Velocity stacks

[Giggy]

I have a Yamaha K-Series 2.6 with a stage 2 kit.
Engine runs great, but I wonder if adding velocity stacks is a wise choice before investing in a stage 3 kit.

[whatsamerc??]

mr ray neudecker (yamaha guru) talked me out of buying a set from him so i have never given them a second thought...............benji

[Giggy]

Thx for the reply.
not to sound stubborn, but what is the reason behind not using the stacks?

[Markus]

not to sound stubborn, but what is the reason behind not using the stacks?

They make your engine look prettier, but don't make it run better.

[Giggy]

Even if you allow better/stronger airflow directly into the stacks by opening up the front of the engine cover and placing a louver type grill there?

[engineermike]

Mine is a 3.3, but I did a lot of back-to-back testing. The velocity stacks were worth a solid 2-way-run GPS-tested 2 mph. However, one function of the airbox is to collect all the oil that dribbles out of the intake and route it back to the crankcase on the next startup. I found the oily mess in the cowling and pan to be untolerable. My next try was to modify the stock airbox to allow more air in, but retain the oil containment functionality. It worked, and still gained the 2 mph.

[Giggy]

Ok. Makes good sense. Thx for the info and ur time.

[DoktorC]

Mine is a 3.3, but I did a lot of back-to-back testing. The velocity stacks were worth a solid 2-way-run GPS-tested 2 mph. However, one function of the airbox is to collect all the oil that dribbles out of the intake and route it back to the crankcase on the next startup. I found the oily mess in the cowling and pan to be untolerable. My next try was to modify the stock airbox to allow more air in, but retain the oil containment functionality. It worked, and still gained the 2 mph.

Was that 2mph difference from the stock airbox or from no airbox?

[engineermike]

Was that 2mph difference from the stock airbox or from no airbox?

The velocity stacks and the modified airbox both ran the same speed. BTW this was on a 300 with Hydrotec cut heads.

[DoktorC]

The velocity stacks and the modified airbox both ran the same speed. BTW this was on a 300 with Hydrotec cut heads.

Was the 2mph gain over the stock airbox or no airbox? I'm thinking your gain was simply feeding more air to the motor....

[engineermike]

Was the 2mph gain over the stock airbox or no airbox? I'm thinking your gain was simply feeding more air to the motor....

I ran it with stacks, modified airbox, and stock airbox. I never ran it with nothing. The stacks and modified airbox were the same speed, or about 2 mph faster than the stock airbox.

[DoktorC]

I ran it with stacks, modified airbox, and stock airbox. I never ran it with nothing. The stacks and modified airbox were the same speed, or about 2 mph faster than the stock airbox.

Cool...that makes sense. The hydro tec velocity stacks are just the inside of the stock airbox with the rest of the box cut off so it stands to reason that a modded airbox would work as well. Thanks for the info.

[engineermike]

...The hydro tec velocity stacks are just the inside of the stock airbox .... Thanks for the info.

That's where I got my stacks from. ;)