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Hi guys. New member from Sweden. I own a z1000sx from 2014. My bike have full exhaust with high flow mufflers and K&N airfilter with airbox mod (drilled holes 4 per each side see picture) I have also run a full dyno and remap of the bike and results landed in 142hp on rear wheel and 123nm in torque.

My question is : is this airbox mod bad? My friend says it's very bad and that the engine gets warm air from the engine through the holes and that the holes are ruined the air dynamics from factory. Is that true?

I'm planning on buying a new airbox so I can run a non airbox mod but I just wanted to hear if that is necessary or if a can run this setup I have now.
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It's not uncommon for folks to mod the air box when doing exhaust, high flow filters or jet kits on carburated bikes.

The only downsides I can see are the possible ability for more water to set sucked in when riding in those type of conditions.

They were designed at the factory to perform a certain way with all stock components and air/fuel settings. Once you start adjusting things that's not always the best anymore.

As for sucking in warmer engine air, theoretically that's possible. Colder aid will always give more HP, but I'd think the temperature difference is negligible between the holes and the OEM intake position.

As for aerodynamics, I don't think how the outside air flows around the box / bike will have any significant difference. Yes it will change any pattern there may have been inside, but again I don't think it's an issue. As far as I know there never was any special swirl or vortex pattern the air box was designed to make when stock. It was more to hold the filter, prevent water ingress into the air box, and likely to provide a certain amount of back pressure. (possibly for optimum stock air/fuel ratios, and any vacuum or PAIR (emissions) systems on older bikes.)
 

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If you were in the US, I'd swap you my stock airbox!

I plan on modding mine since i'm going to a full system.
 

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Long and short of it is if the bikes been tuned for it then keep it, it’ll run rich with a stock box. I have a 3rd gen. I started with slip ons, tried a pc5 wasn’t really happy with the maps, went to a full exhaust and got Ivan’s tune with the block offs and I modded my airbox in a similar manner. The map is designed to go with the airbox mod. I notice with the stock air box and this tune it runs on the rich side. You can smell it and it’s a little bogged down sometimes. Kind of like a canned pc5 map. But not as bad.. With the holes drilled it leans it back out where it was tuned to be. It’s much snappier, a little louder, and actually pulls up top better with a modded air box with my particular tune. So if your bike is tuned with that airbox, keep it. If it was tuned with a stock airbox, you’re probably running on the lean side
 

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It would be nice if a person could tune, by smell.

You didn't smell the stock exhaust because it has a catalytic converter in it. Yes, they actually do something and, go figure, you smell the exhaust after you remove it.
 

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It would be nice if a person could tune, by smell.

You didn't smell the stock exhaust because it has a catalytic converter in it. Yes, they actually do something and, go figure, you smell the exhaust after you remove it.
I’ve been tuning and tinkering with engines since before fuel injection and before any bikes had a cat. Same with cars you can tell if somethings running rich or lean by the smell. And I’m not comparing smells cat vs no cat I’m comparing tuned vs modded air box and tuned and there’s a substantial difference. Go figure
 

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Makes perfect sense. You've done it for a long time, so it has to be a great idea.

It makes me wonder why people bother with dynos and sensors when the smell would have given them the correct result and saved so much money.

The airbox mod has been proven to do very little. Especially down low, although it may make a dramatic difference in smell.
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So a rich running engine smells the same as an engine in proper afr and that’s the same as lean? I don’t know why you came here to pick a fight with me over a basic fact. Then sent the admins on me. No wonder these forums are dead
 
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