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firehawk618 · 03-29-2015, 03:23 AM

I wonder to myself, is it better for economy to intentionally keep the rpm's in range to use LB or is it better to shift if you're not in the highest gear and be out of LB rpm range.

Some will say that the vacuum gauge is the best way to tell if you're getting the best MPG possible but I am not completely sold on this.

A scenario is cruising along in 5th gear, flat ground. Let's say my vacuum gauge is sitting right at 15. Now LB kicks in and I now have to give more throttle to maintain my speed. The vacuum gauge will now read 7..... You can see where I am going with that.

I can say that when I am in LB in 3rd or 4th gear the shift up light will be illuminated the entire time and if I shift up a gear I will be out of the RPM window for LB. This would be even worse with HX gearing in the transmission.

Once I get my MPGuino in the mail I should be able to figure this out easily.

I guess I could watch the injector duty cycle and figure it out, but it's kind of hard to get a real good picture watching the scan tool.

I have to think, that in the most simplest terms, the lower your injector duty cycle at any given time the better your economy will be.

Seems like ultimately that's what really matters.

03-29-2015, 03:23 AM	#3 (permalink)
firehawk618 EcoModding Apprentice Join Date: Oct 2014 Location: Marysville, wa Posts: 221 97 Civic HX sedan VX trans - '98 Honda Civic LX + HX + VX 90 day: 41.9 mpg (US) Thanks: 23 Thanked 42 Times in 24 Posts	I wonder to myself, is it better for economy to intentionally keep the rpm's in range to use LB or is it better to shift if you're not in the highest gear and be out of LB rpm range. Some will say that the vacuum gauge is the best way to tell if you're getting the best MPG possible but I am not completely sold on this. A scenario is cruising along in 5th gear, flat ground. Let's say my vacuum gauge is sitting right at 15. Now LB kicks in and I now have to give more throttle to maintain my speed. The vacuum gauge will now read 7..... You can see where I am going with that. I can say that when I am in LB in 3rd or 4th gear the shift up light will be illuminated the entire time and if I shift up a gear I will be out of the RPM window for LB. This would be even worse with HX gearing in the transmission. Once I get my MPGuino in the mail I should be able to figure this out easily. I guess I could watch the injector duty cycle and figure it out, but it's kind of hard to get a real good picture watching the scan tool. I have to think, that in the most simplest terms, the lower your injector duty cycle at any given time the better your economy will be. Seems like ultimately that's what really matters. __________________ 1998 LX with a full HX swap + VX transaxle.