Civic Si: Your Gas Mileage

[K757]

Originally Posted by OrdnanceMarine

The key is not to ask for a lot out of your engine at those low RPMs. I use my ScanGauge2 with LOD (% of available torque currently being produced at present RPM) and don't load my engine much above 60% at low RPMs so cylinder pressures are pretty low. I also watch IGN (ignition timing) and notice it doesn't drop too much so the engine is not abnormally retarding ignition to prevent detonation.

you are hard core (not a bad thing). interesting read and analysis, I am learning by reading your posts. And to think I was happy with my 25 mpg with the constant vtec'ing. I want better now damnit. If I ever put all of this together (and stay out of 6k+ RPMs), I may start getting better mpg

[OrdnanceMarine]

Originally Posted by K757

you are hard core (not a bad thing). interesting read and analysis, I am learning by reading your posts. And to think I was happy with my 25 mpg with the constant vtec'ing. I want better now damnit. If I ever put all of this together (and stay out of 6k+ RPMs), I may start getting better mpg

Hard core is probably a good description. I'm the kind of guy that has to be messing with something most of the time. I'd get bored driving if I didn't have something to do other than "just drive". At 31 years old, married, kids, house, career, and so on I'm not interested in flooring it everywhere I go so instead I've found a different way to entertain myself by seeing what kind of MPG I can extract from the Si. I fully don't expect everyone else to do the same thing as I do and I'm not advocating that everyone should, I'm just figuring out what's possible and explaining how I'm able to do it so others can pick and choose from what I learn if they wish

[darita]

On another thread, I'm reading about installing the Cobb AP, with pretty dramatic increases in MPG as well as overall performance and elimination of rev hang. Anybody here using this and can you confirm any of the results?

[Poweraide]

I just got 385 last week and im about to fill this week at 370. Running the A/C alot too

[Bboy_Burst]

my car was tuned and the rev hand is remove. i haven't had the chance to test out my mpg with the rev hang removed. my guess is that i might use more gas in the city because now the rpm drops right away when i let go of the gas pedal causing me to get back on the gas sooner.

[OrdnanceMarine]

Originally Posted by Bboy_Burst

my car was tuned and the rev hand is remove. i haven't had the chance to test out my mpg with the rev hang removed. my guess is that i might use more gas in the city because now the rpm drops right away when i let go of the gas pedal causing me to get back on the gas sooner.

Let us know as your results come in. My thought is that a better tune *should* equal better MPG. It's one of the things I'm considering as I'm trying to justify the COBB AccessTuner and Hondata FlashPro.

My last dyno at under 5000 miles when I did the Hondata reflash with the stock intake and no NST pulleys (all other mods the same) came up with 210 HP on Church's Dynapack. I figure the intake and pulleys have to be good for 5-10 HP, putting me at 215-220 right now. I'm thinking the tuning options have to be worth at least 5 HP and closer to 10 HP or it's not even worth changing over to me.

I did see that COBB mentions a fuel economy setting and I'd be interested to see what that's all about. That would be great if I could run one program for MPG and then switch over when it's time to play and even have a 95 octane tune for when I go down to Willow Springs and hit the track.

[darita]

[quote=OrdnanceMarine;5921586]Let us know as your results come in. My thought is that a better tune *should* equal better MPG. It's one of the things I'm considering as I'm trying to justify the COBB AccessTuner and Hondata FlashPro.

My last dyno at under 5000 miles when I did the Hondata reflash with the stock intake and no NST pulleys (all other mods the same) came up with 210 HP on Church's Dynapack. I figure the intake and pulleys have to be good for 5-10 HP, putting me at 215-220 right now. I'm thinking the tuning options have to be worth at least 5 HP and closer to 10 HP or it's not even worth changing over to me.

I did see that COBB mentions a fuel economy setting and I'd be interested to see what that's all about. That would be great if I could run one program for MPG and then switch over when it's time to play and even have a 95 octane tune for when I go down to Willow Springs and hit the track.[/QUOT
Could you please explain just what the Cobb Access Tuner and Hondata Reflash are and what they do?

[OrdnanceMarine]

Originally Posted by darita

Could you please explain just what the Cobb Access Tuner and Hondata Reflash are and what they do?

Head on over to the ECU Tuning Forum at ECU Tuning Information - 8th Generation Honda Civic Forum

Too much information to try and discuss in the MPG thread

[darita]

Originally Posted by OrdnanceMarine

Head on over to the ECU Tuning Forum at ECU Tuning Information - 8th Generation Honda Civic Forum

Too much information to try and discuss in the MPG thread

Looks complicated for a nontec type. I was hoping it was something I could go in and get, like a tune up...guess not.

[OrdnanceMarine]

Originally Posted by darita

Looks complicated for a nontec type. I was hoping it was something I could go in and get, like a tune up...guess not.

You don't have to be a serious techie to apply the basics. Spend some time reading and you'll start to catch on. Each of the systems have general tunes that will be a 90% solution for your given modifications.

As a Si hypermiler and modder I'm always interested in solutions that will improve both power and MPG so these have my attention!

[boostownsme]

I just got my sedan, and have averaged over 34 mpg the last couple fillups, and I still have fun with the car. I part of it might be I was in several boosted cars before this one, and I was always watching the vacuum/boost gauge when I was driving. That gets you a lot more in tune with speed and throttle position etc.

[darita]

Originally Posted by boostownsme

I just got my sedan, and have averaged over 34 mpg the last couple fillups, and I still have fun with the car. I part of it might be I was in several boosted cars before this one, and I was always watching the vacuum/boost gauge when I was driving. That gets you a lot more in tune with speed and throttle position etc.

How is this possible? I have 2500 miles on my 09 Si, coast whenever I can, never get revs over 35K and still can only average 26 to 27mpg! I'm always one of the slowest cars on the road.

[K757]

Originally Posted by darita

How is this possible? I have 2500 miles on my 09 Si, coast whenever I can, never get revs over 35K and still can only average 26 to 27mpg! I'm always one of the slowest cars on the road.

it may be true... but not everything posted on a forum is true.

saying that, your engine is not fully broken in yet, so no worries about the mpg, 26-27 is about average

[jnguy91]

Originally Posted by K757

it may be true... but not everything posted on a forum is true.

saying that, your engine is not fully broken in yet, so no worries about the mpg, 26-27 is about average

thought your car breaks in at 500miles

[K757]

Originally Posted by jnguy91

thought your car breaks in at 500miles

On my other Hondas, there was a magical boundary that occurred at ~10k miles... the mpg jumped about 2.

[jnguy91]

Originally Posted by K757

On my other Hondas, there was a magical boundary that occurred at ~10k miles... the mpg jumped about 2.

how exactly do you know if you "break-in"?? does it feel different or something?? my friends told me to take it easy on the car.. ie: not vtecing or high revving it till i hit 500 or 1000 miles for the "break-in"

[K2OH2SLOW]

i filled up friday nite...so far, i have driven like 350 miles, still have three notches on the meter... also had a k and n drop in for most of that time...put on a fujita sri two days ago, and have hit vtec 4 times...i guess thats pretty good considering

[K757]

Originally Posted by jnguy91

how exactly do you know if you "break-in"?? does it feel different or something?? my friends told me to take it easy on the car.. ie: not vtecing or high revving it till i hit 500 or 1000 miles for the "break-in"

the manual says something like 600 miles and then it's broken in. I'm just stating what I've experienced with other Honda engines.

[boostownsme]

Originally Posted by darita

How is this possible? I have 2500 miles on my 09 Si, coast whenever I can, never get revs over 35K and still can only average 26 to 27mpg! I'm always one of the slowest cars on the road.

Its possible, but like others have said your car might not be broken in yet. One mistake I see alot of people make is thinking the faster they can get into the next gear, the better gas mileage they will get. It all has to do with your throttle percentage. If your going up a hill in say 3'd gear, your going to be off the gas a lot more than say your lugging it up in 5th. Sure your rpm's will be lower but youve lost almost all of your vacuum. I almost never shift below 3200 for this reason and get the mileage that I do. Hoped this cleared it up a little bit?

[darita]

Originally Posted by boostownsme

Its possible, but like others have said your car might not be broken in yet. One mistake I see alot of people make is thinking the faster they can get into the next gear, the better gas mileage they will get. It all has to do with your throttle percentage. If your going up a hill in say 3'd gear, your going to be off the gas a lot more than say your lugging it up in 5th. Sure your rpm's will be lower but youve lost almost all of your vacuum. I almost never shift below 3200 for this reason and get the mileage that I do. Hoped this cleared it up a little bit?

I'm confused...many here say that it's best to keep revs below 3k. Can someone clear this up?