question about airbox, pods, and restriction

[piester]

I have read pretty much every thread on this site in regards to switching to pod filters. My main question is where does the change in restriction come from? The loss of the air box, the change in filter type, or the combination? Would pod filters inside of the stock airbox act the same?

[Turtleface]

I think you have more filter area with the pods, which helps bring in more air. The airbox itself (at least on my bike) breathes through a small hole in the bottom, so you open the filter elements themselves to more air.

Essentially, more filter material to flow air through, and they're out in the open, instead of stuffed inside a box. Pretty sure most quality pod filters are also K&N oiled type, which usually have less restriction than the OE paper filter media.

[doctorgonzo]

Yes, the stock airbox is feeding all 4 carbs from a single small hole. Pods (or velocity stacks for that matter) are open to the air, and then also pulling it through a less restrictive filter. The performance gain (such as it is) is because more air allows you to add more fuel while maintaining a correct mix to burn efficiently.

[Dave8338]

Stock box should net you more fuel economy.

[Macguyver]

So am I correct in assuming...

If you put pods in your airbox, it will behave pretty much the same as a regular airbox then. Since it only has that small hole to draw through, which is the limiting factor.

Depending on the airbox, it may be easier than trying to get the stock filter to fit just so on the factory pillar.

[spyug]

You've read it in the other posts but switching to pods can open up other issues you will need to address. In most cases ( but not all) pods are less restrictive and this makes for leaner conditions in the carbs. Note that all pods are not created equal. Some low priced brands ( Emgo comes to mind) have little to no filtering which is almost like running without a filter and therefor more lean than is likely good for the engine, not to mention allowing in dirt and crap. Usually you will need to richen up your carbs ( i.e. larger jets) to compensate. Getting the right balance of smooth running and performance can be a bear requiring much trial and error. Often, you will find a "hole" at certain rev ranges where power may drop off. You also can experience popping and backfiring on deceleration.

As mentioned, putting pods in your airbox is defeating the purpose so no sense in going that route.

Best bet would be to ask what guys have done with the same bikes as yours and use that as a guide to what you do.

Let us know what you end up doing.

Cheers,
Spyug

[piester]

Well i have pods and pieces of the airbox. But its kinda beat up. Doesnt fit together much at all. Im waiting on funds to but a set of carbs and then probably the dj3 but i was just curiouse

[Octain]

Well i have pods and pieces of the airbox. But its kinda beat up. Doesnt fit together much at all. Im waiting on funds to but a set of carbs and then probably the dj3 but i was just curiouse

What bike?

[duaneage]

The airbox provides a stable pot of air for the carbs. It reduces turbulance and pulses from adjacent carbs as well. The benefits of an airbox are greatest at idle through midrange. Velocity stacks on the carb side of the box are carefully designed to straighten the airflow into the throat. Some are even different sizes for the inboard and outside carbs. Not all pods have this consideration, even when there are little stacks they are seldom tuned this way. Especially when one model fits 12 bikes.

Air inside the box provides compliant air that is free of turbulance caused by the bike moving forward. At high speeds there is a lot of swirl around the carbs without a box. The airbox also keeps hot air from the engine away from the carbs, hot air doesn't have as many molecules as cold air.

In the rain an airbox keeps things dry. Wet pods don't flow as much air as dry ones.

Most of the justification for pods centers around how easy it is to remove the carbs for rejetting for pods. I have taken my carbs off 3 times in 6 years so I don't think I wasted too much time with the box.

If you're after a 3% improvement in speed take off the centerstand and lose 20 lbs around your midsection.

I'd leave the airbox in place, lovingly replace the air filter with a new element, and appreciate how nice and behaved the bike is around town. Shortly someone will be along to disagree with me strongly.

[chef1366]

The airbox provides a stable pot of air for the carbs. It reduces turbulance and pulses from adjacent carbs as well. The benefits of an airbox are greatest at idle through midrange. Velocity stacks on the carb side of the box are carefully designed to straighten the airflow into the throat. Some are even different sizes for the inboard and outside carbs. Not all pods have this consideration, even when there are little stacks they are seldom tuned this way. Especially when one model fits 12 bikes.

Air inside the box provides compliant air that is free of turbulance caused by the bike moving forward. At high speeds there is a lot of swirl around the carbs without a box. The airbox also keeps hot air from the engine away from the carbs, hot air doesn't have as many molecules as cold air.

In the rain an airbox keeps things dry. Wet pods don't flow as much air as dry ones.

Most of the justification for pods centers around how easy it is to remove the carbs for rejetting for pods. I have taken my carbs off 3 times in 6 years so I don't think I wasted too much time with the box.

If you're after a 3% improvement in speed take off the centerstand and lose 20 lbs around your midsection.

I'd leave the airbox in place, lovingly replace the air filter with a new element, and appreciate how nice and behaved the bike is around town. Shortly someone will be along to disagree with me strongly.

You almost talked me into getting an air-box.

[qwqb]

hearing all those positives makes me want to put the airbox on. i just bought my bike in non-running condition with pods on it, but it also came with the stock airbox. i guess when i get her fired up, if it runs too lean then ill consider the airbox instead of rejetting =)

[Steve]

Most of the justification for pods centers around how easy it is to remove the carbs for rejetting for pods. I have taken my carbs off 3 times in 6 years so I don't think I wasted too much time with the box. ... Shortly someone will be along to disagree with me strongly.

NO disagreement here, Duane.

I agree that the most common reasons to install pods (besides liking the look) is that it makes it so much easier to remove the carbs. I am just wondering why you have had your carbs off so many times. I rebuilt the carbs on my wife's bike 5 years ago, they have been off the bike ONE TIME since then, and that was to take care of the cam chain tensioner. I will be taking them off a second time in a couple of months when I replace all the upper-end gaskets.

.

[piester]

its an 83 gs750E, i have the 2 halves of the airbox and the velocity stacks. the airbox has definetly seen better days. it doesnt fit together when i try to put it together off the bike so im thinking it will be impossible on the bike. the po left the airbox pieces laying around in his garage for a few years and it got all beat up.

[duaneage]

NO disagreement here, Duane.

I agree that the most common reasons to install pods (besides liking the look) is that it makes it so much easier to remove the carbs. I am just wondering why you have had your carbs off so many times. I rebuilt the carbs on my wife's bike 5 years ago, they have been off the bike ONE TIME since then, and that was to take care of the cam chain tensioner. I will be taking them off a second time in a couple of months when I replace all the upper-end gaskets.

.

First time was to get to the starter.

Second time was to fix a stuck float.

Third time was to rebuild them and that was about 3 years ago.

The next time it will be to strip the bike for restoration purposes. Maybe next winter.

[duaneage]

its an 83 gs750E, i have the 2 halves of the airbox and the velocity stacks. the airbox has definetly seen better days. it doesnt fit together when i try to put it together off the bike so im thinking it will be impossible on the bike. the po left the airbox pieces laying around in his garage for a few years and it got all beat up.

The 1100E uses the same box. You can probably find someone with an 1100 and pods that has no use for their box. Just don't show them this thread and tip your hand,

If someone was using starter spray on the bike it can distort the plastic. I bought a bike for parts that had been tortured with that stuff and it distorted the filter frame and airbox lid.