

 

[jimmyae101]

wow..great job...:proud:

 

[^pomen_GTR^]

yeah....autospeed have been my references long time agooooo

a lot can be learn from there....

 

[arturo]

pomen...any plan get their elec kit?damn interesting n a lot of potential.

Izso...many prius mods.d turbo-ed prius? D burnt batt pack damn educational.these guys damn got guts.

 

[^pomen_GTR^]

yeah i like the way the do the prius..really neat job...and truly amazing diy...


which electronic kit???i see a lot of diff type kit....maybe need to order from the dealer (*jaycar isn't it?)

 

[D7zul]

i use pvc pipes for my CAI...hahaha!

The journey begins: CAI using PVC Pipe- DIY Style!

i think i'll do d same to my Levin..

will take in air from a hole in my bumper next to d plate no

that's the 2nd highest pressure according to Autospeed..

 

[amirmambo]

Very useful info man,nice write up aswell