S2E18: We test a lean burn system on our Saturn . Will it get better MPG?

[@Texassince1836]

I ran my carbed V8 at a 16.2:1 (steady state cruise) for a few years using an Innovate wide band to set it. One thing to take into consideration is lean mixes burn slower, so you'll need a few more degrees of spark advance to keep the thermal efficiency up

[@bv3078]

@8D Soundz There is. But with diesel, you don't have control over how much air gets into the engine as the air side is usually wide open. You could change the injector setup so it injects less diesel or put on a turbo to offset the af ratio that way. Diesels usually handle more air pretty well but don't overdo it. It will get very hot.

[@_..-.._..-.._]

@@bv3078 excess air in a diesel cools it off, that’s why old diesels had a hard time warming up at idle where the AFR is probably 40/1

[@detaart]

@@bv3078 That's called your right foot ...

[@detaart]

@8D Soundz Yes, a turbo

[@dantheman1998]

any issues running lean? like engine damage?

[@tiagofigueiredo2529]

Honda had an engine back in the 90´s with the code D15Z6 that ran lean when the "Econo" light showed up on the dash, then, when you put your foot to the floor, the "Econo" light would turn off and the engine would run rich. When running lean, the ECU would disable one intake valve per cylinder creating a vortex in the intake into the cylinder (running on 12 valves), when running rich, the ECU would tell the E-VTEC solenoid to open up the oil passage and the other intake valve would also open (running on 16 valves). There were another Honda engine capable of doing that, the B15B 3 stage VTEC. It worked the same way as the D15Z6 but at higher rpm's, the bigger cams pushed the intake valves further to get more air into the cylinders.

[@evil_me]

From what I've looked into previously about lean-burn you reportedly have to adjust the ignition timing to see any real advantages.

[@Hewitt_himself]

would make sense that it needs something to offset the wasted energy of wasting energy compressing excess oxygen,

[@sumduma55]

Increasing compression and adjusting ignition timing is what I've understood. The Mazda skyactiv X setup also does the injection timing but I think they are reaching almost 30 to 1 ratios and using a spark induced diesel cycle (compression ignition) when this happens. This lean burn series is going to be really interesting. In older carburetor cars, if you ran things too lean for extended periods of time you ended up with hot spots that would damage things inside the cylinder. It looks like selective usage might overcome that.

[@VndNvwYvvSvv]

Insight has an offset crankshaft too.

[@slickyblick]

this is due to the high vacuum in the intake, lowering the compression of the air entering the engine. The loss of compression results in a slower traveling flame front. In order to compensate, you need to advance the ignition timing. This creates a more efficient burn and produces much less emissions.

[@gasolinefumes]

Yes, the Insight will go to around 30° advance in LB.

[@50shadesofbeige88]

This is the type of stuff I think about while drifting off to sleep. As a mechanic turned coder, I'd love to do this type of stuff for a living.

[@mommapanda5736]

To all the very valued viewers of this fantastic channel and primarily to JIMBO OF ROBOT CANTINA ..It's December and the Holiday season is upon us, with celebrations like Christmas, Hanukkah, Kwanzaa, Mid-winter or Yule, and New Year all approaching. Wishing you a joyous Holiday season and a happy and peaceful New Year. Thank you for a fun ride.

[@Fk8td]

There are plenty of reasons just leaning out the car like this won’t increase mpg. The flame front length of burn is too short to create downward force on the piston, complete fuel burn and good torque efficiency. Being lean can create unburned pockets of fuel because certain areas within the cylinder don’t fully ignite. The combustion chamber needs to be designed for lean burning. The change in air velocity due to more throttle input has an effect on fuel mixture inside the combustion chamber. Running lean requires more throttle input which means a different map sensor reading. Less vacuum puts the car in a different spot in the ignition tables which is always going to be less ignition timing cause the ecu sees it as higher load. Running leaner could also require different ignition timing in order to get a complete burn. You have would have to recalibrate the ignition timing tables to be the same in order to actually verify a lean burn would even work in the first place. I’ve been a diagnostic tech a lot of years and I’m also a high performance tuner. I’ve had plenty of cars actually get better mpg on a slightly richer mixture after tuning. Some better than stock mpg. You have to take into account all these variables during a test like this. Your 47 mpg isn’t unrealistic at 55mph because they are rated at a high speed for their mpg and seeing 40mph on manual single cam Saturns with power steering and ac are common. You removed power steering and ac. Regardless of the fact ac free spins it’s still going to improve mpg removing it.

[@ocdman202]

Thank you for this well articulated and well thought through response... There so many smart comments on this channel.

[@AustinPerdue]

I had a Honda K24 running around 18:1 for a few years without issue. I averaged mid 40's mpg, with my best tank being in the 60's - though that was an outlier and might have been pump error. With careful driving, mid 50's was possible. This was a high revving ~230whp engine. Ended up needing 6-8 degrees of extra ignition advance in the window I had it leaned out. Honda was putting lean burn electronics in as far back as 1992, as far as I know. The VX trim of the 5th gen had it. For what it's worth, the Scangauge will not show a fuel economy improvement, because it doesn't take air fuel ratio into account.

[@SNH1305]

bro, this type of video is magnificent, you show all the action without hyperbolic reaction, been looking everywhere.

[@hattyfarbuckle]

Now 80.4k subscribers 🎉... Although in the spirit of nerdy accuracy 80,400 divided by 1024 (1k) = 78.515625k. Great experiment as ever and sticking with the "for dummies" section means i now understand broadband/ narrow band much better

[@felixaudet5860]

Water vapor / water mist takes care of the NOx emissions, increases power and reduce the risk of engine damage due to overheating, that's is a common problem with lean burn. Water mist will also trick the O2 sensor into thinking the mixture is too rich, because O2 sensors can't tell the difference between unburnt hydrocarbon and water vapor in the exhaust. So the ECU will natually lean out the mixture without tweaking the sensors. An easy way to get water vapor is to use engine vacuum and engine heat. If you don't add another fuel, it's hard to get better than stock efficiency by just substracting fuel. Or at least using another way to deliver that fuel, such as gasoline vapor. One way that would make a viable daily driver would be to lean out stock injection and add gasoline vapors as a booster.

[@eugennomatterr7311]

producing nitric-acid in the process

[@ultimatecleveland]

@@eugennomatterr7311 All you need is about one or two cc's of water per minute to make a difference. Just look up how much water is already in the air.

[@eugennomatterr7311]

@@ultimatecleveland millions of cars spraying acid for fuel economy just what we need now. We already dumbed down generation of people using leaded fuel,. Look for tu 160 bomber take off videos, just a bit of acid rains after.

[@taylorsutherland6973]

Aside from the heinous planet vehicles produced by GM in the 90s, this channel is fantastic. Questionable jungle site chicom made stuff too! Fantastically applied sarcasm is great!

[@Kohoso95]

We've been waiting weeks, you know we're up to it!

[@mommapanda5736]

I love hanging out with friends and family, going to the beach or just being a couch potato and binge watching TV shows or watching a good movie.

[@mommapanda5736]

I usually watch a lot of ROBOT CANTINA I even binge watch on the weekend.

[@kansasrose2909]

@@mommapanda5736 CONGRATULATIONS JIMBO..105k subscribers!!👍👍 ROBOT CANTINA is providing the fun and educational content that viewers enjoy! Let's keep that number rolling on up! THANKS TO YOU JIMBO!~

[@ocdman202]

@@kansasrose2909 Gratitude unlocks the fullness of life. It turns what we have into enough, and more. It turns denial into acceptance, chaos to order, confusion to clarity. It can turn a meal into a feast, a house into a home, a stranger into a friend. Gratitude makes sense of our past, brings peace for today and creates a vision for tomorrow..

[@kevin9c1]

Having experimented with lean burn I can tell you that you will need to add quite a bit of spark advance because the lean mixture takes a while to get lit off and burn. Without doing so engine response will be extremely soft and you just won't get the efficiency gains that are possible. Also, finding the optimal AFR can be tricky but you probably want to be in the 17-18 range. Exhaust gas temps drop as you move past the ~16 range. Finally, I suspect that lean burn works best at lighter engine loads. So this could work well with a lawn mower carb (which can't load the engine fully) but would NOT really be compatible with cylinder deactivation. What I also recall is that I gave up fooling around with switching O2 offsets and just ended up in open loop mode so I could directly command an AFR. With the engine all tuned in (i.e. VE) this works well but you lose feedback control obviously. It is possible that HP Tuners (for example) offers a way to tune the stock Saturn ECM which would allow this experiment to be a little easier I think, plus you can control spark advance at the lighter loads where you intend to do lean burn. With the lawn mower carb you already have an air bleed solution from Thunderhead289. That is a standalone solution with WB feedback control, but you would still need to play with ignition timing. Looks like both HP Tuners and EFI Live do NOT support Saturns earlier than 2000. Other fun fact: GM had some factory lean burn applications in the 80s/90s on certain vehicle applications.

[@tkmad7470]

Totally agree. Timing is a big part of combustion efficiency.

[@kevin9c1]

@@tkmad7470 With his skills I bet he could intercept the ignition module and add a spark advance offset (engine RPM is a required input), but simply dialing a knob for a constant offset is not really the best approach. BUT it could help gather valuable data which we like.

[@EricErnst]

I agree that adding timing should help. I'm not sure how to trick the computer into adding timing, however. I'm using the stock fuel injection system in my 1992 Chevrolet C1500 pickup to get pretty good mileage. I got a modified ecm so that I can tune the engine's computer with my laptop. I added anywhere between 4⁰-22⁰ of timing throughout the spark advance tables. I spent a lot of time tuning the spark tables to ensure that the knock sensor stays quiet and happy. The changes in the tables don't take much time, and it only takes a few seconds to flash the changes to the ecm. If I see knock, I'd pull over and pull timing and reflash the ecm. I'm using 87 octane gas. I'm also running an Innovate Motorsports LC-2 wideband O2 sensor like the one he unboxes in the video. The only modifications I've made to the physical engine is the exhaust. I also installed an aftermarket 2000rpm torque converter. I should have paid a little more and gotten a stock replacement converter. It is too loose for in-town driving and my gas mileage suffers. When the torque converter clutch is locked and I've got the cruise control set to 55, the instantaneous mileage is in the 28-30mpg range. I have the clutch set to lock at 45mph but you need to pass 45mph until it locks and then slow down a couple mph to consistently lock the TCC with cruise on. The truck has 267k miles and is a great daily driver. It enters Lean Burn mode when the engine coolant is up to around 190⁰F. I had previously installed a 180⁰ thermostat and the computer would never trigger lean burn. So I installed a 195⁰ thermostat with a 1/16" hole drilled in it. The hole allows air bubbles to pass through and a small amount of coolant. Certainly not enough to overcool the 5.7L 350cid engine.

[@kevin9c1]

@@EricErnst Cool stuff. I started almost 20 years ago tuning my 93 Caprice 9C1. That car did have a factory lean burn mode. The strategy was that it required pretty steady highway driving and would still bump out of lean burn to check fuel trims. That car lost a cat (disintegrated and clogged the exhaust flow) and research revealed that lean burn may not be too friendly to cats. So I never really fooled with it again on the Caprice. But I did try some lean burn on my 95 Cadillac Fleetwood w/ LT1. That was the car that required open loop and ultimately I put it all back to stock but the experiment was cool. I would say my big tuning resume item was on my father in law's 1983 C10. Originally shipped with the 250 I6 and 3 on the tree. He slowly evolved it. There was a point where it had a 292 and a 4 speed floor shift. He converted to TBI (from a 1992 G20) and I tuned it for him. Then he put the 700R4 from the van in and I tuned again. Finally, he added a turbo/intercooler and I tuned that with EBL. EBL is amazing btw. Take a look (unless you are already using it).

[@chelee6302]

Would've just use the speeduino to control fuel & spark, make it easier

[@kansasrose2909]

A teacher is a person who helps you solve problems you would never have without them.

[@ocdman202]

Gratitude unlocks the fullness of life. It turns what we have into enough, and more. It turns denial into acceptance, chaos to order, confusion to clarity. It can turn a meal into a feast, a house into a home, a stranger into a friend. Gratitude makes sense of our past, brings peace for today and creates a vision for tomorrow..

[@Rookys]

Hey Jimbo, the Arduino has an integrated map() function which should easily map the signal from wideband to narrowband :) Just approximate values after ADC wit 0V=0 and 5V as 1024: Narrowband signal is ~0.95V or 194 ADC for

[@brettjasonheadinventor]

Regarding comments about advancing timing this is my thought. Fuel has very little time to combust and release its energy. The pressure created from the combustion of the fuel/air mixture should be at its greatest close to 15 degrees after top dead center. If the fuel is slow to combust fully at that point potential energy is lost. Meaning the pressure from combustion isn't delivering full potential on the power stroke, resulting in loss of power and higher fuel consumption. On the other hand, if the fuel was ignited earlier by over advancing the timing of the ignition spark, peak energy release would occur too early and possibly occur before the piston reached top dead centre. Therefore, fighting against the power stroke, therefore, reducing the power and increasing the fuel consumption.

[@ouch1011]

Lean-burn is part of the reason why Hondas of the 80s and early 90s could get 50mpg with a carburetor. It doesn’t really exist anymore of NOx emissions skyrocketing when engines run lean and regulators are much more concerned about emissions than fuel economy. On the Insight (as well as a handful of other vehicles) they would use a NOx absorption catalyst, something kind of similar in concept to the DPF on a diesel. In lean burn, the NOx absorption catalyst would “store” the NOx. The problem is that in order to clean or purge the catalyst, they would have to run the engine slightly rich. The catalyst would then process the incoming CO (from the rich mixture) with the stored NOx (from the previously lean mixture) to output nitrogen, oxygen and CO2. Needless to say, the lean burn time was limited and the effectiveness was reduced. Older cars (back when we didn’t care as much about NOx, primarily due to our ignorance about its negative effects) cars could run for much longer in lean burn, and that, combined with the fact that it used to be common for eco boxes to make substantially less than 100hp and the fact that crash safety wasn’t even remotely a concern (so vehicles could get away with weighing about the same as a pile of feathers), cars from the 80s could get 50 or more MPG easily.

[@micheldemers8893]

I think over on LegitStreetCars, he remapped the ecu on a manual Corvette so when it was in 6th gear going 65 mpg, it was running lean and getting 40 mpg. Like everyone has said, maybe more advance in timing could be the trick to better numbers. Keep up the great work!

[@smokenchoken1736]

His lean burn kicks in at low load 6th gear 55-70 mph and avg 40-42 mpg hwy and when he mashes the go pedal he still has 420+ RWHP on tap for Corvette reasons lol

[@punker4Real]

Yeah but you need to run 91 or higher other wise you will run the risk of blowing the engine

[@rydplrs71]

This episode is a whole new level of complex. Great job. I had to run my sl2 with no ac. It sucked to much power for even moderate hills, and caused overheating when stopped. 4-70 was the only plan to stay cool and keep going. 4windows down, 70mph If you’re going to turn the mirror to prevent identifying the follow vehicle I would add a backup camera and hide the monitor. I have $40 jungle site in both of my trucks. It makes the rack body drivable, and makes it so I can actually get attached to my trailer. On the other truck it just makes hooking up the trailer an easy one shot deal.

[@j.m.5995]

Your Radiator and Condenser must of have been clogged with dirt and debris

[@lasskinn474]

@@j.m.5995 or bearings. more likely something up with the compressor really.

[@hunterm9]

This channel is so cool, really helps to understand complex modern engines by doing things like this on a slightly simpler engine. I want more insight projects though!

[@All2Skitzd]

There used to be a magazine website from Australia that would mod that car for better economy that had a lot of great information but I can't find it now

[@southerndiy1]

autospeed? my first comment was removed

[@All2Skitzd]

@@southerndiy1 yeah that's it, thank you

[@ka24det]

Back in my Mazda tuning days, AEM had a piggback called AEM F/IC. It had this narrowband-signal-modifying much like what you made. Handy.

[@gregholloway2656]

Great video, Jimbo! Thanks for all the detail. I’ve been using an Innovate wide band sensor on my truck for the last 12 years, and it still works great. As for the fuel economy run, I’m thinking you need a calibrated fuel cell, with a reserve. Run 4 gallons, or whatever, thru the engine and when it quits, note the miles covered. Then switch to reserve to get home. 👍

[@willclark491]

Yes!! Science is about the results! Of course, finding something unexpected can and does mean validating your experiment before making a declaration. I love that you're doing it right. (Well as right as possible; you don't have a hundred-million-dollar laboratory after all.)

[@wealthyblackman2655]

Just "tuning in" to this channel AND it's awesome

[@revotuners]

Thank you for all your time on your amazing videos! I love watching them. If you were curious, lean-burn is actually something used on a lot of Australian vehicles afaik (to reduce fuel consumption, but in return increase emissions). Because of this, GM implemented lean-burn on the 99-06 LS (in Silverado trucks, GMC, Tahoes Express Vans and more) I've tinkered with for a long time. They have implementations for reducing the commanded fuel (14.7 -> 16.2) and increasing spark advance anywhere from 1* to 5*. It's cool to see you came up with your own way of implementing it in a completely harmless way.

[@JoseSilveira-newhandleforYT]

Crazy interesting project 🙂 Apart from the Arduino segment, the automotive part is completely out of my background, but I thoroughly enjoyed it. As always, another pleasant episode.

[@ElectronikHeart]

Thank you for all your work! This channel is an absolute treasure!

[@mommapanda5736]

To all the very valued viewers of this fantastic channel and primarily to JIMBO OF ROBOT CANTINA ..It's December and the Holiday season is upon us, with celebrations like Christmas, Hanukkah, Kwanzaa, Mid-winter or Yule, and New Year all approaching. Wishing you a joyous Holiday season and a happy and peaceful New Year. Thank you for a fun ride.

[@kansasrose2909]

Nevada: Valley of Fire Road It doesn't have the most inviting name, but the Valley of Fire Road is 23.3 miles of desert bliss. Surrounded by bright red Aztec sandstone formations, this bumpy roadway winds through the Valley of Fire State Park, Nevada’s oldest state park. Hollywood is a big fan of this desert valley-in fact, it was here that Captain Kirk fell to his death.

[@carterlee8344]

Amazing video(smart guy)and smart commenters. Many are noting the need for much more advance. There is a certain point that maximum cylinder pressure needs to be exerted-the sweet spot. My research says 32 feet per second is the flame progression of the combustion of gasoline. Certainly variables come into play such as compression. Not messing with the timing to early ignite the mixture misses the point of the experiment entirely. It’s not apples to apples. Take into consideration that the entire environment is changed with the leaner mixture’s combustion event. Earlier ignition is what you will use to match the pressure peaks between the different setups to be all in by 14 degrees ATDC. You will need a table for various Air Fuel Ratios to set the all important ignition advance. I love your channel!

[@dongordon2754]

Thanks Jimbo!

[@martienthestar]

I too read somewhere that the correcg way to run a leanburn system was with a few more degrees of ignition advancement, because of something like a slower flamefront/burnspeed

[@millerfab1320]

Possibly when filling up at the pump the auto shutoff might be clicking off at an unreliable point a more accurate fuel consumption system would help alleviate possible fluctuations between tests

[@jamesashe]

I think the comments about ignition timing are also valid, but this is the first thing I would try to correct. Based on AFR, I would expect about 10% better fuel economy. If the pump auto-shutoff was a quarter gallon short on the control fillup, but correct on the lean burn fillup, that would make up the difference in economy. One channel I watch occasionally makes sure to use the same pump at the same station, fills to first auto-shutoff, waits 30 seconds, then fills again to auto-shutoff. It might be a good set of rules to explore.

[@vinnieluther6589]

He could use a portable gas can and an inline fuel pump, then weigh the gas can before and after.

[@jamesashe]

I think that's a good suggestion.

[@mikescudder4621]

Yeah, it should be the same pump at the same station at a minimum.

[@timothyhays1817]

Once you get the diesel installed and dialed in. I would to see how it handles hills. Now since you are down in south central Kansas known as the flatlands. A road trip up into the Flint Hills would be a worthy trip.

[@victordahn2150]

I have used lean burn with megasquirt on all my street cars. NEVER had an issue and they are both 9 sec turbo street cars. on a 6.0 I run it till it coughs and then creep up on the timing 18:1 and about 44deg. you should monitor timing when making a run because you are at different MAP areas when in lean burn VS stoic.

[@alex4alexn]

Thank you Anthony, Aaron and Stewart, you are all the man!

[@mommapanda5736]

To all the very valued viewers of this fantastic channel and primarily to JIMBO OF ROBOT CANTINA ..It's December and the Holiday season is upon us, with celebrations like Christmas, Hanukkah, Kwanzaa, Mid-winter or Yule, and New Year all approaching. Wishing you a joyous Holiday season and a happy and peaceful New Year. Thank you for a fun ride.

[@michaeldunning7471]

I ran lean burn experiments on my 2002 Subaru WRX (that I would much rather be in than a Saturn LoL!) for about a year and can confirm the other comments. I was stock ECU limited to running 16.2 AFR and without alternate timing advance, you just end up in the throttle more to compensate for the drop in power and response. My best results, the ~10% theoretically achievable savings, were therefore during lean idle (saving fuel at drive thrus) and steady flat cruise on interstates.

[@yetti_31]

thank you anthony!

[@danielsmith-ze3wy]

Good morning everyone are afternoon/night depending where you are. Hope everyone is having a blessed Sunday

[@ocdman202]

🌞🌞🌞🌞⭐⭐⭐⭐

[@PistonAvatarGuy]

The Honda Civic VX was fuel injected and made use of lean-burn technology in the '90s, it was also very reliable and fairly inexpensive.

[@1987FX16]

Civic hatch and coupe, VX and CX. Used factory wideband O2 and got 45+ in the early 90s. And my Prius gets the same mileage in 2022. lmao xD Japan in the 90s were way over doing it.

[@markusfalk9459]

@@1987FX16 This was discontinued because of the high amounts of NOx that lean burn produces, if I remember right? Still, it seems like a definitive way of raising MPG.

[@PistonAvatarGuy]

@@1987FX16 Over doing it? Like, being excessively innovative? I can't imagine anyone ever being too innovative.

[@PistonAvatarGuy]

@@markusfalk9459 Yes, it's THE definitive way to raise mpg, because we should destroy our health and have acid rain destroying everything, just to save a few bucks on gas... /s

[@dantheman1998]

A SOHC Saturn without a blown headgasket!?! Thats a rare beast right there

[@kansasrose2909]

To all the very valued viewers of this fantastic channel and primarily to JIMBO OF ROBOT CANTINA ..It's December and the Holiday season is upon us, with celebrations like Christmas, Hanukkah, Kwanzaa, Mid-winter or Yule, and New Year all approaching. Wishing you a joyous Holiday season and a happy and peaceful New Year. Thank you for a fun ride.

[@fenstermakerwj]

One thing I found out is lean burn can also be created on older vacuum advanced distributors by apparently having a vacuum port that is closed when at idle. Think Chrysler did this on some. That’s just the general explanation I got, probably more to it. But that would be for using less fuel at idle I’d guess.

[@ricksteinwand7909]

Laz and I had Chevy Volts with custom tunes that used lean burn. We no longer drive Volts, but you really should take his comments seriously. He really knows his stuff. We had 4 people using our tune.

[@TopsieT]

I had an Audi A2 which had the 1.6 “Fuel Stratified Injection” engine. It used direct injection and when it entered stratified mode, the throttle body would open wide and a flap in the inlet would move to create a more turbulent flow. Lambda would go from 1 to 3. It was of course a very temperamental system and Audi dropped it by 2005. I managed to get mine to drop into stratified mode once or twice and was impressive to see the engine running so lean. (I was sad enough to drive with Vagcom connected monitoring lambda!) The idea behind it was to ignite the mixture within a pocket above the piston create by shaping of the chamber, the injected fuel and turbulent air from the manifold protecting the engine from detonation.

[@meagloth3336]

I think Honda had something like this, at least the idea of a "vortex" combustion chamber, offset from the main cylinder area. The idea being that this aids in burning the lean mixture. It was a while ago but I had an '85 CRX HF which was carbed and had a very nasty rats nest of vacuum lines to operate the system.

[@mommapanda5736]

@@meagloth3336 HEY JIMBO..... congratulations on reaching 100k subscribers.. ROBOT CANTINA is providing the entertainment and fun that viewers enjoy..

[@Loopyengineeringco]

Excited to see that little kubota engine in action! I have a D662 which is a under-bored version of the 722 and it turns 2x 12v truck alternators to power my off grid workshop. Great little engine!

[@kansasrose2909]

Nebraska: Outlaw Trail Infamous for harboring thieves and notorious ruffians, the Outlaw Trail along Nebraska Highway 12 stretches 231 miles from South Sioux City to Valentine. Make a stop in Crofton to hide out at the Historic Argo Hotel for a night or two, unless the paranormal activity in the hotel’s basement is too spooky.

[@mommapanda5736]

“Stop worrying about the potholes in the road and enjoy the journey.” ~

[@jmoyet]

The 92-94 Geo Metro XFi has a lean tune on the ECM. Along with only using 2 piston rings an using a different camshaft from the base model Metro.

[@that_jamesguy]

Thank you for the great video! Insane the amount of work you put into this so we don't have to! And yes, you need to play with timing to get full advantage of lean AFR. Flame speed is likely changing a lot.

[@Roanen]

Love robot cantina and love this comment section. A lot of smart people all round

[@johnherdener6801]

Like Aidan I have owned many many Saturn's. I got 41 MPG on a long ( 2000 mile ) Hiway trip in an SL2 with an auto trans. I had a SL1 with an auto that would get 43 Hiway MPG. So yeah, I believe 47 with a SC1 5-speed. My current Saturn is an 2001 SC2 auto.

[@reidster87]

When I saw the thumbnail, I briefly thought it was @100PercentJake 's silver Insight with the red door.

[@ElectronikHeart]

It's possible your cheapo o2 sensor already as an offset built into it. I had a bad o2 sensor and if too lean you clearly get very bad MPG. It awesome someone got you a better kit.

[@1magnit]

A bad 02 sensor makes it run extra rich and use more fuel.

[@ElectronikHeart]

@@1magnit Depends on the o2 sensor failure. Mine made the car run extra lean. I had to crank up the fuel pressure every 100 km to keep my engine working to go home... I would have preferred the o2 sensor to fail the other way.

[@bigce]

Awesome video, excited to see more testing. Lean Burn has always fascinated me.

[@elvsrbad2]

Hey robot, I'm new to the channel and recently binged through most of your stuff. Just wanted to say I really enjoy your content and the style of your videos. Great work!

[@cfg83]

I am sure you already know this, but a diesel swap into a Saturn S-Series was done in 2007 and mentioned in saturnfans. I don't know if they succeeded, but they had mad skillzz like you do.

[@NickBDesigns]

I wonder if there was any mpg gains from removing the power steering pump that may have skewed the data.

[@haqitman]

on my 92 Civic Si removing the PS belt is good for 1 to 2 mpg easily, and a seat of the pants boost in power.

[@ronniedale6040]

I too suspect that is part of his discrepancy. When the weather cools a bit I am absolutely deleting the power steering on my SL1

[@vinnieluther6589]

I didn't bother putting my power steering and ac belt back on after turbocharging my Miata 20 some years ago. The state inspection guy told me I had to put it back to pass inspection since it came with power steering.

[@NickBDesigns]

@@vinnieluther6589 that’s sucks, I’d install a false pulley just to pass and drive it the way I want to

[@james10739]

I didn't realize or would not have thought that the signal would be opposite

[@thomashowlett8295]

Honda's CVCC system back in the '70s and early '80s was an early lean burn.

[@robotcantina8957]

Yes!, I didn't mention that because most folks don't remember those cars.

[@mommapanda5736]

@@robotcantina8957 HEY JIMBO..... congratulations on reaching 100k subscribers.. ROBOT CANTINA is providing the entertainment and fun that viewers enjoy..

[@rjung_ch]

Love what you do Jimbo, many thanks from Switzerland 🙂

[@kansasrose2909]

To all the very valued viewers of this fantastic channel and primarily to JIMBO OF ROBOT CANTINA ..It's December and the Holiday season is upon us, with celebrations like Christmas, Hanukkah, Kwanzaa, Mid-winter or Yule, and New Year all approaching. Wishing you a joyous Holiday season and a happy and peaceful New Year. Thank you for a fun ride.

[@lrrromicronpersei8294]

Congratulations on 80k subs

[@kansasrose2909]

I come here for the experiments and stay for the fun of these videos.👍👍.. All very entertaining !💥💥💥

[@ocdman202]

I turn 32 at the end of this year, and as much as I love my life and the choices that I have made that have lead me to where I am, it’s hard not to feel “behind” when looking at friends who are engaged/married/have kids/have fancier job titles/bigger pay checks/more prestige. Are these things that I even want? I don’t know, but I feel like I should know by now, and it scares me that I don’t.

[@ocdman202]

For a long time in my work life I’ve been tumbling from one closed door to the next open window, nothing like I planned or dreamed, and feeling like there was so little choice. But I think it’s so true that with time/age and resources we can work on creating the life we wanted, picking up those lost threads when we are finally ready.

[@ocdman202]

I take pride in the slow bloom! I’m a goddamn swan! I take pride in the trust that I have in myself, that I’ll improve with practice. My tenacity is a super power. Do I wish I had the means to be a homeowner? Do I wish I was remotely coordinated? Do I wish I had my own business up and running? Do I wish I had my little sister’s brains and bone structure and my big sister’s social skills and physique? Helllllll yeah

[@mommapanda5736]

@@ocdman202 HEY JIMBO..... congratulations on reaching 100k subscribers.. ROBOT CANTINA is providing the entertainment and fun that viewers enjoy..

[@gafrers]

Interesting and very well explained

[@hypercube33]

I loved my SC2 when I had it. I always wondered what a mini-duramax would be like in it from the cruze line.

[@reverse_engineered]

This was an amazing video! I actually quite enjoyed the details of how you implemented your wideband-to-narrowband conversion and the offset between them. Rather than a lookup table, you could do a bit of math to convert between them. There are four operations you need to do: offset to a pivot point (e.g. shift the ideal AFR to zero), multiply the slope (by a negative value larger than 1 to invert and scale up the signal), offset again to shift the signal where the narrowband would be (e.g. shift the ideal AFR to 0.5v), then clip the output value to [0, 1]. This might be fewer operations and more reliable than a lookup table, but it might take a few tries to get it right if you aren't used to it.

[@ajl9491]

Meeeeeeaaaahhh!!!

[@omegarugal9283]

this

[@mommapanda5736]

@@omegarugal9283 HEY JIMBO..... congratulations on reaching 100k subscribers.. ROBOT CANTINA is providing the entertainment and fun that viewers enjoy..

[@johnramsey2009]

I’m curious to know what’s up. Leaner burn more fuel used. Something else isn’t right. Can’t wait to see the next episode.

[@FirstNameLastName-tp5bu]

As a few others have pointed out, using the gas station pump as a way to measure the volume of fuel consumed, isn't accurate enough. The auto-shut-off isn't a precision device and will not fill your tank to a consistent total volume. Like you did in past videos, I think measuring total fuel consumption by weight is your best option.

[@brettjasonheadinventor]

It gives a good on-road average result if repeated 3 times.

[@scottinWV]

I love this channel! Just doing whatever comes to mind just to find out.

[@hojnikb]

As others have noted, you'd likely need more timing for improved efficiency (leaner mixture needs more time to combust properly) and at lean burn point there might have been loss of power, so you needed more throttle and as such more fuel was wasted. With good wideband you got supplied and a speeduino 4 cylinder board (hopefully that can be adapted to saturn wiring/sensors) you could control everything properly, without tricking stock ecm. This way, an economy fuel/ignition map with lean burn could be made and perhaps this way some more fuel economy would be possible. I think your previous NO2C could also be used for saturn, but you'd lose sequential ignition/injection (probably not that big of a deal). Perhaps exploring other options like injectors with better spray pattern and hot air intake might also benefit for MPGs. Obviously this would take some time to properly implement, but it's an idea to explore nonetheless, before diesel swap that is.

[@ritter_cracker]

I did this to my VW Mk3 Jetta 1.8 with single point injection using an old innovate LC-1 wideband controller. Mounted the wideband sensor downstream and left the original narrow band sensor in its place. Then took a 2-way switch to change between the narrowband signal from the original sensor, and the simulated wideband signal from the innovate LC-1. I then proceeded to program the LC-1 to target about 16.8:1 AFR and send that as stoich to the ECU. Been driving like this for a couple of months now and it works good. Haven't compared the fuel consumption yet though. But it feels as if a tank lasts longer than before.

[@robotcantina8957]

That's exactly what we are going to try next, except we will be switching between the two sensors with a small signal relay. We will still use the arduino, but this time it will monitor just the MAP sensor and automatically switch between sensors.

[@ritter_cracker]

@@robotcantina8957 Awesome. I would probably need to do something similar since it runs a lot leaner on high load than what i am comfortable with. But just gotta be careful. Ideally i would fit an MS3 and use table blending to run both E85 and gasoline. E85 can be run pretty lean without any real Nox being produced.

[@mommapanda5736]

@@ritter_cracker HEY JIMBO..... congratulations on reaching 100k subscribers.. ROBOT CANTINA is providing the entertainment and fun that viewers enjoy..

[@frightcrafter]

I've owned a few Saturns, an SL1, SL2, and SC2. MPG in the high 40s was about my experience with the SOHC Saturns. If those cars were anything they were fuel efficient and reliable, that's why I've always tried to keep one around as a beater. DOHC nets you a little more power with slightly lower fuel economy but it's still gonna be low 40s high 30s. The automatic brings down the MPG drastically, to low 30s with the DOHC.

[@BeamerTheFox]

so single cam 5 speed SL2 is what i want then

[@tonycrabtree3416]

Interesting, probably the transmission being a 4 speed not allowing freeway cruising without crushing acceleration or set for pure ease of acceleration and running too high of RPM on the freeway. My 01 corvette had the performance axle and was auto. I could get 22.5 in town, but only 24 on freeway. The M6s would get 19 and 28. Since I drove mostly city the 22.5 was very much welcome.

[@themouse5666]

@@BeamerTheFox While you may find or assemble a single cam SL2, it is not clear what that is. The S means S-series, L means 4 door, C means 2 or 3 door, W means wagon, and then the number is the number of camshafts. (SL is a base model single cam with manual steering and transmission, and SC is the SC2 before the SC1 came out.) The twin cam cars came with closer transmission ratios, 15" wheels, rear sway bars and exhaust resonators. There were also different upholstery options, front seats, speedo and tacho scales, and body colored door handles and mirrors. ...and the short wheelbase SCs had different front bodywork with popup headlights... I suspect you will want the single cam transmission with the taller 5th gear. Using the close ratio twin cam transmission with a single cam engine is pretty funny, but probably not sensible.

[@alanwelch8545]

@@themouse5666 good overview of Saturn’s SL engine architecture and nomenclature. I reluctantly owned an SL2 with an automatic only because my wife did not drive stick. Still going strong when I gave it to a friend. Miss it 🙁

[@SIXPACFISH]

That was some great special effects today! You did better than Disney's CGI in She-Bulk! Albeit that is a very low bar to pass, you still far surpassed the mark! Keep up the great work! Oh! I had a SW1 5 speed and that thing got hella good gas mileage. It got over 42 highway and a solid 38 city.

[@zimsplat]

It’s common to run aircraft piston engines “lean of peak (EGT)”. usually about 40 degrees LOP or about 16:1 afr is generally considered the sweet spot where there is fuel to be saved without loosing too much power. Although some can be regained with ignition timing the lean side of the power curve drops off more quickly than the rich side. For some comparison, my airplane burns 10gph at 165 knots at 12:5 AFR(16 mpg), or 7.5 GPH lean of peak, but will slow down by 10 knots. (20mpg)

[@brettjasonheadinventor]

What is the fuel consumption when you maintain the same speed?

[@mommapanda5736]

@@brettjasonheadinventor HEY JIMBO..... congratulations on reaching 100k subscribers.. ROBOT CANTINA is providing the entertainment and fun that viewers enjoy..

[@ocdman202]

Be who you are and say what you feel because those who mind don't matter and those who matter don't mind.

[@kansasrose2909]

Love that Lean Burn in a Saturn💖💖💖💖

[@ocdman202]

Gratitude unlocks the fullness of life. It turns what we have into enough, and more. It turns denial into acceptance, chaos to order, confusion to clarity. It can turn a meal into a feast, a house into a home, a stranger into a friend. Gratitude makes sense of our past, brings peace for today and creates a vision for tomorrow...

[@mommapanda5736]

@@ocdman202 HEY JIMBO..... congratulations on reaching 100k subscribers.. ROBOT CANTINA is providing the entertainment and fun that viewers enjoy..

[@isaacmirandajs]

What great news. You guys are amazing!

[@kansasrose2909]

New Mexico: Enchanted Circle Scenic Byway The 83-mile loop of the Enchanted Circle Scenic Byway in New Mexico crosses the Rio Grande, the sage-covered mesa of Taos Canyon, the Sangre de Cristo Mountains, the Hondo River and many colorful towns along the way. Brake for chicken-fried steak and eggs at Shotgun Willie's in Red River.

[@ocdman202]

Gratitude unlocks the fullness of life. It turns what we have into enough, and more. It turns denial into acceptance, chaos to order, confusion to clarity. It can turn a meal into a feast, a house into a home, a stranger into a friend. Gratitude makes sense of our past, brings peace for today and creates a vision for tomorrow..

[@snappers_antique_firearms]

I used to do a lot of ecm tuning in mostly GM. I used hp tuners. Most people don't know this but most GM vehicles from about 97 to 2005 have what they call lean Cruise which is the exact same thing that you're talking about here. This system is not activated or set up but being I learned how to set it up and it was one of my better money makers when I was younger. Every single car or truck I ever did it on had a fairly decent bump in fuel economy.

[@KentuckyFriedFixes]

This one is certainly a head scratcher. If I understand the setup correctly, the lean burn box is sending a fibby O2 sensor signal to the ECU that the engine is running rich, it should have leaned the engine to compensate and gotten more MPG. I'm confused why the MPG was better without the lean burn signal? Maybe the ECU has been in a dishonest relationship before?

[@antibrevity]

I'm not suggesting that this was a problem in your experiment, but I do think it worth mentioning that I've been tracking fuel economy on my cars with every single fill-up for more than 25 years and I've learned that pumps vary in their calibration, even though they're tested and stickered by state regulators (i.e. agriculture department here in Kentucky). As a result, I usually use the same pump for most fill-ups. As most of us likely use the same station most of the time for location or discount reasons, it's often not difficult to use the same pump unless you arrive at a busy time. I'm not crazy, though, and use another pump if the usual pump is taken. It's just a casual thing and obviously isn't possible on road trips. Long-term fuel economy will average out over many fill-ups, regardless, so this issue only affects individual fill-ups. Even the same pump may vary in its cut-off point depending on multiple factors, including how the nozzle is positioned in your filler neck. Most of us likely hold the nozzle in the same position each time, so that's not usually an issue. I otherwise just accept the numbers shown as I'm not performing lab experiments ;).

[@kansasrose2909]

Creativity is imagination having fun🤓🤓👍👍

[@ocdman202]

Gratitude unlocks the fullness of life. It turns what we have into enough, and more. It turns denial into acceptance, chaos to order, confusion to clarity. It can turn a meal into a feast, a house into a home, a stranger into a friend. Gratitude makes sense of our past, brings peace for today and creates a vision for tomorrow...

[@Rusty8592]

GM had a lean burn function in the third generation F bodies but its only enabled in 85 and 86. The TPI computer's lean burn mode activated for 60 seconds at a time and ignored the O2 sensor while calculating a 16:1 A/F ratio and advanced the timing 8-10 degrees. This activated when the guesstimated load on the engine was low, there is no MAP sensor and just a MAF.

[@randyrobb1860]

Thanks for another amazing video, the hoops you jump through to make this stuff understandable and entertaining is astounding! Questions: Do you think that the lean burn may be causing the engine to run hotter than normal? Hotter than normal can causes more fuel burn? From personal experience with small displacement air cooled scooters. you don't think that the parasitic draw from both the ac compressor, and the power steering pump would help you pick up that ~3 mpg that you saw, from some experience keeping older cars running, dropping an old ac compressor can pick up 1 mpg pretty easily. Thank you again this is so great to watch.

[@Skungalunga]

Hey, Great work/experimenting. Keep it up! Of late I've been using a haltech with an AEM wideband to target 16.0 for a closed loop. I think fuel economy is worse as well. I think the LC-1 wideband has an NB simulated output switchable to 15.5 afr. The problem with your setup is that in a closed loop. the fuel trims kick in and the ECU will correct....which is what you want. but there are low, mid and high long-term fuel trims. as well as short-term fuel trims. short term fuel trims are eventually added to the long term. This will mess up the fuel map tuning at higher loads even though you are monitoring the MAP. To mitigate this you would have to monitor fuel trims and adjust your driving accordingly.

[@Marc_Wolfe]

Something that's crossed my mind from time to time is hot water. Nearly boiling, so combustion heat quickly and easily turns it to steam pressure.

[@WahooNo2]

You should see if the egr operation is changing when you are running the lean burn system. Try to reset the ecu between lean and normal runs. Check when the ecu switches from open and closed loop between your lean and normal runs. Also check your short and long fuel trims to see if they are changing... if things are too far out of spec the ecu may just try to richen it up. Also monitor your coolant temps and egt if equipped, since they can cause it to try to run richer as a fail safe. I love the work you have done so far here. OEM ecus have all sorts of internal offset tables from my research in the past. Subaru's for example will change the injector pulse width as voltages go up and down and will do similar with engine temps.

[@kansasrose2909]

To all the very valued viewers of this fantastic channel and primarily to JIMBO OF ROBOT CANTINA ..It's December and the Holiday season is upon us, with celebrations like Christmas, Hanukkah, Kwanzaa, Mid-winter or Yule, and New Year all approaching. Wishing you a joyous Holiday season and a happy and peaceful New Year. Thank you for a fun ride.

[@rhekman]

As others have mentioned air flow and spark advance could be in a weird spot with the mapped wideband O2 sensor. I'd love to see a datalog that included the MAF reading and commanded spark advance by the ECU.

[@ajl9491]

Meeeeeeaaaaahhhh

[@john_barnett]

can't wait to see that cuh-boot-uh engine in action

[@kylebattagin621]

As someone who has owned many S series, The single cam coupe can very easily get high 40`s and even low to mid 50`s if kept at 50 to 55 mph (assuming there is little to no wind on flat roads)

[@ambirbtruckdriver]

That’s honestly nuts for a car that size. How!?

[@life_of_riley88]

Light weight car, pretty simple efficient engine, proper gearing, and decent aerodynamics. I had a 62 for falcon that would get 29mpg with a 260 v8 and a carburetor. It's all about setup, weight, and gearing.

[@mommapanda5736]

@@life_of_riley88 HEY JIMBO..... congratulations on reaching 100k subscribers.. ROBOT CANTINA is providing the entertainment and fun that viewers enjoy..

[@bhash96530]

Can't wait till next weeks episode! Hope you can test in some cooler weather!

[@kansasrose2909]

Jimbo == We love the unboxing of things.. Like undoing treasures.

[@mommapanda5736]

[@mommapanda5736]

[@mommapanda5736]

[@ocdman202]

@@mommapanda5736 Gratitude unlocks the fullness of life. It turns what we have into enough, and more. It turns denial into acceptance, chaos to order, confusion to clarity. It can turn a meal into a feast, a house into a home, a stranger into a friend. Gratitude makes sense of our past, brings peace for today and creates a vision for tomorrow...

[@kansasrose2909]

You will never be bored when you try something new ... there is really no limit to what you can do!!👍

[@ocdman202]

Help is near,,, he is an engineer!!

[@PistonAvatarGuy]

Nothing about this is new.

[@ocdman202]

@@PistonAvatarGuy Gratitude unlocks the fullness of life. It turns what we have into enough, and more. It turns denial into acceptance, chaos to order, confusion to clarity. It can turn a meal into a feast, a house into a home, a stranger into a friend. Gratitude makes sense of our past, brings peace for today and creates a vision for tomorrow...

[@PistonAvatarGuy]

@@ocdman202 Am I supposed to be thankful for a life I never wanted? All I've ever known is pain, I will be thankful when my nightmare is over.

[@PistonAvatarGuy]

@@ocdman202 What happens if I don't want life? Because it doesn't seem like there's a way out. If there is the potential for peace, there must be a way out of existence, right?

[@AustinPerdue]

My second comment - the Scangauge to my knowledge does not use injector pulse width, but is instead predicts fuel economy, making assumptions from RPM and load, and assuming the AFR. You have an offset value you can use to fudge the readings in line with what you actually observe. I've tested with an aftermarket ECU where I had full control over the air fuel ratio, and running hella rich did not change the reading on the Scangauge, providing some supporting evidence. If you're going to lean out past the 15's, I doubt you'll see any improvement without control over ignition advance. Combustion speed slows down and you need to advance ignition.

[@802Garage]

One of my biggest concerns is using the gas pump to check how much fuel you used. I have noticed even using the exact same pump to fill up that sometimes it shorts me and I get amazing fuel economy for the last tank, but then the next tank my fuel economy is way back down when I fill up that extra half gallon or so that the pump shorted me the last time. Unfortunately, to get really accurate data you should use a separate fuel cell and use fuel weight, like when Mythbusters tests fuel economy. Even just temperature can affect how much fuel you get at a fill up. If you can use a separate fuel container, it will also let you make shorter trips since the data will be much more accurate.

[@Workinprogressmaxi]

One thing that confuses me "the lean burn turn on".From what I know about ECU control is that they have a short and long term adjustments. When you are turning on lean burn, you are fooling the ecu in thinking its running richer than it actually is, which uses the short term adjustment to reach the fake 14.7 mixture. Now that adjustment will get more and more added to the long term adjustment. This means your car will naturally have a leaner adjustment. When accelerating(which generally ECUs use another map or enrichment tables) I could already see from the mixtures displayed, it should be between 14.7 and 13.5, but you were rocking above 14.7. In the end that is where my confusion is, you don't need to "turn off" lean burn as it's applied across the board after a certain while.

[@ayourk1]

What happened to S2E17?

[@54mgtf22]

Love your work, Jimbo 👍

[@michelhadid]

Really cool video!

[@francistheodorecatte]

on my uego meter, I had to modify it with a grounded coax for the narrowband output, among other things, for it to actually work with my ECU (Trionic 5).

[@francistheodorecatte]

the included harness output, being completely unshielded, will have the tiny narrowband output completely annihilated by noise even over a short distance in a car.

[@knurlgnar24]

The scangauge pulls MAF and MAP data and assumes 14.7. It does NOT use injector pulse widths - this is not possible as injector pulse widths are constantly adjusted to maintain proper AFR due to fouling and other issues. Vehicles have no metering device for fuel and just make assumptions based on history of fuel tank fuel levels and MAF/MAP using LT trim levels. I have used scanguages for nearly 2 decades and they are great tools but are limited in their abilities.

[@kansasrose2909]

“The smell of pine needles, spruce and the smell of a Christmas tree, those to me, are the scents of the holidays.” 👍👍👍

[@kansasrose2909]

“I will honor Christmas in my heart, and try to keep it all the year.”

[@kansasrose2909]

“The perfect Christmas tree? All Christmas trees are perfect.” -