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Post by 90GTVert on Apr 3, 2016 16:03:24 GMT -5
The Air Box Dilemma.doc (346.5 KB) The document above was sent to me by ThaiGyro . Since you posted such a great deal of data on your air box modification...I thought maybe some folks could use some history before making decisions about "air". Read it and post any way you think is fit. It is simple to understand with more complex, BS references altered or removed. My site ID is in there "ThaiGyro", so people can ask questions. Note that I am not an aero expert, just a mechanical engineer who has had many experiences...good ones and bad ones.
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Post by frank50e on Apr 3, 2016 21:30:14 GMT -5
Excellent info Brent in relatively plain English.We all spend a lot of time trying to outwit factory engineers who figured this long ago.Worked on literally hundreds of late 70's early 80's Hondas that just refused to run right without the factory airbox.At that time most of us were used to running bikes with open carbs.Quite a learning curve for me at the time.
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Post by Lucass2T on Apr 4, 2016 0:54:24 GMT -5
There's a but here.
There are differences between stock airboxes and stock airboxes.
Those high performance high power high tech racemachines (bikes, cars, 2t's and 4t's) discussed in that document ofcourse have specially performance oriented designed airboxes.
On our mass produced scoots the airbox is only desgined for maximum ease of production, maintenance and keeping dirt out of the engine. There is no performance goal.
But yeah I think a well designed airbox is better than an open filter.
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Post by aeroxbud on Apr 4, 2016 7:52:11 GMT -5
True Lucass2T so many vehicles are ruined by pod filters. Not forgetting on some scooters like the later Gilera runners the air box is actually used to restrict air flow. One of the best mods to the later 50cc runner is fitting the earlier triangle air box. |
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Post by TheAmishSasquatch on Apr 4, 2016 9:16:51 GMT -5
The document won't open for me.  |
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Post by 90GTVert on Apr 4, 2016 10:02:41 GMT -5
I use the free Open Office suite to open it and most other docs. It's a nice free prog that's handy for a lot of things. www.openoffice.org/ |
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Post by FrankenMech on Apr 4, 2016 16:53:21 GMT -5
I use the open office program also.
The article was mainly about cars, cold air intakes, under-hood air and open filters, ram air boxes, etc.
I run an open filter on my scoot with a modified carb and it works great. But then I know how a carb is supposed to operate. Some of these scoot carbs are a POS unless they are modified. With many the air box is essentially a part of the carb and fuel metering circuits. With proper modifications an air box is not required.
I run a cold air intake on all of my older vehicles along with a thermostatic warm air induction system. I just laugh at the idiots with shiny chrome open filters installed on so many 'performance' vehicles.
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Post by cwazywazy on Apr 4, 2016 19:49:46 GMT -5
I just have a pod filter because why not. I don't know if it's better or worse, but it works.
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Post by ThaiGyro on Apr 5, 2016 5:15:53 GMT -5
I think the whole point is that, yes...anyone can tune a pod or no filter or no reed valves or ay other combination to actually function and function well. If the desire is upmost horsepower at the top end, no problems. If the desire is for more performance any where else in the power band, then the story is quite different.
Given the F1 data, I am looking at intake tract air speed and pressure waves to see if REAL gains can be made. I am not so sure...but finding out might be! I don't care much about top end power...I am not racing this little thing, but I do want it to shit-n-git from the line! I do not have to even register a 50cc or under, but altering it with cylinder bores and such, while fun, creates more issues.
If I could get a water cooled 49cc kit, I would be super happy, because I know that a Minarelli vertical engine can produce 8 hp or more easy...in low to mid range. I want to wheelie my Gyro off of speed bumps, but not end up in the bone ward.
Please don't be negative about the data...it is real. Understand the intent. You can install anything that makes you feel good, or makes power down low. If you want peak HP? Another story.
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Post by Lucass2T on Apr 5, 2016 5:28:34 GMT -5
Did you already check the helmholz resonator theory? Building an airbox of a certain volume from a certain material will cause some sort of pressure which aids flow.
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Post by Lucass2T on Apr 5, 2016 5:30:37 GMT -5
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