Just curious. Glad the torrie doesn't have an ECU.
Edited by Yella SLuR, 24 August 2006 - 03:19 PM.
Computer ECU's
Started by
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, Aug 24 2006 03:18 PM
7 replies to this topic
#1
_Yella SLuR_
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Posted 24 August 2006 - 03:18 PM
At a very basic level, all the computers on cars do is control the spark for optimum burn. Given that basic concept, what difference does chipping up a car do? i.e. is it just a faster computer, or does it do other things, i.e. more agressive spark advance, etc.?
Just curious. Glad the torrie doesn't have an ECU.
Just curious. Glad the torrie doesn't have an ECU.
#2
_LH SL/R 5000_
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Posted 24 August 2006 - 03:55 PM
Not just spark but also fuel. Fitting a new chip or reprogramming a chip will modify a heap of ECU outputs the principle one being fuel and spark timing. The amount of fuel and timing of fuel delivered constantly changes along with the spark timing. These parameters are constantly changing with reference to the signals received from the engine sensors. Reprogramming is usually only required when you have changed something ie. cam, manifold, exhaust, /wheel/tyre size.
#3
_whiteLC_
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Posted 24 August 2006 - 04:01 PM
I'm no expert by any means, however....
Some computers control fuel only and some control fuel and spark.
So depending on what you want from a particular engine (eg. performance, fuel economy or something in between, etc.) the computer, through sensors, works out what is needed, ie. more/less fuel, different spark timing and probably much more, depending on how complex the computer is.
Also the chip needs to be altered if you make too much of a change to the engine (eg. different cam, forced induction etc.) This is so the 'program' in the chip understands what is happening with reference to the new equipment installed.
That's my understanding anyhow.
Some computers control fuel only and some control fuel and spark.
So depending on what you want from a particular engine (eg. performance, fuel economy or something in between, etc.) the computer, through sensors, works out what is needed, ie. more/less fuel, different spark timing and probably much more, depending on how complex the computer is.
Also the chip needs to be altered if you make too much of a change to the engine (eg. different cam, forced induction etc.) This is so the 'program' in the chip understands what is happening with reference to the new equipment installed.
That's my understanding anyhow.
#4
_JBird_
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Posted 24 August 2006 - 04:11 PM
The more advanced computers can be tuned to achieve the max air/fuel/spark ratios/timing for certain rpm ranges, rather than having a 'one-size fits all' tune that regular ECU's have. Especially where cams are involved, a more advanced ECU is required to take advantage of it.
A chip is just a 'piggy-back' to the main ECU, so cold start etc. stays the same, but the chip contains information for the different RPM or amounts of air in relation to how much fuel to let in etc. This generally makes more power, because its no longer conservative (from the factory) and possibly not be able to pass ADR exhaust regulations etc. A chip has to be flashed (erased and new memory saved each time), so theres less possibilities for tuning. Where as a MoTec etc. you would be able to tune in real time Off a laptop (on the road or dyno) - making things constant, especially if you have a wide band air/fuel meter.
A chip is just a 'piggy-back' to the main ECU, so cold start etc. stays the same, but the chip contains information for the different RPM or amounts of air in relation to how much fuel to let in etc. This generally makes more power, because its no longer conservative (from the factory) and possibly not be able to pass ADR exhaust regulations etc. A chip has to be flashed (erased and new memory saved each time), so theres less possibilities for tuning. Where as a MoTec etc. you would be able to tune in real time Off a laptop (on the road or dyno) - making things constant, especially if you have a wide band air/fuel meter.
#5
_devilsadvocate_
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Posted 24 August 2006 - 04:18 PM
Chips are mapped for a particular market. A motor marketed for a particular car in Australia may spend half a year on the dyno getting its chip mapped for Australian regs and conditions, whereas the same motor sold in another vehicle in another country would have to undergo the same dyno development to meet the requirements of that vehicle. A big part of this apart from performance is meeting emission controls when the motor is in all operating states. As mentioned previously, all inputs such as road speed, gear, throttle position, rpm, o2, temp, engine load - aircon,powersteering etc, manifold pressure......... or everything that can be measured which has an influence on how the engine will perform. The chip will determine the best combo of fuel/air mix and spark timing to achieve all of this....amongst other things. Changing a chip for performance obviously can do many things, like give it slightly richer mixtures, change rev limiter and obviously emissions may be changed too, perhaps on the non conforming side.
#6
_LX_SS_
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Posted 24 August 2006 - 04:24 PM
depends on what computers your talking about, there a many and i mean many different configurations in cars today, for example, different ecus using vaf, maf , map, different types of ways measuring airflow.
most ecu's control the cars fuel and ignition, it uses an airflow meter, or map sensor to determine airflow / vacumme and using that cross referenced by rpm and your throttle position sensor, water temp sensor, and o2 sensor (if applicable) to determine how it should run. its sorta a basic run down of it, without getting technical.
aftermarket ecu's allow full control over the ignition and fuel map on the ecu, as well as monitoring sensors etc... beware tho most aftermarket ecu's don't have knock feedback, which is very very handy to have. most standard ecu's run knock sensors :-)
you can still tune standard computers in real time using an emulator, once you have you map right its a simple matter of burning the chip and plugging it in.
any mods done to the engine should be retuned to suit, this goes for carby as well, the biggest advantage is the tunability at different rpms as carby isn't as great in tuning, this ability to tune so much more of the power range gives better fuel economny, power, and driveability. lots of people will say when u go efi u won't go back, because its a big advancement in running your car reliably.
most ecu's control the cars fuel and ignition, it uses an airflow meter, or map sensor to determine airflow / vacumme and using that cross referenced by rpm and your throttle position sensor, water temp sensor, and o2 sensor (if applicable) to determine how it should run. its sorta a basic run down of it, without getting technical.
aftermarket ecu's allow full control over the ignition and fuel map on the ecu, as well as monitoring sensors etc... beware tho most aftermarket ecu's don't have knock feedback, which is very very handy to have. most standard ecu's run knock sensors :-)
you can still tune standard computers in real time using an emulator, once you have you map right its a simple matter of burning the chip and plugging it in.
any mods done to the engine should be retuned to suit, this goes for carby as well, the biggest advantage is the tunability at different rpms as carby isn't as great in tuning, this ability to tune so much more of the power range gives better fuel economny, power, and driveability. lots of people will say when u go efi u won't go back, because its a big advancement in running your car reliably.
#7
Dr Terry
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Posted 24 August 2006 - 06:15 PM
Hi Yella SLuR.
Here's my 2c worth.
ECUs in cars do a lot more than just control spark. To fully explain this you have to do a small history lesson in EFI first.
The very early EFI systems (Bosch D-Jetronic -1969 VW was the very 1st) controlled only the fuel by varying the width of the injector pulse. The ignition system was still the same as carburettored cars with points & both vacuum & mechanical advance. Even the fuel pump was controlled externally to the ECU. These were EFI at its most basic. As time went on, the systems got progressively �smarter�. The ignition systems went electronically triggered, but were still separate, remember the VK EFI system had a separate Bosch HEI dissy, no oxygen sensor or the like. Later again, they added oxygen sensors & idle control motors etc. The next step was when they added digital processor, making programming easier & the availability of proper fault code diagnosis.
The big step was when they made the ignition advance curve fully electronic & let the ECU take full control of not only the fuel but the ignition curve as well. The VN/VP Delco ECU is probably the best of this type, as it controls a multitude of tasks. They directly control, not only both fuel quantity & spark advance timing but also idle control speed (for all loads & temperatures), fuel pump operation, engine cooling fans, fuel canister purge, air conditioning clutch, torque converter clutch etc. just to name a few. Later again, (VR/VS etc) they have full control over auto trans shifting & work in with the ABS to give traction control etc. & also communicate with the anti-theft immobiliser. Most current systems also have a fully electronic throttle i.e. no cable or linkage; the ECU does all of this.
Getting back to the original query, what does �chipping up a car� do? Well, that�s probably the biggest single myth the automotive industry. �chipping up� literally means reprogramming (or swapping) the main processor IC in the ECU. You can reprogram it to do anything you want, but if you think you can get more �free� power by just re-mapping the fuel & spark curves think again. The car manufacturer has just spent probably millions of $ getting the best combination of performance, economy, drivability & reliability out of his ECU so it�s better than what the opposition can offer in a very competitive market place. Can a �backyard� programmer do better than that, probably not? They could make it feel better or different by changing some of the parameters, like shift points, rev limit or throttle feel, but unless the manufacturer had deliberately detuned the ECU for some reason in the 1st place (pollution, marketing, safety etc) there isn�t any easy way to �unlock� more �free� power.
The best way to view �chipping� is reprogramming to suit modifications that you�ve done to the engine. For instance, if you put a different cam, exhaust & set of heads on your old carby Torana, to get the best out of these mods, you would go to a guy with a dyno & get the dissy recurved & the carby re-jetted to match these mods. Well the ECU is no different, if you change cam, exhaust, heads or whatever you need the fuel & ignition maps in the ECU reprogrammed to match those mods. This is where the aftermarket tuners do their best work.
On your old car how much power or economy gains would you get by fitting a larger jet or recurving the dissy on a completely factory stock engine, not much I would say. So, re-chipping an ECU to get big increases in power with no other mods is a bit of a fallacy IMHO.
Dr Terry
Here's my 2c worth.
ECUs in cars do a lot more than just control spark. To fully explain this you have to do a small history lesson in EFI first.
The very early EFI systems (Bosch D-Jetronic -1969 VW was the very 1st) controlled only the fuel by varying the width of the injector pulse. The ignition system was still the same as carburettored cars with points & both vacuum & mechanical advance. Even the fuel pump was controlled externally to the ECU. These were EFI at its most basic. As time went on, the systems got progressively �smarter�. The ignition systems went electronically triggered, but were still separate, remember the VK EFI system had a separate Bosch HEI dissy, no oxygen sensor or the like. Later again, they added oxygen sensors & idle control motors etc. The next step was when they added digital processor, making programming easier & the availability of proper fault code diagnosis.
The big step was when they made the ignition advance curve fully electronic & let the ECU take full control of not only the fuel but the ignition curve as well. The VN/VP Delco ECU is probably the best of this type, as it controls a multitude of tasks. They directly control, not only both fuel quantity & spark advance timing but also idle control speed (for all loads & temperatures), fuel pump operation, engine cooling fans, fuel canister purge, air conditioning clutch, torque converter clutch etc. just to name a few. Later again, (VR/VS etc) they have full control over auto trans shifting & work in with the ABS to give traction control etc. & also communicate with the anti-theft immobiliser. Most current systems also have a fully electronic throttle i.e. no cable or linkage; the ECU does all of this.
Getting back to the original query, what does �chipping up a car� do? Well, that�s probably the biggest single myth the automotive industry. �chipping up� literally means reprogramming (or swapping) the main processor IC in the ECU. You can reprogram it to do anything you want, but if you think you can get more �free� power by just re-mapping the fuel & spark curves think again. The car manufacturer has just spent probably millions of $ getting the best combination of performance, economy, drivability & reliability out of his ECU so it�s better than what the opposition can offer in a very competitive market place. Can a �backyard� programmer do better than that, probably not? They could make it feel better or different by changing some of the parameters, like shift points, rev limit or throttle feel, but unless the manufacturer had deliberately detuned the ECU for some reason in the 1st place (pollution, marketing, safety etc) there isn�t any easy way to �unlock� more �free� power.
The best way to view �chipping� is reprogramming to suit modifications that you�ve done to the engine. For instance, if you put a different cam, exhaust & set of heads on your old carby Torana, to get the best out of these mods, you would go to a guy with a dyno & get the dissy recurved & the carby re-jetted to match these mods. Well the ECU is no different, if you change cam, exhaust, heads or whatever you need the fuel & ignition maps in the ECU reprogrammed to match those mods. This is where the aftermarket tuners do their best work.
On your old car how much power or economy gains would you get by fitting a larger jet or recurving the dissy on a completely factory stock engine, not much I would say. So, re-chipping an ECU to get big increases in power with no other mods is a bit of a fallacy IMHO.
Dr Terry
#8
_Yella SLuR_
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Posted 24 August 2006 - 06:44 PM
Thanks for that guys. That's what I couldn't work out, if the computer optimises the burn through fuel and spark via the 02 sensor, then how can changing a chip change it. The only thing I could think of is the chip is optimised for fuel economy, and a performance chip optimised for power. Even then, I couldn't see that there would be much difference between the two.
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