Lambda Controller
 

Over the past few months I've been working on designing, building, and programming a lambda adjustment module. It reads the O2 sensor voltage and gives a lambda percentage readout on 10 LEDs. It also outputs the O2 sensor voltage which is controlled by a potentiometer. In the center range of the pot it outputs an unmodified O2 signal. From center you can adjust the mixture either leaner or richer. The adjustment occurs in six steps as you turn further away from center. It has colored LED readouts for the adjustments....green for no adjustment, red for a rich adjustment, and blue for a lean adjustment.

The project is based of of a Microchip PIC18lf2525 microcontroller for which I've written a little less than 1800 lines of code for. Awaiting delivery of a few last minute parts, I'm planning to start the beta testing in my 90 300TE by next weekend. :D

Sounds interesting.... You'll obviously be using a wide-band O2 sensor, correct? A narrow-band won't do what you are proposing. Will your output be controlling the EHA? I'd also consider using a digital readout for better accuracy.

No wide band, it's using the factory sensor. The range of adjustment is only 30% lambda either way. It doesn't affect the EHA directly. It only changes the O2 signal enough that the CIS-E will make the fuel adjustments automaticly. The management does have to be in closed loop before the controller can adjust it.

I didn't do a digital readout for 2 reasons. 1. The lambda signal is constantly moving so tracking it down to the milivolt would just keep a fluctuating readout. The 10 LED readout acts as a buffering interface. If the lambda is in the 50% range the 50% LED will be lit. I don't see the need read out the lambda within a closer tolerance. A 10% discrepancy in actual Lambda would just barely be within the range of being able to notice a difference from behind the wheel. 2. Keeping it simple. A digital readout would add to the complexity and after 1793 lines of code in Assembler, I'm not looking for more complicated.:eek:

Thanks for the input, though. All ideas are welcome. I hope to be able to develop it to the point of having a good product that will perform well in the field.

im not sure how well this will work if at all,
the standard o2 sensors only read from about 14.2-15.2 and the whole time the standard computer bounces between these two figures in closed loop for fuel economy, i cant see any benifit from making it richer while at light load?
and wont it still just adjust within this range?

what im saying is can you explain a bit better what it will actually do? and how it will adjust to make the car richer or leaner, as the computer automatically adjusts to small differences, or is it to be basically just a guage.
possibly your car might have a different ecu with different fuel adjustments to myne and hence i shouldnt have posted anything?

The idea behind the project is to be able to make adjsutments to the fuel mixture on the fly while in closed loop. With the lambda set to ~50% for normal unadjusted driving, the controller should be able to move the lambda up or down ~30% in 5% increments. So with a good 50% basic adjustment you could adjust the lambda to either a maximum of 80% or a minimum of 20%. I didn't see any situations where a normal engine (non forced induction)would want or be able to operate outside of those tolerances.

The controller adjusts the mixture richer by outputting an O2 sensor voltage that is leaner than it actually is, thus allowing the CIS-E to adjust it richer. The inverse is also true, if you want to adjust the mixture leaner then the controller outputs an O2 signal that is interpreted as rich allowing the CIS-E to adjust itself leaner. The CIS-E module tries to oscilate the mixture around 50%. The controller is designed to basicly allow you to select different values (other than 50%) around which it's adjustments are centered. Such that if I want to center the CIS-E around 40% then I decrease the O2 sensor's voltage by 10%. This lower O2 sensor voltage is interpreted as 10% lean, and the CIS-E will adjust it 10% richer. All the while the CIS-E thinks it's still centering around 50%

The concept behind the controller is to be able to dial in a bit more fuel at the stoplight when there is a BMW next to you, or to be able to dial the mixture leaner when you are on the highway at a nice cruise, and then be able to set it so there is no adjustment for general putzing around. All with just a turn of a knob.

Hmmm... I'm a bit skeptical about the whole idea but "maybe" it will work as long as the altered signal looks exactly like the NBO2 output and shows a slightly lean condition. It may throw a CEL though....

Here's your biggest problem.... The optimum AFR for making power is around 12.5:1 the stock NB02 sensor won't even come close to reading that.

In my opinion, the best way to do this would be to bypass the factory ECU and use a WBO2 to control the EHA directly. Optimally you'd also need load and RPM inputs but by then your basically looking at EFI. Theirs not many hidden patches to engine management other than reconfiguring everything. With what you are proposing, it sounds like a minimal power gain with the possibility of a CEL.

Take my post with a grain of salt however. I'd hate to get your hopes down and would like to see your results. I'd personally love to see you prove me wrong. Gonna need to see some dyno charts though! :D

Good Luck!
Adam

Man, no sweat, I appreciate your input. The controller should very closely mimic an unaltered O2 sensor. The controller reads the O2 sensor digitally, decides to modify or not, and then outputs the new voltage through a MAX5354 DAC, once every repetition of the program. I havn't decided on maximum clock frequency yet, and have only simulated at ~125khz, but 8Mhz is theoreticly possible with the hardware I'm using. I'm going to determine clock frequncey once I can test it in operation.

I'm not too convinced that it'll need a wideband O2. Remember that I am getting a richer mixture by fooling the ECU leaner. Although I'll admit to not doing the math to figure out how much my 30% lambda ajustment will alter the mixture. FIgured it easier to measure it once I have it functional in the car. I'm lucky enough to have a gas analyzer at work.:D I know as an experienced mb tech that a car running at 20% lambda is pig rich. I'd expect peak power to have fallen off somewhere before 20%, though maybe not.

Don't forget that the controller is designed to lean out the mixture too. This idea was hatched back when gas was still near 4$ a gal. After a 14hr@4000RPM road trip last summer when gas won't cheap, I was really into the idea of being able to run lean on the long hauls.

Granted there are a lot of shortcomings compared to a stand alone EFI. My design goals were to keep it a simple interface that requires no other mods than to plug it in to the cig lighter and O2 sensor. Technicly, you won't even have to open the hood to use it. There's all sorts of tweaker gizmos for the EFI guys but almost nothing for us CIS-E tweakers. What I'm shooting for is a simple, easy to use interface that gives the CIS user control of the fuel mixture over most of the usable range of a/f mixture during closed loop.

Whether I pull it off or not remains to be seen but so far, so good.

I completely agree with your train of thought. It sounds like you did your homework and plugging in a piggyback controller between the O2 sensor and ECU would be a way simple mod to "trick" the ECU into performance mode.

However.... look at this. The factory ECU was designed to see a signal from the stock NBO2 sensor as is. If you have ever wired an LED meter to your stock O2 sensor (which I have....) you will notice the reading goes off the chart on a regular basis.

The only thing the ECU is looking for is what you can see on the LED display.

What you are proposing.... (for a legitimate performance gain) Will create a condition for the stock NBO2 to go "off the charts". If you leave it at this condition (what the ECU sees) for long enough the ECU will just look at the reading as being false and send the management into LHM and give you a CEL.

In my opinion, the factory ECU will see that the O2 sensor is "telling a lie" and ignore it. Never tried it myself but that's the "ECU logic" norm for what you are proposing.

If you'd like, I can "loan" you a WBO2 sensor with homemade controller (you have to put down a deposit though) to properly configure, test and tweak your system. It's one accurate mofo! :D

I think the big thing ECUs validate is whether the O2 signal oscillates and the time from peak to peak. The controller will track the oscillations and mimic them. Part of the "beta testing" will be determining how far from 50% I can deviate the signal before the ECU calls shennanigans. The CIS cars can get away with a pretty poor tune and don't set C/E lights easily. Hopefully I can run it right to the edge of the chart and not "off the charts" so to speak. The neat thing about having the LEDs display the Lambda is that it will let me know when the O2 signal is called out for a fault with a fixed 50%.



I'll keep you guys posted with progress. Right now I'm waiting 5-10 days on a delivery of components, which is torture since I've spent the last several weeks getting the code written and debugged.

Sounds pretty good to me! You've obviously done your research. I can't wait to see your results. If everything turns out okay; I am an expert in board development! :D

My prototype...

http://www.putfile.com/pic/8453430#

My final product....

http://i512.photobucket.com/albums/t...2/P1031498.jpg

Let me know if you need any help in this area....

Adam

That's a nice clean organized looking board. If everything works as planned I am going to be looking into making PCBs. If that time comes, you're my man. Etching a board is something I don't have experience with. All of my projects to date have been on prototype boards. I've tried downloading a few free schematic editors that can design the PCB layout but havn't had much luck with any of them. There always seems to be a catch, like needing to define component footprints and such.

Enrichment alone at idle and initial acceleration is not going to make your car any faster.

If you want to work on something for performance then why not look at a timing adjustment.
Fuel enrichment and timing on a NA engine go hand in hand...

And then there is the ECU.

I don't think it'll work even for initial acceleration since opening the throttle passed a certain % the car goes into open loop and doesn't listen to the signal from the O2 sensor. The greatest benefit from this may be for fuel economy when cruising (leaning out the mixture) and maybe a bit more performance at part throttle (when enriched) but then you'll lose fuel economy.

on my old NA setup i had 2 variable resistors which if i recall did alter the resistance of the temp sensor input to both ecus injection and ignition. Any way did dyno the car and ended with a 203 hp M103. Later on with a more flowing exhaust i got it up to about 210 but then i had to move the R16 euro ECE SWITCH to inside the car as that also changes timing advance / retard. Did that cause i had become so used to knowing to which position the R16 needs to be at depending on ambient temps. Winter / summer and sorts.

The throttle switch on CIS cars doesn't activate until WOT, so the car should remain in closed loop until it is activated. Part of the beta testing will be to determine if the full load throttle switch needs to be disconnected.

I agree that timing has a good bit to do with power production but at this point I'm not too concerned with it. Open hemispherical combustion chambers (like open chambered 103s) tend to not tolerate much spark advance so I don't think there is a lot of room for improvement. For now I'm just concerned with control over fuel, given that the ignition trim resistor give a small bit of control over the spark map.

Take it from me, this car will love advance, enriching wont give u much pwr especially if u consider how restricted the air flow is in those cars at low engine speeds. what the M103 lacks is pull low end, and advance will improve that. IMHO. I admire your efforts and i understand the drive behind tuning this system, good luck

Modifying the temp sensor signal works to some extent since unlike the lambda, the ECU doesn't ignore the input for the temp sensors at WOT. I'd guess what happened in your case is that you changed the resistance to report colder temp which in turn caused the ECU to advance the ignition and add a bit of fuel :)

On the topic of ignition advance, I found that my m103 engine is happiest with about 28-29 degs at WOT (road tune, haven't verified this on a dyno yet), which is not that much of an advance.

P.S. Jay, do you know exactly how much total ignition advance you run on the dyno when you got 203hp ?

I see one problem here and that is that if the WOT switch is disconnected than the ECU would think that it's at part throttle and will not enrich the mixture, you could go around this problem by enriching the mixture with the controller but that would mean that you'll be also running very rich a part throttle i.e. when cruising ... what you could do is maybe disconnect the WOT switch from the ECU and then have it activate the controller, it might work but it's not the best solution. Best way in my book is to find a way to modify the signal to the EHA, say monitor rpms, engine load (map sensor) and modify accordingly .

unfortunately no :S

but every car is some what specific, and mine was swis specs, slowest as they come (so i've heard) any way any 103 should be close to 200 hp with a free flow and a bit of advance.

but i have a few vids in my utube chan to show how sweet the engine was in N/A form (they are the early vids, new ones are with TT)

be careful dux not to do any damage running w.o.t while too lean.
rules of thumb=
Air/Fuel Ratio Limits.------------------- lambda
6.0:1 Rich run limit
9.0:1 Low power, black smoke------- .61
11.5:1 Rich best torque at WOT ------ .78
12.5:1 Safe best power at WOT ----- .85
13.2:1 Lean best torque at WOT --- - .89
14.7:1 Chemically ideal ----------------- 1
15.5:1 Lean light load, part throttle ---- 1.05
16.2:1 Best economy, part throttle ---- - 1.1
18-22:1 Lean run limit

i dont think u will be able to get out side the 14.2-15.2 range because this is the range in which a standard narrow band o2 sensor reads, which wont make bugger all difference,
and i think if you try and trick the computer it will just vary massively while "searching" for its middle point of 14.7
i have a piggyback hooked to my ecu and a wideband o2, and i know that when the ecu cant equalise easily enough into the narrow range it just starts varying massivly and goes real rich then real lean looking for the medium,
so if u set the new medium at say 20% richer it at say .4v it isnt going to read down to -.1v so you still only have the same scale,
in closed loop my car will bounce continuously between 14.2-15.2 the whole time when parked at idle, and accelerating at low throttle positions,
it doesnt settle at say 14.7 like youd think, if it did then yes i think u might be able to adjust it, but its a constant yoyo.
but using ur technique in my mind i think u will be only able to adjust within the range that the standard o2 can read,
are u proposing that ul get it to bounce within a smaller range instead, say 14.2-14.7? for example?

^that was all in my head and i wouldnt of been happy without saying it because i wasnt sure if u got what i ment last time,

feuw what a story.

I'm not surprised that you made best power below 30 degs timing. The open chamber just doesn't support much timing. Some closed chamber engines are happy at 40 degs.

I'm not worried about disconnecting the throttle switch and cruising rich b/c half of the function of the controller is to be able to dial fuel out as necessary. Given that my car has a catalyst and has to pass annual emissions testing, running it really rich will only happen in short bursts. Running 20% for very long will likely melt down the catalyst.

I've been an M/B tech for 12 years and worked on a lot of CIS cars. I've had 100k engines come in that have never had a lambda adjustment and were running at 80% with no C/E light. I've also seem em come in running less than 30%. Trust me, from behind the wheel you can tell the difference.

I don't doubt that my controller will leave some power on the table. I'm not shooting for the be all, end all of CIS tuning. Maybe some day, but for now I'm just getting proficient at programming PIC microchips in Assembler. For now, a simple interface that gives a fair adjustment over the normal range will be what I consider a success

Delayed again
 

:mad: Well after waiting a week there is still delays. For some reason that I havn't figured out the new PICs I'm using are write protecting after only one write. So basicly I waited a week to change the code 3 times before I ran out of PICs. I don't have the PICs configured to write protect or code protect so I'm pretty stumped. I programmed the old PIC dozens of times and didn't change anything except a few instructions in the code and the actual chips themselves. The lesson... don't get careless and short out your working PIC. :o Back to the datasheet I guess.

Socket one of your PIC's in upside down and power up your board for a second. That'll generally knock out all the values. Or fry it. Trust me, done it hundreds of times with success.

You can also try a different programmer. I eventually broke down and bought a $600 BK Precision programmer. I never have any trouble with that sucker.
Good Luck!
Adam

Well it was a programmer problem, but it wasn't a big deal. I had a marginal ground which would pass enough current to read and to write but not enough to erase, which of course has to happen before before a write, but not an overwrite of the same data. A little touch up with the soldering iron got it straightened out. As luck would have it, I had bought this programmer just for this project. It turns out that my old programmer didn't support the 18LF2525 device. Needless to say, this isn't a 600$ programmer.:rolleyes:

With my programmer issues sorted out, I got the code in the chip and functional on the board this evening. I'll start the beta testing over the next couple of days and let you guys know of my successes and failures.

Keep your fingers crossed for me:D

I did my first testing today:D I logged about 20 miles without a C/E light. Most of that driving was with the controller set for no adjustment, outputting the same O2 voltage as was input. I did most of the driving with no adjustment making sure that my circuitry would be able to mimic the O2 signal sufficiently to fool the CIS. So far, the CIS module is interpreting my output fine. I put the Lambda tester on it at the shop and it had good oscillation. After work I pulled it in and put it on the gas analyzer. Turns out it worked better than I though it would. I recorded my CO and HC values at idle and at 2000 RPM. Unadjusted my idle CO was ~.40 - .70% and at 2000 my CO was ~.55 - .85%. The Lambda controller would lean the idle to .12% and lean 2000 to .16% CO. Not bad, I must say, but it turns out it will richen much better than it leans. At full rich adjustment idle would go over 7.0% CO and 2000 would go to ~6.6% CO. I really didn't expect it to richen that well but my ASSumption is that the CIS is willing to work harder to prevent a severe lean condition than a rich one. Remember that I get an adjustment by fooling the CIS lean to get it richer and vice versa.

I did get one good stoplight to try an enriched acceleration. I'm not going to say that it was night and day but I did notice a bit better pep. :) I am not confident saying that there is more peak power but it felt like the power band had gotten wider. Typically my TE doesn't get any steam behind it until the revs are up quite a bit. Enriched, it felt like it was willing to pull with gusto sooner and longer.

Having the O2 sensor voltage display is neat to watch but also distracting in traffic. I was surprised how much time is spent in a decel fuel cut. If there is one thing CIS does well, it is cut and apply fuel without hiccups. Maybe that smoothness is why Mercedes stuck with it well after most manufacturers switched to EFI.

I did all of my driving today with various amounts of negative enrichment. At the higher settings the power loss is evident. I didn't notice any pinging but it is pretty cold here and the air is thin. Pinging isn't normally a problem for my TE, even in the summer with 85 octane, but I do see 103s that will ping on cheaper fuel once in a while.

With another 20 miles under it's belt, still no C/E light:)

Today was a mix of driving with fuel being added and subtracted. No real problems to report. There is a bit of a delay from setting the controller to add fuel until the CIS actually adjusts it. Since the controller affects the CIS's feedback system, it has to see the adjusted values for a bit before the mixture actually starts to change. I noticed this on the gas analyzer and now during actual driving. The dealy seems to be around 10 to 20 secs. I think that when the O2 sensor is really good and hot the delay is less. At stoplights I adjust when the crosswalk signal changes and that seems to work well. I have gotten a couple of good enriched accelaration runs today. It definately likes the extra fuel. I have a fair hill near the house that has a 30mph limit. At 30 mph, I normaly am just on the border line of being able to climb it in high gear without a down shift. When leaned out a downshift is certain, when enriched it pulls the hill in high gear with ease. Not emperical data, I know, but proof of concept none the less.:P

I've been talking with my co-worker about trying it in his stroked 500SL. That puppy really likes to run rich but he keeps it tuned pretty lean most of the time.:rolleyes:

I tanked up today so that has been one tank full through the car with the controller providing the O2 signal. That's a bit over 200 miles and so far so good, no problems or c/e light. It cruises quite well when leaned out. Most of the driving so far has been spent with it leaned out. Why burn more gas than I have to right. A couple of times I've dialed in more fuel but that has only been in short bursts. When leaned out I just back off on the fuel until I feel a slight power loss and leave it that way. I havn't pulled the full load contact and as of yet don't think I need to. Since most of my driving is with it leaned out I like having the full load contact there to bring it out of closed loop when I need the power back for merging and such. I may still experiment with removing the full load contact but don't see it being critical to the function of the controller.

WOW! Sounds like your project was a success! However, If you could manage to get some dyno time along with a WBO2 in the tailpipe. You'd then have some real data to look at. It's not cheap but it would be adventagious to you as numbers would really help sell your kit if you plan on producing them.

yea sounds like it works well! im sorry about all my sceptical questions!
it all worked well in the end, and ur obviously like me with the fact that you made it yourself and it works makes it so much cooler

No apologies needed, I posted here about it so that you guys could come up with some things I didn't consider. Criticism is appreciated, though it appears that the controller does indeed work as designed. I did all my driving today with it on the car but I don't think I got in closed loop much at all. It was so cold that with the heat blowing inside the engine wouldn't warm up enough to get out of open loop. So much for trying to measure an MPG improvement over this tank of gas.:rolleyes:

I did a lot of driving over the holidays. Almost all of which was with the controller pulling fuel out. I managed to increase my average fuel mileage by 3.5 MPG!!! Sure wish I had this back over the summer when gas was at 4$ a gal. That increase in MPG was with various amounts of lean running and not just full lean so there is probably just a little bit more MPG to be had. Granted it's no powerhouse running lean but it does still go down the road just fine. I havn't noticed any pinging at all, even at the full lean setting but the weather is cool and the air is thin up here near Denver. It may be a different story when summer gets here.

Still no negative issues, no C/E light, or problems to report.:D

Duxthe1,

I just found this thread, and am VERY intrigued. I have recently been talking to a fellow enthusiast about this very subject; fooling the ECU via a modified 02 sensor output. (However, the intended application is not a CIS or CIS-E car, but instead LH-SFI M119 applications.)

The CIS-E cars have a certain degree of simplicity which is very much in your favor; I believe getting the ECU to “digest” an altered signal is fairly straightforward and WILL work well, as you have discovered. (It would also work for the older CIS systems with a frequency valve instead of an EHA.) I applaud your inventiveness & diligence in developing the methodology. I particularly like the idea of being able to adjust the mix on the fly.

I was not looking at partial load situations, but strictly full load enrichment. I had envisioned a much cruder system: using a resistor to drop the voltage sensed by the ECU, thereby feeding a false lean condition with the modified signal being switched into & out of the circuit via a double pole relay tied into the kickdown switch. Unfortunately, this is where my ignorance of the LH-SFI system comes into play – if they go open-loop at full throttle, then my idea will not work - it would then take an actual re-mapping of the fuel flows burned into the LH unit. (And I do know that the 1992 LH systems DID have WOT enrichment, but probably not “enough” to achieve full power potential in lieu of emissions & catalyst life expectancy)

Also, being an MB tech and therefore being MUCH more knowledgeable than myself, I was wondering if there is any way to adjust the basic lambda settings on an LH car? (and if so, would that only effect idle settings, or would it shift the entire fuel map commensurately? (the only analogy I can think of is when adjusting an old (non-lambda) CIS car with a hex key near the fuel distributor head, OR adjusting the control pressure via modifying the warmup regulator.)

I would LOVE to hear your feedback on this stuff!

Thanks in advance!


P.S. - If you are planning on producing these controllers as kits, you will find a much wider market if you were to include the LH-SFI cars in your target market. Meanwhile, if you need a guinea-pig to test your prototype on an LH-SFI car…

P.P.S. On your friend’s stroked 500SL, was this simply a long-throw (5.6) M117 crank into a M117 engine, or into a M119?

Works on a KE-Jetronic ...concept or mod to the LH-SFI?

http://www.autotech.com/prod_engine_pwrmod.htm

As built my controller should be able to work on any system that uses a single oxygen sensor. That pretty much excludes most if not all of the LH-SFI stuff, possibly not on some of the early ones, maybe. Interfacing with the mass air flow meter signal is the generally accepted way to tune most EFI. I built the controller to give us CIS cars a way to alter the mixture.

So far I've got around 1k mi on the car with the controller in charge of the O2 signal. So far so good.

My buddys SL is an 84 500 Euro block with the 560 crank rods and pistons.

There is no basic adjustment on a US spec LH-SFI. There are a few ways you could hack it but nothing simple.

The rear o2 sensor of most SFI cars doesn't affect the fuel trims of the car, including Mercedes, so I think your controller would work. It would be helpful to tune the closed loop fueling of the car, making the transition from closed loop to open loop smoother when making custom fuel maps.

I believe all LH-SFI use a single O2 sensor. The dual sensors didn't start until ME injection rolled out in 1996, AFAIK. Interesting idea about modifying the MAF signal on LH cars, though!

:boat:

RBYCC - Thanks for the suggestion, but that unit works by feeding a false signal directly to the EHA, therefore it is not applicable to LH-SFI systems.

Turbo E320 - I believe that the function of any second (post-cat) O2 sensor is strictly to provide feedback on catalyst efficacy.

GSXR is correct, the LH-SFI systems ARE single 02 sensor systems, therefore (in theory) this type of signal "correction" could work.

Duxthe1: Any interest in potentially expanding your market beyond CIS-E?

P.S. I'd love to hear more about setting the baseline lambda mix on LH-SFI cars, even though it is a "difficult" hack. Nothing worthwhile is easy.. (usually) ;)

Exactly, The O2 sensor in "most" fuel injection systems have very little "say so" in mixture adjustment. If you're running LH injection it would be best to look at altering the mass air signal for fuel enrichment as duxthe suggested. In fact, I have a piggyback controller for this application if anyone wants to buy it.

As far as being able to hack an adjustment for the basic fuel delivery, I have two words.... fuel pressure. :eek::cool:

In years past I have taken a bosch style fuel pressure regulator and cut off the dimpled end and replaced it with a threaded adjuster. Not exactly pretty but very effective.:D

Only problem with altering just fuel pressure is that it's very "linear" which engine power curves are not. With this method you'd be running too rich in areas where you should not.

I did say it was hack but is more effective than your argument suggests. Since the map is unaltered in the ecu it will run richer for the same inputs across the entire range of delivery. Whether the engine will run better enrichened across the whole map, and whether the ecu will adapt out the enrichment are not addressed.

The last time I used this trick was on a speed density setup where I was pushing 21psi at 2 liters. :eek: It was making approx 100hp over stock on a stock ecu.

Yes, the ECU would adapt and negate the enrichment, up to the system's inherent adaptation limits. It would do the same with fuel pressure hacks, or anything else where the ECU sees the mix at the 02 sensor as being anything other than stoichiometric. (obviously speaking of closed-loop mode here.) WOT enrichment is one thing, but "on the fly" tweaking during closed-loop operation has some inherent advantages, as Duxthe1 has discovered.

Those are the reasons why I'm so interested in Duxthe1's methodology. Same questions apply:
1.) are you planning to produce this?
2.) would you like to expand into a wider potential market?

I know that there would be PLENTY of interest from certain groups of enthusiasts that have LH cars!

Of course I'd like to be able to sell it to anyone who would buy it. Right now it's still in what I would consider the testing phase. So far it has performed great but there are a few things I think I'd like to incorporate into the design. Foremost I've been considering adding a small pushbutton that would chage the 10 led display from displaying the O2 voltage to displaying 1 through 6 representing which level of enrichment the controller is set at. I've still got one pin left on the microcontroller and I think that would be a nice addition to the controller.

The next thing to consider is the design of a PCB and the assembly of the unit. I've thought about selling the controller as a kit. It would be cheaper and easier for me to supply the schematic, parts list, instructions, and programmed chip. Though having to build your own would probably turn off a lot of potential buyers. There is a lot of consideration when turning a hobby into a business. Honestly, I havn't put much effort into that yet. At this point you are the first person that has expressed interest.

I bet you'd get a lot more interest with some dyno numbers,,,, Hint, Hint... ;)

There are no dyno numbers coming. The way I see it, this isn't a bolt on HP mod and I don't intend to make claims that it will add "X" amount of power. It's simply a closed loop fuel mixture controller. If your engine is running at less than ideal mixture for power then yes, it will add power. Unfortunately, every engine would respond differently depending on it's baseline setting.

For those that want to bolt on "X" amount of horsepower for "Y" amount of dollars spent, then I simply wouldn't recommend this controller. If one wants control over the closed loop mixture then this would be a good addition.

It's your word against real world numbers.... See the problem here? Everyone else claims this and that and the other thing. Until I see numbers, your device is equal to this.

http://ec1.images-amazon.com/images/...mL._SS500_.jpg

Selective editing will not entice me to waste time and money on a dyno. Dyno numbers are just snake oil to sell worthless cold air intake systems to wannabe racers. I did post the numbers that actually matter. In real word testing done at a permier Mercedes shop the controller was able to lean the mixture to .16% CO and enrichen it to 7.0% CO. That is what the controller is designed to do and I can stand behind the fact that it does. The controller is not designed to add "X" amount of power. It can add or subtract power by simply adding or subtracting fuel. Additional power doesn't simply come from plugging the unit in but comes from the users abilty to use it to tune their engine to its potential. I can't and won't put a dyno number on that. If you give 10 wannabe tuners the ability to adjust their fuel mixture over a 6.5% range I'd bet you could count the ones that ended up with more power on one hand.

I'm not selling a tornado, heck at this point I'm not selling anything. I do believe I have seen the Tornado advertised as gaining up to 20hp. I'm sure they had dyno numbers to prove it too. Those numbers did little to meet unrealistic expectations in real world applications.:rolleyes: