"Ram Air" for V11 Le Mans??

[al_roethlisberger]

..ok, this may sound like a bonehead question, but given that the stock airbox on the V11 Sport/Scura/LeMans has two long forward-facing runners that end right above the heads, couldn't one easily fabricate horns/extensions to grab air and pressurize the airbox at speed, gaining a little efficiency??

 

Now I've not done any arithmetical work regarding volumetrics and airflow of the air-box or intake, so this is just purely conjecture. But I thought I'd ping those "in the know" about such things.

 

Especially in the case of the new LeMans, it would be very easy to route the runners just about another 5 inches to the side of the fairing and make a small hole the same diameter as the runner-tube(right behind that decorative side plate/deflector, so you wouldn't see it) and direct air right into the runner.

 

At the very least, it seems to me that this would grab some cooler air than the snorkels that stock are right above the cylinder heads. At the very best, it could ram air right into the air-box and make for greater volume.

 

Thoughts? Is this even a worthwhile experiment?

 

al

[Guest JohnInNH]

Al,

 

Yep... I think there is real world increase possible here. The air is hot where the intake is in the stock set up. If you look at the "cold air intake kits for Miatas, and Honda's, and the #'s due to the dense air it offers the motor I'm sure it would make a noticeable difference for the LeMans too.

 

HOWEVER

 

Rain is an issue. We do not have the luxury of space to route a water separator/collector. I bet one could be designed and made out of the same material the rear fender is made out of, but for us $ limited and resource limited folk a simple ram air set up would be hard to make that is suitable in all weather conditions.

 

There are a lot of opportunities for increased potential of the LeMans.

 

Right now I'm more interested in basics.

 

1) Good easy bolt on 1.5" risers/bar backs. (No solution yet)

2) ECU management system, (FIM and or PC)

3) exhaust + x over (Stucchi? + ?? pipes which are not to loud??)

4)Foot peg shifter/break lever relocation. (No solution yet)

[al_roethlisberger]

True, and my list includes:

 

- exhaust (...will someone PLEASE post some Staintune photos! )

- crossover, leaning toward Stucchi

- Flowed heads (....this winter when I'm not riding, and maybe more)

- Perhaps a PC, or just re-mapped at my dealer

 

I already have a K&N filter in the stock airbox, got my heated-grips, my clock, thermometer, bags on order, seat, headlight/tail-light modulator, signal minder, fender gone.... so I've got most things as I'd like them.

 

Regarding water/rain issues with ram-air. Keep in mind that the runners are already designed with a water drain/catch about halfway down.

 

al

[al_roethlisberger]

....oh, and I'm entertaining Ohlin's suspension front & rear, but that's REAL MONEY... ouch =P

 

al

[Mike Stewart]

Hey Al,

 

I have been thinking of a ram air setup for my V11Sport for sometime now. I have installed the Moto Especial oil sump and removed the oil cooler to make room for the air intake. I have seen reports of the ram air setups on rice rockets and the horsepower starts at a lower speed due to increased intake air resenence. I would be happy with 2 to 3 H.P. at 120 mph!

 

Mike Stewart

[al_roethlisberger]

Yep, well I'll be giving it some thought. One fella posted on another list that the Ram-air on the old Sports was completely ineffective due to the air actually being pushed out over the intakes by the nose of the bike..... actually creating a vacuum. ...yikes, that wouldn't be too good.

 

But I'll keep my brain-wheels turning and see what I come up with. I'll need to get some sort of method devised to measure air-flow at the location I'm considering....

 

al

[al_roethlisberger]

Well, after several conversations on two other boards and one mailing-list, it appears that the consensus is:

 

1 - the ineffieciencies of "Ram Air" won't buy anything. In fact, in some cases it may be a detriment if the air-flow isn't exactly correct around the fairing, by creating vortices that impede air-flow into the snorkels. Also, it was generally concluded(and not just by conjecture) that at 100mph+, one might expect only a 1% increase in HP under ideal circumstances. If ideally designed, one might expect a modest increase at very high velocities, but not at normal riding speeds.

 

2 - there may be a slight benefit in routing the ducts to grab cooler air, but that is debatable as well.

 

The consensus was that if one is interested in increasing air-flow, go with the individual pod solution or do like some Ducati owners and find a way to secure the air-filter without the air-box lid(or perforate the lid).

 

So, for now I'll just shelve this idea, put in the background, and work on it as I learn more over time. But I think, at least in respect to the cool-air function, it may have some merit. We'll see.

 

al

[Guest David Laing]

I think ram air could work if done properly. A big intake and proper placement is essential. Rain intake could be a problem.

I think another interesting idea is to mount a pair of pods on the front of the intake snorkels. (put filters on the drains too). Advantages would be:

1) Potentially more filter area than rear pods. You could use huge filters if your oil cooler is (re)moved.

2) Some ram air and or cool air benefits(at speeds over 100mph, which is where you NEED it!)

3) It would be a two into one into two setup which is more efficient(if porting nuances are not mysteriously messed up)

 

My goal is to reach redline in 6th gear! So far I have only seen an indicated 130MPH, and usually it seems to only want to go about 125, but the bike is all stock except for the PCIII and I usually only have a short run before safety necessitates slowing. I have read a claim that Stucchi crossover with Mistrals should get the bike up to 140MPH (indicated)

Dyno tuning of course, is the icing on the cake!

[al_roethlisberger]

...maybe, but my conversations with Will Creedon on the Guzzi Forum seem to be less encouraging.

 

He's done some mathematics, and based on other experience he's had in aeronautics, he's not convinced it would make much difference... except maybe in the cool-air area.

 

For more info, check out the thread at:

 

http://guzzi.com.au/forum/guzzi/

 

 

I'm still keeping it "turning" in the back of my mind, but it's on the back-burner for now. And since I plan to keep my oil-cooler, I can't take advantage of the scenario you describe... but for those that install the deep oil-sump, it may be a different story.

 

 

al

[Skeeve]

..ok, this may sound like a bonehead question, but given that the stock airbox on the V11 Sport/Scura/LeMans has two long forward-facing runners that end right above the heads, couldn't one easily fabricate horns/extensions to grab air and pressurize the airbox at speed, gaining a little efficiency??

....

Thoughts?  Is this even a worthwhile experiment?

195[/snapback]

 

I've looked at the "runners" you mention, at first thinking they *were* some evolution of the Sport/Daytona "ram air" fairings, but if you stand in front of a V11 Le Mans & look thru them, you'll see that they pretty clearly are there to direct air at the inside of the (air-cooled) cylinder heads. Stealing cool air from those might not be the best plan for motor longevity?

 

For ram-air to work, the air must be taken from a high-pressure area (in cars, this is done a the base of the windshield) and fed to the engine. This works by simultaneously reducing the parasitic drag on the engine from creating a vacuum in the airbox, and reducing the aerodynamic drag of the vehicle. So yes: it works best when the vehicle is going fast. Motorcycles typically have dreadful aerodynamics [up around .5 to .8 where a flat plate pushed flat side forward = drag coefficient of 1] and actually stand to benefit more from the reduction in drag coeff. than they do from the intake [since they already tend to have very efficient i.c. engine designs and exemplary power/wt ratios...]

 

Unfortunately, on the Le Mans, the traditional round headlight is sitting smack dab in the middle of the highest pressure point on the fairing. If you look at the MGS-01, that's right where the fake ram air port is located. Hmm; seems someone forgot to connect the ductwork!

[Guest davidb]

I haven't dyno'ed my bike, but from 40 to 120mph, I can tell a difference in the higher elevations. Rain isnt a problem as there is two water drains on the runners. I have rode it in downpours with no problems. Mine is fiberglass. I had to make a small heat shild to protect it and ensure cool air intake at stop lights. I have posted pics of it on this site. I have noticed alot of calculation and speculation on whether it would work or not. May I suggest that sometimes it is just better to try it, than ponder it. (unless it would Damage your bike) The offer still stands: Anyone that owns a guzzi in my area that wan'ts to test ride mine... can

[pete roper]

You have to remember that pressurisation only happens at, (I think, ask Will, he'll give you the good oil.) at the cube root of speed. What this effectively means is that you will percieve no real benefit under about 120MPH so who gives a fat rats arse? Rossi and all those knobbers in GP can benefit because most of the time they are in that sort of speed band. Us mere mortals? Forget it, especially on a turdbox like a Guzzi with it's breathing compromises and weedy little 2 valve combustion chamber .

 

Where I do think there is a LOT of merit is moving the air intakes from just behind the exhaust headers ( What f#ck-head thought that one up????) to somewhere else where there is a chance of ingesting air that isn't already hot. Could this perhaps be a weirdo Guzzi answer to the endemic problem of the wretched things running rich in winter???? Suck in hot air and fool the ATS into giving a mesage to the 15M that it's hotter than it is to lean out the mixture? (Bangs head on keyboard!) Sounds like a typically half-arsed Guzzi solution !

 

Before anyone asks, no you can't reverse the heads and use forward facing ram tubes

 

Cali owners seem to find big benefits from opening up the airbox. I'd expect V11 owners to get a similarly good result, but only if the FI can be adjusted to suit as the important thing is to keep the stoichimetric (????) ratio correct at *about* 14.7 to 1, Yes, you may gain slightly more outright power by going slightly richer but that will depend a lot on the cam/breathing and where you want the go.

 

Cool, dense air, and a proper ATS and ETS plus an EGA to set the poxy thing up on a Dyno are the only real way to sort out this sort of crap to get it to work properly. This takes time, knowledge and skills I don't have, (Did I ever mention I like Carbs ) but others do. The simple fact that the motor is having lighter, less dense air pushed into it though means that performance will be compromised even if everything else is set up precisely so it works right. More oxygen atoms in the cylinder means that you can add more fuel so the chemical reation when ignited makes more heat which will expand the gas in the chamber more exerting a greater force on the piston which will cause more torque at the crank, (Torque= Force x Distance.). Power= Torque x Revs. There are a lot of other important issues to consider but that is the basic bottom line.

 

Increasing the pressure at the atmospheric side of the manifold by the weedy amounts you'll get below that *rough* 120MPH mark will achieve nothing. Getting dense air in will make a significant difference!!!!!

 

Pete

[zebulon]

My 2 cents

No theory for me , just practice :

 

My daytona rs standard (so read a normal 1000 cc only with racing exhaust, eprom) without airbox & with 2 individuals K&N always take the redline at 9 000 RPM in 5th without troubles and non need of 6 km straight line

 

For my 1225 daytona rs & 1225 Supertwin it is the same, without the air box the bike took the 9 000 red line easely & work like hell even in 5 th

 

So the ram air is not something so necessary to me, btu that is just my 2 cts way of thinking

[dlaing]

The fact that the guzzi intake system is not ideal compared to multivalve DOHC engines leaves all the more potential for HP gains if the air pressure can be increased in the intake.

Granted if the ram air intake is the size of the intake valve you are not likely to get much benefit.

Likewise, if the ram air intake is angled like the intakes on the Daytona, you might actually lose air pressure.

 

True there are many issues when it comes to ram air design.

I think Will Creedon mentioned a stagnation point where the pressure just cannot be made to go up regardless of wind speed...of course I am butchering what he said...

 

But aside from these challenges, it seems to be common sense that if your snorkles are at 1 atomosphere and your engine is sucking, you are gonna get less than one atomosphere in your intake.

The ram air is not going to give you Turbo boost, but it will keep you from heading towards a vacuum.

 

The critics of ram air often mention that gains do not occur until you are well into triple digits. I beg to differ, and believe that air can be funneled in such a way that one is getting more than one atomosphere at the intake valve. This can be done with intakes that are significantly larger than the Daytonas. Perhaps the intake face could be as large as the air filter intake area...maybe (2) 10cm diameter circles would be about right.

I am pretty sure David B.'s intakes are more than twice the size of the Daytona intakes.

To maintain air pressure when the engine is cruising along at 80MPH and 5000RPMs of potential vaccuum the air should be funnelled in. The ram intake should probably be twice the size of the throttle bodies, and if it is, I beg that gains could be made.

Note that I am not an aeronautics engineer as I believe Will is, so I could be mistaken due to aeronautic physics laws that defy laymans common sense.

But if you have ever walked by a skyscraper on a day with a ten mile per hour wind, you can verify the existence of a much more powerful wind.

Funneling is the solution. Start big, end powerful.

The one thing that concerns me is the difference in fuel mapping needs.

If we can double the air pressure, then we might need alot more fuel, and the Guzzi airpressure feedback is not likely to be able to compensate for this. A flow meter would probably be needed. Of course, I could be wrong about this too.

I wonder if Will calculated the engine's flow at RPMs into the stagnation equation???

 

Heat shielding on the airbox could also be a good idea, as Pete suggested that keeping the air cool by not drawing it in by the pre-heating engine fins, could make a difference.

 

Sorry, enough rambling for now.

[pete roper]

I know I've used the word once today but I've since gone and flagellated myself with hot barbed wire but THERE IS NO SUCH THING AS "SUCK"!!!!! You can increase the pressure differential between the cylinder and the inlet tract but you acnnot "SUCK" anything into your engine. All the gas and fuel that gets in there is pushed in from the outside, not sucked in from the inside. There is a difference.

 

Pete