I guess now is a good time...

[RobertISaar]

to introduce myself.

i'm not certain what parts of this will be interesting and what won't but take it for what you will.

by trade, i'm a machinist, though i've pretty much been out of that field of work since ~2009 or so due to the massive economic slowdown that occurred. since then, i've been studying a lot of different areas that interest me, usually funding my projects and efforts with automotive mechanic work that occasionally comes around.

anyways, sometime in 2010, i got interested in two somewhat similar fields: electrical engineering and programming. now, when i say electrical engineering, i basically mean reverse engineering what i have to learn how it works and to make it better. and by programming, i mean disassembling automotive calibrations to see what makes them tick and how to improve them as well. i'd like to think i'm well known in the GM OBD1 tuning community, i'm starting to transition into the OBD2 game as well if only to speed up the development of open source/free/cheaper tuning tools like the OBD1 community has.

with OBD1, i haven't done just simple calibration like most people ever get into, i tend to patch in sections of code to add in neat things that the factory never intended on being possible, like additional rev limiters based on clutch/brake status, additional spark advance added when the engine enters highway fuel(you guys seem to call it lean burn) mode to account for the slower combustion speed of AFRs leaner than stoich, etc... i'm VERY fluent with stuff like the Motorola 68HC11 and am working on the Motorola 68000 series currently, though the Arduino language looks like it will be a very friendly environment to work with when i get to needing to use it.

anyways, i'm here for two reasons, to share my knowledge and experience where i can, and to learn from others where i have not to improve my own vehicles further.



that being said.... there's only so much i'm willing to compromise in search for fuel efficiency. i can't make my vehicles into purpose-built economy machines that don't have room for the cargo/passengers i need to carry. stuff like that. so i essentially look for vehicles that have a solid base upon which to improve.

i also can't modify certain driving habits either.... driving under the speed limit CANNOT happen, i seem to be the ~5% around here that actually obey the speed limit and still almost have been run down by the idiot drivers around here. i don't mind modifying how i accelerate or decelerate since most people seem to notice when those events are happening(though there have been exceptions ).

i'd like to think i do well with driving route already, though until recently i accelerated at a slower pace than what a lot of members here have implied to be optimal(something like ~80% load, which BTW, what is "load" based off of, vacuum?). according to my fuelly logs, with my 1995 monte carlo, i've averaged 29.5MPG over the past 4,400 miles. my wife tends to do at least bit worse(~27MPG average) for some reason or another(either route or driving style), which brings me to another requirement: if my wife isn't willing to accept a change, then i don't really see it being an effective modification, since she drives this particular vehicle nearly as much as i do.





anyways, i think that's long enough for a general intro. i guess i'd like to hear some suggestions, should anybody feel there is something i'm missing. i've checked out the vehicle modifications and behavior pages, when it comes to driving style, there is very little i do not already do, and the ones that are left are ones i'm not willing to deal with(pulse/glide and EOC). the vehicle modifications.... that's where i think i'll find my largest gains, since they are things will constantly be in effect and not require much if any driver interaction.

so, does anybody have any suggestions on where to start?

[MetroMPG]

Hi - welcome to the forum!

Sounds like you've got a lot of knowledge.

For instance...

Originally Posted by RobertISaar

when the engine enters highway fuel(you guys seem to call it lean burn) mode to account for the slower combustion speed of AFRs leaner than stoich

I'm curious to know more about this 'highway fuel mode'. (Which cars, how far from stoich / 14.7:1 ?)

The lean burn you see talked about typically here is the Honda stuff, where ratios go quite far away from stoichiometric - e.g. the 1st generation Insight goes as far as 23 to 1 aided by swirl in the cylinder induced by leaving one intake valve closed under light load. (Not sure on the ratios available in the Civic HX & VX models). When lean burn kicks in on the Insight, MPG goes up ~25 mpg.

i accelerated at a slower pace than what a lot of members here have implied to be optimal (something like ~80% load, which BTW, what is "load" based off of, vacuum?).

FYI, that only works if you can also control RPM (manual transmission) to keep engine speed relatively low while under relatively high load. (It also only works if you NEVER have to brake or otherwise slow down soon after a high load/low RPM acceleration event, otherwise you just tossed more fuel out the tailpipe than a slower acceleration event would have burned.)

so, does anybody have any suggestions on where to start?

I always start by recommending instant MPG instrumentation. Your car's entry says "custom" there. Vac gauge? Anything else? Ideally you want a resettable MPG gauge so you can start playing the game. (High score on typically repeated routes, and also potentially for testing mods.)

Aside from that, given where you live (Michigan), and the time of year we're sliding towards, I'd start looking into mods that address winter conditions like a partial grille block (also helps reduce aero drag); block heater. If you spend most of your time above 40 mph, focus on the aero mods for sure.

[RobertISaar]

Originally Posted by MetroMPG

I'm curious to know more about this 'highway fuel mode'. (Which cars, how far from stoich / 14.7:1 ?)

it isn't enabled in a factory calibration, but the code exists to do so and requires setting only a single option to enable it. the code currently exists to allow up to a 25.5:1 AFR, though it could be modified to a higher range if needed. factory calibrations actually have the target AFR set to 15.4:1, but since it won't enter it due to the option not being set, it never happens. set the option, and when in low load(adjustable, though i usually have it disabled when hitting ~80kPa or higher) and at a high enough speed(also adjustable, i like the ~50MPH range to enter, drops out under 45), the PCM goes into open loop fueling and ignores the O2 sensor until highway fuel mode is exited, upon which closed loop fueling resumes. even after very extended periods in highway fuel, the O2 sensor seems to come alive pretty much instantly(starts switching), so no delay when going from lean cruise to closed loop has been necessary for me. i tend to run a 16.2:1 AFR since it's about as lean as i can go before i feel it's too close to a lean misfire.

Originally Posted by MetroMPG

The lean burn you see talked about typically here is the Honda stuff, where ratios go quite far away from stoichiometric - e.g. the 1st generation Insight goes as far as 23 to 1 aided by swirl in the cylinder induced by leaving one intake valve closed under light load. (Not sure on the ratios available in the Civic HX & VX models). When lean burn kicks in on the Insight, MPG goes up ~25 mpg.

i know with my engine, there is no possible way for me to get anywhere near that kind of ratio, once above ~17:1, it will lean misfire consistently. i guess when the engine is built to do so, some wonderful efficiency benefits can be realized.

Originally Posted by MetroMPG

FYI, that only works if you can also control RPM (manual transmission) to keep engine speed relatively low while under relatively high load. (It also only works if you NEVER have to brake or otherwise slow down soon after a high load/low RPM acceleration event, otherwise you just tossed more fuel out the tailpipe than a slower acceleration event would have burned.)

i can do this to some degree.... i've messed with TCC lockup points considerably since the factory settings were made more for smoothness than efficiency, now the TCC will lock as low as 28MPH in 3rd gear and will stay locked through the shift to 4th gear at as low as 43MPH. i may have to impliment the ability to lock the TCC in 2nd gear normally(which the PCM will do anyways if it detects the transmission as overheating) as well, since i may see a benefit there. the factory torque converter is rather loose with a ~2100RPM stall speed, so giving any significant amount of throttle will cause the engine to shoot up to at least that speed. BTW, the factory settings didn't allow the TCC to lock until ~45MPH regardless of gear... with that converter, you could feel the engine just rev but not actually move the car. kind of ridiculous.

i can see why it's not always the answer to briskly accelerate, especially with short and potentially short distances before needing to slow down, it's certainly something you learn to anticipate driving around here.

Originally Posted by MetroMPG

I always start by recommending instant MPG instrumentation. Your car's entry says "custom" there. Vac gauge? Anything else? Ideally you want a resettable MPG gauge so you can start playing the game. (High score on typically repeated routes, and also potentially for testing mods.)

currently, using my laptop while logging to monitor the engine for an instantaneous display. i cannot seem to get an an accurate average fuel economy calculation to work with it though, but the software i'm using to log(tunerpro RT) was never intended to be used for that anyways. depending on how long i plan on keeping the car around, i may use the trip computer from a 94-95 grand prix or a 88-93 cutlass supreme for use as a instant/average MPG estimation. i love the cutlass units due to the blue/green vacuum florescent display.

Originally Posted by MetroMPG

Aside from that, given where you live (Michigan), and the time of year we're sliding towards, I'd start looking into mods that address winter conditions like a partial grille block (also helps reduce aero drag); block heater. If you spend most of your time above 40 mph, focus on the aero mods for sure.

grill blocks and aero mods in general are certainly something i've given a lot of thought to, and in the winter, i could probably get away with blocking the entire air dam area and having the little "grille" slots provide enough cooling.

http://www.theautochannel.com/media/...e_carlo_ls.jpg

not the greatest picture, but it should show enough to get a decent idea. if i had the money to do so, i would likely look into something to actuate a grill block to full open and full closed based on coolant temps, similar to how certain new cars are doing so, and then it could be left on year-round without worry.

i live in nearly the middle of nowhere(on the edge of a population ~500 village), so my trips are about ~5% speeding up and slowing down from 55MPH, ~5% traveling at in-town speeds, and 90% just maintaining that 55MPH speed throughout the hills around here.

[MetroMPG]

Interesting about that lean burn mode! Probably factory disabled for emissions reasons (raised NOX). The 1st gen Insight handles the emissions question with an additional (read: expensive) catalytic converter for handling NOX. At cruise, the car drops out of lean burn every few minutes to purge the stored NOX and catalyzes it with a richer mixture for a few seconds.

90% just maintaining that 55MPH

Definitely aero mods for you, then. As far as getting good MPG, that sounds pretty close to an ideal driving environment. Lots of moderate speed cruising.

And definitely get yourself that resettable MPG gauge. Makes this much more fun than messing with a laptop (unless it lives in the car, permanently mounted!).

As for over-riding the OEM torque converter logic, I'm SURE there are people here who would love to know more about this! We've got one thread here (maybe more) about hacking an auto transmission to electrically take control of the torque converter ( http://ecomodder.com/forum/showthrea...tch-10028.html ), but if it's not hard to do it electronically, that would be another great option.

[MetroMPG]

re:
http://www.theautochannel.com/media/...e_carlo_ls.jpg

Do you happen to know the car's drag coefficient / frontal area?

[RobertISaar]

Originally Posted by MetroMPG

Interesting about that lean burn mode! Probably factory disabled for emissions reasons (raised NOX). The 1st gen Insight handles the emissions question with an additional (read: expensive) catalytic converter for handling NOX. At cruise, the car drops out of lean burn every few minutes to purge the stored NOX and catalyzes it with a richer mixture for a few seconds.

living in a non-emissions testing area(and state entirely, i think).... i don't have to worry about the EPA breathing down my neck about it.

Originally Posted by MetroMPG

Definitely aero mods for you, then. As far as getting good MPG, that sounds pretty close to an ideal driving environment. Lots of moderate speed cruising.

occasionally, i see some 70MPH travel on the highways for long trips and have a ~550 mile round trip coming up VERY soon that i managed to squeeze 37.6MPG out of in a 1990 grand prix a year ago. i'm interested to see what i'll be able to do with this car on roughly the same route, preferably with some kind of improvements done before it happens.

Originally Posted by MetroMPG

As for over-riding the OEM torque converter logic, I'm SURE there are people here who would love to know more about this! We've got one thread here (maybe more) about hacking an auto transmission to electrically take control of the torque converter ( http://ecomodder.com/forum/showthrea...tch-10028.html ), but if it's not hard to do it electronically, that would be another great option.

depending on what level of control someone is looking for, you could use something as simple as an arduino with excellent results, assuming it wouldn't make the main PCM think the transmission is acting odd. some like to calculate TCC slip and other things based on what it assumes the gear the transmission is in, along with TCC status. if it goes outside of a boundry it likes, it can make the engine operate differently as well, shut certain things off or force others on.... i'll reread through that thread, i seem to remember skimming though it before.

Originally Posted by MetroMPG

re:
http://www.theautochannel.com/media/...e_carlo_ls.jpg

Do you happen to know the car's drag coefficient / frontal area?

Vehicle Coefficient of Drag List - EcoModder

according to that, .36 and 22.6, though i could have sworn the LS was a little less aggressive, like .33. the Z34 model got a front bumper with the air dam extending down a little further to catch more air. i'm not running a spoiler either.

[Weather Spotter]

that lean burn mode has my attention, how would i tune my 2006 matrix to get this mode turned on?

I want to hit 100 MPG and emissions can suffer if needed (heck I am using 1/3 of the fuel per mile so i think the ends get a better result).

[RobertISaar]

Originally Posted by Weather Spotter

that lean burn mode has my attention, how would i tune my 2006 matrix to get this mode turned on?

i'm the wrong person to ask.

if it's GM OBD1, ~99% chance i could tell you how to do it, but anything else and i've never messed with it. i'm just now getting into GM OBD2 stuff, so toyota OBD2 is currently way out of my league.

[Weather Spotter]

it should be the same as the Pontiac vibe.

[RobertISaar]

true, but it's also 11 years newer than the newest stuff that i have experience with.