2014 / 2017 airbox snorkels

[PowerDubs_imp]

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[SportsterDoc]

Wonder why the change (2107 on left)?

 

[PowerDubs_imp]

Hard to say.

Smaller ports tend to increase velocity.

Larger ports can flow more ultimate cfm.

Longer runners tune for lower rpm, shorter lengths= higher.

The ‘bowl’ on the end may act like a plenum a bit. Smaller equals throttle response, larger equals better top end breathing.

I don’t expect the difference on the horn to make any drastic difference on it’s own.

I also have the TSR plate that replaces these horns. I will be testing and comparing all 3 on the dyno.




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[SportsterDoc]

I sliced the "bowl" off mine.

 

[PowerDubs_imp]

Yea- negating any resonance tuning of the entire thing.

I'm pretty sure you would see a loss on the dyno- especially if it was lower/mid rpm and part throttle.

 

[DaSwami_imp]

Interesting...

 

[Razor]

Interesting...

It is interesting & cool. Imagine a motorcycle manufacturer that’s had a model out since 2010, and they’re still reviewing engineering perspectives... and making changes. Good chance it might also be the tighter European emission standards.

Thanks for sharing, love this stuff

 

[SportsterDoc]

Yea- negating any resonance tuning of the entire thing.

I'm pretty sure you would see a loss on the dyno- especially if it was lower/mid rpm and part throttle.

Is that the effect of the TSR plate?

 

[PowerDubs_imp]

I actually think the TSR plate could hurt, but the dyno will tell.


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[dave]

I actually think the TSR plate could hurt, but the dyno will tell.


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Can you please explain what a TSR plate is?

 

[PowerDubs_imp]

Hi Dave,

It is a small flat piece of metal with a radius lip that is put in place on the airbox by removing the factory snorkel entirely.

Reference- https://www.samurider.com/?p=16803

 

[SportsterDoc]

The TSR plate retains the filter when the silencing tube/snorkle is removed for less restrictive flow.

On blower applications, flow to the blower is affected by the following, based upon the maximum CFM:
1. Tube diameter
2. Number of turns

Whereas a velocity stack is intended to improve flow by accelerating the air flow from a larger diameter "funnel", the TSR plate simply has minimal restriction for flow to the filter.

Although there is a science for intake manifold design, whether from a single carb/throttle body, or dual quads, or tri-power to a single cylinder or a V8, a silencer tube does just that-it decreases noise level. The "bowl" on the CB1100 silencing tube/snorkel appears to allow incoming airflow to turn 90 degrees with less restriction.

When the term snorkel is used, such as on a New Triumph Bonneville, it is designed to draw air with a minimum amount of water content, when riding in the rain.

My 1967 CB160 could have used a snorkel. Whenever I road in heavy rain, the filter element under the side cover would saturate and the motor would die.

The mod on my CB1100 would not be the best for riding in heavy rain.

 

[PowerDubs_imp]

If you are implying this part is strictly for sound deadening, I can assure you there is more to it than that.


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[SportsterDoc]

If you are implying this part is strictly for sound deadening, I can assure you there is more to it than that.


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No, this part serves several purposes:

1. It reduces sound. With the top of bowl sliced off on mine, the airflow is louder than my stock exhaust.

2. It serves as a snorkel, in that it (a) draws air from a location less likely to drown the motor in heavy rain and (b) that air may be cooler than closer to the motor (think cold air induction).

3. Properly designed, it should also direct airflow to pass through the air filter evenly. On my 2016 Nissan Frontier (4.0) the air box internal deflector should have done that, but one section of the flat air filter was getting dirtier than most of the pleated area, until I modified the deflector.

To determine if the sound reduction is at a cost of flow efficiency, measure the area of the snorkel intake in comparison to the filter inlet.

A typical V8 in the sixties and seventies had a silencing tube feeding a round filter with the silencing tube inlet smaller than the carb throat. A high flow intake could be easily achieved by simply using a taller air filter, so that air flow came from the entire circumference.

On pre-04 Sportsters, a high flow intake was easily achieved by using a filter backplate which allowed the ham can more space around the air filter. There may also be an increase of CFM with a different air filter. Instead of spending over $100 for a Screamin' Eagle high flow intake (which came with a K&N, pre 04), the same/close to the same results came from drilling the backplate with several 3/4" holes around the outside perimeter of the air filter.

For the CB1100, 171 CFM is required at 8,500 RPM.
1140 cc x 8,500 RPM (redline) = 9,690,000 cubic centimeters
Divide that by 2 for a 4 stroke = 4,845,000 cc = 171 cu ft per minute.

I contacted Hi Flo to ask if they have a CFM rating on their HFA-1932 and if they have a comparison to the stock Honda air filter. I found no CFM rating on the K&N site for their HA-1301.

A K&N HD-900 is rated 203 CFM. A CV40 carb on a pre-04 Sportster will handle 185 CFM. The 1200 cc motor will draw 131 CFM at 6,200. A 1250 will draw 165 CFM at 7,500 (very high revs for a push rod motor).

I suspect that the stock Honda filter does not impede flow. If that is correct, air flow will be maximum if it enters the air filter with minimum interference (negatives include smaller inlet, turns, surface friction).

Intake manifolds (carb to heads) can be designed for different requirements. For example, the old Edlebrock SP2P manifold for small block V8s was designed for torque and fuel efficiency, but not particularly effective over 4,000 RPMs. This is where plenum configuration and runner design has an effect. A "high-rise" intake manifold allows flow with less turn interference.
Received this response from Hi Flo:

All our HFA air filters are designed to be functional duplicates of the stock filter they replace. I do not have the individual specs for each filter as we are not selling them as better than OE but as direct replacements.

So, still no CFM info.
If the CFM rating for stock Honda 17210-MEJ-981 or HFA-192 exceeds the 171 CFM that the 1140 cc can pull at 8,500 RPM, then there would be little, if any advantage to a K&N.

 

[PowerDubs_imp]

I am amused at a company called Hi Flo, admitting in writing that they have no data and are no better.

I agree I do not expect the air filter to be any restriction whatsoever.

Initial dyno date has been set for Tuesday June 5th. I will be doing a baseline (stock w/ Staintune muffler) and then putting on the '17 snorkel and the TSR plate to see any differences as the bike sits.

 

[SportsterDoc]

I am amused at a company called Hi Flo, admitting in writing that they have no data and are no better.

I agree I do not expect the air filter to be any restriction whatsoever.

Initial dyno date has been set for Tuesday June 5th. I will be doing a baseline (stock w/ Staintune muffler) and then putting on the '17 snorkel and the TSR plate to see any differences as the bike sits.

I also chuckled regarding the HiFlo name...with no flow data. OTOH, finding CFM data for most K&N filters is difficult.

Wonder if the Staintune will give a better read with the TSR plate than a stock muffler?

 

[LongRanger_imp]

Doc, great read and very insightful. Thanks for posting.

 

[SportsterDoc]

Doc, great read and very insightful. Thanks for posting.

Thank you
I emailed K&N for CFM ratings on their HD-900 for the CB1100 and received this auto-reply:

Thank you for contacting K&N Engineering. We are currently experiencing a high volume of e-mails and will respond to your request as soon as possible. If the matter is urgent, contact our Customer Service Team at 800-858-3333 and a customer service representative will be happy to assist you.

K&N appreciates your continued business and strives to provide the highest level of customer service to our customers. Thank you again for your interest in K&N Engineering, Inc.

Hopefully they will provide data within a few days.

 

[PowerDubs_imp]

I am amused at a company called Hi Flo, admitting in writing that they have no data and are no better.

I agree I do not expect the air filter to be any restriction whatsoever.

Initial dyno date has been set for Tuesday June 5th. I will be doing a baseline (stock w/ Staintune muffler) and then putting on the '17 snorkel and the TSR plate to see any differences as the bike sits.

I also chuckled regarding the HiFlo name...with no flow data. OTOH, finding CFM data for most K&N filters is difficult.

Wonder if the Staintune will give a better read with the TSR plate than a stock muffler?

For some reason TSR says not to use the plate with the stock muffler.

They do not elaborate.

 

[teamvisegrip_imp]

I bought the TSR Plate and Intake kit... have yet to install it.

Reading this topic with excitement. Cannot wait to see the results from Powerdubs.

Heck, cannot wait to ride the bike... not till July 5th now.