[ace.cafe]

That should do it.
 

Now that the intake and filtering is settled,  we can discuss tuning the airbox itself.
 

[Otto_Ing]

Oh dear... than we have to relocate the filter again. 

The good thing is, with this arrangement there is plenty of space inside the Airbox to attach any kind of Velostacks of almost any lentgh.

[ace.cafe]

Oh dear... than we have to relocate the filter again. 

The good thing is, with this arrangement there is plenty of space inside the Airbox to attach any kind of Velostacks of almost any lentgh.

Actually, it can be fairly easy.
An experimental telescoping velocity stack can arrive at intake tract tuning,. Some construction foam can be used to adjust and shape the inside of the existing airbox. Closed cell foam appears as a solid for this use.

We can consider the cold air inlet aspect complete,  since this filter breathes air from behind the rider's leg.

[Otto_Ing]

Looking at the intake tract ... fairly long, you think it could benefit from being longer?

[ace.cafe]

Yes, for the 3rd harmonic frequency,  it could be anywhere from 1" - 3"(or even more) longer, depending on what rpm you want your target to be.
We have typically used 12" length for the Fireball at 6000 rpm.
Length is measured from the back of the intake valve to the bellmouth. I can't remember the length of the UCE intake port.
Also, the calculated length is the center of the affected rpm range, so it has results above and below the actual center, to some degree. And if you want a "hard and narrow" tuning, you can use a straight walled stack with a small flare. If you want a "softer and wider" tuning, you can use a widening wall stack with a big flare. Keep the effective width of the bellmouth less than 3.5" if possible, for best harmonic effects based on lower cutoff frequency affecting the wave reflection.

Some experiments with the length can yield benefits because the calculation only gets you in the ballpark.

[iRideRoyalnVA]

This could go into the airbox thread, but I think it should stand alone.



I may order this, or look at moding the stock cover.  I believe it'll be a velocity VS. volume thing.

Where did you find this?

[Farmer_John]

Where did you find this?

Hitchcocks, our friends from the British Isles.

[iRideRoyalnVA]

Ok thanks FJ

[Otto_Ing]

Yes, for the 3rd harmonic frequency,  it could be anywhere from 1" - 3"(or even more) longer, depending on what rpm you want your target to be.
We have typically used 12" length for the Fireball at 6000 rpm.
Length is measured from the back of the intake valve to the bellmouth. I can't remember the length of the UCE intake port.
Also, the calculated length is the center of the affected rpm range, so it has results above and below the actual center, to some degree. And if you want a "hard and narrow" tuning, you can use a straight walled stack with a small flare. If you want a "softer and wider" tuning, you can use a widening wall stack with a big flare. Keep the effective width of the bellmouth less than 3.5" if possible, for best harmonic effects based on lower cutoff frequency affecting the wave reflection.

Some experiments with the length can yield benefits because the calculation only gets you in the ballpark.

6000rpm surely is the right target without destroking it.

I've just measured the intake port and it is about 3,5" long adding to it the (228mm) 9" intake tract...makes 12,5".

That should be it in that case, pretty close match. The bell mouth could be of course somewhat bigger than the 3mm radius.

[Otto_Ing]

Just found this porsche diagram. While mostly all calculators point towards 12" this diagram suggests 15". Any idea where the discrepancy comes from?

[ace.cafe]

Just found this porsche diagram. While mostly all calculators point towards 12" this diagram suggests 15". Any idea where the discrepancy comes from?

Could be related to the valve timing, vs wave arrival time. The usual goal is for the wave to arrive just prior to intake  closing at the desired rpm range.

There are a lot of factors involved, including temperature.  That's why I recommend length experimentation.  The calculation gets you in the ballpark, and the real world length adjustments fine tune it. Just like exhaust systems too.

Any pipe length is tuned to some rpm, so they will all do something, but the goal is to aim it where you want it.

[Otto_Ing]

True, safes however some itterations and dyno time if one knows what to do and prepares some variants to test. 

[KD5ITM]

Look what I got in the mail today!

[gizzo]

I don't want to sound mean, but if you're content to pop around under 3500 rpm, you might not notice any benefit with the better breathing.

[KD5ITM]

Engines need to breathe. Weather there popping at 100 rpms or cranking at 5000 rpm. But don't worry. I've got that under control :-)

I am curious to see if my gas mileage goes up any. I really don't think it will change and if it does it will probably be a minimal change.

I have to make the 90 mile round trip to the dealer tomorrow so we'll see how it goes!