Eco remapping aka chiptuning
 

Has anyone had their car's engine software remapped to improve fuel efficiency rather than gain more power ?

Rica in the Netherlands claim up to 15% increases in FE for the 1.6D engine in my car with an E-power upgrade !
RICA Engineering - Performance and Economy Tuning for Volvo, BMW, Audi, VW, Mercedes and most other makes and models

The FE numbers shown are not the official European testcycle ratings, but rather the results of their own (outsourced) testing.


Considering it's actually less (!) expensive as having my rear windows professionaly tinted, I'm tempted to give it a try.

euromodder -

I think it depends on the car you own. If the "subculture" exists, then I think remapping the ECU/PCM should be affordable. I have also been curious about such products like Megasquirt (see here and here, but ICE only, :( ). What I like is that they modify the fuel-injector maps without going "inside" the car-puter, so they should work on most ICE drivetrains.

CarloSW2

Hi Euromodder
I looked into this idea myself a month or so ago and didn't have much success due to my car's age and I wanted to do it myself so I could continue to tune the best parameters

The thread I started is here. It has some good responses
http://ecomodder.com/forum/showthrea...ion-13824.html

The concept is definitely a good idea, the ECU configuration and design for the whole car is set up for the worst case conditions and some things are set up for drivability at the expense of wasted fuel.

Unfortunately the implementation can be difficult. For my car in particular I have a car that doesn't have the programming connection instead it has inbuilt configuration values. From what I have read you can usually change out the eeprom or connect up a daughter board which will override settings but I personally wasn't willing to spend that much on the modification and there is a risk of killing your car completely so if your doing it yourself I highly recommend getting a second ECU from a wrecker or something like that.
If your getting a chip tuning place to do the work for you there is the disadvantage of you might not understand what they are tuning out so you may not get the best efficiency or they might cause damage to the car (running too hot or something like that)
You can also go down the path of replacing your whole ECU with a customizable version which is often done in racing however it can cost a lot of money for a customizable ECU.

If you have a bit of a search on google you will find some chip tuning web sites and instructions which might help.

As for my solution I will just be "fooling" the ECU by either overriding its outputs or changing its inputs so it does what I want.

Good luck.

I've been thinking about eco-tuning, but all the ads I've seen were performance mods claiming that lower fuel consumption was a by-product of greater power and torque. I really don't need a power summit around 4000 rpm since I almost never go above 3000 rpm. What I need is more torque around 1500 rpm, since that's where I'm sitting most of the time. I'm more than willing (depending on the price, of course) to sacrifice high-end performance for lower fc as long as low-end performance doesn't suffer.

How much, more or less? I couldn't find the price on their page.

Thanks saand, I'll look into that thread.

Volvo used this concept on their DrivE-models fitted with the same engine - apart from the usual ecomods (LRR tyres, lowering, wind deflectors), they also have a remapped ECU that makes them use less fuel.
Actually, these eco-versions also have a better driveability than the original version of the car that I have

Their official FE went from 5 L/100km on my car to 4.5 L/100km on the first DrivE version, then to 3.9 L/100km (with a start/stop function) - that's a 22% change !
If anyone got that sort of FE improvement just from applying the usual ecomods and switching off the engine more often, I think they'd be very happy ;)

The upgrade I'm looking at is fully reversible, and is done over the OBD2 port.

In a worst-case scenario, I could have the Volvo dealership overwrite the upgraded software.


I doubt I'll ever understand exactly what they're doing ;)

But these E-Power remaps are specificly meant to improve FE, not so much the output power (though their is a slight power and torque gain at low RPM)

Most of what's out there, is about pure power upgrades, with better FE claimed as a by-product. I don't care about the extra power.

That's the sort of upgrade I'd not do - but it may be the only option for your car.
That way you're fooling the logic in your car into thinking some parameter is different from what it actually is.

Exactly - and where the engine is a bit lacking and struggling in my V50.
Engine load is often above 90% or even maxed-out in that region.

Rica's E-power upgrade claims 41 Nm (16%) more torque at only 15 rpm more than now, and a 15 HP increase @ 4000 rpm.


According to their published claims, top end power is higher than stock, no need to make sacrifices there even though we'd seldom go there


Use RICA Engineering - Performance and Economy Tuning for Volvo, BMW, Audi, VW, Mercedes and most other makes and models to select your car.
Price info is in the text on the left of the power curves.
Price : €580.00 EUR + VAT (€435.00 EUR + VAT for cars over 3 years old)

Looks like they only have a power upgrade for your Svietlana though.


The E-power upgrade on my car is €363.75 EUR + VAT as it is over 3 years old - so with VAT (state tax in the US) it's still under 450 euro (and more) I got quoted for the tinted windows :cool:

Are you sure the engines are exactly the same ?

OEM generally will try its best to met high MPG, not sure how much they would lean out and any ignition advance would probably mean higher octane .

Now, if like above poster you want to lower the sweet spot of power band you could say use a camshaft with less duration and lift . That and slight tuning if necessary should help .
I haven;t checked in long time but many camshaft makers had eco/low rpm efficiency profiles available .

Edit : I was referring to you post on DrivE-models .

At least skin deep - their easily checked statistics are the same except for FC and emissions.

As their FC figures are very different and they also drive differently, there have to be some differences - ECU mapping certainly is one of them, but I can't tell if they also put in different camshafts and the like.

Checked the site, looks interesting , the gas versions seem to address more ignition timing to optimize FE as they say 98 fuel recommended .
The E-power being TDI looks good ,though not sure what they do to achieve that .

If you add too much torgue to low revs like below 1500 rpm the cluth will broke and after it has been upgraded the transmission gears will broke more easily... In my 1.9 tdi engine you cannot add about much more torgue just move it little bit more towards 1000 rpm range. sligth increase is still ok

I missed the price, duh. I also noticed that only the power tuning is available for my model. Maybe they haven't noticed that it's the exact same engine as the 1.6D in the Volvo?

From Volvo V50 DRIVe:
The longer gears are probably what is most noticeable from the driver's POV. I'd like to know how the steering was optimalized... Maybe they went to electric P/S?

You're lucky, since you can swap your transmission for the DRIVe's, or get some of its underbody panels. If I were you I'd be leave my phone number and a few beers at the local scrap yards;)

I'm very easy on the clutch and gears - I've never had to replace a clutch.

BTW: the extra torque only comes in @ rpm when the clutch is already fully coupled anyway.

Worst case, you upgrade a few parts to take the stress. If you get a better, more efficient car with a more useful powerband as a result, it's worth it.

megasquirt rules. The older the car is, the more there is to be gained by playing with the fuel+spark tables. It's also quite a bit of fun to try different AFR's to see how they drive.

Now that Euro got me salivating again I went to Rica's page and read about their iSoftloader box. I wonder if it is a one-timer, ie you can flash your ECU only once, or if you can keep the software and re-flash as many times as you want. The latter might allow A-B-A testing, but I think a one-timer may be safer (unless there is some way to make sure only one ECU is flashed).

The price isn't that bad, but until I start driving more (and I'm doing my best not to!) there is no way I could justify the expense in our family's budget at the moment:(

Piwoslaw, even I have a hard time convincing myself that I need this :)

The E-Power remap is around 440 euro.
Let's say I'd get the claimed 15% fuel reduction.
That'd mean the payback time is 2 years for me (@ 27000km/year).
Fuel price is gradually going up though, so it might happen a bit sooner.

Could a remap lower idle speed, or would I have to go adjust that parameter in another way?

Euro, iirc you had a problem with idle speed - was it too low? Would I see similar problems if I went from 800 (760) rpm to 650 rpm, for example?

Changing the idle can be done without remapping.

On my car, it took some extra software though, and the guys at the Volvo dealer had to ask how to do it.
I'm afraid it's no longer a case of turning a knob :rolleyes:

Vibrations with the AC on @ idle.
Dipping rpm when coming to a stop - the moment you push in the clutch, it'd dip pretty low - below 600 rpm.
I had the idle increased to cure the symptoms, not the cause.

I wouldn't be surprised if these symptoms were gone after the intake path is renewed though.

Cold, I'd expect it to run rough.

666rpm would be nice though ;)

What I meant was would a remap be enough? If I'd go with it I'd kill two birds with one stone. Of course, before I get around to remapping I may get a chance to hook up to an OEM übercomputer anyway.

I read somewhere (very probable that on EM) that a diesel doesn't need high rpms to keep turning and the only reason idle speed is ~800rpm is for noise/vibration/comfort reasons.
Mine idles >800 when rolling and ~760 when stopped, but I haven't checked with the A/C. I'd think that it would be possible to go lower except when cold or running the A/C.

Don't kill birds ;)

I don't know if the idle setting is achieved by what we refer to as remapping.
It's a pretty basic function in an engine.

The software they downloaded to adjust the idle cost 1,x euro .
You don't get remaps for that :p
It basically enabled them to adjust the idle.
These cars have all the potential built in, but you need to buy/install the software to actually enable them.

Next service, I'll be asking them to switch the OBC to km/L rather than L/100km.


The 1.6 HDi sure doesn't.
When I'm too quick to turn the ignition back to position II when trying to kill the engine, it will drop to very low rpm, but then catch on again.

@saand
those are impressive numbers on your 626, I know a bit about those cars and they are very hard to tune unless going for more power.

for my protege5, I can have it flashed for the MP3 ECU (or just install an MP3 ECU) and it will clean up my powerband (which bounces every which way, including loose....) along with a gain of 2-3 mpg over stock, according to the several people on mzda247 who have done so.
that would be a good base to start with, then I could maybe have that fine tuned even more to gain every ounce of FE as possible.

I don't, unless I want chicken for dinner;)

It's that cheap? I'll ask at my Pug forum about it, somehow I can't believe that my Peugeot dealer would take less than 50€ for anything, no matter how small... Maybe I'll call him up?

I thought that's a parameter that can be done by the driver? I'll check my OBC when (if) it stops raining.

It sounds like what the dealership is using is similar to GMs TechII that can change some parameters.

Changing the idle speed can be done via a remap on most ECUs and should have a few lines in the table. On the cars (gas) that I have looked at they have the following:

The Y-axis is:
AC off in drive
AC off Neutral/Park
AC on in drive
AC on Neutral/Park

The X-axis is:
Coolant Temp

The corresponding cells contain the desired idle RPM. This way the idle will be higher at low temps drop down at operating temp then rise a bit at high temp to spin the water pump more for cooling. Also it will bump the RPM up a bit when the AC is on.

So Hondata's s100 is only $195 and allows tweaking of the air/fuel tables on an OBD2 ECU, such as on my 1998 Civic. Lots use it for street racing, of course, but it should be tunable for MPG, no? Has anyone tried it? I'm not ready for such a move yet, but if anyone has tried it or has an opinion, I'm curious.

Im pretty sure most of your aftermarket tuners come with the ability to tune for power or economy.

This is interestingly a two-edged sword. If you look closely at a lot of the dyno charts for these tuners they show their highest gains below peak. What you are really getting is a broader power curve with more gains down low. (This is generally what I have seen.) That's accomplished by taking out some of the fuel under those parts of the curve. Through the 90's and probably into the 00's manufacturers seemed to be adding a little fuel to the curve to ensure reliability of the motor. This explains how a tuner can give both power and economy simultaneously. To that end, be careful when you go changing your maps for efficiency. Most motors can't take big changes.

while most tuner type tune/reflash does improve efficiency , its partly done by leaning A/F at high loads and increasing ignition timing , its tuned for 91+ fuels .

Now for eco uses you want to remap part throttle area, but this area of load is closed loop modes and is mapped to the A/F of O2 sensor . So you have to somehow adjust this or any changes will be reverted, learned back to the ECU O2 closed loop values, which are for most vehicles around 14.7 .

So depending on the unit and type of hardware (reflash, daughter board, piggyback ,etc) this will be a go or no go depending if you can adjust closed loop modes .

Sorry, I saw this in the email 'best of' today and just had to comment. There are really three main approaches in altering factory tunes:

1. Reflashing
2. Piggy Back
3. ECU Replacement

Reflashing is a broad term. For many ECU's, there are make/model specific parameters that can be tweaked with factory tools and/or ripped off versions of factory tools.

For even more hardcore reflashing, code in the ECU's is functionally altered. For most makes/models there is a an active community in this area, though some makes/models are easier than others. For example, Suburu and Mitsubishi ECUs have been heavily hacked and reflashing hardware is cheap and readily available. On the other hand, vintage Hondas are often reflashed by taking apart the ECU and replacing masked ROM parts with reprogammable memory chips.

Piggy Backs generally use stock ECU's, but then fool them into doing desired things. They do this by replacing sensor signals. If I under or over report MAF or MAP to an ECU, it's response is going to alter. Piggy backs are less flexible, but often perfectly adaquate for typical light weight performance mods. I change the airbox, VE of the engine is changed, so I need just a scootch more fuel...

ECU replacment is sort of the ultimate in control. These range from inexpensive DIY projects, like Megasquirt, to very expensive replacment ECUs. There is a very nifty line out of Australia that uses FPGA technology and a pictoral scripting type language so that you can, effectively, alter virtually anything that the ECU does.

In order for any of these things to be used to get economy, some considering has to go into where fuel is wasted, and why. When a relatively modern vehicle is 'closed loop', it is almost always running very close to lambda 1.0.

People refer to this as 14.7:1, but that is wrong. The actual air fuel ratio to acheive lambda 1.0 is fuel dependant, it moves around a lot just with altering fuel blends. The ECU is not using AFR, but one or more O2 sensors. The sensor itself measures 'equivelency ratio', or 'fi'. Lambda, the scale we use in engine science, is the recipricol of fi. Until the last few years, most cars used 'narrow band' O2 sensors. That is, they only measured 'fi' over a very narrow band. Basically, 'lambda 1.0 = 450 mV'. If you go richer or leaner, the sensor very quickly shoots to about 1V or about 0V.

So, in those vehicles, the only point that the vehicle knows actual lambda with any confidence is lambda 1.0. To understand why this leads to fuel being wasted, we need to understand why this point is being targetted in the first place.

Lambda 1.0 is the 'stoichiometric ratio' for the fuel. That is, it is the optimum mix of air and fuel for the most thermal energy released. This is why it is relatively easy for a narrow band sensor to detect. If combusion is richer, then there are unused HC's in the exhaust, if leaner, excess O2. This sounds really efficient, but it's not. If you want 'best power', you run richer, somewhere around .86 lambda. If you want 'best economy' you run leaner, around 1.05 lambda.

This is because a combusion engine is not a steam engine. It isn't just about how much thermal energy can be released, but how much mechanical advantage can be gained pushing against a piston with expanding heated gases. Running richer than lambda 1.0 also changes the speed and chemistry of the flame front, so peak pressure is moved to a point of more mechanical advantage. And since fuel is plentiful, all O2 gets used. Conversely, going leaner means that all the fuel can get used which, combined with the changing properties of the flame front, still has reasonable mechanical advantage.

The reason that the car runs at 1.0 is purely for emissions. Lambda 1.0 has two important properties. First, it is a point where certain polutants kind of 'bottom out', go away from that point and things like CO and HCs soar. Second, it peak EGT. Peak thermal reaction means hottest exhaust gas. And that heat is needed for a modern cat to work. In fact, cat efficiency plummets very quickly as you move away from peak EGT.

So, much of the time, the vehicle is targetting lambda 1.0, strictly for emissions. But when you stomp on the gas, this is not the place to be. CHTs are fairly high (proportionally) at lambda 1.0 (they peak just rich of stoich, in the .9's), so if you stomp on the gas and stay there, you won't get best power and you'll have high CHTs, lots of fuel, lots of heat and lots of pressure is basically a recipe for detonation. So the ECU runs richer. Best power not only means more power to do whatever it is you stomped on the gas for, it also means lower CHTs.

But, remember 'narrow band' above? An ECU armed only with this sensor doesn't really know for sure where it is running in this case, so factory tunes virtually always error towards 'richer', which costs power, but also brings CHTs down further (by moving peak pressure, not by actually using fuel as some sort of 'spray on coolant').

Performance tuners lean this out (and potentially shift peak pressure with timing as well). They want the lost power back. But this also means better fuel economy for this mode of operation.

Newer vehicles are much more likely to have a 'wideband sensor', or a better idea of exactly where they are running in the .7 to 1.3 range. So those factory tunes generally waste less fuel in those cases. Though there is generally still some waste. The most cutting edge is to use wideband closed loop at targets other than 1.0, but that is another subject.

But people here already avoid that case. So, while they will get savings, it won't be as much as my lead footed wife might get with the same change.

If you don't care about the environment, better economy is not all that hard to acheive. I've done this with a number of vehicles on the dyno and in test environments, like UC Riverside. Basically, I remove the narrow band sensors and replace them with wideband sensors. I then simulate the narrow band signal for the ECU. Think of it this way, the ECU is targetting 450 mV. On a narrow band, this is lambda 1.0, but if I'm reading the exhaust mixture with accuracy at other points and simulating this signal, I can make 450 mV anything I want. If you slowly shift it towards theoretical best economy and let the ECU's adaptive algorythms catch up, you can typically get some clearly measurable fuel savings for same weight, speed, and distance. If you optimize timing to match, there is more savings still.

But emissions get terrible and you potentially destroy your CAT. On my development 'road bed' I still simulate the narrow band signal, but 'tighter' than a real narrow band. That is, I collapse the normal S curve of a typical narrow band. If you track O2 sensor voltage with an OBD-II scanner, you will typically see it oscilalte back and forth, rich/lean/rich/lean as it chases stoich (lambda 1.0). These swings are nec. for cat operation (you need some O2 to burn), but they are a little sloppy. So by making my stock ECU chase a tighter signal, measured emissions actually go down (because the cat spends more time at peak efficiency). There is a tiny fuel savings, but it is so small that it is certainly not worth persuing for its own sake.

When I run with the non stock ECU, I generally run closed loop even in rich operations, which gives the typical driver a lot of savings, but, again, not so much for folks here.

My point in all this is that there are savings to be had here, but the big Kahuna is off limits unless you don't care about emissions. Still, there are some non obvious things that ECUs do that can also be tweaked for savings. Like tweaking shift points to match your driving habits.

Sorry to just jump in (and somewhat rehash), but it is 'my area', so to speak.

No offense but if it was easy I would have retuned my 3800 98 buick to run lean on the highway, the Emission of NoX increases but the majority of the rest of the exhaust (as found) is cleaner. Since I live in a rural area the levels of NoX my 35-52mpg car emits are likely irrelevant and will just turn into fertalizer. Now if I were in downtown LA I might worry more but evidence shows NoX may not be as much of a bad guy as the US government believes.

I would love to lean out my 010 Cobalt the rest of the way at steady state loads but finding proper tools is not all that easy or reasonably priced.

Not to mention most tools don't do lean.

Heck many Honda cars ran lean including the gen 1 insight and had EXCELLENT emissions. I don't doubt their technique would have been far superior to our pig rich and CAT approach.

Anything out there for hacking a 1995 Buick Century V6 or 2004 Dodge Dakota 4.7L V8 to get a bit more MPG?

The Buick nudges 30 with a mix of city, highway and freeway driving. Just recently turned up 60K. Dunno what the Dakota will do yet, just bought it, needs some repair and seems to have a leaky valve on #8 so most likely the engine will need replaced. 140K miles on it.

EFI Live, Hp Tuners, AFC 2.0, to name a few. A U-bend delete should improve your power and mpg a bit. There is ALOT to be done to that vehicle. A WB02 with adjustable output ($200-up) should have gotten you somewhere with no tuning at all. That plus a $80 Alex Pepper scan-tool could have showed you all of your numbers, but not allowed you to change them.

To the OP, I think that checking your intake manifold and getting it cleaned if needed, or looking into water injection would help you out a bit. The re-flash would be good only if the company was good.

Obviously I wasn't clear above. The reason that the tools don't 'do' lean is that, aside from situations like coast down with injectors closed, a modern gasoline vehicle is running stoich, or richer.

Stoich is measured, with excellent precision in normal combustion, by the O2 sensors. So the ECU typically adds fuel relative to that measured point.

Well, "easy" for me is a matter of experience, not access to all the goodies I have.

You could do what I describe above with readily available performance aftermarket stuff now. For example, I happen to have an aftermarket wideband setup sitting on one end of my bench now. The UEGO sensor used would screw right into the same bung your pre-cat O2 sensor is screwed into now. This particular unit has two analog outputs built in, both programmable. By default, one is a wideband output (0-5V DC for .5 to 1.5 lambda) and the other is a simulated narrow band (1V output with 450 mV at lambda 1.0), but you can reprogram either one to whatever you want.

There are some gotchas, like having to put a load resistor on the heater circuit for the removed O2 sensor so you don't throw a check engine light or drop open loop. And you generally have to either mimic the signal with an offset from a small discrete circuit (or just program the 2nd analog output) so that the ECU sees a shift on the post cat sensor in the right direction (HC's being removed). But aside from maybe having to double things up (I can't remember if the 3800 V6 used independant banks or not), pretty straight forward stuff. Since the cat will be rendered ineffictive you can use a bypass (another readily available performance market piece) and pick up a little economy that way (less back pressure in the VE/RPM curve).

You generally would want to periodically reprogram the analog outputs slightly leaner in small steps because a big jump messes up your fuel trims. But the limit is generally not your ability to shift the lambda measurement, but the limits of the fuel delivery system. As you get leaner and leaner you typically hit a point where fuel is not evenly distributed and the engine runs rough. Some engines will actually get to theoretical best economy, some won't. Sometimes swapping around or changing injectors will help.

I recently did instrumentation for an ag study, specifically regarding exhaust and possible positive impacts on soil for cultivation, but I'm not really going to go there. Even at technical conferences specifically in this area discussions tend to drift from what the science tells us (which is all I'm interested in) into people's political ideology.

The problem is in scaling it up for a larger engine and higher powers. For power generated, modern engines are typically more efficient and cleaner, but we're dragging around much heavier vehicles loaded down with built in Barca Lounges and home entertainment systems.

There are two good SAE papers on the system your talking about, including a good one from Horii on the problems of scale encountered. They are fairly technical, but worth slogging through.

I recommend getting a SuperChips FlashPaq for your Dakota. It's what I'm using.

What MPG do you get on the Dakota with the FlashPaq?

About 18.5-19.0 MPG, mostly highway driving.

A Fiat Dakota? Nahh, it's a Hudson. Hudson bought Nash, then bought Chrysler, then Mercedes, now Hudson own Fiat. ;)

I have not posted for a year or two nor have I updated my gas log. I am still running in the 50-55mpg range with my Saturn SL1. I had not heard of the UEGO but a Goggle search showed it to be reasonably priced and it sounded very capable. I tried an innovatemotorsports wide band to narrow band converter several years ago but I did not have the recommended serial port to USB adapter and messed up the calibration. It would not revert to factory settings. This trimmed my Saturn so lean it almost would not run. I barely made it back home and was afraid I had ruined the cat at first. After re-installing the original EGO sensor it took almost 50 miles for the computer to fully trim back to normal operation. I bought the right serial to USB converter but never got around to hooking the system back up. When I first bought my Saturn and added warm air intake the plugs ran white. Over the years the plugs have gradually gotten darker. I am sure the innovate system is better but I bought and installed a "digital" dual quad EFIE from FuelSaver-MPG. I am only treating the pre-CAT sensor so far. As one adjusts for a leaner mixture it takes some time for the computer to adjust the trim. The claim is that this signal modifier can go leaner with a narrow band sensor than other similar systems. I have only driven it about 800 miles so far and as anyone familiar with a Scangage can tell you it can not be trusted after changes like this until it has been recalibrated for a couple tanks. Given that caveat this simple device appears to have added back the mileage that my car has lost over the years. The current tank is at 59 mpg for 380 miles but the calibration may take some of that away. Again I would concur the the wide band sensor is the way to go but This EFIE can make the most of your narrow band sensor and the installation was quite simple. Just needs power, ground and the sensor wire. The adjustments are truly quite precise and easy. I am running a 0.40 volt shift right now with no drivability issues. My plugs are getting white again. I find this to be one cost effective approach if one is not hung up over NO emissions. Ernie

If the s100's interface is anything like KManager (I've got Kpro for my RSX), yes. Not only did it give me a slight improvement of fuel economy (but mostly, more power) at WOT, it very significantly improved my P/T fuel economy. This was achieved by a combination of running leaner, pulling a little ignition timing out for safety when running leaner, and advancing the intake cam further (at P/T) to reduce the vacuum in the intake manifold.

All this required significant time spent tuning it though, and not just a one-time tune and forget either. Because I'm running it at the extreme limits (farther than an OEM would be willing to go) I do have to occasionally take my laptop out and make some changes, otherwise, detonation. It provides an option, though, to flash the CEL if it detects a knock - and the knock sensor is much more sensitive than the human ear. If I can actually hear it knocking there's a major problem.

I don't mind having it taken much farther than an OEM would be willing to, though, because I can always just plug in my laptop and make some changes.

For what it's worth, if the s100 is anything like Kpro, not only can you shut off closed loop (making this all possible), you do get temperature compensation tables for both fuel and spark timing. They take a tremendous amount of time to get dialed in, but they're very helpful.

Hope this all helps. If you do purchase it and need some help with tuning let me know. I'm pretty accomplished, I do all the tuning in my little group (95% power tuning, for the most part I'm the only one who's done any FE tuning, but still)

I think that fooling with cheaps resistors complex control systems will only improve the budget of the seller.

I think that ECU eco tuning it's Greenwashing Greenwashing - Wikipedia, the free encyclopedia most of the times.

I did several high precision data logging sessions measuring fuel consumption with a 0.05 L/100 km precision, and never got any saving.

I have a lot of data and I decidet not tu reflash a fleet because of the results.

Savings are only noticeable depending on gearing and in high slope roads or full weight capacity towing or loading.

The high precision tests needed to obtain optimal fuel consumption and minimum BSFC I think there are no chiptuner that invested time or money enough to develop a scientific research or a scintific independent assesment to ensure the consumer that it's all true.

I know it is possible to obtain little improvements if you don't matter emissions regulations of CO, HC, PM, NOx,... but I have not found any chiptuner that can explain why their new numbers in the ECU will save fuel (according to physics, engeenering, R+D assessments,...). You will get hundred of words, the more you ask the more you will not understand (or, if you have enough sci-tech knowledge in the matter, the more disappointed).

I got coherent savings results in ABA testings when I improved driving techniques, aerodynamics, tires, gearing, repaired thermostat, and sensors who where not precissely tuned or fooling the ECU.

I will appreciatte if anyone could post a BSFC map of a tuned engine. I did not find one.

I have chipped my 1.4 hdi. The box has 2 maps. 1 for economy and 1 for power. The box plugs in series into the fuel rail pressure signal. I know that it is simply increasing fuel pressure earlier than standard but it does work. The car used to be flat above 3000 but it continues pulling now. The economy part simply comes from the fact that I can now use 4th where I would previously have to be in 3rd. Lower speeds but higher gear without labouring the engine.