vx - lean burn vs vtec-e?

[dlb]

you guys talked me into it, now you're in for it. thus begins my merciless assault of noob vx questions! just kidding, i'm not totally helpless. just unfamiliar with the car right now.

i have a basic understanding of vtec and vtec-e but what i'm wondering is, can vx owners feel the vtec-e kick in around 2500 rpm? i notice it, or something similar, in my car very clearly. when accelerating, between 2500-2700 rpm i notice a sudden and distinct increase in power. i read on wikipedia that 2500 rpm is the vtec-e switchover so i figure that that is most likely what i am feeling. can someone confirm or deny this?

my next related question is, when people talk about the vx switching in and out of lean burn, what exactly do they mean? is that just another term for what vtec-e does, and if that's the case, is anything under 2500 rpm considered lean burn since (basically) only one intake valve is opening? or is lean burn something else altogether? if it's something else, how does it work and how do you know if/when it switches on or off?

thanks in advance, everyone.

[War_Wagon]

There is a post somewhere on this forum about installing a light on the dash that tells you when you are in lean burn. Sorry I don't have more info, but going from my swiss cheese of a memory that's the best I have for you. There is also an article on another site on how to make a simple circuit to add to your setup to keep it in lean burn longer. It is based on a first gen Insight, but it might work for you too. I think I even linked someone else to it at one point but I sure can't find it now. Something like "Insight lean burn throttle smoothing" might assist your Google-Fu.

And lean burn, to my knowledge, is the ability of the fuel injection system to work with a wider ratio of air to fuel ratios. So a normal car will run at 14.7:1, and try to maintain that ratio. But a lean burn system has the ability to read a wider degree of ratios, and adjust accordingly. So in other words, it may start off at say 15:1, but when you are on the highway, cruising at light load, it will start to lean the system out. Now it's at 18:1. Then it's at 21:1, etc. It will do this until there is a change in load that makes it work harder and fatten up. This is also why Insights and VXs had weird emissions systems on them, because even though they are very efficient, running a car really lean makes for more nitrogen production. At least that's what I seem to remember, someone please correct me if I am wrong but I am doing the best I can given the amount of empty beer cans on my countertop right now ha ha.

[Ryland]

You can sometimes feel lean burn kicking in at very light throttle, think flat road, it almost feels like you let off the gas just a little, it takes a while to feel out.
the 2nd intake valve opens up above 2.500 RPM and that is pretty clear, the engine is going over 2,500 RPM, at that point you are using a ton of gas, lean burn never kicks in at that high of revs.

[dlb]

thanks guys, that makes a lot of sense. i have noticed that even at lower rpm and keeping the throttle steady, if i start taking a hill or something the car seems to pull just a little bit harder so i guess it is just fattening up the mixture then. so that along the with 2500 rpm vtec-e switchover makes me rest easier as to what i need to look into and repair on the car. it needs a bit of work before it becomes a dd but i wasn't sure if those two characteristics were normal for a vx or not.