my quest for more MPG's

[deevergote]

That is exactly why pork chops don't taste like chocolate!

[mugencivic4dr]

nah but diesels love the boost though. look at the 1.4l twin charged vw offered in europe

but our cars aren't diesels

[SOHC-FTW]

I think the accord is one of the worst hondas for fuel mileage in its time. My cb around here with rolling hills gets no better than my 93 3.4 camaro probably less truthfully and it got 24mpg around here. I was highly disappointed in my cb's MPG driving like a responsible adult, i'm sure ya'll with nothing but freeways and flat land get ALOT better.

You want MPG get an HF crx or do like i did with my ed6, HF swap with an si trans and ecu peppy for a 8v and got well over 40mpg on a hard day.

[PR CB7]

A customer that i had in jax, he's a member of ecomodders.com, and he bought one for $2k, had me remove the head, clean everything, replace valve seals and valve job, egr cleaned (used the cb7 tdiy)
13' wheels, with tall tires, nitro filled, etc

From Virginia, all the way to Jacksonville Florida a total of 735miles on one tank cruising in lean burn, drafting behind semis, etc.
This guy was really into the shit, first person that i see that bought all four injectors and filter straight from honda

[mugencivic4dr]

I'm waiting for my fuel filter, dizzy cap, and valve cover gasket from rock auto. Hopefully this will help me a bit with my goal

I think the accord is one of the worst hondas for fuel mileage in its time. My cb around here with rolling hills gets no better than my 93 3.4 camaro probably less truthfully and it got 24mpg around here. I was highly disappointed in my cb's MPG driving like a responsible adult, i'm sure ya'll with nothing but freeways and flat land get ALOT better.

You want MPG get an HF crx or do like i did with my ed6, HF swap with an si trans and ecu peppy for a 8v and got well over 40mpg on a hard day.

yea, i was disapointed when i got my cb and found out that it didnt get good mpg's (expected is the actual word i want to use).

i was looking into a 96-00 hx civic but realized it'll be a waste of money since it'll probably be stolen short after i have it. So i'm going with the moto i've always went with "work with what you got" lol

[mugencivic4dr]

valve cover gasket came in the other day, just waiting for this crappy weather to change a bit to replace the gasket, fuel filter and dizzy cover. hopefully these will improve my MPG's a tiny bit.

i filled up today and calculated the MPG's and i improved about .5, i was getting a combined of 23.44 and improved it to 24.09. only things i've been doing are coasting a lot (exits and down hills) and driving like a grandma.

current goal at the moment is trying to get as close to 25MPG as possible with combined (25%city/75%hwy) driving.

[mugencivic4dr]

I changed my dizzy cap, i was trying to change the fuel filter but it was a b!tch to get off so i left it one. it looks like it was recently changed so i should be good. Only thing left to do is change the valve cover gasket and hit up the junkyard to find a clean/replaced tranny ecu.

this last fill up i did 23.6 mpg, only thing i've noticed that i did different was driving 70-75 mph versus my normal 65 mph when i drive to work. Hopefully with this last fill up i'll improve a bit from my previous 24.4 that i didnt post.

[toycar]

Hey guys, skimmed through the thread and wanted to offer a few things;




-The added air flow of a turbo doesn't always equate to less gas mileage. Assuming the added turbo warranted a tune, you could get better mileage if tuned correctly and you kept your foot out of it. The engine works less to move more air. So, since the engine is working less it is doing what exactly? What exactly does "Work less" mean? Less RPM's for same flow. And for every revoloution of the crank(RPM) the injector(s) fire. So, less RPM's while adding airflow CAN equate to better MPG's.


Just wanted to point that out.





-Since the F22a registers air flow via a map sensor, a larger plenum/intake will actually lean out the tune. Why? Because the MAP sensor detects pressure. The pressure is found using an assumed overall volume in the manifold. The total volume that was present in the OEM manifold has been altered. The given value/total volume of the manifold is NOT updated in the ecu, so when it sees a given pressure the ECU makes a false assumption based on the original input. If the manifold has a larger volume capacity, than it takes more air to generate the same pressure. You guys follow?



So, actually a larger manifold CAN increase gas MPG's without a tune because it will flow more air at the same pressure as the previous manifold, and the pressure is how the ECU determines how much fuel to supply. Well, one of many things but you get the point. The MAP(Manifold absoloute pressure) sensor detects pressure, not flow. It assumes air flow, based on the known total air capacity of the manifold and the pressure that the sensor is detecting. Change the capacity of the manifold, and the "known" is no longer accurate. A larger manifold will take more airflow to generate the same pressure. If the airflow was measured with a MAF (Mass Air Flow) sensor, the extra fuel would be added and you would lose gas mileage. Since the system is pressure orientated, the change would actually lean out the tune providing less fuel for more air since there would be a drop in pressure relevant to the increase in volume capacity in the manifold.

[8ball]

Hey guys, skimmed through the thread and wanted to offer a few things;




-The added air flow of a turbo doesn't always equate to less gas mileage. Assuming the added turbo warranted a tune, you could get better mileage if tuned correctly and you kept your foot out of it. The engine works less to move more air. So, since the engine is working less it is doing what exactly? What exactly does "Work less" mean? Less RPM's for same flow. And for every revoloution of the crank(RPM) the injector(s) fire. So, less RPM's while adding airflow CAN equate to better MPG's.


Just wanted to point that out.





-Since the F22a registers air flow via a map sensor, a larger plenum/intake will actually lean out the tune. Why? Because the MAP sensor detects pressure. The pressure is found using an assumed overall volume in the manifold. The total volume that was present in the OEM manifold has been altered. The given value/total volume of the manifold is NOT updated in the ecu, so when it sees a given pressure the ECU makes a false assumption based on the original input. If the manifold has a larger volume capacity, than it takes more air to generate the same pressure. You guys follow?



So, actually a larger manifold CAN increase gas MPG's without a tune because it will flow more air at the same pressure as the previous manifold, and the pressure is how the ECU determines how much fuel to supply. Well, one of many things but you get the point. The MAP(Manifold absoloute pressure) sensor detects pressure, not flow. It assumes air flow, based on the known total air capacity of the manifold and the pressure that the sensor is detecting. Change the capacity of the manifold, and the "known" is no longer accurate. A larger manifold will take more airflow to generate the same pressure. If the airflow was measured with a MAF (Mass Air Flow) sensor, the extra fuel would be added and you would lose gas mileage. Since the system is pressure orientated, the change would actually lean out the tune providing less fuel for more air since there would be a drop in pressure relevant to the increase in volume capacity in the manifold.

awesome post

are you saying a larger plenum with turbo or with out turbo increases MPG?

*(i know there is a limit to what size turbo you can use with out dropping mpg I guess one that spools quicker)*

[toycar]

Neither really. I was more commenting on how a turbo can add airflow without sacrificing mpgs, and how manifold capacity effects afr's on a map system.

Until a turbo compressor reaches positive pressure, its assumed that its not doing anything. Actually, more air flows vs natural aspiration regardless of positive pressure. So, the engine breathes more air at lower rpm's as a result which can equate to better mpgs, just like higher compression would do the same.

As an example, Mercedes has been doing this for years. Mercedes is now owned by fiat. Guess what, my wifes fiat is almost 12:1 compression, oem. Gets 46 mpg on the hwy. More airflow with less rpm is what you are trying to accomplish. for every revolution you fire the injector, so moving more air with less cycles is the objective here.


The difference in manifold size and relevance to mpgs is that the ecu determines fuel supply in part off of intake manifold pressure. Since it takes more air to generate the same pressure, the ecu will supply less fuel in accordance with less pressure. The engine won't generate any extra pressure without changing valve timing and compression.
So as a result you will flow more air at a lower pressure in the manifold and less fuel will be supplied, due to less pressure in the manifold.

This will lean out your tune, and yield better mpgs as a result. Just like 12 psi on a huge ass turbo means different flow than 12 psi on a tiny turbo. The fuel delivery measures pressure, and assumes flow. In that assumption, the total capacity of the manifold is directly related to the ecus assumption of air flow.

If you change the manifold, the manifold capacity will change as well. This value is predetermined in the oem tune, so it can measure the pressure in the manifold, multiplied by known capacity of the oem manifold, and determine flow.

You don't change the assumed value of the capacity of the manifold when you swap intake mani's right? So, the ecu reads the pressure, and assumes the previous manifold is in place when actually its not. .5 bar on a tiny manifold is flowing considerably less air than .5 bar on a giant manifold.

Does that make sense? But the ecu assumes the original volume, and so it supplies fuel based in that incorrect assumption. It sees less pressure, because the capacity is larger, so it supplies les fuel thinking you are flowing less air do to less pressure in the manifold.

[jhondayaaj]

Don't know how my old f22a got so good gas mileage, but it just had the f22a4 exhaust manifold, h22 plenum, h22 t body, f22a6 runner with egr ports cleaned up, iceman intake with hks filter, cat back exhaust, pt6 ecu with working IAB, full intirior, 16" racing hart rims, no system, automatic, and best I got on a full tank was around 550 miles with no use of ac. When I did use my ac, I got around 450-475. But this was with no hard driving either. Keep in mind, the engine was the original engine with around 400k. Then I got happy and put bisimoto parts on it and my foot got heavy and blew the engine.

All in all, I truly believe that it depends on how healthy your engine is. And all ignition conponents were factory parts. 87 octane with chevron gas. Even with the bisimoto parts and stand alone, I got around 425-450 to the tank fully tuned. I know my post didn't help much, but that's my experience.

Off topic, now I drive a toyota t100 4x4 v6 with a supercharger tuned and I get shitty ass mileage. Lol.

[8ball]

I recently just pulled 35mpg driving hella slow and conservative in 2/3 high way 1/3 city. I dont have the PS or AC belt installed

[mugencivic4dr]

toycar, thanx for explaining a bit on those subjects

Don't know how my old f22a got so good gas mileage, but it just had the f22a4 exhaust manifold, h22 plenum, h22 t body, f22a6 runner with egr ports cleaned up, iceman intake with hks filter, cat back exhaust, pt6 ecu with working IAB, full intirior, 16" racing hart rims, no system, automatic, and best I got on a full tank was around 550 miles with no use of ac. When I did use my ac, I got around 450-475. But this was with no hard driving either. Keep in mind, the engine was the original engine with around 400k. Then I got happy and put bisimoto parts on it and my foot got heavy and blew the engine.

All in all, I truly believe that it depends on how healthy your engine is. And all ignition conponents were factory parts. 87 octane with chevron gas. Even with the bisimoto parts and stand alone, I got around 425-450 to the tank fully tuned. I know my post didn't help much, but that's my experience.

i have an auto that is completely stock, so far i average about 340- 360 on a full tank which is about 25mpg's. i'm trying to pull more out of my 300K motor lol. You were getting about 28-31mpg, if that was straight hwy its doable but if it was combined then that's really good. That's what I want to do consecutively

I recently just pulled 35mpg driving hella slow and conservative in 2/3 high way 1/3 city. I dont have the PS or AC belt installed

you must have a 5spd with those numbers, i wish my CB was a 5spd because i would def be able pull numbers like that

[mugencivic4dr]

my mpg's went up to 25.5 after the dizzy cap swap. my current combined goal has been met, next combined (city 30%/hwy 70%) goal is 26mpg's. hopefully after i change the valve cover gasket and tranny ecu i'll get closer to it.

after i change those 2 things i'll start working on the cosmetics that i believe will help me increase my mpg's and meet my over all combined goal

[mugencivic4dr]

i purchased the tranny ecu from the junkyard yesterday, car shifts a lot smoother and overdrive stays on. hopefully this will let get consistant mpg's, its been going up and down. Best i've gotten was 25.5 which i only got once.

i also bought a legend lip from the junkyard as well, this is the first for the cosmetic mods that i personally believe will help with my MPG goal. after installation i will explain why i believe it'll help, i'm sure some of you are wondering how that'll help my MPG's