stock 92 civic vx vtec question?

[83gs1100g]

Originally Posted by vrmouseyd15b

Check his other threads. All the same. No garage info. No mpg info.

ya and? im new here. im just getting started. ya gotta start sometime? hey im not here to talk trash sorry im honestly trying to understand this stuff and thats why im here. but i think we are talking about the same thing but just saying it different?

[user removed]

Post 5

"i don't know"

Post 6

"i think they are wrong"

Which one is it, it can't be both?

My understanding is at low RPM one intake valve opens normally, the other barely opens. The combination creates a swirl which enhances atomization and allowslean burn at lower revs. VTEC enagages at 2500 RPM to allow more power when needed. Lean burn engages at higher manifold vacuum. This allows mixtures to be very lean but it is a very sensitive area as far as loads, throttle position, as well as any other condition such as clogged egr ports, ignition problems, even dragging brakes, all acting together to push the car out of lean burn. Even tire choice can affect lean burn operation. When I changed the ORIGINAL tires on my 94 VX in 2008 at 37 k ORIGINAL miles the averge MPG dropped by 7 MPG, just from the tires.

An argumentive postion and responses is not condusive to "learning" and you have access to some of themost knowledgeable VX owners and techs on the planet right here.
The only way you can fail to learn is to not believe the truth when it is staring you in the face and that is your choice.

regards
Mech

[83gs1100g]

Originally Posted by Old Mechanic

Post 5

"i don't know"

huh? maybe you have wrong post? i didnt say that in post 5?

[/QUOTE]My understanding is at low RPM one intake valve opens normally, the other barely opens. The combination creates a swirl which enhances atomization and allowslean burn at lower revs. VTEC enagages at 2500 RPM to allow more power when needed. Lean burn engages at higher manifold vacuum. This allows mixtures to be very lean but it is a very sensitive area as far as loads, throttle position, as well as any other condition such as clogged egr ports, ignition problems, even dragging brakes, all acting together to push the car out of lean burn. Even tire choice can affect lean burn operation. When I changed the ORIGINAL tires on my 94 VX in 2008 at 37 k ORIGINAL miles the averge MPG dropped by 7 MPG, just from the tires.[/QUOTE]

ok maybe i am hung up on the fact that when vx motor goes into L/B you feel a slight loss in power similar to when the a/c kicks on and the shift light comes on is this when the motor switches off the solenoid stopping oil to the 4th valve and goes to 12v mode? to me i feel this so i think this is how it operates. this is why i believe if your not in L/B then the motor is in 16v mode.[/QUOTE]

[/QUOTE]An argumentive position and responses is not condusive to "learning" and you have access to some of the most knowledgeable VX owners and techs on the planet right here.
The only way you can fail to learn is to not believe the truth when it is staring you in the face and that is your choice. [/QUOTE]

it just doesnt add up by the way the vx runs and drives as to how people are describing the vtec-e operation. sorry guys its just the way i see it and i will keep asking till i find the answer that makes sense to me. i am reading the fuelly forum now to see what they say from the post that was posted earlier -http://www.fuelly.com/forums/showthread.php?t=3567&highlight=Lean+Burn+Monitor+ Info

[user removed]

Originally Posted by 83gs1100g

so at idle its 12v? i disagree. when you accelerate from idle and dont let it get into L/B and you rev past 2500 rpms does the motor gain a sudden increase in power? no it doesn't. then this means vtec it always engaged from idle on and only disengages for L/B.
i dont know how test the 02 sensor to confirm this though. how would you do this? just a volt meter?

Engaging vtec just engages one additional valve per cylinder for a total of 16 valves.[/QUOTE]

correct.[/QUOTE]

read your own post.

[user removed]

Originally Posted by 83gs1100g

yep and i think there wrong.

post 6

[83gs1100g]

Originally Posted by Old Mechanic

Engaging vtec just engages one additional valve per cylinder for a total of 16 valves.

correct.[/QUOTE]

read your own post.[/QUOTE]

correct. i know this. whats your question? when in L/B and only when in L/B is 12v mode. when not in L/B then its 16v mode. this is how im seeing it?

[user removed]

Originally Posted by 83gs1100g

huh? maybe you have wrong post? i didnt say that in post 5?

My understanding is at low RPM one intake valve opens normally, the other barely opens. The combination creates a swirl which enhances atomization and allowslean burn at lower revs. VTEC enagages at 2500 RPM to allow more power when needed. Lean burn engages at higher manifold vacuum. This allows mixtures to be very lean but it is a very sensitive area as far as loads, throttle position, as well as any other condition such as clogged egr ports, ignition problems, even dragging brakes, all acting together to push the car out of lean burn. Even tire choice can affect lean burn operation. When I changed the ORIGINAL tires on my 94 VX in 2008 at 37 k ORIGINAL miles the averge MPG dropped by 7 MPG, just from the tires.[/QUOTE]

ok maybe i am hung up on the fact that when vx motor goes into L/B you feel a slight loss in power similar to when the a/c kicks on and the shift light comes on is this when the motor switches off the solenoid stopping oil to the 4th valve and goes to 12v mode? to me i feel this so i think this is how it operates. this is why i believe if your not in L/B then the motor is in 16v mode.[/QUOTE]

[/QUOTE]An argumentive position and responses is not condusive to "learning" and you have access to some of the most knowledgeable VX owners and techs on the planet right here.
The only way you can fail to learn is to not believe the truth when it is staring you in the face and that is your choice. [/QUOTE]

it just doesnt add up by the way the vx runs and drives as to how people are describing the vtec-e operation. sorry guys its just the way i see it and i will keep asking till i find the answer that makes sense to me. i am reading the fuelly forum now to see what they say from the post that was posted earlier -http://www.fuelly.com/forums/showthread.php?t=3567&highlight=Lean+Burn+Monitor+ Info[/QUOTE]

"It just doesn't add up"

Based on your post and the quote where you accused me of not reading the above statement can not possibly be based on experience, since you admitted you don't know how to test an oxygen sensor. I think you like to argue for the sake of argument.

I'm done here, since there will be no benefit for either party. My knowledge is based on 60k hours of experience. I have no idea what you base your knowledge is based on, but good luck getting help from people who take the time to try to help, only to have that time denigrated by useless arguments that teach noting to anyone.

[97-civic-ex]

Old Mechanic, don't even bother. I explained it on his other thread and I guess it wasn't what he wanted to hear. So he started this one.

Just because I am nice i will give the OP a few more things to chew on since his last post still shows how confused he is.



1)vtec is a mechanical solenoid. When the ecu activats it, it switches from 12V to 16V. Don't expect it to throw you back on your seat, it is meant to be a smooth transition, especially in a SOHC vtec-e motor. It is not a turbo kicking in!

2)Lean burn mode is a change from stoic to a lean mixture. If you don't understand what that means, look that up first.


There is no corrolation with the vtec engagement and the lean burn mode so stop trying to tie the two together.

straight from wiki:

VTEC (Variable Valve Timing and Lift Electronic Control) is a system developed by Honda to improve the volumetric efficiency of a four-stroke internal combustion engine. The VTEC system uses two camshaft profiles and hydraulically selects between profiles.

Lean burn refers to the burning of fuel with an excess of air in an internal combustion engine. In lean burn engines there can be 65 times as many air molecules as fuel molecules, yielding an air–fuel ratio of 65:1. The air–fuel ratio needed to stoichiometrically combust petrol, by contrast, is 14.64:1. The excess of air in a lean burn engine combusts more of the fuel and emits fewer hydrocarbons. High air–fuel ratios can also be used to reduce losses caused by other engine power management systems such as throttling losses.

One may be a requirement for the other, but not the only requirement, so you could be in 12V and not in lean burn!

[vrmouseyd15b]

No. I don't believe that you need to see this shift light to say you are in lean burn. The shift light days to shift, OR YOU WON'T BE IN LEAN BURN FOR LONG!

[83gs1100g]

Originally Posted by 97-civic-ex

so you could be in 12V and not in lean burn!

this is whats hanging me up? im assuming you can only be in 12v mode when in L/B. this is what i am trying to figure out?

i know its not going to snap you back and all that. i posted it is so suttle a similar feeling like when your a/c kicks in. changing from 12v to 16v is the same soft suttle change. am i the only one that notices this?