Scoop or Cowl?

[Slip Kid]

I'm sure there's a lot of opinions on this, but what is more effective at drawing air in, a forward facing hood scoop or a rear facing 'cowl induction' scoop?

 

[XJ_ranger]

I'm sure there's a lot of opinions on this, but what is more effective at drawing air in, a forward facing hood scoop or a rear facing 'cowl induction' scoop?

for a wheeling rig that will probably get a lot of dust - id go with a cowl... mostly because that will allow the dust a longer time to get out of the air before it hits ur rig...

 

[Osprey413]

I don't think the diffirence in distance is going to change the amount of dust in the air, or atleast not to an extent that actually matters. But, I have heard that cowls are actually better than scoops, and there was some technical aerodynamic explination for why, but I can't remember it.

 

[HodgePodge]

I don't think the diffirence in distance is going to change the amount of dust in the air, or atleast not to an extent that actually matters. But, I have heard that cowls are actually better than scoops, and there was some technical aerodynamic explination for why, but I can't remember it.

Easy... Magic! :lecture:

 

[thedarkprince]

they are better at drawing air into the engine bay through the front. The lower pressure zone behind the cowl allows air to flow through the radiator better at speed. At the speeds you will be wheeling.... a cowl would be better cause it would help deflect some mud from getting in, whereas a scoop would, well, scoop it in. For getting air directly into the intake, a functional scoop thats sealed onto the end of the intake will ram the air in and get more in, for better overal engine cooling a cowl works better

 

[Osprey413]

There you go.

 

[MaXJohnson]

The highest pressure is at the front of the vehicle. Pressure drops sharply at the break-over point (front header) to the hood. The base of the windshield (cowl) is a positive pressure area, but doesn't measure up to the grill area.

The cowl should out perform a scoop in the center of the hood, but if you place the opening of the scoop at the leading edge of the front header panel, ala early 70's Olds 442, the pressure should be greater. I have seen pressure diagrams that support this, but don't have access to them at the moment.

 

[Legacy]

The hood scopes are designed for bringing in air and, the cowl is designed to help cool down the engine it does not draw in air. I'd go with the cowl hood it will help cool down your engine better. the only time a scoop works is at high speeds and I don't think you will ever be going fast enough. you will not get a ram air effect with a scoop no matter how hard you try. Good Luck.

 

[2001XJeep]

I'd go for the Cowl. Don't have the link, but there's a new steel cowl hood for the XJ that looks really good and would be totally functional. I wouldn't bother with trying to use it for engine air intake, but rather to dissipate a lot of heat on the trail in the summer. If you did decide to extend the engine air inlet to the cowl it WILL draw in fresh air at higher speeds (factory examples include SS Chevelle/Camaro).

The leading edge, forward facing scoops (like the 4-4-2 Olds) will also admit plenty of fresh air, and yes they will produce a ram effect at high speeds (have you ever held a cup out the window, open end forward, on the interstate???) but on a Jeep I think the likelihood of drawing in water and/or mud would be too great.

 

[thecozmo65]

Heat rises. That combined with air movement through the grill a cowl would provide a better place for the heat to go than down the fire wall and out the bottom. (That makes sense right?)

 

[Legacy]

The leading edge, forward facing scoops (like the 4-4-2 Olds) will also admit plenty of fresh air, and yes they will produce a ram effect at high speeds (have you ever held a cup out the window, open end forward, on the interstate???) but on a Jeep I think the likelihood of drawing in water and/or mud would be too great.

Exactly what good is a scoop on the trail? you are not going at interstate speeds, the only time a ram air effect is created is at high speed like I said. So what good would it be on the trail?
Go with the cowl it will help keep your engine cool on and off the trail. If you go with a cowl don't use it as an intake, that would be the worst spot for a intake the air would travle over the warm hood heating it up it would be a waste of time and money.

 

[NHextremeXJ]

One word.............BOTH. buy a cowl induction hood and mount a scoop near the front. Place a screen in the scoop to keep the mud out. :cheers: Oh, and don't forget your spotter to tell you what's on the other side of your hood. :lecture:

 

[2001XJeep]

Go with cowl, will give you the best of both worlds.