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Discussion Starter #1
So I took off the air intake covers and saw the plastic covers that cover the air filter for the first time. (New bike) and on the muscle has a what I would think very restrictive black plastic cover! Has anyone drilled a hole or plural (many holes) to make more air to filter. Any water problems???
 

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Discussion Starter #2
If I do will bike need new tune? Would like the auto tune max thunder but can’t afford right now.
 

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Some guys go topless, removing that upper cover completely. Might give you .5 Hp @ 9000 Rpm - rest of the time engines just sucking hot rising engine air with honking intake sounds - Believe it or not that OEM airbox was extremely well designed. Try it without the lid on it, it won't go any faster but you might like the sound of it -
 

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Discussion Starter #4
Some guys go topless, removing that upper cover completely. Might give you .5 Hp @ 9000 Rpm - rest of the time engines just sucking hot rising engine air with honking intake sounds - Believe it or not that OEM airbox was extremely well designed. Try it without the lid on it, it won't go any faster but you might like the sound of it -
Thanks for the reply. I did go topless.
 

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Laid back grump
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My understanding of that "trumpet" air intake design on the front of the airbox is it reduces the amount of sound emitted by the intake during WOT by accelerating the air near to the speed of sound, thus "swallowing" the sound. Notice how it necks down? Bernoulli at work.

Old Jag V-12s had the same setup on their airbox covers.

 

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In effect the box is a well designed intake silencer. Leaving it as is or topless there will be next to no gains in a stock engine. Just more induction sound. At one point I compared data logs stock and topless and trimmed bottom and to the most saw no reason to modify the tune, since nothing really jumped out as being different between the two.
Ron
 

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Cool Air Rules

Yea, that pretty much proves it right there Ron, the engines getting enough air either way - also I've read a little about the theory behind the snorkels like Mark out West showed, one the suction it causes speeds up the airflow and actually draws in more air, especially for a couple seconds when the throttle is closed momentarily (like when shifting) a sort of inertial air charger - I'm not sure if that could help a little with reversion issues with N/A high overlap cams or not but I'm sure the designers optimized it with the stock cams. Two the snorkel gets the pickup point farther away from engine heat and like air gap auto intake manifolds and roto spun cold air intakes it helps to get the coolest and most dense charge possible inside the airbox, which is a max power requirement. I see no reason to throw away the upper airbox and snorkel on a stock engine. Maybe a built big bore, cammed up engine could benefit from a revised diameter and/or length of the snorkel (to optimize it for that application) but IMHO I still think the stock airbox is a better overall performer than topless or bottomless setups, especially for a stock or a Stage 1 street ridden V Rod. :blahblah: :D
 
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