Newbie Driving Questions about my VX...

[gijoe985]

So, just started driving the VX today. I have a few questions that maybe you guys would know or be able to help with.

1) When does VTEC engage on a VX? I assume it is different than the run of the mill performance oriented VTEC.

2) Does it try running in lean burn MOST of the time or typically only at freeway speeds? I felt like I was in it a lot., but I am still trying to determine if I am feeling it correctly.

3)Since lean burn allows a lot more air into the system, would my theory be correct that when lean burn engages, you would observe a drop in vacuum? I feel like I saw that. So, while I am typically trying to get higher vacuum for good FE, when I see that sudden drop in Hg, but without me making a change, I assume that is lean burn allowing more air in.

4) HILLS?????? I have a few small mountain passes that I go over in my daily commute. I am still a bit confused as to what the main goal is for best FE. If I don't want to drop below 60mph, should I "floor" it in 5th or give it a little bit of throttle in 3rd. I have much higher vacuum when in 3rd, but in 5th I am at lower rpms... I guess I struggle with the overall balance of rpms and Hg in the hypermilage game...

Any and all comments and advice would be a big help, thanks!

[MetroMPG]

Get yourself an MPGuino - it'll help your driving SO much. It also works as a lean burn indicator, since your instant MPG will jump up noticeably when you enter L.B.

Originally Posted by gijoe985

2) Does it try running in lean burn MOST of the time or typically only at freeway speeds? I felt like I was in it a lot., but I am still trying to determine if I am feeling it correctly.

It's load based. So it's possible you're feeling it at lower speeds and in gears other than 5th.

3)Since lean burn allows a lot more air into the system

In lean burn, air consumption stays about the same for a given power output. It's the fuel input that drops. If your VX is like my Insight, you may have to open the throttle very slightly more to maintain a given speed when you enter lean burn, which would show up on your vacuum gauge.

4)Hills .... If I don't want to drop below 60mph, should I "floor" it in 5th or give it a little bit of throttle in 3rd.

An MPGuino will answer this ... and will tell you to stay in the highest gear you can.

Also: MPGuino, MPGuino, MPGuino. (Big fan of instrumentation. It's invaluable.)

[basjoos]

1) VTEC engages when rpm goes above 2500.

2) Once the engine reaches normal operating temperature, it runs in lean burn whenever the manifold pressure remains above a preset limit (under low load, mostly closed throttle). Lean burn limits are controlled by manifold pressure Usually you can feel a slight stumble as the engine enters and leaves lean burn.

In my car I get better mileage when flooring it in 5th rather than running partial throttle in 4th.