# Secondary Butterflies

**URL:** <https://forums.speedlife.net/t/secondary-butterflies/24175>\
**Category:** NYSpeed Automotive\
**Created:** [February 6, 2007, 6:42pm UTC](https://forums.speedlife.net/t/secondary-butterflies/24175 "2007-02-06T18:42:13Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![JonnyAZ](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/jonnyaz/32/7363_2.png) [@JonnyAZ](https://forums.speedlife.net/u/JonnyAZ)\
**Post date:** [February 6, 2007, 6:42pm UTC](https://forums.speedlife.net/t/secondary-butterflies/24175/1 "2007-02-06T18:42:13Z")

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I just put in a new black box and hooked up all the vaccuum lines to run my secondary butterflies this past weekend on my gsr motor… I’ve asked around a little and haven’t got any answers… Basically, how can i find out if the secondary’s are working… I don’t feel much of a difference when I get up into high RPM’s but that doesn’t mean there not working. Thanks

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**Author:** ![MHill](https://avatars.discourse-cdn.com/v4/letter/m/ea5d25/32.png) [@MHill](https://forums.speedlife.net/u/MHill)\
**Post date:** [February 6, 2007, 7:18pm UTC](https://forums.speedlife.net/t/secondary-butterflies/24175/2 "2007-02-06T19:18:23Z")

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From what I can recall and the quick research that i did, Your power gain should have been down low. The secondaries when inactive are normally open. This creates a shorter intake primary for increased efficency at higher RPMS.

When functioning properly on a stock ECU VTEC should engage at 4400 RPM and your butterflies should open at around 5600 RPM. With an intake and not a rediculasly loud exhaust you should be able to hear a distinct change in engine tone at each of those RPM points.

So to change what your looking for, you shouldnt feel a difference at higher RPM only lower RPM.