Air Box Alternatives

[luhbo]

It would be most helpful if Meinolf would repeat his statement in plain German. Snorkels are better, ok, but what about the figures?

[Meinolf]

Hi Luhbo,

 

the plain german statement is here: http://www.guzzi-forum.de/Forum/index.php?topic=30093.0

 

For those not fluent in German. I was interested in the effect of the snorkels on the volumetrics of the engine and the impact the snorkels might have on the intake air temperature, so I measured AFR and air temp with and without them. The finding was that the engine run leaner to the tune of 1-6%. As the injection values were constant, the leanness resulted from more air moving through the engine at the breakpoints where I measured. The air temp didn't show any significant changes.

 

When analyzing the logged data I also found that the fluctuations of the Lambda values went down from an average of +/- 0.25 to +/-0.08 (That is a factor of 3, and not of 4, as wrongly stated in my previous message. I'm not good at arithmetics). Which, to voice an opinion, indicates a much more laminar airflow with the snorkels than without.

 

The summary is that well shaped air inlets, even if the diameter of the inlets is smaller (than the inlet in the airbox), are more efficient than sharp corners. Which is not a new revelation, but a long established fact.

 

So, if one wants to do sound tuning, remove the snorkels. If one wants a more efficient system, keep or add them.

 

Cheers

Meinolf

[luhbo]

...

When measuring air throughput with and without snorkels I found that it increases 1-6%. And air Lambda fluctuations decreased by a factor of 4.

...

Funny, how much such a small correction can improve read- and understandability

 

BTW: Are you sure about the "laminar air flow"? That's quite a deep can of worms you've opened with this statement ...

 

Hubert

[Meinolf]

Hi Hubert,

 

properly speaking, no, I'm not sure about the improved laminar flow. I normally try to stay within the bounds of my knowledge, this was an guesstimate and not a fact.

 

Cheers

Meinolf

[rossi46]

anyone tried the ram air snorkels like this

[al_roethlisberger]

As I recall, I think we had a vigorous debate many (10+) years ago about "ram air" and the consensus was that at road speeds there is no benefit as the velocity isn't enough to "ram" any more air into the airbox than atmospheric pressure, and in fact turbulence introduced from any such exercise must be considered too as that could impede airflow. 

 

However, there was agreement that any method to get cooler and unimpeded air into the airbox was generally a "good thing" 

 

But I can't speak to the photo above.

 

Because of my tank modification I can't run an airbox anymore (unless I remove the tank balance tube), so for me it is pods.  Plus I think they look pretty cool and I got good dyno results with them once tuned    

 

Al

[docc]

As I recall, I think we had a vigorous debate many (10+) years ago about "ram air" and the consensus was that at road speeds there is no benefit as the velocity isn't enough to "ram" any more air into the airbox than atmospheric pressure, and in fact turbulence introduced from any such exercise must be considered too as that could impede airflow. 

 

Al

Here's one of the "ram air" threads from Days of Olde ( Sep 25 2003):

 

http://www.v11lemans.com/forums/index.php?showtopic=1340&hl=+air%20+intake%20+bell

 

And I (finally) found (again) the post by Phil A/19 Sept 2006 (in Paper Filters & Airbox Lid Mod/ Sep 18 2006/ How to . . . /OP: Greg Field) detailing findings about modifying the airbox intake (albeit on a V10 with the same airbox as a V11). Looks to me as the data are dyno generated:

 

____________________________________________________________________________________________________________

 

 

Posted 19 September 2006 - 01:19 AM by Phil A

Greg,

can see there is a few here interested in this so I dug out some data gathered while developing the V10 inlets. Dont shoot me please the box is the same as the V11

 

The facts as I have them are these:

All of these steps are independent of each other.

 

If your remove the origional mufflers(snorkels) off the inlet and bell mouth the inlets to approx 35mm id you get approx 2hp between 4500 and8000rpm.

 

If you remove the filter but leave the lid in place, you get approx 1.7hp.

 

If you drill 3 one inch holes in the top rear of the air box lid (one in each corner an one 2'' forward in the center) and retain the air cleaner element you get approx 1.5 hp.

 

If you remove the lid and leave the filter in place you get approx 3.5hp from 4300-5500rpm it increases steadily to approx 7hp at 6300 then tapers of to approx2 at 8000 or so.

 

Once you totally remove the air box but retain the std bell mouths on the injector bodies the gains above 6300 do not taper off as above with the gain being approx 5hp at 8000 or so.

 

Probably the most noticeable gain with this last set up is 4 or 5hp in the middle of the dip at 4000- 4800rpm.

 

If you increase the bell-mouth id to approx 50mm and retain the holes in the rear you get 4.5hp all up.

 

Once I had remapped the MY16M to match I have exactly the same power with the airbox (with origional filter) as with no airbox what so ever!

 

A total gain of approx 7hp while running the stock filter.

Probably the best gain was 9ft/lb at 2700rpm! with a 5ft/lb gain at 4300rpm.

 

Hope this is of interest.

 

Phil A.

 

V10 sport.

 

 

 

"All is not always as it seems"

 

Phil A - Sep 19 2006

[sp838]

My bike, running a GPR 2-1 exhaust and my own 3D printed intakes fitted with 70mm k&n pods, gets +5 peak hp (83 max) on the dyno.

 

Curious to know what it will make now, with all the work I did over the last year...

[moto fugazzi]

My bike, running a GPR 2-1 exhaust and my own 3D printed intakes fitted with 70mm k&n pods, gets +5 peak hp (83 max) on the dyno.

 

Curious to know what it will make now, with all the work I did over the last year...

I've always wondered how much real world riding differs from a dyno run with pod filters as far as hp goes. With pods, the bike will run leaner at 70mph vs. sitting on a dyno with a large fan blowing on the motor.

 

A few years ago, I took a spare airbox (sparebox?), drilled a few holes in the top, removed the snorkels, and enlarged the intakes. Turns out that the faster I went, the leaner the bike ran, and consequently, the worse it ran. I have since gone to the stock airbox setup.

 

Just my thoughts and findings.

Ken

[knumbnutz]

Hi Everyone,

Sorry to drag this up but as i am getting to know the Guzzi again i was thinking to put pods on. I have read a lot of people saying there are no gains, but from what i can read below he says there is decent gains.

eg:

Once you totally remove the airbox but retain the std bell mouths on the injector bodies the gains above 6300 do not taper off as above with the gain being approx 5hp at 8000 or so. Probably the most noticeable gain with this last set up is 4 or 5hp in the middle of the dip at 4000- 4800rpm.

Probably the most noticeable gain with this last set up is 4 or 5hp in the middle of the dip at 4000- 4800rpm

 

 

I was thinking to put a decently large set of pods on or at the very least remove the top of the airbox and let the sound flow, the induction noise is terrific.

Who has pods ?

 

 

 

 

Posted 19 September 2006 - 01:19 AM by Phil A

Greg,

can see there is a few here interested in this so I dug out some data gathered while developing the V10 inlets. Dont shoot me please the box is the same as the V11

 

The facts as I have them are these:

All of these steps are independent of each other.

 

If your remove the original mufflers(snorkels) off the inlet and bell mouth the inlets to approx 35mm id you get approx 2hp between 4500 and8000rpm.

 

If you remove the filter but leave the lid in place, you get approx 1.7hp.

 

If you drill 3 one inch holes in the top rear of the air box lid (one in each corner an one 2'' forward in the center) and retain the air cleaner element you get approx 1.5 hp.

 

If you remove the lid and leave the filter in place you get approx 3.5hp from 4300-5500rpm it increases steadily to approx 7hp at 6300 then tapers of to approx2 at 8000 or so.

 

Once you totally remove the air box but retain the std bell mouths on the injector bodies the gains above 6300 do not taper off as above with the gain being approx 5hp at 8000 or so.

 

Probably the most noticeable gain with this last set up is 4 or 5hp in the middle of the dip at 4000- 4800rpm.

 

If you increase the bell-mouth id to approx 50mm and retain the holes in the rear you get 4.5hp all up.

 

Once I had remapped the MY16M to match I have exactly the same power with the airbox (with origional filter) as with no airbox what so ever!

 

A total gain of approx 7hp while running the stock filter.

Probably the best gain was 9ft/lb at 2700rpm! with a 5ft/lb gain at 4300rpm.

 

Hope this is of interest.

 

Phil A.

 

V10 sport.