We are asked regularly why we do not sell or make jetting recommendations for "Pod Filter" air intake kits (since it would be simple for us to assemble one). Here is what our testing and opinion on this type of setup is.
The
V Star 1100 is equipped with 2 Constant Velocity (or "CV") carbs which are designed to work together as a unit utilizing the "black air box" to accomplish the bikes best performance. This
gives the bike the performance advantage of two individual smaller carbs at lower RPMs (creating more torque), but also gives them the added advantage of working together like much bigger
carbs at higher RPMs (creating more horsepower). It's not unlike the way a two into one exhaust system works but on the other side of the cylinders. The two carbs scavenge vacuum off of each other to create better performance.
The "black box" (as it is often referred to) actually stores vacuum created between the carbs.
This vacuum causes the slides in the stock CV carburetors to lift quicker which creates better bottom end, low rpm performance. It also draws fuel through the main jets faster causing it to hit the tip of the needle with more force
and speed which causes the fuel to atomize significantly better, creating a much better air fuel mixture for combustion.
When you install a pod filter system, you loose that suction function (that sounds like a "Schoolhouse Rock" song) and forces the
two carbs to work independently from each other. This is why pod filter systems require you to go from a 112 main jet all the way to an absurd 150 or even larger main jet. Think of it like sucking your favorite beverage through a straw, as opposed to just letting it flow through the straw on its own. To get the same fuel flow without the vacuum, the pod system needs a jet
with a much larger hole to go through. By compromising this way, it can allow enough fuel to feed the engine, but at a much slower velocity which reduces atomization and performance.
Performance gains that are "felt" with a pod filter system is actually deceiving. Yes, you do gain some horsepower at the very top
end, but only once the engine finally creates enough vacuum on each separate individual carb. But, you loose performance gains at the low and mid RPM range (where a cruiser is designed
to run). So, when the RPMs finally get high enough to properly atomize the fuel, it "feels" like a rush of power which is deceptively magnified by the actual
loss
of power at the low RPM range. But by the time you get to that RPM range, unfortunately it's time to shift gears and you're right back to the lower RPMs again. What actually is happening is
a loss in bottom end power, with a rush at the top end.
So, in the real world, from a stop light what you would experience is this; the bike with a
traditional performance air intake setup will accelerate quicker off the line, through the mid range and up into
the higher RPM range. Only once the RPMs get high enough, the bike with the pod filter system will start to catch up. Problem is, by the time that happens, it's time to shift and it all starts
over again.
All
of our testing has shown power develops much faster and at lower RPMs with a traditional performance air intake system
utilizing the "black box".
Putting pod filter systems on the stock carbs has had great social advertising, but if there was truly an advantage with them, we
would simply make a kit ourselves. We have decided to not take advantage of that hype.
Another question we are often asked is, "I've installed a pod filter
air kit, which performance cam should I install to get some of the bottom end performance back?" Well, converting
the CV carbs into a pod setup, makes that a proverbial game of "whack a mole". The solution isn't a different cam, it's a properly designed air intake setup. Then the cam will be able to realize
its performance purpose and potential.
We hope that helps with any questions you may have.
