Variables in intake mods

[dlaing]

[al_roethlisberger]

... the "snorkels" on the photo of the Sport1100 from CookedGoose are simply extensions from the airbox snorkels since they removed the faring and didn't have access to clean, cool air, not "ram-air". If they hadn't added those hoses they would have had the same poor OEM hot air pickup locations as our V11 This solution is what I have always advocated.

 

I've talked to the LSR guys, and they use larger air-boxes, not ram-air though. The "dryer vents" extensions in the photos above would not be rigid enough, nor are smooth or "tuned" in any way to produce a "ram-air" effect. At speed, they are just going to flop around. These are just for "fresh air".

 

 

That being said, I agree with what Jeff cites, but I don't consider that "ram-air" either. That is intake tuning, and engineering the intake to get access to a cool and clean airflow.

 

IMHO, the term "ram air" takes a volume of air and compresses it through velocity and physically constricting the volume of the intake, hence creating a supercharger like effect. This just isn't possible at the speeds we all ride normally. And is the conundrum I've cited above.

 

However, incorporating intake runners that increase air-box volume, and manipulate the air-flow to and within the air-box to increase efficiency is certainly possible and beneficial. This is more related to the benefit I mentioned of indeed engineering intake runners that get access to a clean and clean air-stream. As I mentioned before, there is certainly a benefit to this as the location and design of our OEM intake snorkels are terrible.

 

Perhaps this is more an issue of semantics, but my definition of "ram air" on a motorcycle, is hype

 

al

[Guest Jeff Kelland]

Al, I understand what you are saying but it is in fact the pressure being rammed into the intake opening that stabilizes the box pressure. It is probably not enough pressure to generate a supercharging effect at speeds we are riding at, but it is pressure just the same. The key to intake flow is a smooth uninterupted stream of air into the cylinder, resonance is like a bell ringing, waves of pressure confusing the flow. The pressure from ramming air into the box has the effect of placing a finger on the bell, it quiets it. I think it is important not to underestimate airflow science, Honda has all but negated radiator drag on it's F1 cars by careful shaping of the fins. When the air through the radiator picks up heat it is caused by this shaping to accelerate. While Honda was mighty proud of this, it is also important to note that the Italians had done the same thing with racing aircraft radiators mounted flat in the wings eliminating drag and creating lift, in the 1930's! Air is funny stuff, it reacts to shapes that don't always make sense at first. A good intake runner can start small and expand as it reaches the air box, just the opposite of what seems to make sense.

[al_roethlisberger]

Al, I understand what you are saying but it is in fact the pressure being rammed into the intake opening that stabilizes the box pressure. It is probably not enough pressure to generate a supercharging effect at speeds we are riding at, but it is pressure just the same.

 

Jeff, I agree with that ....and goes to my comments about tuned intakes being a different discussion than "ram air", and indeed being potentially beneficial. We've seen solutions capitalizing on this technology on a variety of engines over the decades, even some of the old original 1950's Chrysler Hemis and their "longhorn" intake runners

 

Obviously a well-designed intake will create some flow and positive pressure, pulses, etc... at speed, but yes... my point was that with which you concur, any "ram air" marketing referencing a "supercharging" type effect is hype at the speeds(=pressure) we ride and would generate. Also as I was saying, I think a lot of the confusion on topics like this often seem to simply be rooted in semantics, and IMHO unfortunately much of that is the fault of manufacturers marketing hype

 

That being "settled" .... as we mentioned briefly in the "what is a cross-over" thread, the design of higher-tech solutions like a variable exhaust takes huge engineering and financial resources, such that up to this point small manufacturers like Guzzi haven't been able to produce these solutions like Yamaha, Honda, etc. I think the same has been true of intake technology for our bikes.

 

Moto Guzzi has been able to do the "basics" around intake airbox(and exhaust) design, but probably didn't have the resources to do any better, plus the one could still argue that especially with a relatively low-tech engine like the V11, the returns on such an intake is stilly probably minimal at normal speeds.

 

But that being said, I'd be interested what people can come up with for the V11 in regards to tuning a more effective intake versus our relatively crude OEM air-box/snorkels... and admittedly simplistic mods currently at our disposal such as air-box lid eliminators, pods, etc...

 

However, on-the-other-hand... going by what I've seen on various other forums on more "advanced" motorcycles, a lot of them end up ditching OEM solutions and still bolting on simple pod and drilled lid kits like we've already got.... so is it worth the effort to design a tuned intake "ram-air"-ish system for our bikes?? Maybe, who knows, but it's hard to come up with an equivalent solution in the garage that takes manufacturers some significant computing HP to design and deliver.

 

I'll be interested to see what may come up though. At the very least I'm very interested in any solution that delivers access to a cool and clean air-stream, although since I've eliminated my air-box for a variety of other "advantages"... in my case I probably would stay with the pods

 

Somewhere out there, there's even a fella that flipped the jugs over so that intake ports are up front

 

al

[gthyni]

An important reason to use an air box is meeting the demands

on sound levels. Pods make much more noise than the air box.

 

Even a well designed factory intake is a compromise between

free flow and noise level.

As we dont't care about (or even like) a bit more noise, we

open up our intakes to get a less restricted flow.

[al_roethlisberger]

...that is true regarding noise regulations to some degree, but air-boxes also provide an important performance engineering function, providing a large "reservoir" of still and relatively constant pressure air on demand. An intake system, and specifically an EFI/carb can benefit from eliminating as many variables/unknowns to deliver expected performance as designed, and guaranteeing that the intake charge is at a relatively constant pressure, velocity, etc helps a great deal in tuning the intake... hence air-boxes. Utilizing the largest airbox within reason usually is most beneficial, but of course limitations on the available space under the fuel-tank make an infinitey large box impossible.

 

If you ran the engine on a motorcycle sitting still, at constant pressure, with completely efficient intake, then you could consider the atmosphere the perfect and infinite air-box But of course, with the bike moving, changing elevation, etc... engineers design the air-box to smooth out those effects as much as possible. Believe it or not, this sometimes includes making the air inlet/snorkel relatively restrictive. It's all a package, intake to exhaust....

 

However, I don't think our Guzzi's are quite that well thought out. But maybe the new ones will be with Aprilia's investment

 

al

[dlaing]

However, I don't think our Guzzi's are quite that well thought out.

What gets me is that they have a wind tunnel, so you would think that they would achieve some level of excellence.

I have not ridden a LeMans, but aesthetically they are beautiful.

I have not heard complaints about turbulence so they must be doing something well in the wind tunnel.

The Guzzi cruiser wind screens are another story, at least from what I have heard on other lists.

Back to the topic:

The snorkels appear to be a bad design, only good for noise reduction and keeping rain out.

[Skeeve]

There was a long discussion on ram air in the swedish sportbike forum -...

... There was an actual calculation of the effect of a normal ramair

configuration. The result was ta-ta-damm:

 

2% at 200 km/h

4% at 300 km/h

 

That is 7 hp at top speed on a Hayabusa

at that speed aerodynamics are more inportant than power.

10907[/snapback]

 

The key to ram-air efficiency is in your last statement: it isn't just feeding the engine higher-pressure air [a la' turbo- or super-charging], but the fact that the higher pressure air is stolen from some point on the vehicle's aerodynamic envelope, effectively decreasing the vehicle's drag coefficient. Since motorcycles typically have much higher drag coefficients than cars, they have more to gain by pursuing this source of increased engine output.

 

BTW, 7hp at top speed on a 'busa is good for another 3mph? or so, which is very important when the primary source of your unit sales is the title "fastest production motorcycle sold..."

 

Ride on!

[BrianG]

Not that this is particularly germane since my experience is aeronautical. In my old Mooney... which sports a carbeurated 360 cu, 180 hp 6 cy air-cooled boxer engine, there is an "air filter by-pass system fitted. This re routes the intake air from a rather circuitous system that includes an air filter, to a direct - straight shot to the carb mouth from right behind the propeller, path. At about 150 mph this produces about 2" of manifold pressure difference for ram-induction. Nothing to write home about, and certainly resulting in questions about efficacy at 60 mph, since physics dictates a (v)squared=energy relationship.

 

The question of induction restriction is quite another subject, however. On an old RZ 350 and a dyno, we discovered that drilling 4, 1.5" diameter holes in the airbox lid increased the hp about 2 hp per hole...... the 5th hole added nothing more.

[callison]

On my Sporti, when riding in a quartering wind, the snorkels set up a resonance so bad that the engine seems way out of tune. As soon as you head directly into the wind, the problem goes away.

 

Ram air? TANSTAAFL (There ain't no such thing as a free lunch).

[Admin Jaap]

 

a.k.a. "The Shredder"