The stock air cleaner that comes on the current Street Glides is basically an enclosed air box with a single forward facing intake. This is a dramatic departure from most previous Harley air cleaners. Is this because they've done their research and determined that it is an improvement over the open element concept favored by all Stage 1 air cleaners? My local shop service manager told me that the current air cleaner delivered more horsepower than the old football cleaners. But HD and many others claim that the Stage 1 open elements breathers will deliver more air flow for better performance. I was about to order a Stage 1 Heavy Breather Elite cone air cleaner when I read an interesting post from someone named Ted that said ...
"Ok, I admit confusion. I spent 2 years in motorcycle school; taught by a certified Harley PHD instructor. We learned that the best performance comes from a source of STILL air, as in a box or with a cover. Reason? A more consistent mix of air and fuel. Turbulence from an open air filter reduces optimum combustion. I have seen this several times on a Dyno. So what is the deal with this Hi Pro Intake?"
Ted later wrote...
"On a Hayabusa the air filter is in a sealed box under the fuel tank. Cool air goes in through the intake and stabilizes into “still air” in the box. Most Hi Pro motorcycles use this type of filter box. My cage is a BMW 330 CI. It has an intake on the front of the engine for cool air and that is fed into a sealed box which has the air filter. My competition BMW M coupe has Dinan cold air intake with a cone filter but that is behind the air dam and is protected from turbulent air. A Dyno tech can tune an open filter but remember that the bike is sitting still on the Dyno. The air fuel mixture changes when the bike is doing 60 mph. A football air cleaner cover will provide better performance than a cone in the wind. "
Is Ted right? Are we being deceived by marketing and myths? Is the stock "box" air cleaner on the modern Harley's more efficient at riding speeds than the cooler looking expensive Stage 1 air cleaners?
"Ok, I admit confusion. I spent 2 years in motorcycle school; taught by a certified Harley PHD instructor. We learned that the best performance comes from a source of STILL air, as in a box or with a cover. Reason? A more consistent mix of air and fuel. Turbulence from an open air filter reduces optimum combustion. I have seen this several times on a Dyno. So what is the deal with this Hi Pro Intake?"
Ted later wrote...
"On a Hayabusa the air filter is in a sealed box under the fuel tank. Cool air goes in through the intake and stabilizes into “still air” in the box. Most Hi Pro motorcycles use this type of filter box. My cage is a BMW 330 CI. It has an intake on the front of the engine for cool air and that is fed into a sealed box which has the air filter. My competition BMW M coupe has Dinan cold air intake with a cone filter but that is behind the air dam and is protected from turbulent air. A Dyno tech can tune an open filter but remember that the bike is sitting still on the Dyno. The air fuel mixture changes when the bike is doing 60 mph. A football air cleaner cover will provide better performance than a cone in the wind. "
Is Ted right? Are we being deceived by marketing and myths? Is the stock "box" air cleaner on the modern Harley's more efficient at riding speeds than the cooler looking expensive Stage 1 air cleaners?
