Replace airbox with single car pod...

So this is either completely stupid or sheer genius...

I was riding home today and I was thinking about pods... they looks sexy, like four very good friends but we all know the problem with cheap ones blocking parts of the intake and even good ones not providing a single air source. I almost hit a squirrel that flew out the back of this HEMI trunk when it dawned on me... the airbox is ugly but maybe, just maybe it could be replaced by a large pod... one that is used on cars/trucks...surely this would look even sexier cos we all know one big one is better than four small (erm..not sure now I wrote that down) and it "should" allow the carbs to pull from a single airsource just like the box..

...discuss...

First one to mock this up get's a free cookie..

If it's for a single carb and you can fit a velocity stack inside the pod, then you can make it work.

If it's for a multi-cylinder bike with multiple carbs you are going to need some sort of airbox, so it's kinda pointless.

you need to get your head on straight
the stock airbox is sexy because it functions really well
the japs got it right you are not smarter than the smart fuckers that built the airbox
pods look fucking stupid,they dont look sexy
why ?BECAUSE THEY ROB HORSEPOWER ferfucks sakes
when i see pods i think stupid fucker and i am right,stupid stupid stupid
quit fucking up the performance of the engine and spend the time effort and money on something you can improve
PROPERLY SET UP QUALITY SUSPENSION(not a "single sided swinger or some other single shock conversion)

brakes,tires and controls

Do you need a belly rub? You sound grumpy. I guess you missed the fact that I was suggesting putting a huge giant truck pod on a motorcycle and went right on thinking I was serious so you had someone to lay your "I hate stupid stupid stupid fucking pods.." rant on... now I need a shower...thanks dude!

Actually there was a guy who had done that to his GL. Although the inlet to our air box kinda lends itself to the set up. Here is a pic of how our air box is built and a link to a guy selling a bike with the same swap. There was no problems with him converting it to this as far as jetting or reliability.
http://images.cmsnl.com/img/partslists/air-cleaner-gl500-silver-wing-1981-usa_bighu0172f1b18_703f.gif

http://www.bike4sale.co/detail/APcPVmuuAFAAuceoum/1982-honda-gl500-custom-cafe-racer-rat-rod-street-fighter

A few 4 cyl bikes had 2 piece air boxes like this GS1100:





In which case you could simply replace the section with the filter with your car pod.


But, tells us what bike you are thinking of doing this with before we go any further.

Midwestgl500 said:

Actually there was a guy who had done that to his GL. Although the inlet to our air box kinda lends itself to the set up. Here is a pic of how our air box is built and a link to a guy selling a bike with the same swap. There was no problems with him converting it to this as far as jetting or reliability.
http://images.cmsnl.com/img/partslists/air-cleaner-gl500-silver-wing-1981-usa_bighu0172f1b18_703f.gif

http://www.bike4sale.co/detail/APcPVmuuAFAAuceoum/1982-honda-gl500-custom-cafe-racer-rat-rod-street-fighter

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That's awesome - I like it. I'm all for function first and I appreciate this hence why I'm not just throwing on pods myself but maybe I can make this work on the XJ650... probably have to fabricate something to go between carb rubbers and super pod.. anyway, like I said I was joking when I posted this but maybe it's got legs.. I might just do it to give people something to bitch about..

Its not about how a SINGLE large air filter will perform over several small ones. Its about HOW you have to connect all carbs TO said large filter. Using an intake PLENUM to connect the carbs to a filter is the same exact thing those Smart Engineers did 30 years ago and continue to do because it makes sense. This allows for a large free flowing filter to be used and this also allows that plenum to shape the flow of the air into the carbs, thus making the air flow SMOOTH. I'm an Electrical Engineer, not an Aerodynamics Engineer but that is the jist of it.

Basically its like LEAVING the nasty looking factory air box in place and using a performance filter in place of the factory. So if you take that factory air box, clean all the sharp corners and sound baffles OUT of it, you are left with nice curves and a free flowing design. Stick a high flowing filter on the end and you are doing what every hot rodder has done since the begging of engines.

So is it better to reinvent the wheel or leave it alone? Believe me I've been staring at a CB550 tying to figure WTF I'm gonna do with the air filter, PODS are NOT in the equation.

And if it works the only thing they can bitch about is how much better your bikes runs compared to theirs.

Makes sense to me dude... This is on the list for the build when I get to it. Even if it doesn't work I reckon I'll learn a shit ton about airboxes and plenums in the process.

side note... is that you on the cell tower? I'm a network engineer and I design cell-networks amongst other things but I'm pretty blown away by the folks that climb up these things - just watching this video makes me shit my pants

It links but you have to click on the youtube icon to open it in youtube for it to play... it won't play directly here.

https://www.youtube.com/watch?v=qW5LCqg_Tnc

Apparently K&N made something like this for the Honda CBs, I think back in the 70's. They're hard to find though so I made an adapter myself to mate with the intake plenum on my '78 CB550k. I haven't installed it yet but since it maintains the original intake plenum it should be easier to jet. Carbs really need still, uniform air to work well. Personally, I like this look better than pods, but pods are still cool, haha. Anything but that god awful, well designed, very functional air box.

My adapter:


This picture is not my bike, but a member on SOHC4.



---
1978 Honda CB550K

Yep, that's great IMHO. The standard dog ugly airbox was designed without any aesthetics in mind, which they could do cos it was hidden. When it comes to engineering design you have to take aesthetics into account if the part is visible and surely it's what we're all after at the end of the day, a very good running motorcycle that is unique and looks great too.. Looks are certainly the later part but they are an important part.. it's like a cake, if it tastes like shit it doesn't matter how it looks but if tastes good then the baker wants it to look good too.

Personally I think the single large air-filter looks friggin awesome, much cooler than the pod look and logically it can be made to function better than the stock airbox. So what's not to love about it?

And then there is mine....


I had other concepts also...



Sent from my iPhone using Tapatalk

Ribo said:

side note... is that you on the cell tower? I'm a network engineer and I design cell-networks amongst other things but I'm pretty blown away by the folks that climb up these things.

Click to expand...

Yes, one of those crazy fools that climbs towers to put up equipment, although I don't climb so much anymore I have a team for that now.

I have a similar job to you as I design and build networks for my company which is a wireless ISP in rural southwestern Oklahoma.

Mech - it's a good thing you didn't go with the concept you posted. Drawing air from the sides like that causes the inside carbs to get less than the outside carbs. Cool setup you have now btw!

Big Rich said:

Mech - it's a good thing you didn't go with the concept you posted. Drawing air from the sides like that causes the inside carbs to get less than the outside carbs. Cool setup you have now btw!

Click to expand...

thanks for the kudos. on my bike gs850, the cylinders arnt sucking at the same time. firing order is 1243. I could baffle the pipe so that any back pressure didnt affect the adjacent carb(s).

Having a single filter element feeding multiple carbs isn't a new concept. K&N has a "lunch box" filter that's a standard mod for the GS500:


I had set of these, side by side, on an FZR600 years ago:


Going without an airbox is slightly more effective on singles and twins than on fours, but if you have stock carbs and a stock top end, you will be losing performance and reliability, regardless.

I guess I'm a little confused by this.... if you replace the stock airbox with a single large external air-filter, surely the performance would improve as the bike will be pulling air from a single source that is "cleaner", in that it has less to traverse - taking for granted that a smooth plenum with no velocity issues is used right?

Ribo said:

I guess I'm a little confused by this.... if you replace the stock airbox with a single large external air-filter, surely the performance would improve as the bike will be pulling air from a single source that is "cleaner", in that it has less to traverse - taking for granted that a smooth plenum with no velocity issues is used right?

Click to expand...

I think too many people try to apply automobile knowledge to motorcycles when it comes to the way a top end works. The airbox on a car is not the same as the airbox on a motorcycle. Before the air gets to the cylinder head on a car, it has to go through the airbox, the intake pipe, past a series of sensors, the carb or throttle body and the intake manifold. By the time the air gets to the heads, the flow has been smoothed, evened out and divided equally among the intake ports. Removing a car's airbox and putting on a big cone filter only changes the quantity of air, but the rest of the intake tract is still doing its job so, theoretically, you will get more performance (if the rest of your top end is up to the task).

On a typical multi-carb motorcycle setup, there is no intake manifold between the airbox and the carbs. It's airbox, airbox boots, carbs, intake ports. The airbox isn't just a filter housing, it functions as a plenum from which all carbs can draw still air, equalizing the flow to each intake port. The airbox boots are shaped like velocity stacks because that's what they are. When you eliminate the airbox and boots, it's the same as eliminating the intake manifold on a car. Try sticking individual carbs and pods directly on each intake port of your car's cylinder head and it won't matter how "free flowing" the pods are, your car will run like crap, if it runs at all. If they're CV carbs, it'll be even worse because you won't be able to get the slides to open equally no matter what you do with the throttle.

On a bike, twins will fare just a tiny bit better because both carbs will technically be exposed to equal amounts of air. Add some velocity stacks under your pods and that will improve it even more by smoothing out the flow. Use VM carbs and you're in business, assuming you use the right size and jet them properly. This is all very over-simplified, but that's the gist of why just replacing the stock airbox with a big filter won't automatically yield better performance.