Modded airbox pics
06-09-2013, 07:38 AM
#7
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yes, it's on there to mask the unsightly glue runs (plus add a small measure of added strength)..... while not aesthetically pleasing in their own right either, they will be practically invisible when mounted on the bike..... I never said it was pretty, lol Heck, it may not even work... but if you don't try you'll never know........ the cost was one used airbox, four tubes of 5 Min epoxy, and some spare time....... oh yes, and a third of a roll of electrical tape......
Last edited by mikstr; 06-09-2013 at 07:40 AM.
06-09-2013, 08:23 AM
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yes, it's on there to mask the unsightly glue runs (plus add a small measure of added strength)..... while not aesthetically pleasing in their own right either, they will be practically invisible when mounted on the bike..... I never said it was pretty, lol Heck, it may not even work... but if you don't try you'll never know........ the cost was one used airbox, four tubes of 5 Min epoxy, and some spare time....... oh yes, and a third of a roll of electrical tape......
Basically, it's a lossy process, you loose about a 1/4 to a 1/3 of the material doing it, but if you have a couple of spare pieces to use as sort of soldering tin, it's a permanent bond, just the same as the factory mould, and it cleans up nicely with just a little sanding, making it look like stock...
06-09-2013, 08:56 AM
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You are aware that with a old soldering iron with a fairly thick tip, you could have just melted the ABS plastic together intead of adding all that epoxy, right?
Basically, it's a lossy process, you loose about a 1/4 to a 1/3 of the material doing it, but if you have a couple of spare pieces to use as sort of soldering tin, it's a permanent bond, just the same as the factory mould, and it cleans up nicely with just a little sanding, making it look like stock...
Basically, it's a lossy process, you loose about a 1/4 to a 1/3 of the material doing it, but if you have a couple of spare pieces to use as sort of soldering tin, it's a permanent bond, just the same as the factory mould, and it cleans up nicely with just a little sanding, making it look like stock...
Maybe the next one I do, lol
06-10-2013, 05:09 AM
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well, I have another airbox to play with, so will try to keep things a bit more conservative this time, more akin to Lloydie`s box (without the turbuulence inducing signature, however, lol). AS suggested by my esteemed collegues, I will "weld" insrtead of glue this one......
Will try both (the one in the pics and the Lloydie-esque one) and see what happens......
Will try both (the one in the pics and the Lloydie-esque one) and see what happens......
06-10-2013, 06:11 AM
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It`s a simple matter of exapnding the airbox vlume to allow the engine to breath better. The stock airbox volume is 9 L (from what I read ion a Honda press release at the time of the VTR`s launch), not quite enough to alolow the engine to breath properly, efectively choking it at higher rpm.... an engine is an air pump, the more air it can take in, the more power it can make.......
06-10-2013, 06:15 AM
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LloydieVTR's box seems to make more sense to me. Mikstr, I'd expect yours would create more turbulent air in those lower pockets rather than creating more useable airbox volume???
06-10-2013, 06:26 AM
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could very well be Matt... I got carried away, lol That is why I got another box and will be going the same route as Lloydie (though I will keep the forward crank vent inlet in place, and re-installing one on in the back position (a 19mm PVC tee) as I will continue to run the Krankvent in the box; very little volume loss there, and it saves me from having to deal with the crap of long hoses and an external catch can and filter).
06-12-2013, 05:11 AM
#17
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started work on the "new" modded box and must say that using a soldering iron is a wonderful thing; much easier and a lot cleaner.... will look almost OEM when I am done.....
am also looking forward to getting the modded airfilter done up too (yes, another "welding" job....)
am also looking forward to getting the modded airfilter done up too (yes, another "welding" job....)
06-12-2013, 05:21 AM
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maybe this has no relation at all.. but a lot of people on here keeps saying that K&N are crap and that your bike will run better with stock air filter, yet it's obvious that the K&N would allow the bike to breath better, all you have to do is compare the stock vs K&N. the K&N is almost see through.
So if more air is a bad thing why would you want to modify an airbox to get more air?
So if more air is a bad thing why would you want to modify an airbox to get more air?
06-12-2013, 05:46 AM
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Good question.
I have rad in numeous places that an engine`s airbox volume should be at least 10 times its displacemnt for good breathing and power production (in a performance application anyhow). This is especially true in the case of a big twin since it takes in large gulps at irregular intervails (unlike an I4 which takes small and regular "breaths"; read up on V&H`s numerous challenges when they began work on their V-Rod drag bike for an idea). So, giving a larger reservoir of air to draw from should enhance teh engine`s ability to draw in needed air. Also, as the thing which actually "pushes" air into the engine is the pressure differential between the airbox (essentially atmospheric pressure) and cylinder (partial vacuum), adding volume to the airbox reduces the rate of pressure drop (due to larger volume), so, in theory, keeping the pressure in the airbox slightly higher should help to push more air into the engine at each induction event (=greater cylinder filling = more torque).
Two other points: Roger Ditchfield (unrivalled VTR guru) has told me on numerous occasions that the VTR engine (a modded one anyhow) is strangled by the stock airbox, particularly at high rpm, so increasiong the volume should help alleviate this to some degree (esepcially seeing as how my snorkel has been opened up already, and I have two 1" holes in the lid, for better air replenishment).
Finally, one should not confuse airbox volume with intake velocity. It seems to me that the problem with the K&N may be that it doesn`t offer sufficient resistance (essentially acting like a hose with an open end, with the water just flowing out as opposed to having your finger on the end in which case it shoots out), leading to stagnant airflow. That is just a theory or thinking out loud, however.....
In the end, given the negligible cost of trying a larger box, what do I have to lose......
I have rad in numeous places that an engine`s airbox volume should be at least 10 times its displacemnt for good breathing and power production (in a performance application anyhow). This is especially true in the case of a big twin since it takes in large gulps at irregular intervails (unlike an I4 which takes small and regular "breaths"; read up on V&H`s numerous challenges when they began work on their V-Rod drag bike for an idea). So, giving a larger reservoir of air to draw from should enhance teh engine`s ability to draw in needed air. Also, as the thing which actually "pushes" air into the engine is the pressure differential between the airbox (essentially atmospheric pressure) and cylinder (partial vacuum), adding volume to the airbox reduces the rate of pressure drop (due to larger volume), so, in theory, keeping the pressure in the airbox slightly higher should help to push more air into the engine at each induction event (=greater cylinder filling = more torque).
Two other points: Roger Ditchfield (unrivalled VTR guru) has told me on numerous occasions that the VTR engine (a modded one anyhow) is strangled by the stock airbox, particularly at high rpm, so increasiong the volume should help alleviate this to some degree (esepcially seeing as how my snorkel has been opened up already, and I have two 1" holes in the lid, for better air replenishment).
Finally, one should not confuse airbox volume with intake velocity. It seems to me that the problem with the K&N may be that it doesn`t offer sufficient resistance (essentially acting like a hose with an open end, with the water just flowing out as opposed to having your finger on the end in which case it shoots out), leading to stagnant airflow. That is just a theory or thinking out loud, however.....
In the end, given the negligible cost of trying a larger box, what do I have to lose......
06-13-2013, 04:36 AM
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Modded box #2 is now done. All that is left to do is to to sand over the "welds" a bit and she`ll be ready to install.... The new BMC and old OEM air filters shouild be arriving soon too, for the airfilter element (punny, yes?) of the experiement to get underway.... will post pics later
06-13-2013, 05:33 AM
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well Lloydie, you know what they say, to make an omelette, you have to break a few eggs....
BTW, thanks (to you and Markus) for the pointer on welding instead of glueing.... much, much easier and cleaner......
BTW, thanks (to you and Markus) for the pointer on welding instead of glueing.... much, much easier and cleaner......
06-17-2013, 05:41 AM
#25
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recently finished my newly modded airbox (less the pockets all over the place, lol). This one is smooth and essentially follows the natural contours of the stock box (much like Lloydie`s). While I had originally looked at routing the valve cover vent hoses into the airbox (where the Krankvent would sit), I decided not to do this for a few reasons, namely to not lose volume, to not feed warm air from the engine into the airbox (cooler charge = more power) and finally, to not obstruct internal airflow. So, the hoses will be routed outside the new bos, where they will meet the KV, which will dump into a OEM plastic holding tank (which I will locate under the fuel tank somewhere) and be vented through a small cone filter (to prevent dirty air from entering the engine should the KV`s one-way valve properties somehow be messed up). I will be using plastic clips on the underside and backside of the airbox to keep the hoses in place.
The last step in my intake experiements is to fashion a modded hybrid BMC/OEM air filter. I am waiting for the two filteres to arrive then a an hour or so of work should have that project up and running too......
The last step in my intake experiements is to fashion a modded hybrid BMC/OEM air filter. I am waiting for the two filteres to arrive then a an hour or so of work should have that project up and running too......
06-17-2013, 01:09 PM
#26
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maybe this has no relation at all.. but a lot of people on here keeps saying that K&N are crap and that your bike will run better with stock air filter, yet it's obvious that the K&N would allow the bike to breath better, all you have to do is compare the stock vs K&N. the K&N is almost see through.
So if more air is a bad thing why would you want to modify an airbox to get more air?
So if more air is a bad thing why would you want to modify an airbox to get more air?
06-17-2013, 11:39 PM
#27
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The K&N will flow more, which is a good thing (except that it doesn't do a very good job of filtering). The problem comes from trying to tune the carburetors. The needle profile in the carbs is based upon the mass airflow through the carbs at a given slide position with a stock air filter and airbox. When you change the mass airflow, without changing the needle profile to match, you end up with poor fuel mapping. It will run fine in some areas, but not everywhere.
Long story short, on a stock engine you gain NOTHING with a K&N apart from the ability to clean it... On a modified engine on a trackbike or similar where fuel mileage isn't important, and you can really wring the bike out, the K&N is a great option...
What you "loose" on both occasions are several hours worth of tuning, prefferably on a dyno bench to get it running right, since it's a lot different than the stock filter...
So no, the K&N isn't "crap"... But with people buying into the commercial, and doing what K&N recommends, and "dropping it in" and expecting improvements without work, then the result is pure and simple crap...
06-18-2013, 04:44 AM
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I got the used OEM filter from Wolverine yesterday (thanks again!) and began getting it ready for my forthcoming filter experiment. One thing that stood out as I took out the filter medium, is the small pocket moulded into the OEM filter, essentially providing additional clearance for the front (IIRC) stack. based on what I have read elsewhere about airflow and the effect of things in close proximity to the stacks, this seems to be a definite bonus. Curiously, this is not present on either the K&N or BMC filters......
am just waiting for the BMC filter to arrive (today or tomorrow) and I will be able to finish putting together my experimental hybrid filter.....
am just waiting for the BMC filter to arrive (today or tomorrow) and I will be able to finish putting together my experimental hybrid filter.....
06-21-2013, 06:19 PM
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Got the BMC street filter today and cut it all up to get the one-off custom air filter done up. It's now all done (ie. BMC filter element atop the OEM filer base, the object being to raise the filter element away from the intake stacks, so as to not interfere with the airflow, the result of having them too close.) A by-product of this is that the raising of the filter just increased the post-filter volume by about half a liter, which should offer benefits on its own.
I used the BMC base to fab a spacer, in this case to raise the lid over the now, much taller air filter. Will post pics in the next couple of days...
I used the BMC base to fab a spacer, in this case to raise the lid over the now, much taller air filter. Will post pics in the next couple of days...
