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Strat79
Dodge Dakota
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2/09/2003
12:57:28
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 Subject: air box/air hat
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I noticed that a lot of the aftermarket intake kits for the 4.7 are just a large diameter tube that connects right to the throttle body with no air hat/airbox. Based on some other engines I've seen and dealt with, including my motorcyle, it seems that keeping some kind of large volume airbox right at the throttle body is a good idea, to provide a large reservoir of air to be sucked in when the butterfly opens quickly under sudden acceleration. It seems this is done to provide better throttle response. Otherwise, all that sudden airflow requirement has to flow just through the tubing.
Anyone have any thoughts or theories (or better yet, dyno data)?
I've seen a lot of posts lately that say that the best solution is to just keep the standard filter box, tubing and airhat/airbox, and just use a K&N drop in filter. This does seem to be the simplest, easiest way to get most of the intake benefits & performance gain. It seems all those aftermarket intakes that have the bent aluminum tubing just are more for looks than actual documented performance gains.
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Slanty Shanty
Dodge Dakota
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2/09/2003
13:17:17
|  RE: air box/air hat
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I was thinking of trying build my own ram air/ forced air box. Got the idea from www.ramairbox.com I don't know what parts to use off of that page? But I think it would be nice.
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NDakota
Dodge Dakota
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2/09/2003
13:50:56
| RE: air box/air hat
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AEM is a company that offers dyno results on their Brute Force intake. I've used their products in the past, and they work very well.
http://www.aempower.com/trucks/brute_force_app.html
Click on the red circle thingy next to the product and it will show the dyno results. They're also one of the only companies that documents their dyno procedures...these are not peak results. They're averages over 3 runs. If something looks unusually high or low, they throw it out.
www.coximports.com sells them for about $225, I think it's one of the best applicatoins on the market for our 5.2 and 5.9 liter engines.
For the 4.7, I think Nitrous Steve has the market cornered.
My .02 ;)
Ryan
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Slanty Shanty
Dodge Dakota
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2/10/2003
14:45:18
| RE: air box/air hat
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That box that actually holds the filter on a 4.7L dak... how much would one of those cost? Well, actually, how much would two of them cost? And, where could I buy them, junkyard?
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Strat79
Dodge Dakota
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2/10/2003
18:27:29
| RE: air box/air hat
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No, I'm not talking about the air filter box that sits beside the engine on the passenger side, I'm talking about the rectangular airbox right at the throttle body on the '02 4.7. There's no filter in it. It's just a large volume airbox right before the TB.
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Texas Todd
Dodge Dakota
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2/11/2003
09:38:59
| RE: air box/air hat
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Strat,
have you taken the air hat off and looked inside it very well? It's not a 'large volume air box'. It's a 90bend, with a another chamber that goes nowhere, or it would suck unfiltered air. It has a baffling effect for sound. On my 01, there were NO wires going to the air hat at all.
Looks like a big square box from the top, look inside though. MY 90degree fernco fitting, is pliable, firm rubber that clamps well to the TB, eliminates the air hat, is is slightly larger I.D., I got rid of the accordian tube, with a piece of PVC-no glue or cement anywhere, it all clamps with the fernco fittings. The internal diameter has no ridges or steps, works great, been almost two years, no problems. I don't see how a hard PVC will clamp that well to the TB.
Match up a PVC, and a fernco fitting. the PVC is a very tight 90 degree bend, wheras the fernco is a long gradual 90 bend. If I was air flowing down that tube, that PVC would be a definite bottleneck, crashing bend!
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Strat79
Dodge Dakota
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2/11/2003
12:16:56
| RE: air box/air hat
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Todd, Thanks for the info. I'm just still wondering if there is some performance benefit to the air hat, for throttle response maybe? I can understand the manufacturer's concerns about minimizing intake noise, but a lot of high performance motorcycles have an airbox too, right at the entrance to the carbs or throttle bodies, supposedly to enhance throttle response.
And how could the airhat on the 4.7 suck unfiltered air? Is there another inlet opening into it somewhere other than the accordian connection from the filter box?
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Texas Todd
Dodge Dakota
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2/11/2003
13:27:03
| RE: air box/air hat
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Strat,
Sorry, I meant that the little chamber, the connects with the 90degree bend inside the air hat, goes nowhere. Therefore, it won't suck any air, dirty or otherwise. It's kind of a baffle. By eliminating this entirely, dyno gains (small ones) have been documented.-small ones.
The ductwork inside the air hat, is not the same as the outside shape of the hat you see when you open the hood.
Don't get me wrong, I don't think it's really much different one way or the other,(hat or no hat), Experiment, and use an objective way (like a dyno) to measure it.
8^D
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Strat79
Dodge Dakota
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2/11/2003
19:50:42
| RE: air box/air hat
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Thanks for the post Todd. I think I'll probably just try the drop in K&N filter for now. And maybe do some tinkering to try to get rid of the airhat and the accordian tube.
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Ricky
Dodge Dakota
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2/03/2004
18:29:10
| air hat?
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Does anyone know where I can get a 3" throttle body air hat?
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elixir
Dodge Dakota
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2/05/2004
00:29:01
| RE: air box/air hat
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i too wanted to get an intake. volant intakes make a closed box for the durango and an open box for the dakota. whats best? i heard closed boxes. i was wondering if the durangos intake fit my truck? same engine, same year.
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RR
Dodge Dakota
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2/05/2004
02:53:06
| RE: air box/air hat
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I bought the aluminum 3" inlet air hat made by powerdyne at krcperformance for $125. That would be considered a very small volume enclosure and I don't notice any power loss although it is somewhat noisy. (whistle sound) They also make a larger 3.5" inlet with more volume, same price. 360airintakez has a 3.5" inlet plastic air hat for $50. Not as pretty as mine.
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Dave Mitchell
Dodge Dakota
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2/05/2004
19:14:15
|  RE: air box/air hat
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I believe the air hat's function is to reduce the noise from harmonics. When the engine reaches and RPM where the length of the air passage matches a 1/4 wavelength multiple of the sound frequency the intake passage (or exhaust) becomes an amplifier. The side chamber helps to dampen the harmonics.
I would think a good aftermarket or custom built cold air intake may make a very loud noise at some certain RPM that is a harmonic of the intake length if held there for a time. The noise would get louder as the length of time that RPM is held.
This is the concept behind "tuned" exhausts and ram-air intake systems of the hot rod era.
My older brother had put a header system and tuned dual exhaust on a Datsun 510 with a Del Orto side draft carburetor. At 90 mph in 5th the engine was at the tuned RPM and the ehxaust would get louder and louder and eventually would start vibrating in the hangers so bad it would thump against the floorboards.
I would tune the intake and exhaust to the max torque R.P.M. for the most pulling power.
Dave
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Jeff
Dodge Dakota
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2/05/2004
21:02:07
| RE: air box/air hat
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Yup, the shop manual calls this thing a resonator and it eliminates most of the intake noise.
The 4.7 HO engine comes with a high flow intake made up of a specially designed resonator, tube and filter box. Maybe some of these parts will fit the dak. They are pretty cheap from Mopar.
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01Motorsport
Dodge Dakota
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2/06/2004
09:17:58
| RE: air box/air hat
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I removed the air hat and accordian tube and replaced them with 3" aluminum alloy tubes and rubber boots between the throttle body and air box. The system is barely louder than stock. I also use a K&N drop-in and removed the 90 degree snorkel. The rubber flap at the radiator is removed, and a 4"/4" Fernco inlet is used. My homebrew story is under the thread "What is the best intake?". The system has been working well for about 18 months now.
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Vortec
Dodge Dakota
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2/07/2004
20:20:15
| RE: air box/air hat
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Vortec makes an aluminum air hat.
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