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Ethanol ECU-Related Master Thread

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This thread is for everything computer related concerning ethanol tuning. Ethanol is compatable with existing computer technology in your EFI equipped car. This thread is for the number crunching electronic portion of things. The add-on computers have their own sections of the site. I was thinking this would be more for programmable ECUs, relfash information, computer map files, bi-fuel injection systems, and other piggybacks that don't have their own forums.


Please include:






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Wow total gohst town here :P


My name is Chuck B from the Boost Factory in Minneapolis MN (where E85 is everywhere).I do alot of ECU tuning on cars (motronic  BMW,VW,merc and almost all other european vehicles) along with most GM,Honda,and a few others.My experience comes with modifying cars to run for boost and the same technology works for tuning with E85.My shop van is a 88 GMC 1500 with 4.3l TB injection converted to E85.If anybody needs a chip file for this vehicle I can email it to you.

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I never posted in this thread what I made it for. Better late than never LOL.


What I'd like to highlight is different ECU-related options for those looking to tune for higher ethanol blends. Through fuel and timing tuning, you can make more power and regain lost mileage. With later model EFI cars, we do this through the computer rather than jetting a carb and setting the distributor. I've stated before that tuning your engine for ethanol uses a lot of the tools already on the market. I'll attempt to relay a lot of that here.



Stock vehicles:




No, you don't need Robbie the Robot to diagnose your car's computer. You can pick up an OBD scan tool from your corner auto parts store. It will list almost everything your car computes on a readout screen. You can read the oxygen sensor values, injector duty cycles, spark timing, throttle opening, and a myraid of other values used by your car's computer. The scan tools can run anywhere from $150-$500. It ONLY reads information. You CAN NOT change any values in the computer with one of these. No in-depth wiring knowledge is needed, either. These tools are very much non-invasive. They plug into your car's existing OBD computer port located near the steering wheel or inside the glovebox. They can pull error codes from your computer as well as give live readouts of most of the computer's values. Tucked inside those values, it will be helpful to learn what to watch for when trying different blends of ethanol. Look for injector duty cycle (how busy your fuel injectors are), spark timing changes, fuel pump signal, and throttle opening (driveability changes slightly on ethanol) for beginners.


Another option is a little more involved but not awfully hard. If you have access to a laptop computer and an OBD cable, you can see everything a scan tool would but with a prettier interface. There are many programs available online to turn your laptop computer into a powerful scan tool. You can even surf the internet while reading your computer's values. Although, doing such while driving is highly ill-advised ;). OBD scan programs available online can work with a desktop, laptop, or even a PDA. (I'll list a few of the options later.)




Everyone else...


Perhaps you're well on your way to tuning a ridiculously fast beast of a vehicle. There's a few tools that will come in handy that you may or may not already have.



Wideband exhaust sensor

One of these handy little tools will read CO, CO2, and NOx in your exhaust. It is considered one of the ultimate tools for dialing in your fuel mixture no matter what fuel you are using. They cost between $200-$400. You'll need a bung welded into the exhaust similar to an O2 sensor's bung. (huh huh uhhhh huh huh...bung.)


EGT gauge

Exhaust Gas Temperature is what EGT stands for. Basically, your exhaust is hot. How hot it is or isn't can tell you a lot. If the mixture is too rich, EGT's drop by a couple of hundred degrees and power dives. Running too lean, EGT's rise. The catch with ethanol is that it doesn't detonate when lean like gasoline does. You can hear a lean condition with gasoline, but can't hear it with ethanol. Coupled with a wideband and some practice, you will quickly be able to tell if you are running rich, lean, or just right. The EGT gauge will need a bung welded in the exhaust. Hardcore racers have one EGT gauge per cylinder. The rest of us can live with only one EGT gauge. It is helpful to know which cylinders might run leaner, though. Not all cylinders in a factory engine flow the same even though they're pretty close. EGT gauges cost between $100-$300. Money is well spent on higher end gauges. Cheaper models only get more innacurate as the price goes down.


Programmable computer

This is the creme-de-la-creme of adjustments for your car. Don't panic, though. You don't need one of these to simply run on ethanol. You'll need one of these if you are tuning for POWER.  All three of these tools listed are a commonly available combination for power tuners. It's also the same tri-fecta of tuning tools that you would use to run on gasoline. The trick with using them with ethanol is knowing what values change and how. Adjusting fuel and timing curves, or "mapping", is the key to dialing in power and efficiency on either gas or alcohol. Comparing tuning for either, there are a few things worthy of noting. (computers can cost anywhere from $400 up to $20,000 for the hardcore types.)


Firstly, you have to run richer fuel mixtures on ethanol blended fuel. Above 30% ethanol mixtures is where you have to be a little more concerned with how rich or lean your engine is running. If you've been doing your homework, you know that this richer fuel mixture is a dead-set requirement on higher blends. The only exception is cruising speeds and light loads. Here, you can cheat somewhat by running a leaner fuel mixture to pick up fuel mileage. This ONLY works at lighter loads and smaller throttle openings. E85 still needs to be around 9-10:1 AFR to be happy under wide open throttle (WOT). E98 and E100 will like it closer to 8:1 @ WOT. E30-E50 mixtures will like things around 11-12:1. Both fuel and timing curves are also smoother with ethanol compared to gasoline. You aren't tuning around detonation like crappy pump gas.


Timing requirements don't really change much for ethanol blends. You CAN run more timing, but you don't HAVE to. "Timing" is referred to as when the spark plug fires in relation to the crankshaft's rotation. The piston's location of TDC, or top dead center, is considered a standard reference point for setting timing. The farther your timing is ahead of the piston's TDC location, the more "advanced" the timing is. If the spark plug fires closer to TDC or after, it is considered "retarded". Fire the spark plug too early and you'll get spark knock. Fire it too late and the flame from will chase the piston down the cylinder instead of pushing on it. Timing requirements are different at various engine speeds, loads, and throttle openings. The basic idea behind timing is to ignite the fuel at just the right time. This makes the burning fuel act on the piston for the longest possible time. Since the fuel never burns all at once, it has to be ignited at the right time to burn appropriately pushing down on the piston.


What are your options for ECUs?


It is highly advised that you only purchase an adjustable ECU if you are a diehard car guy. you're likely shopping for one already if this paragraph still interests you. If you do not have a wideband AND an EGT gauge, get those installed first. You may find your stock system operates just fine. If you are truely ready to go this route, then view your options below.



Piggyback systems


"Piggyback" computers are called so because they work in unison with your stock computer. Mostly, they alter output signals to your fuel injectors and ignition from the stock computer. Driveability is retained as is flexibility of the stock computer. At least, that's how the theory goes. In practice, they work somewhat differently. Your stock computer is coded to understand input, processing, and output data. It checks values against previously programmed figures or historical data that it recorded during operation. If one of these three aspects gets changed and the computer is "checking itself", then you can run into problems. A computer is basically stupid and only does what it's told. Even though the stock computer may be giving instructions it thinks is correct, those instructions might not work with your modified engine package. The computer wants to do what it's told to do with it's own software, not what you the squishy human wants it to do. When altering signals that the computer needs to operate, it's like putting the computer in a house of mirrors. It can't see straight and doesn't know it's looking at a disorted image. No sensor on your car is there for show. there's not redundant sensors but there are redundant instructions in the computer. One sensor alone can be used in hundreds of different computations. Think about that when you're messing with EFI. Truthfuly, the less that you mess with the computer, the better off you are. Only change what you have to or really really want to to achieve more power.


There are different kinds of piggyback computers available. A complex one would be the Greddy E-Manage. It can control everything. The Unichip and UTEC are other popular options. All of them work basically the same. You could consider them a "hard wired virus". They all three jack signals from the stock computer and let you make your own instructions. When the stock computer fights the piggyback for control of the car, it makes for it's own headaches. You can get mysterious check engine light codes or the car might skip into "limp mode" and not run very nicely. You're looking to balance the car literally on the head of a pin the more you try to get power increases out of it. (Cost $400-$2,000)


Other kinds of piggyback computers only highjack or augment certain parts of the stock computer. Chiefly, you can buy separate fuel and timing controllers to fit your needs. An add-on fuel system can still do many things for an ethanol powered car. You can run a separated secondary fuel system to carry ethanol or some other fuel. You can also supply extra flow capacity for the existing fuel system on demand. The secondary injectors can be triggered at specific RPM's, loads, or boost levels to accomodate fuelling needs of boost, nitrous, or both. Often, secondary fuel systems only intercept signals and don't modify the output. They only need the existing computer signals for referencing their own instructions. They don't change the factory systems. They're more of a genuine add-on instead of a half-baked replacement for something stock that likely works fine anyway. Timing controllers can be a cheap and easy way to dial in a bit more or less spark timing and leave the stock computer mostly alone. Boost-referenced timing retard systems, like the J&S timing retard system, back off a few degrees of spark timing as boost pressure rises from a turbo or blower. This staves off detonation, which is far more of a problem on gasoline than ethanol.


Stand-Alone Computers


Stand-Alone computers are for the hardest of the hardcore. You often replace the stock computer and it's wiring harness entirely with a new setup. It is a very time and labor intensive thing to do. You are usually given no base maps to work with, either. Often, a class or three is required to fully understand the capabilities and limitations of such systems. Get ready to pay for a lot of dyno time, a lot of tuner time, or both. This is the realm of F1 and drag racing and should not be taken lightly. It is NOT a "Fast and Furious" upgrade. You should read and learn as much as possible before going this route. It is one problem you can not throw money at and expect things to work. If you drive your car only rarely, and were seeking a cheap fuel to support plenty of power, you probably considered this route already. Altitude, humidity, and temperature can all three mess with the accuracy and efficiency of the computer mapping you generated. This is for only the highest strung cars and individuals ;).



Whew! I hope that covers some things for now. I'll edit this post later. I have a bad habit of rambling while at work when there's nothing to do ;).


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Just so you guys know its really easy to reprogram most ECUs.Here is the configurable program that I use for tuning most of my cars at the shop.Its free for personal use and recomended to pay some $$ for licence if you are using it for making money.




A cheap chip burner from this place is the rest of the puzzle for tuning your car.




You will also need a laptop with good battery an eeprom and possible conversion board for whatever vehicle you have (look on moates site for this).You will also need a definition file for your perticular vehicle to use with tunerpro.If you have any questions where to get these files just let me know and I'll point you in the right direction.All total you should be able to tune most GM cars for ~ $100 and fords will be marginally more expensive.

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Chuck is spot on! This is another tuning method wholly deserving of more attention. I've pushed all along that stock computers have more power than they've been given credit.


OBD1 factory computers, mostly domestics, have what is called a PROM chip, or "Programmable Read Only Memory". The PROM chip is often a removable piece on the computers motherboard that you have to crack the case, or at least unscrew a small panel, to reach it and physically change it. This chip contains the fuel and timing "mapping values" that I mentioned earlier. It's fairly easy to change those mapping values with the right computer equipment, too. The evolution of the PROM chip lead to what is called "flash memory." Instead of popping chips in and out, later model OBD2 cars can have their internal mapping instructions "flashed". What mapping is, is really instructions for spark and fuel. Having such a wide range of adjustability coupled with pinpoint accuracy is the appeal of EFI in the first place. With reflashes, you can change those instructions virtually on the fly, in just a minute or two.


Where I really believe there is a lot of potential in factory cmoputers is using reflash and prom technology. It's not nearly as invasive, complicated, or time consuming as the options I mentioned earlier. (Thanks for reminding me to type this up, Chuck ;).) A potential complication is having to switch maps if you want to go between gasoline and ethanol. You can only use one map at a time.


If fuelling were given more adjustability, outside of the 25% +/- adjustability that the stock computer has, you'd basically have a flex-fuel car already. Frankly, I don't know how to pull that off. But, I can build new maps with the right equipment! So can you! All you have to do is Google ECU options for your car, or talk to someone who's got the right connections. Imports are harder to crack than domestics have been. As weird as it may sound, it seems like domestic companies WANT you to work with their ECU's, while foreign counterparts don't. While that isn't an attempt at pointing fingers, I do think domestic companies have the right idea of giving the customer the flexibility he needs.


BIG +1 for reflash and PROM technology. You can use those methods to work with many existing factory cars. Swapping bigger fuel injectors and retuning the stock computer is the ideal solution, IMO. Unfortunately, it doesn't work for everybody. Thankfully, there's more than one way to skin a cat, and reflashing/prom tuning is one of the easier ways to pull it off if there is a support system for your car.

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ChuckB --


                Have any experience with the Saabs 93 (turbo) running E85??


            Would it take a little tuning after a (larger) injector changeover??


            We live at 5000 ft altitude and frequently take this car to the hills west of us..


            (you may have seen us on the news recently .. we actually made it back thru that blizzard)


              I figure a  5000' run up in elevation may give some interesting fuel consumption datapoints

            (it's mostly non-stop driving UP the hill , at least ).


              This is a '99 93 with about 160K on it ,  still running strong..


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Here are some of the options as far as switching goes.




On my van I just switch chips under the drivers seat for now.On most of the GM ECUs there is a main injector scaler # where you can almost tune it for E85 by changing one 16bit value.If we can find another input thats not being used by the processor we may be able to move that value into a seprtate loop to run a fuel sensor to change it automatically.


If the Saab 93 is a motronic car I could do it with some work,if its not a motronic car it can also be done although its even more work.

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