OK.. here is a stupid question, but how do you know if the secondary butterflies are opening on a b18c. how could you check?

 

When I had secondaries, it was noticably louder when they opened!

 

They only open (or fully open) in vtec right?

 

You'll hear it become noticeably louder at 4400 rpms when it hits stage 1 of VTEC and then twice as loud when it hits 5800 rpms or so when stage 2 hits. If it doesn't become any louder at 5800, I'd say that'd be pretty decent evidence that they weren't opening.

 

is there a test i could carry out to check if they are working and even fully opening

 

right^^^^
also make sure the car is at operating temperature

 

Slow down a sec, black ack is right to a degree but your wording could seriously confuse newcomers. There is only one "stage" of VTEC. Its either on the lobes or its not. The actual VTEC on a b18c1 engages at 4400rpm. The purpose of the secondaries is to keep the air intake somewhat restricted while the VTEC kicks in to allow for the ridiculously low engagment point. At 5800rpm the secondaries "butterflies" open up to fully realize the larger cam lobes.

 

ok. i understand this part already.. but at 5800rpms, does the SOUND changeover like vtec.. i can clearly hear my vtec come in at about 4400rpm.. but i dont hear anything significant after that.

 

if they werent opening the car would feel a bit sluggish after 5800

 

okay guys.. i think they are opening... thnks