| Author | Message | ||
     David_e |
I've seen so many options on air box systems. I'll be getting my ecm remapped for D&D pipe with k&N and open air box. What would be my best option for the air box? Thanks in advance. David E. | ||
| Jflaig |
You have three choices: 1. Cut your original - similar to the 07 2. buy the 07 airbox @ $40 3. go to open air kit, top plate cover over filter only This has been discussed several time here. You can do a search for air box info. I did the 1st option. Saw the factory cuts through the Lightning's translucent cover, then cut mine to be similar. I followed the ribs to try and not go too wild in cutting. Good luck. | ||
| David_e |
Thanks Jflaig...Since the air is taken in behind the fuel filler cap I opened up the area just behind it and closed the vent on the right side of the 06 air box thinking that this may create a ram air affect. What do you guys think? | ||
| Bombardier |
There is a theory, to which I subscribe, that recognises that air that expands cools down. I may well be wrong, however I think that the comparatively small intake area behind the fuel filler is just big enough to let the right amount of air in and the larger airbox area behind is the expansion area which results in cooler air being drawn into the engine. | ||
| Al_lighton |
I'm calling BS on this one... Yes, it is true that when you expand a gas, it absorbs heat in the process. But that heat is the same energy that it took to compress the gas to begin with. Basic thermodynamics. Once upon a time, I even learned and understood it all... but that was many years ago. The only provider of the energy to move it through that screen is the intake draw from the piston moving downwards (plus some very small amount of scavenging from good exhaust design). I don't think there is any expansion anyway. There may be a reduction in flow resistance due to a change in the duct size, but I don't see any gains there. Al | ||
| Bombardier |
It would be interesting to place a thermometer on both sides of the opening to see if there is in fact a change in temperature. I do remember something about colder air being denser which is better for making power. Not really sure what you mean by BS though. | ||
| Court |
What you are talking about is the "Ideal Gas Equation".  I have an opinion much like Al's. | ||
| Blake |
"Since the air is taken in behind the fuel filler cap I opened up the area just behind it and closed the vent on the right side of the 06 air box thinking that this may create a ram air affect. What do you guys think?" Even in ideal conditions, intake out nearer free stream at front of machine, Ram air effect doesn't kick in until speeds climb to well over 100 mph. Here's the math: Normal ambient atmospheric pressure is around 14.7 PSI or 2,116 PSF where "PSI" and "PSF" are units of pressure in pounds per square inch and pounds per square foot, respectively. The available dynamic pressure increase at speed can be found from the simplified equation as follows: PD=V2/391 PSF Where "V" is speed in MPH. So at 100 MPH the available RAM air dynamic pressure increase is 1002/391 = 25.6 PSF That is equal to just 0.178 PSI, either way just 1.2% for a theoretically perfect ram air intake. Even MotoGP bike and Formula-1 cars don't achieve that level of ram air intake efficiency. Avoid drawing intake air from over the hot engine? Pull it from cooler ambient areas? Sure! Al and Court speak truth. If air is expanding then even though it would be cooling, it is also becoming less dense, which means less air is getting into the engine. So though expanding air would cooler, it would be less dense and not beneficial to performance. As Al says, the air is not expanding. The large airbox provides for an adequate volume of supply for the engine while diminishing intake noise. Think of it as a capacitor for engine air flow, where the engine takes a big gulp of air for every intake stroke. The flow is not steady state. | ||
| Bombardier |
Is the psi or psf dependent on the area of the intake? The larger and more exposed the opening would mean more of a ram air effect would it not? | ||
| Dhalen32 |
Bombardier: Al, Blake and Court are giving you good info. Think of it this way: For the air to expand and cool it would first have to be compressed. Compression in the intake tract is what is not really happening in the circumstances you described above. Dave | ||
| Jlnance |
Is the psi or psf dependent on the area of the intake? That's already built into the formula. The answer is per square inch or per squre foot, which are both units per area. The area of the intake would affect how much air you can suck out of of the intake with out lowering the pressure unacceptably. | ||
| Court |
>>>For the air to expand and cool it would first have to be compressed. Not exactly. If you take the V component it really doesn't much care where it "started" it's the amount of change. If air is at 14.7 PSI and is lower, by either of the other two (T = Temp or V, the volume, is increased) T will act accordingly to bring the equation into equilibrium. There are a host of other peripheral factors (careful . . you are dealing with me while I am sitting in Butler doing homework) at work. As an example, and I'll tie this to the discussion in a moment, air is a fluid and like any fluid (generally in a gas or liquid state) is has some viscosity so response time comes into play. Think of trying to pull the bottle of Log Cabin syrup from the refrigerator and pour it out FAST . . . . an extreme example to be sure, but you need to understand what's at work here. The "tie in" is that the numbers, magnitudes, quantities and flow rates are so small as to, where you and I ride, be inconsequential. How much, for instance (since we all tend to evaluate against USD) would you be willing to pay if a guy told you he could lower the ambient temp in your intake tract by 2oF? . . . would you pay $2,000 for such a device? . . $200? Now there ARE (Blake, Erik, Al or Steve Anderson could give you some details) places where these things need to be calculated, known and make a difference. Bottom line is that since the discussion involves paying something to get something, I'd suggest that the benefit is negligible and therefore so too, should be the price. If you want to get a sense for exactly what temperature does. . . . slap the carb heat on while landing a Cessna 172RG on a cold day and watch the manifold pressure. But . . I am a construction worker. . . I'll toss you back to the Engineers.  | ||
| David_e |
Thank you very much guys...I'm going with Al's open air box kit. | ||
| Smiley1eye |
I've been spending alot of time looking at the inside of my airbox and I've noticed the following: it seems to draw as much air from gaps over the rear cylinder as it does from the vent on the front of the airbox by the filler cap. And there's still the gap that runs all over the outside edges of the box as well. Between the engine heat, the flyscreen blocking "ram-effect" into the filler cap vent and the fact that the airbox can't be pressurized no matter how fast you go; I'd say that there's no practical way to get colder, compressed air into the intake without mechanical help (turbo/supercharger) It seems to me that the only practical idea is to block as much of the engine heat as possible and at least bring the temp closer to ambient. And the only idea I've seen for that is the heat blankets like on the FAST system. Wow, that's really starting to sound like a lecture, which was NOT my intention! | ||
| Smiley1eye |
Oh, and I installed the open airbox kit from Al as soon as I got the bike. Just seemed like such a shame to not be able to look through that clear blue airbox. Thanks for it Al. | ||
| Al_lighton |
Much of the air comes in around the perimeter gap between the airbox cover and the frame. It doesn't look like much area, but there is more area in that perimeter slot than there is in the 49mm throttle bore. Al | ||
| Vagelis46 |
What was the reason Buell gave up the hole throught the frame intake path, like in the 04' models ? it looked as this was the best way to get cool ambient air to the engine... Was it frame stifness ? | ||
| Bombardier |
Wanting to know if the hole is still there under the metal covers. Ideal place for a forced induction delivery tube. (Message edited by Bombardier on February 25, 2008) | ||
| Bombardier |
BUMP |
