Honda Civic HX lean burn Notes/How To

[tony_2018]

Today I refilled my tank and dumped another 4oz of mmo and now I think I'm really feeling eco mode. I was having a little hard time going past 2500rpm. As I continue to hold my foot on the gas pedal steady I notice the car was moving on its own, as if I was on cruise control. I tried giving it gas little by little until I was finally speeding up. Wow was that really eco mode?

[SpeedyCorky]

likely you were in lean burn. you are likely experiencing

"* once it enters lean burn, power will drop signifigantly (maybe 15%?) - requiring you to increase throttle SLOWLY to maintain the same speed. If it drops out of lean burn, power will increase - so you must let off throttle a bit to avoid accelerating. all this is totally normal. "


an ultra gauge will tell you 100% if you are in lean burn or not. SUPER helpful and downright necessary IMO if you are serious about getting good MPG with the HX



on a not so related note; with ~65 degree temps today, i averaged 58mpg on my commute home. which is daaamn good. warmer weather and a bit better MPG on the street getting to the freeway and i'll break 60mpg no problemo!

[forerunner343]

I've recently purchased a 99 HX, but I don't know much about it so I'm hoping some of you can help me understand how to drive it better. I understand the lean burn for extended highway driving, but I do mostly city driving and I don't know good shifting practices for maximum mpg. Where should I try and keep my RPMs for city driving? Should I try to be in highest gear all the time (if not on an incline)?

[SpeedyCorky]

Originally Posted by forerunner343

I've recently purchased a 99 HX, but I don't know much about it so I'm hoping some of you can help me understand how to drive it better. I understand the lean burn for extended highway driving, but I do mostly city driving and I don't know good shifting practices for maximum mpg. Where should I try and keep my RPMs for city driving? Should I try to be in highest gear all the time (if not on an incline)?

i'd answer these questions, but start yer own thread! this is the lean burn tips thread!!!

[forerunner343]

Question for you: Why are you running both UntraGauge and MPGuino? Aren't they the same, just MPGuino is harder to set up and has less features? I'm looking at getting a gauge and I want to do it right the first time.

[SpeedyCorky]

Originally Posted by forerunner343

Question for you: Why are you running both UntraGauge and MPGuino? Aren't they the same, just MPGuino is harder to set up and has less features? I'm looking at getting a gauge and I want to do it right the first time.

UltraGauge: tells me engine temp, throttle position, engine load, if i'm in lean burn, intake temp, coolant temp

MPGuino: tells me super accurate instant MPG, trip MPG, instant speed to the hundreth MPH (very helpful for keeping a constant speed, or rather a slightly decelerating speed between P&G)


they are both very useful for their own merits

[forerunner343]

Originally Posted by SpeedyCorky

UltraGauge: tells me engine temp, throttle position, engine load, if i'm in lean burn, intake temp, coolant temp

MPGuino: tells me super accurate instant MPG, trip MPG, instant speed to the hundreth MPH (very helpful for keeping a constant speed, or rather a slightly decelerating speed between P&G)


they are both very useful for their own merits

So, the MPG functions of UltraGauge are not compatible with the HX?

[tony_2018]

Originally Posted by forerunner343

I've recently purchased a 99 HX, but I don't know much about it so I'm hoping some of you can help me understand how to drive it better. I understand the lean burn for extended highway driving, but I do mostly city driving and I don't know good shifting practices for maximum mpg. Where should I try and keep my RPMs for city driving? Should I try to be in highest gear all the time (if not on an incline)?

I think to achieve the best mpg during city driving try to stay below 2500rpm or else you will engage the 16v mode. I'm sure the d16y5 works the same as the 3 stage vtec but just without the 3rd stage at 5300rpms. During city driving i shift at 2500rpm and the lowest I'll keep it is 2000rpm.

[iveyjh]

Civic HX D16Y5 Vtec switches 3000-3200 rpm, maybe lower under heavy load. At least mine does.

[firehawk618]

I have been able to go MUCH over 30% tps when in LB without it dropping out.

I will gather more information and post my findings.

97' HX swap.


EDIT: Not a lot over 30% really, can go over 30% but by that point the engine load is nearing 90%. You pass much over 90% and you will drop out of LB.