intake coming out of the hood? good or bad idea

[Matthewmongan]

im thinking of making a cowl or ram stile intake by useinf the blitz intake kit from motorsportswherehouse and fabing some tubing through my hood. i then could put a mailbox to shroud it... i dont know yet it works for the domestic muscle cars why not the svx. i havent cut anything yet still just a twinkle in my eye (among many others). but yeah at the least it would be origional

[Landshark]

how will you keep water out?

[Matthewmongan]

good question.... havent thought that far ahead how do they keep the water out of the ram air on the pontiacs... i dont know.

Well, considering the Blitz steel mesh intake is a pretty horrible filter, coupled with the fact that you'd have some serious water induction problems, I'd advise against it. In fact, you may want to put a real filter on your car before you get in a dusty area and suck particulates into the motor.

[Chicane]

As long as you use an air filter, the water would stop there.... and... evne if you did get some water in the engine, it's not a big deal. A little water is actually good, they even make water injection kits. Water doesn't compress, so it raises your compression a little bit, it cools the heads, and it can help clean the combustion chamber a little. Hydrolocking is what you ahve to watch out for, and I don't see how you'd hydro lock your engine unless you were driving with your HOOD under the water.

- Rob

[Matthewmongan]

yeah hydrolock is hard to come by day to day driveing small amounts of water is atomized in the intake plenum. and the m.a.f. typicaly shorts out stalling that car when it gets too wet. but to about the mesh intake i know its bad i use a fabric shroud to take care of the small particulates (its like a corona bag i place over the filter). but im not to worried with waterinduction because the filter is above the line of the hood so water cant reall poor into it while parked and hood scoop is about 5.5 inches off the hood and the opening is at the top and its only maybe 1'5-2'0 inches i imagine it is a fezible project the only reason i havent done it yet is that if i dont like it i have a big hole in my hood.

someone makes an intake attachment which will basically close up if too much water touches it.. or at least i think that's what it does. i'm wondering how the car breathes if the intake gets completely shut..

[Matthewmongan]

i know what your talking about. in a cold air intake where the filter is in the front fender the filter gets saturated oftin. so they cut out a section a put a thick foam section in above the old one. it sucks when the other doesnt.

All of which is well and good until you're in that one really HUGE downpour, and you can't see the road in front of you because of all the water, and then your SVX stops running properly because of all the water it's sucking in, and the Check Engine Light is flashing at you indicating that it's detecting misfire, and then your car shuts off on you in the middle of the road during the worst storm you can ever remember being in.

Ask me how I know this...

[immortal_suby]

Originally posted by Porter
Ask me how I know this...

I think I remember this from my first dragon run, Jason.

Didn't you have your hood up on the cherhola with a soaked air filter?

[Chiketkd]

Intake systems mounted in the hood of a car provide a great boost in performance - as the air passing over the hood is flowing smoothly and the 'ram air' effect is more pronounced than if the intake was mounted in the fender of the car.

The Viper, Camaro SS, WS-6 Firehawk and even Ferrari 550 Maranello all utilize this set-up.

This mod will provide great gains in hp, but you run a high risk of ruining your engine with an improperly designed system. I would also add that a 'scooped' hood doesn't fit into the general lines of the SVX as well as it does in the more 'muscular' Viper (IMHO).

Originally posted by immortal_suby


I think I remember this from my first dragon run, Jason.

Didn't you have your hood up on the cherhola with a soaked air filter?

Yup!

[Chicane]

Originally posted by Chiketkd
Intake systems mounted in the hood of a car provide a great boost in performance - as the air passing over the hood is flowing smoothly and the 'ram air' effect is more pronounced than if the intake was mounted in the fender of the car.

Erh... not to be picky, but only sort-of. The air is NOT moving that fast along the body of the car... there's a boundry of slow moving air right next to the vehicle's surface. Above that, is the fast moving air... now, CERTAIN vipers, and the ferrari, as well as a few other cars use that 'nasa' intake, the one that you see on the sides of the ferrari F40. That one supposedly has the least amount of drag, but even it doesn't provide the boost that some scoops do. What am I referring to?



The only one I could think of off the top of my head: 1970 challenger TA. I can't find a real good pic of the scoop, but the intake is about 1" ABOVE the hoods surface, so it isn't in that 'boundry of slow air'.

- Rob

[Landshark]

Originally posted by Chicane
now, CERTAIN vipers, and the ferrari, as well as a few other cars use that 'nasa' intake, the one that you see on the sides of the ferrari F40. That one supposedly has the least amount of drag, but even it doesn't provide the boost that some scoops do. What am I referring to?

that would be NACA duct.

"NACA stands for "National Advisory Committee for Aeronautics". NACA is one of the predecessors of NASA. In the early days of aircraft design, NACA would mathematically define airfoils (example: NACA 071) and publish them in references, from which aircraft manufacturers would get specific applications

The purpose of a NACA duct is to increase the flowrate of air through it while not disturbing the boundary layer. When the cross-sectional flow area of the duct is increased, you decrease the static pressure and make the duct into a vacuum cleaner, but without the drag effects of a plain scoop. The reason why the duct is narrow, then suddenly widens in a graceful arc is to increase the cross-sectional area slowly so that airflow does separate and cause turbulence (and drag).

NACA ducts are useful when air needs to be drawn into an area which isn't exposed to the direct air flow the scoop has access to. Quite often you will see NACA ducts along the sides of a car. The NACA duct takes advantage of the Boundary layer, a layer of slow moving air that "clings" to the bodywork of the car, especially where the bodywork flattens, or does not accelerate or decelerate the air flow. Areas like the roof and side body panels are good examples. The longer the roof or body panels, the thicker the layer becomes (a source of drag that grows as the layer thickens too).

Anyway, the NACA duct scavenges this slower moving area by means of a specially shaped intake. The intake shape, shown below, drops in toward the inside of the bodywork, and this draws the slow moving air into the opening at the end of the NACA duct. Vortices are also generated by the "walls" of the duct shape, aiding in the scavenging. The shape and depth change of the duct are critical for proper operation."

i got that info from here: http://www.up22.com/Aerodynamics.htm#NacaDucts
some more good info there, too.

[Chiketkd]

You're good Rob. Thanks for keeping me honest... I totally forgot about that slow moving air that flows just above the surface of the car. The following pic from cars101 illustrates your point:



About the design of the NACA duct being crucial to optimum performance - one example that comes to mind as an illustration is the Camaro SS/ WS-6 Firebird saga. Both cars make 320hp and 345ft-lbs on the engine dyno, but drag racers have known for years that the Firebird was 'faster'. Popular Mechanics touched on this point during their 1999 Test Acceleration Nation.

-Chike

Originally posted by Chicane
Erh... not to be picky, but only sort-of. The air is NOT moving that fast along the body of the car... there's a boundry of slow moving air right next to the vehicle's surface. Above that, is the fast moving air... now, CERTAIN vipers, and the ferrari, as well as a few other cars use that 'nasa' intake, the one that you see on the sides of the ferrari F40. That one supposedly has the least amount of drag, but even it doesn't provide the boost that some scoops do.