I hate noise from open lid or from lid with removed snorkel. So I've designed airbox lid with oversized integrated snorkel which is about 2x size of the KDX and which also doesn't obstruct air filter. Literally it occupies the maximum available space under the seat and provides maximum cross section airflow area given airbox and seat constraints.

Here is part 1 of the snorkel/intake review. In the next part there will be dyno comparison.

 

Look, I get it - you don't like an open airbox due to the "power noise" it creates. This is very much a personal and subjective opinion/position. That open airbox sound is marvelous, IMO..

But let's write the end this story :
You're going to build lids with a snorkel on top. The "snorkels" will have ever greater sectional cross-sections compared to the KDX snorkel. The larger the snorkel cross-section, the more sound and performance you'll get.
At some point, you will choose one of your "lid with snorkel" as being the best compromise between power and sound. This choice will be a personal, subjective, opinion.
Done - end of story.

Here is the REAL story - as seen in your dyno charts - AFR @ WOT ( Air Fuel Ratio at wide open throttle)
The more "open" you make the intake system, the more performance operations go lean.
It is amazing that your lidless chart line eclipses the others even though the WOT AFR goes all the way up to 15:1
The explanation is that the lidless airbox radically changes the performance of the engine.
At 15:1, the engine is running MUCH TOO LEAN during wide-open-throttle ( WOT) operations.
Even the chart line for the KDX snorkel shows overly lean WOT ops.
The performance of a lidless airbox ( and the KDX snorkel) would improve significantly if fueling were corrected back down (richer) to where it is supposed to be - 12.6 to 12.8 @ WOT.

Point is, as your AFR charting shows, modifying the airbox causes lean fueling AND more performance. This invites much WOT operation by the owner. As such, airbox mods should not be done unless one has the ability to reset fueling to compensate for the increased airflow ( IMO based on your AFR charts)

 

Wideband sensor is not connected on the charts, so it shows dummy AFR 15:1 all the time, so it's not relevant.

 

Thank goodness.

 

I GREATLY appreciate the effort you put into this entire thread.
INCLUDING the airbox and lid.
I will be making some kind of change in the near future.
Thanks again.

 

Hi folks. Finally put together a video with the intakes dyno testing and updated intake section at planetklx2 - .
For those who want to learn something I highly recommend to watch the video and let's discuss results!

Short takeaways:

• First of all I'm very surprised that my custom snorkel performed even better than lidless! It's over 2.5 hp over standard, 2 hp over KDX and 1 hp over snorkelless. I think it's better that lidless due to likely lower flow velocity. Given that my custom snorkel just slightly more loud that KDX it's a big win and far beyond my expectations from that project.
• Secondly I found lidless is more or less is the same as snorkelless (lid in place, snorkel out).

All intakes


All intakes


Custom-vs-standard


Custom vs standard

Custom-vs-KDX


Custom vs KDX

Custom-vs-snorkelless


Custom-vs-snorkelless



Snorkelless-vs-standard-vs-KDX


Snorkelless-vs-standard-vs-KDX


Lidless-vs-snorkelless


Lidless-vs-snorkelless

 

For senior forum member who would like to get my custom snorkel - send me PM, I will sell you at a nominal price (cost of 3d printing).

 

I love intake noise on all my bikes.

 

The "odd" results of the lidless airbox, in your testing, is likely explained by the AFR ( fueling ) charting ( which you do not show ).

A open airbox requires different fueling - Without re-tuning the fueling for the increased airflow of a open airbox, the AFR ( fueling ) probably went so lean as to cost power.

The relative restrictiveness of your lid ( compared to a lidless airbox ) likely caused the fueling to remain within tolerance for power production.

Nonetheless, BRAVO for the work you've done and new option you've given to all.

I salute you.

 

I honestly don't think fueling is the reason lidless performed on par with "snorkelless" this time.. Maybe the reason is because a particular dyno run discrepancy.. According to my tests max power could be found at a pretty wide range of AFR ratios. I would say anything between 11.5:1 to 14:1 would lead to the same power level with 3% measurement error. The only reason people target about 11.5-12.5:1 is because it keeps engine cooler compared to more lean mixtures.
I was targeting about 12.5:1 with my snorkel. So lidless might be about 13:1. Still within an AFR range which provide max power.