Hello everyone !

For the information I don`t know much about HONDA.

My civic got SOHC engine with VTEC solenoid.
I dont understand how this thing works.
Sometimes I can feel burst at 4500 RPM but not always.

 

I'm not saying this to be a jerk but I would start here and the FAQ's

Let me google that for you

VTEC is not nitrous, it's not boost, it should never be a "kick in the pants", in a nutshell:

"The VTEC system provides the engine with multiple cam lobe profiles optimized for both low and high RPM operations. In basic form, the single barring shaft-lock of a conventional engine is replaced with two profiles: one optimized for low-RPM stability and fuel efficiency, and the other designed to maximize high-RPM power output."

 

I am Familiar with GOOGLE and I remember VTEC sound + performance on my own car.

At this moment it does not work.(It works very rarely).
I thought such experience could be known for forum members.

 

How did you verify that vtec is not engaging? Butt dyno's don't mean ****. I could sit behind you and watch your tach and when you're near vtec engagement I'll just kick your seat just to make it feel like its engaging.

 

Lol, damn this forum is a tough crowd.

You can get one of those vtec indicator lights installed.

 

Any led will do, it's just to see if vtec is engaging. Not to sit pretty on the dash, but that's for the op to decide.

 

At least there is specific sound when it`s engaged.

 

Check your oil......


Also this: https://honda-tech.com/honda-prelude...thread-830163/

 

When VTEC doesn't activate what are you able to rev to?

https://honda-tech.com/hybrid-engine...rk%22-1812135/

 

Thank you for the useful links.
I will check out the oil first as I have changed oil + oil filter.

 

make a video of this "sound" when vtec engages,

 

96-00 civic EX (Y8 engine) VTEC (stock ECU) is set at 5500ish RPM. Even the ECU's they put in cars sold to trolls have about a 5500RPM cam cross point.

Single cam VTEC can be felt sometimes. The y8's large intake manifold and higher VTEC engagement point make it more audibly noticeable than the Z6. If you have an open filter intake, its audibly noticeable pretty much every time.

Even trolls can hear it.

 

There is an audible noise change with a Y8 and the 5500RPM VTEC engagement. It makes that more urgent/louder noise that you hear in from VTEC engines. Ever driven a B16 car with an intake? Mozart would hear VTEC engage from his grave.

The higher the engagement point, the more dramatic the change usually is (with a similar cam profile change).

The function of VTEC is to transition to a high cam when the low cam begins to wheeze out.

Lets say engine A has a crossover of 4k RPM. This engine's low cam hasn't really run out of breath yet. When the high cam kicks in, you'll barely notice. The transition is smooth. Like a B18C1.

If you then take that engine with the same (or similar) low cam and increase crossover to 6k RPM, the low cam will have been wheezing for a while and the power/noise will flat line or drop off. Then the high cam comes to party. The engine can breath again. Big kick in power. Big noise DELTA (emphasis on delta. Delta is noticeable. Like sticking your hand in 78 deg water after its been sitting in ice cubes. 78 deg suddenly feels hot. DELTA). Think of driving a 99-00 Si.

Moving VTEC up in RPM or making the high cam delta bigger makes for a large audible/feeling change when VTEC crosses.

You don't notice VTEC in GSR's or Z6 powered cars.

You sure as hell notice it in ITR's/B16 cars. Y8 VTEC can be heard with an open filter intake like a SRI or CAI. Not as loud/noticeable as DOHC VTEC. But you'll know.

The difference there is that the RPM is higher and the cam change is bigger. Is a Z6 louder than a Y8 5500RPM? No. But the Z6 has gradually started increasing volume. The Y8 went from 5400RPM normal cam noise to 5500RPM with a bigger cam.

Feel me?

Cliffs:
VTEC is louder and more noticeable when you engage at a higher RPM and/or when the high/low cam profile has a larger difference.

Doesn't necessairly mean its making more power. Just means you notice it more. Remember my 78 degree water comparison?

 

DOHC vtec can definitely be heard, but for a d16y8 its not that easy to distinguish. I drive a 3 stage vtec and I sure as hell can barely hear the crossover at 5500, but you may be right. I need a cold air intake.

 

Without a doubt, you will 100% of the time 100% for sure hear a Y8 crossover (5500RPM) if you have just an intake. An exhaust will drown it out. A stock airbox will muffle it out.

 

Yes, most tunes will lower the VTEC point and usually make it less noticeable. You have to change fuel curve to match the new actuation RPM, but as a general statement, the cars that make power via a tune have less noticeable crossovers.

Hondata even has a sort of "disclaimer" stating that after a tune, the crossover can become almost seamless.