MPG Tooning with ATR

[chuckms6]

Originally Posted by Speed3eak Aerodynamics is something that I think would net better gains than what we're seeing just targeting ~17:1 AFRs. Especially us Genpu-ers with this hood scoop eating up our drag coefficient. I'll bet that front splitter makes a big difference. btw, my last tank was 357.9/11.047=32.397 mpg. It was probably 80/20 highway/city, so the second tank seems to be getting noticeably better gas mileage. Highway was 70 mph, cruise control, no a/c. Still need to make chuck's tweaks so I can get better city mileage. There's no way I'm gonna touch 35 mpg though with the stop and go I see in city driving. As for gearing - while taller gears would be nice, I don't know how much taller I'd like them. I just want to be able to cruise ~75 mph @ 2500-2750 rpm. That IMO would be a good rate to get decent gas mileage and not constantly get passed by mini vans and those high-mileage eco-cars haha.

Speed6killah has diesel gears in his 6 and iirc he is at 2krpm @80mph in 6th. at that rate we could probably get closer to 35mpg at highway speeds, even at 90+mph lol. thatll definitely make this car a highway warrior! a speed 6 would be able to do 500+ miles on a tank at that rate...

i will probably finish the splitter soon so i will see how it helps on the highway. im excited for it, i just have to make some more ducting for my heat exchanger and radiator.

[Wicked]

Oddly, I think I get better city mileage than highway lol.

[chuckms6]

Originally Posted by Wicked Oddly, I think I get better city mileage than highway lol.

i do by about 5-10 mpg. it has to do with rpms, engine loads, and aerodynamics at highway speeds.

[Wicked]

Originally Posted by chuckms6 i do by about 5-10 mpg. it has to do with rpms, engine loads, and aerodynamics at highway speeds.

Agreed, it's just opposite to my observations with previous cars. Which is good, as I city commute 90% of the time

[snailD]

im doing the trip from mass to utah right now. i drove from ut to ma on a typical non gas mileage tune, and the car computer said 29.3. so far on the drive back out the car computer says 32.2. this is between 65-77 mph, windows slightly rolled down, no a/c, 85-102 degrees. the egr is still activated and valves are prob fucked at 45k miles. and typically there is more wind during to utah than going to mass. here is a cool site showing wind close to real time in the us. Wind Map

[Vansquish]

Originally Posted by chuckms6 i do by about 5-10 mpg. it has to do with rpms, engine loads, and aerodynamics at highway speeds.

That blows my mind. I get about 10mpg worse gas mileage in the city than on the highway.

[chuckms6]

Originally Posted by Vansquish That blows my mind. I get about 10mpg worse gas mileage in the city than on the highway.

Well in the city I never get into boost or go above 2k rpm, and I downshift and coast to lights. I guess its mostly my driving style lol

Tapatalking

[Vansquish]

If you're over 30mpg in the city though, that's still damn impressive. I rarely get into boost or go above 2k-2.5k in the city either. I tend to downshift/coast a fair bit as well. Somehow, I can barely ever get above 22-23mpg city. I suspect it has something to do with the roads you're on too. For me it's pretty hilly getting from home to school and work, so I've got pretty heavy load at low RPM.

[chuckms6]

Originally Posted by Vansquish If you're over 30mpg in the city though, that's still damn impressive. I rarely get into boost or go above 2k-2.5k in the city either. I tend to downshift/coast a fair bit as well. Somehow, I can barely ever get above 22-23mpg city. I suspect it has something to do with the roads you're on too. For me it's pretty hilly getting from home to school and work, so I've got pretty heavy load at low RPM.

thats probably it then, the area i live in has a altitude variance of like 100ft lol. when i was in Tallahassee last weekend i kept it around 2500-3k rpms on hills but it still killed my mileage.

[f-castrillo]

I'm getting a tad bit worse MPGs with my latest revisions (AFR cleanup, ign advanced 1*). I got 22.9 MPG this tank. It's hard to put the blame on the revisions right now though, as a lot of this tank was spent driving in high humidity 90-100F weather, AC blasting, me going WOT more frequently (I enjoy watching the BATs drop from meth lol), driving more aggressively overall than before, and getting stuck in stop and go traffic for several of my highway trips.

When I was getting awesome MPGs, summer hadn't kicked in full time yet, so I was able to get away with having the AC off and I drove rather lazily for whatever reason.

I'm going to give it a few more tanks and attempt to drive like I was doing a few months ago to rule out my tune. Maybe it's related to my area's summer gas blend, my driving habits, or both.

[f-castrillo]

Something is dragging my MPGs down. I suspect it has to do with the AFR and ign advance adjustments. Maybe there's a rogue cell somewhere that has some off the wall value that I missed. Or maybe it's a combination of the increase in city driving + the thicker Rotella T6 oil...

I've been carpooling to work the last few days, but will be driving tomorrow, so I will have a chance to log during the cruise. Curious to see if my MAF cal is still good after this latest revision. I don't see why it wouldn't be, but it doesn't shirt to check.

-- Sent from my Jellybean Galaxy Nexus

[snailD]

so on my whole trip i ended up with 31.6 mpg on the carputer, i hit some strong headwinds for a day and a half. overall i am more than happy with the revisions, my car was packed FULL, im on stock springs and the car looked like it was on eibachs. so there was alot of extra weight playing a factor. now that i'm in utah and my car is empty im seeing 35 on the highway for an average (took a small 1 hour drive and reset trip beforehand).

BUT, has anyone experienced fouling of plugs? i did practically drive 2500 miles on almost a constant 17:1. i'm in knock city right now, so im hoping they are just toast, i planned on ordering a new set anyways. going to pull them tomorrow...

[chuckms6]

Originally Posted by snailD so on my whole trip i ended up with 31.6 mpg on the carputer, i hit some strong headwinds for a day and a half. overall i am more than happy with the revisions, my car was packed FULL, im on stock springs and the car looked like it was on eibachs. so there was alot of extra weight playing a factor. now that i'm in utah and my car is empty im seeing 35 on the highway for an average (took a small 1 hour drive and reset trip beforehand). BUT, has anyone experienced fouling of plugs? i did practically drive 2500 miles on almost a constant 17:1. i'm in knock city right now, so im hoping they are just toast, i planned on ordering a new set anyways. going to pull them tomorrow...

i checked mine not too long ago, they looked fine to me, just a little more gap.

what do you consider highway speeds? regardless thats excellent gas mileage, way better than me on the highway. you probably saved an entire tank or two on your trip!

[snailD]

Originally Posted by chuckms6 i checked mine not too long ago, they looked fine to me, just a little more gap. what do you consider highway speeds? regardless thats excellent gas mileage, way better than me on the highway. you probably saved an entire tank or two on your trip!

well i would hope i'm getting alot better than you, im fwd not awd remember... on the other hand you look like your getting rediculously good mileage for the ms6.

my highway speeds are usually 73mph. fast enough but usually slow enough to not get in trouble. on the trip tho it ranged between 55-80, 45mph work zones to 75mph highway streches

[Speed3eak]

I don't want to be a grammar/spelling nazi, but . . .

ridiculous =/= rediculous

The difference between the two, is that one is a word.

Yes, I know I'm a dick. I'm sorry.

[f-castrillo]

chuckms6 bnoon snailD and anyone else in this thread:

in what ranges have you been advancing your timing? idle, light accel (500-1500 RPM), cruise (1500-3500), or all of the above? I've advanced my idle and light accel range by .5*, and cruise range an extra degree. But I've been hearing more grumble from my exhaust note from dead stop to normal acceleration. I might just be hearing things. But, that combined with my unusually bad gas mileage (it's back to stock, and takes a ridiculously light foot to get the same mileage that I used to get until recent) seems to indicate that advancing timing during the light accel range isn't such a good idea.

Part of my last map revision also included leaning out the fueling targets in the 1500 RPM column from 16:1 to 17:1. I suppose the leaner 1500 RPM AF target + .5* advanced timing could be the culprit. I may try reverting my idle/accel area to the previous values to see if that does anything.

Also, have your guys' ECU been holding to commanded ignition values? I took a log on the way to work last night, and I'm finding the ECU isn't always hitting commanded values during steady cruise. Actually it's targeting values far more advanced than commanded, and far more advanced than my Max A/B tables. See screencap below:

logged spark vs ign Max A cruise.png

Note the highlighted row in the log, and compare it to the highlighted cell in the Max table in the background (for reference, my commanded tables are ~1-2* lower than the Max A/B tables).

This tells me the ECU is doing whatever the hell it wants as far as closed loop timing goes, and that most of our tuning should be focused on finding the optimal AFR for cruising. I know the Ign vs ECT comp tables were brought up early on in the thread, as some were experiencing logging less timing than commanded, but this is the opposite case here.

[chuckms6]

Originally Posted by f-castrillo chuckms6 bnoon snailD and anyone else in this thread: in what ranges have you been advancing your timing? idle, light accel (500-1500 RPM), cruise (1500-3500), or all of the above? I've advanced my idle and light accel range by .5*, and cruise range an extra degree. But I've been hearing more grumble from my exhaust note from dead stop to normal acceleration. I might just be hearing things. But, that combined with my unusually bad gas mileage (it's back to stock, and takes a ridiculously light foot to get the same mileage that I used to get until recent) seems to indicate that advancing timing during the light accel range isn't such a good idea. Part of my last map revision also included leaning out the fueling targets in the 1500 RPM column from 16:1 to 17:1. I suppose the leaner 1500 RPM AF target + .5* advanced timing could be the culprit. I may try reverting my idle/accel area to the previous values to see if that does anything. Also, have your guys' ECU been holding to commanded ignition values? I took a log on the way to work last night, and I'm finding the ECU isn't always hitting commanded values during steady cruise. Actually it's targeting values far more advanced than commanded, and far more advanced than my Max A/B tables. See screencap below: Attachment 72580 Note the highlighted row in the log, and compare it to the highlighted cell in the Max table in the background (for reference, my commanded tables are ~1-2* lower than the Max A/B tables). This tells me the ECU is doing whatever the hell it wants as far as closed loop timing goes, and that most of our tuning should be focused on finding the optimal AFR for cruising. I know the Ign vs ECT comp tables were brought up early on in the thread, as some were experiencing logging less timing than commanded, but this is the opposite case here.

my ignition is advanced from the top left cell to 1.00 load x 3500rpm. the more grumble may be from the increase in airflow the advanced timing may create.

the way i understand timing works on this car, what we have to change as far as closed loop timing targets is more of a base map. while the car is cruising the ecu is constantly trying to advance timing to optimize fuel economy. when it sees knock it falls back to the base map and starts over.

for instance, if youre cruising at a constant speed and you have 35° as your target, your ecu may increase advance to 40°, see knock, then back it off to 35°. if the target is set to 38°, it wont fall back below that, but it will still try to advance from there.

i hope i was clear, and anyone feel free to correct me if i am wrong.

[f-castrillo]

Originally Posted by chuckms6 my ignition is advanced from the top left cell to 1.00 load x 3500rpm. the more grumble may be from the increase in airflow the advanced timing may create. the way i understand timing works on this car, what we have to change as far as closed loop timing targets is more of a base map. while the car is cruising the ecu is constantly trying to advance timing to optimize fuel economy. when it sees knock it falls back to the base map and starts over. for instance, if youre cruising at a constant speed and you have 35° as your target, your ecu may increase advance to 40°, see knock, then back it off to 35°. if the target is set to 38°, it wont fall back below that, but it will still try to advance from there. i hope i was clear, and anyone feel free to correct me if i am wrong.

makes absolute perfect sense, but what gets me is seeing logged timing go beyond the Max A/B tables. I always viewed them as absolute limiters, but maybe there are certain conditions that allow the max tables to be ignored, like APP or TPS less than a certain % or something.

I just realized that I need to raise my Ign global max, as my Max A/B of 61* in the first few rows doesn't matter if the global limiter is set to 60* lol



-- Sent from my Jellybean Galaxy Nexus

[bnoon]

Originally Posted by Vansquish If you're over 30mpg in the city though, that's still damn impressive. I rarely get into boost or go above 2k-2.5k in the city either. I tend to downshift/coast a fair bit as well. Somehow, I can barely ever get above 22-23mpg city. I suspect it has something to do with the roads you're on too. For me it's pretty hilly getting from home to school and work, so I've got pretty heavy load at low RPM.

Never downshift for MPG, always coast. Downshifting does go into decel fuel cutoff but it slows you down so much sooner than coasting that you have to reaccelerate sooner and end up burning more fuel.

[Vansquish]

Originally Posted by bnoon Never downshift for MPG, always coast. Downshifting does go into decel fuel cutoff but it slows you down so much sooner than coasting that you have to reaccelerate sooner and end up burning more fuel.

I'm aware. I merely downshift (read heel & toe/rev-match) for when I'm coming to a stop. I've only just had to replace my brake pads and the front rotors at 95.5k, and I think that's probably part of why.

Otherwise, yes, coasting/maintaining momentum is key to good fuel economy. If I'm not mistaken, I still hold the record on this board for the highest fuel economy for a tank in an MS6, at 37.5mpg, after all.

[snailD]

f-castrillo the ign global max you will not see more than while driving. my car will hit 60º even tho 55º is commanded. chuckms6 nailed it. even still i increased my timing values at the point where 55º falls off, to hold high-mid 40's longer. also decreasing my lean afr's sooner, so it goes to 14.7 up a hill is alot more efficient. my strategy is to make the low load situations rack up the most mileage possible, then run about the same in the mid-high load. this way the car doesn't drive any different and you still see a noticeable mileage increase.

[Speed3eak]

Originally Posted by snailD f-castrillo the ign global max you will not see more than while driving. my car will hit 60º even tho 55º is commanded. chuckms6 nailed it. even still i increased my timing values at the point where 55º falls off, to hold high-mid 40's longer. also decreasing my lean afr's sooner, so it goes to 14.7 up a hill is alot more efficient. my strategy is to make the low load situations rack up the most mileage possible, then run about the same in the mid-high load. this way the car doesn't drive any different and you still see a noticeable mileage increase.

I think I may do this for my next map - fwiw I've been seeing some light KR (~.7) at higher load situations (i.e. going up a hill from a stop, or in 3-4 gear but below 2k).

I have over 1k miles now running 17:1 AFRs with a (shitty) catalytic converter (CNT downpipe) and no problems to report. I've gotten a p101 code, but that has to do with the MAF IIRC. I'm still hitting all fuel targets just fine.

FWIW, highway mileage @ 70 seems to have settled out at 32-33, so on average 3 mpg better than the stoich+timing tune. There are a lot of 5-7%+ grades on the highways I've been driving on, so I can't hit bnoon's number of 35 mpg. I'm sure if I were on a completely flat road, I could cruise 70 mph and net 35 mpg no problem.

City mileage is still about 20-23 mpg on this tune. Have not disconnected EGR yet.

[andrewpiro]

So I've been trying to work on this for the last few weeks, and on my latest revision, have run into a problem. I have no LTFT's, and have been hitting an AFR of ~15.4-15.6 when I am targeting 17. I hit my fueling targets perfectly while the car is just warming up, but as soon as it is up to temps, I can rarely make it go as lean as commanded. Highest I will consistently hit is ~16.5.

Now I have ran into a similar problem regarding no LTFT's on a friends car, but that was due to a bad upstream O2 sensor, and was causing 0 LTFT and 0 STFT, and an AFR of 14.8.

I have STFT, but no LTFT, and won't hit my fuel targets between 0.25 and 0.81 loads. Any ideas?

[ANITIX87]

Hey, guys.

I am going to start looking to mods and tunes relatively soon (the itch is starting to get to me), but I had a question about our fuel pressures, etc.

I've read somewhere that our cars (and other stick-shifts) turn off the fuel injectors when coasting in gear and that, therefore, it is better to use engine-braking since you're literally using NO fuel. However, I've now starting seeing conflicting information. Additionally, I've been monitoring parameters with my Ultra Gauge, and I am still getting 200-600 psi of fuel pressure when coasting (depends on RPM, A/C, etc).

Can you guys, who are the experts on fuel maps and such, confirm whether or not we have fuel injector cut-off when coasting?

TIS

[phate]

The injectors shut off, but pressure should remain.

If you have an AP or dash hawk, you can watch injector pulse width or fuel injection amount - they should read 0 during decel.

[dot584]

And afr goes up to like 29, that's why it saves gas.

Sent from my ADR6300 using Tapatalk 2

[phate]

Originally Posted by dot584 And afr goes up to like 29, that's why it saves gas. Sent from my ADR6300 using Tapatalk 2

That's just a sensor limit, really. No fuel = no ratio, lol.

[Speed3eak]

bnoon phate

I finally found an e85 station nearby; I'll start running mixed my next tank. I was running bnoon's timing tables without too much knock, but there was some on hills in 3rd and above.

Given that e85 gives you more freedom with timing, do you guys think there's a point where a small amount of e85 would allow you to run enough timing to get better gas mileage than just straight 91/93? Or is it always mixed < straight premium (in terms of mileage)?

[ANITIX87]

Originally Posted by phate The injectors shut off, but pressure should remain.

I have an Ultra Gauge, so I can't monitor fuel amounts. I also, apparently, can't monitor native AFR command. What it does allow is "AFR COMMAND RATIO" which I assume is some sort of indicator to how close to the commanded one it is. At full throttle, it drops to 0.75 or so. At cruise it's 1.002, but then it never goes higher than 1.003 when I coast in gear. Any light to shed?

TIS


Tapatalkative.

[f-castrillo]

This is from tonight's drive down to Los Angeles from San Francisco Bay Area. 28.4 MPG, 402 miles. AC was set to 72 for all of the drive. The first 90 or so miles was a mix of work commute and around town driving. Had the tank been dedicated to the trip, 430 miles wouldn't be out of the question I don't think






-- Sent from my Jellybean Galaxy Nexus

[Wicked]

Originally Posted by ANITIX87 I have an Ultra Gauge, so I can't monitor fuel amounts. I also, apparently, can't monitor native AFR command. What it does allow is "AFR COMMAND RATIO" which I assume is some sort of indicator to how close to the commanded one it is. At full throttle, it drops to 0.75 or so. At cruise it's 1.002, but then it never goes higher than 1.003 when I coast in gear. Any light to shed? TIS Tapatalkative.

Google Lamda air to fuel ratio. Cliffnotes at bottom

Essentially, stoich (14.7 in a gasoline fueled motor) = 1.000 in Lambda. So, take 14.7 * .75 and you get your wot a/f ratio. So yes, at cruise/idle you should be 1.000 lambda. Using Lambda is invaluable when mixing E85 with gas. Our native wideband reads lambda, then converts that numeric value to a/f ratio in gasoline by the formula of 14.7 * X where X = the llambda value. Why is this important? Well when you mix E85 with gasoline, it changes stoich. Stoich for E85 (from my past use of E85 in my cobalt) is 10.4 a/fr. This means that as long as the car is reading a lambda value, it can calculate the a/fr, and read it to us regardless of the fuel type. It will, however, display it in gasoline a/fr per the parameters of the cars sensor readout. This is not an issue because .75 lambda is still .75 lambda regardless. I had an awesome autometer wideband in my cobalt that allowed my to display my stoich in what ever ratio I wanted. So my saw 10.4ish at idle and 8.0 at wot, my true E85 a/fr. If you ran straight E85 on the MS3, since you can't change the readout) it will show 14.7 as stoich. Again, not an issue because that is 1.0 Lambda. This is why E85 takes about 30% more fueling to reach same targeted Lambda value.

Cliffnotes:
That 1.00 you see is Lambda. Lambda = diff a/fr depending on selected readout from sensor. Gas stoich = 14.7 = 1.0 Lambda. E85 stoich = 10.4 = 1.0 Lambda. This is why E85 takes about 30% more fueling to reach same targeted Lambda value.

Originally Posted by f-castrillo This is from tonight's drive down to Los Angeles from San Francisco Bay Area. 28.4 MPG, 402 miles. AC was set to 72 for all of the drive. The first 90 or so miles was a mix of work commute and around town driving. Had the tank been dedicated to the trip, 430 miles wouldn't be out of the question I don't think

DAMN! Teach me your ways, I'll send you my tune file lmao. Great job tho. My record per tank is 358 (1 block left is the lowest I've gone)

[ANITIX87]

Originally Posted by Wicked Essentially, stoich (14.7 in a gasoline fueled motor) = 1.000

OK, so far, I follow. But if 1.000 = 14.7 in my car, why isn't it jumping to 2.000 or higher when I coast in gear?

Along similar lines, I found another parameter today called "O2 BANK 1" which reads about .950 at full throttle, 0.750 at idle, and 0.000 when coasting. What is this parameter showing?

TIS

Tapatalkative.

[f-castrillo]

Originally Posted by Wicked DAMN! Teach me your ways, I'll send you my tune file lmao. Great job tho. My record per tank is 358 (1 block left is the lowest I've gone)

lol, I started getting nervous when my last bar disappeared at 390 miles. I'm sure I could've gone farther if I had one less passenger (rolled with 3 last night), and if it wasn't so hot and humid outside (the reason i had the AC the whole time)

[Frequentflyer]

Originally Posted by andrewpiro So I've been trying to work on this for the last few weeks, and on my latest revision, have run into a problem. I have no LTFT's, and have been hitting an AFR of ~15.4-15.6 when I am targeting 17. I hit my fueling targets perfectly while the car is just warming up, but as soon as it is up to temps, I can rarely make it go as lean as commanded. Highest I will consistently hit is ~16.5. Now I have ran into a similar problem regarding no LTFT's on a friends car, but that was due to a bad upstream O2 sensor, and was causing 0 LTFT and 0 STFT, and an AFR of 14.8. I have STFT, but no LTFT, and won't hit my fuel targets between 0.25 and 0.81 loads. Any ideas?

I notice that if you don't put 17.0 from .25 to around .63, it'll run something lower (around 15.5). I was using a map that had a more smoothed AFR as load increased and even though I should have been close to 17.0, it was running near 15.5. Of course, it ran a little better though and wasn't as jerky.

[f-castrillo]

snailD bnoon chuckms6 and whoever frequents this thread:

Have any of you tried reverting to stock fueling tables after several months of running leaner AFRs? I'm lazy to make the switch again - I want to try to merge any changes from the newest OTS v231 into my own map, but not until I get my valve cleaning done in the next month or so. But I've been curious if the better AFRs we've been getting is because of a change in driving style more than the lean AFRs. Something about the wandering AFRs we get during cruise probably means we aren't getting the full effect of running a constantly lean, non-wavering AFR, methinks.

Or I might just be blowing smoke. But this has been a reoccuring thought as of recent. Opinions?

[minger]

Not sure. I might switch back...I'm getting 23-25 around town on a 3 gal e85 mix using the fuelling targets from the first post.


Nearly same MPG now...

[chuckms6]

Originally Posted by f-castrillo snailD bnoon chuckms6 and whoever frequents this thread: Have any of you tried reverting to stock fueling tables after several months of running leaner AFRs? I'm lazy to make the switch again - I want to try to merge any changes from the newest OTS v231 into my own map, but not until I get my valve cleaning done in the next month or so. But I've been curious if the better AFRs we've been getting is because of a change in driving style more than the lean AFRs. Something about the wandering AFRs we get during cruise probably means we aren't getting the full effect of running a constantly lean, non-wavering AFR, methinks. Or I might just be blowing smoke. But this has been a reoccuring thought as of recent. Opinions?

ive never gone back. my driving style didnt change at all either, the only changes were in the tuning

[snailD]

Originally Posted by f-castrillo Or I might just be blowing smoke. But this has been a reoccuring thought as of recent. Opinions?

i stated in a few posts earlier that i had found making anything BUT cruise afr's back to 14.7 had netted me the best driveability AND gain. i had seen no increase in mpgs going up hills or with load at 17:1 so i switched back. so now traveling on the highway, if i hit a hill where load goes up it returns to 14.7. this also rid me of alot of the driveability issues when the motor is still kinda cold and has the hiccups at 17:1. i cant give uyou a specific load because maf cals come into play. but check your cruise load, then add a transition back to 14:7 a cell or 2 down from said load.

basically i have changed my idea from trying to get the best all around mpg, to getting the better mpg out of the best mpg areas, the lower load situations. u hit these cruising on flats, and slight downhills. if u can make these go from 40mpg-60mpg then it will still create a noticable increase in milage.

my 17:1 afr doesnt wander, to answer part of the question. at the loads i tell it to it stays solid

try it out and let me know if you have similar results.

[bnoon]

My MPG's are down to 10-11MPG, not sure why.

[chuckms6]

Originally Posted by bnoon My MPG's are down to 10-11MPG, not sure why.

down to or down by?? getting 1/3rd of your usual fuel economy can only mean a failure of a major component or a fuel leak...