I believe Suzuki supplies Arctic Cat with their engines for their sleds. The have a cool battery-less EFI system for their sleds. Maybe the KQ will use this technology and the EFI will not be dependent on the battery. Anybody know?

 

Kodiak1, not quite right (see following)


650V, these systems use a manifold air pressure sensor. They estimate how much air goes into the cylinder by the air pressure in the manifold. Turns out this works well if the engine never changes (sucks harder or less hard). The engineers that made the engine programmed the EFI to know how much air the engine is really sucking at given RPM and manifold pressure. Very simple. Most cars measure the air flow and can adapt to a change in the motor.

It sortof does automagically adjust for higher altitude. It works at high altitude just as if you didn't open the throttle all the way at a lower altiitude. The manifold pressure won't be as high when you floor it at high altitude, and the MAP sensor measures less pressure which is the same as if you didn't crack the throttle open as much at a lower altitude.

However, if you bore it to 800cc, the engine will draw more air. When you floor it, the manifold pressure won't be as high as it was with the smaller motor even though it is sucking a lot more air. The computer won't even get the air mixture close and it will run like crap.

Basically the same thing happens if you change anything from the throttle body all the way back to the exhaust.

 

Maybe I did not understand what he was asking.When the piston moves down the sucking is actually the atmosphere rushing in because of the low pressure created in the cylinder.It's like a prop....it does not push air as people think.....the blade creates a low pressure area in front of it and the prop is drawn to it.I do know that if you take an imaginary chunk of air at sea level and the same chunk at 10k feet there is less o2.The same applies to colder air.I was just trying to say that EFI adjusts for the conditions whether it be temp or air density or both.
Maybe I did not quite understand his question [img]i/expressions/face-icon-small-wink.gif[/img]
I can tell you at 10k feet in a plane the mixture lever is VERY lean and the MP can not hardly maintain 20hg
02 650 camo

 

The point I wanted to make was that the sensors have nothing to do with sensing the concentration of O2. The variation in concentration of O2 is not significant anyway, what is very significant is the drop in air pressure at higher elevations.

The airplane blade pressure difference is due to the bernoulli principle which is simply a mathematical expression of a law of thermodynamics stated mathematically. That is unlike the 4 stoke internal commmbustion engine which is just merely a form of positive displacement pump.

The term suck, as in automobile engines, refers to creating a pressure drop to allow air from a higher pressure source to be ingested. Air pressure is produced by the earths gravity. Everyone knows you can't actually suck on an air molecule. We don't need that lesson again, it is just a manner of speaking.

You do bring up another valid point, there is an air temp sensor too. There may be a coolant temp needed for it too, but in the very least the air temp needs to be known by the computer.

In case any of you guys ask why does my carburetor run fine whether hot or cold? Cold are is more dense, and the pressure drop that is created by the shapes of venturis, needles, slides and things in the carburetor increases to nearly proportionally and draws more gas accordingly. In that sense, carbs sortof adjust themselves to air temp. They don't do it as well as a computer, but they work pretty darn well for the average offroad motorcycle or car.

Another point you guys should be asking, is why does EFI give us more power? The pressure drop created by the carburetor slide (bernoulli again) causes a loss in airflow. On the other hand, the EFI intake is basically a hollow tube - it can flow more air. Add a brain and a gas squirting system to that tube and you have more power than the same engine with a carb. Some people say 10% more, but that is probably too high of an estimate of an increase in power over a motorcycle carb.

 

Oh yea...I am quite familiar with the Bernoulli principle...................Especially in the wing dept[img]i/expressions/face-icon-small-happy.gif[/img]. It sounds to me like you are sold on getting EFI like myself.I just wish I knew what kind of system they will use.......a throttle body type or an actual port injector.I am not the least bit afraid of the reliability and am looking forward to the improved drivability.Like I was saying especially on those cold deer hunting mornings.I had a chance to ride with a guy that had a new 700 Polaris EFI and it was nice but that thing has the strangest sounding exhaust!!!!!!...I think it must be from the eng design.....I swear it sounds like a snowmobile.
Oh well..............who knows the KQ may end up not being what we hoped and we will all be BF owners!!!!!
Do you ever ride at Hatfield McCoy??
02 650 camo

 

I haven't ridden hatfield yet. I will someday.

I like EFI. But, I like a v-twin too. A pair of smaller cylinders can easily whomp a single of the same size. Smaller cylinders are much more effective at pumping air. We know kawi detuned the V in at least two ways to keep it from flipping backwards. So, if the V is detuned too much, a properly tuned single could beat it. We will see. I would not buy one or the other solely based on speed.

I want to hear actual reports from forum owners about the KQ. From what I hear about the BF, it is definitely the best thing out there so far. Now we just need to get some KQ owner input and decide for ourselves which we like.

The engine braking on the KQ is probably a lot better.

The CVT system on the KQ will not be as easily tuned because it is one of those sprag clutches like a griz.

The belt on the KQ will probably last longer because it has a centrifugal friction clutch like a griz.

I think the diff lock on the BF is better. Not that I use it that much, but I like the quick grab of the manual lever so there is no waiting for electronics (or stopping like the griz).

 

I am a fan of the v-twin too.I am surprised they don't all go to more multiple cylinders.If/when these things have to meet emissions it is easier to (clean up) a smaller cyl x2 that one large one.One thing I did see is that the KQ is supposed to have a sealed brake.I assume it is like the Kaw system.That is someting I really like and no one seems to mention too much.After having bikes with the rear disc exposed and putting brakes on frequently I really like that feature.
The belt deal is a factor too..............I had 2500 miles on the trusty Kodiak and NEVER messed with the belt.They are messier to clean if you take one mud or water.They have the rollers in grease and are a hassle to clean.
I guess we are all benefactors of good competition!!!
02 650 camo

 

Just from what I read above on the EFI subject, sounds like they are on the right track with a map sensor, and temp sensor, but to accurately do it, they need an O2 sensor in the exhaust. Cannondale skipped that part, but offered their free comp mapping service to help. Hopefully the zuki will have that o2 bung in the header to check the spent gases.

 

I rode a Brute at the dealer today, and the power is awe inspiring to say the least.
While I personally dont like the IRS, this machine is a beast!! Parked next to a Praire
on the showroom floor, it was like parking a KFX50 next to a KFX400!!
(ok, I am exaggerating a tad)
It will truly be interesting to see these two quads go head to head!!!

 

I'd like to make a comment about an earlier post that was a tad long to mess with by quoting...

EFI makes more HP than a carb because of more efficient fuel atomization and more precise fuel/air metering. EFI has better throttle response because of an electronic throttle position sensor that increases fuel flow simultaneously with the increase in air. With a carb, there is a moment where air pressure drops, then venturi forces pull fuel into the air stream. Also, this venturi effect is responsible for atomizing the fuel, and as you put before, "we all know" that the maximum pressure that can be produced in an atmospheric system is the barometric pressure where you happen to be at the time. At sea level, maybe something like 14.7PSIA. With EFI, you typically have 45-80psi behind the fuel spray, causing much finer droplets, better fuel/air mixing, and, thus, more complete and efficient combustion. Efi rules the day because a carb is a passive control system, dependant on preset mechanical clearances and dimensions, and EFI is an active system, constantly adjusting and compensating. Depending on the system, it can even be adaptive to conditions and riding style. This 'adaptive' system is nothing new at all, as the MPEFI from a 1991 cherokee 4.0 HO that I used on my CJ was 'adaptive'. It used a MAP (manifold absolute pressure) sensor, a 4 wire pre-heated 02 sensor, air temp sensor, and TPS, to adjust and regulate fuel. Ignoring the ignition system, this is a pretty simple setup, especially with a single cylinder. I'm sure that Suzuki will have a stellar performer with the KQ, as they have long years of experience in their company with EFI. I'm totally stoked to have an EFI quad some day! It was the best thing that ever happend to my Jeep, and I'm sure it will eventually revolutionize the ATV industry as it's doing in the snowmachine industry right now.