K-series "Intake Air Bypass Control Thermal Valve"

Karcepts · Post by **Karcepts** » Wed Apr 05, 2006 5:30 pm

I realize that the "Intake Air Bypass Control Thermal Valve" (as named by Honda) is to supply air to the injectors (through the miniature ports seen in the intake manifold above each cylinder port) right at their tips before the fuel is sent through the manifold and into the head. The Helms manual doesn't go into detail as to why this is used or what its function is. Does anyone happen to know what the purpose of it is? I assume it is to provide a cleaner air-fuel mixture. I would like to know if any ill effects have been observed if this valve is plugged or removed on a K-series engine.

Post by **Hondata** » Thu Apr 06, 2006 8:42 am

It is for emissions - better fuel atomization when cold. If using stock injectors, leave the bypass alone, otherwise aftermarket injector block the output and you may remove and plug the thermo valve.

Karcepts · Post by **Karcepts** » Thu Apr 06, 2006 3:41 pm

Hondata wrote:If using stock injectors, leave the bypass alone.

Thanks for the quick response!

So would there be any negative performance results observed if removing the bypass when using stock injectors?

Post by **Hondata** » Fri Apr 07, 2006 8:52 am

So would there be any negative performance results observed if removing the bypass when using stock injectors?

Performance, no. Unnecessary work, poorer emissions and fuel accumulating between the intake and head, yes.

Karcepts · Post by **Karcepts** » Fri Apr 07, 2006 2:53 pm

Hondata wrote:
So would there be any negative performance results observed if removing the bypass when using stock injectors?
Performance, no. Unnecessary work, poorer emissions and fuel accumulating between the intake and head, yes.

Thanks for the info! I was just checking if it is cool for those with K swaps in EG's, EK's, EF's, and DC2's to remove it, since it is a nice location for a desired temperature sending unit. Thanks again!