- Joined
- Dec 25, 2002
- Location
- mont, AL
Here's what I'm going to do/did. I went and researched the more common MS variants, Dug around in the LH hacking world (interesting stuff), and then went and paid little more than basic homage to other off the shelf EMS systems (they wouldn't tell me what I'd want to know anyway, trade secrets and sh|t). This is what I found, and there follows a discussion on fuel injection, some speculation as to how LH works, and a discussion of how megasquirt works. Things (at least I think) everyone oughta know. This is *NOT* a tuning guide...
LH 2.2
Processor specs:
8-bit cpu
max memory of 4k
ram is either 64, 128, 256 (in volvos its 4k rom, and I *Think* 128 bytes of ram)
table size is 16x16
LH 2.4:
8-bit cpu
16x16 table
8k rom, 256 bytes of ram
20mhz max speed (not likely that it actually ran this)
Capable of addressing 128k of external ram (divided into two segments, 1 for storage one for ops) unlikely that bosch added external ram
MS ecu:
8mhz
32k rom, 512 bytes of ram
8x8 table for fuel and 8x8 table for ignition (currently)
8bit
Features: At least two programmable outputs that could be used as: e-fan control, intercooler sprayer/water injection, converter lock up, shiftlight, nos arming, almost anything that can be turned on.
With a code reflash you can have:
Distributorless ignition and fuel control ,along with the two mentioned outputs, A two step revlimiter has been implemented (think flat shift)
Ignition and fuel control with stock volvo components (doesn?t require fabbing of any triggers, not that this is difficult per-se)
Boost controller as well as an aditional injector controller (or additional injector controller along with water injection)
With the addition of a ?daughter board? one could feasibly have full sequential injection, at the very least one gets
Haltech (E6x):
Rpm increments of 500/1000 rpms
32 point maps based on coolant temp? (website was fairly vauge about that)
Features:
Boost control , Engine control (?) , Electric fan , Fuel pump , Nos arming , Turbo timer Anti-lag, vtec, shiftlight, air conditioning, converter lockup
Electromotive Tec3:
? PC programmable and configurable for 1, 2, 3, 4, 6, 8, cyl. engines and Rotories with a 12 cyl.and 6 cyl dual plug option
? Operate in Open or Closed loop
? Run True Sequential, Phased Sequential or Simultaneous Injection with individual cylinder trim
? Configurable for TBI, MPI, TPI and individual throttle bodies
? Additional Injector Output Drivers built-in.. Run Low or High impedance injectors
? Full 150 mJ of Spark Energy directly to the plugs without misfire
? New Dual Rev Limiters with ?Triple Smooth Technology?.. 1st step retards timing to a negative -12? degrees.. 2nd step cuts coil current in half.. 3rd step coil current and fuel are cut-off.. all three steps occurring within milliseconds!
? Waste Gate (Boost Control), Nitrous Control with up to 4 stage retard available
? Four Programmable GPO?s (General Purpose Outputs) to control or activate VTEC, Shift Lights, Water Pumps and Fans, A/C Compressor, Torque Converter and more.
? New Programmable Adjustable Electronic Tachometer Output
? Uses primarily GM type sensors
? Diagnostic monitoring with codes issued through Check Engine Light
? Easy to install bolt-on Trigger Wheel and Mag Sensor Kits available for many applications
Autronic SMC:
Sequential operation for 2 to 8 cylinder engines.
3D fuel and Ignition maps.
User defined up to 32 RPM and 16 Load sites = 512 sites.
Anti-Lag.
Flat Shift (ver 1.19).
Data Logging.
Software selectable trigger angle.
Support for multi-tooth or missing teeth triggers.
Auxiliary outputs other than fuel pump control
8 cyl engine = 1 (1 PWM output).
6 cyl engine = 3 (1 PWM + 2 On/Off)
4 cyl engine = 5(1 PWM + 4 On/Off)
Auxiliary outputs can be defined for boost control, nitrous oxide, camshaft timing, AC, fan control, idle valve etc...
Available with high current drivers if required.
AutoTune option available.
Motec:
Hard to say, couldn?t install their software (don?t ask) and the site doesn?t really do anything but blow smoke, however I?ve heard tell of something on the order of every 12 rpms
So, there we have a breakdown of the features of the stock fuel injection, megasquirt, and a couple other fairly common (at least in the us) aftermarket engine management systems(EMS?s). I really wish I could have gotten the chip specs for the other EMS?s, but I suspect that this would qualify as a trade secret, altho I?m willing to bet they?re just re-badged off the shelf processors. So what does this all mean? At a glance the stock stuff and ms both appear to be rather dated and minimally functional at best, and in the case of the stock ECU?s its hit or miss as to wether or not they?re programmable. As you can see from the above break down of 2.2 and 2.4, the two are fairly close to each other, and as the comment (note to self if you will) says, its not likely that bosch ran the 2.4 processor at its full speed, and the reason I say this is the 2.4 ecus are not ventilated (much like the 2.2 ecus) and even as late as 1990 a 20mhz processor would put out some decent heat. Also, when you look at what they were moving to and coming from, there really wouldn?t be any reason to run it that fast (altho they might very well have, I couldn?t find any specific info on that). Regardless of the clock speed, you?ve got two fairly limited ecu?s, not in power, but in memory, and its apparent why then volvo chose to use a 16x16 map. Why not larger? Bit math comes into play here, 16 * 16 gives you a map with 256 points on it (which many after market ems makers would scoff at?more on this later) The next largest easily divisible number is 32 (16 is 2^4, 32 is 2^5, by using numbers like that you get nice and very easily calculated numbers that greatly reduce the number of calculations the chip has to do just to look up a given point on a table, basically, you fiddle with the address space in a certain way and you get what you need without having to do anything fancy. This might sound silly to you non-software people, but trust me, it?s a common thing), which would net you a table size of 1024. Assuming a byte per point (it could be smaller, say half a byte) you?ve just soaked up ? of the space available on the 2.2 chip, now you?ve only got 3k within which to stick the runtime routine for the chip, the formulas required to interpolate, the coolant ref values, the rev limit, etc. Now, with megasquirt (and really I can only talk in depth about ms, because as stated before, none of the big ems people wants anyone to know whats under their hood), you?ve got a fair amount larger rom space, and twice the scratch pad the 2.4 processor has. The nice thing about the ms ecu is that the clockspeed=bus speed, so generally the processor doesn?t sit waiting for data to come back either from ram or rom (and I?m told there isnt any significant penalty for retrieving from rom vs ram), so things move on through in a fast mannor. With all this extra space, one might be tempted to ask ?Why only 8x8??. This is a good question (And don?t dare ask it on the mailing list unless you?ve got the very best asbestos on). There are a couple of reasons.. the formula megasquirt uses to interpolate between points on the map is fairly well documented as being ?correct? (and for those of you in the crowd that are going to bitch about it having to calculate in between points, understand your beloved LH has to do the same thing, along with every other EMS, and what sepperates the men from the boys is how well coded & what algorithm they use, again, more on this later). The short reason for this (aside from the stauch defense of the blasters ?it works damnit and I don?t want to have to mess with anything bigger?.. noobs) is at the time of implementation, they didn?t really need anything bigger. I?ll insert a bit of tuning theory in here: understand first, that the 8 rpms points and the 8 map points are not hard coded in the ecu, you pick them.. the idea being that you ?cluster? the rpm points around your torque peak (but but but what about the horsepower peak? F the horsepower peak? There is no such thing as horsepower, it?s a calculated number that has no relevance to engine tuning other than bragging rights), what you?re trying to do is mimic on the map what your dyno chart looks like, and for the area where its changing most (the torque peak) you want a couple extra points close together to get that ?good? tune. The points going up to the peak and falling away from the peak are generally linear, and as such don?t require as much attention. Despite this, I personally believe that a 12x12 or even a 16x8 (16 rpm, 8 map) would be nice, the latter probably becoming tiresome to tune. So why then, doesn?t everyone use this and make things easier on the end user. Couple reasons. Bosch didn?t because there?s a certain amount of overhead in calculating (at least in the mannor the ms guys do it, which is grabbing a certain radius of nearby points and working things out from there), and as one can see, theres a limited amount of space. Also, the larger the map the more accurate the interpolation is, and since the lh stuff got setup once, it wasn?t as big a deal to them to have a bigger map. Then there?s the PR factor (or the big dick factor) MY system has twice the map space of his system. What you should read into this is: I, the end user, now have to tune twice the number of points on the map when I change something. And then some of the systems (motec, iirc) have just an insane number of map points (I think e11 is like this as well), and also something many of the companies have to take into account is emissions, the modern motronics have data points ever 5 or 11 rpms (have fun tuning that, I think I?d rather have a carb).
When you start talking about extras, like programmable outputs, those are for the most part, side effects and or unused pins on the chosen chip, and the type and manor in which they function is related to what type of output on the chip that?s being used (basically its up to the engineers that work for a given company, they tend to use what they know best, so if you could get the info on the chips used, I suspect you?d find that they stick with the family of chips they know best, and anything beyond that is bonus). # of outputs has also started to turn into a pissing contest, in reality, you really only need a couple, Fan control is something I?d rather leave to the tried and true thermostat tied to a relay (and a switch on the dash to override the thermostat) NOS arming is also probably best left up to the organic matter behind the wheel (or maybe not depending..). And on a closing note, 8x8 is not limited to megasquirt, electromotive used to(and might still) use an 8x8 map, and it wouldn?t surprise me if others did as well, the methods employed in the megasquirt system are certainly not exclusive to it nor were they thought up exclusivly by its creators (contrary to what some of the zealots might tell you..).
So why is it so cheap would be the next question people ask and use to ?talk down? about it.. For the same reasons commercial systems are expensive.. theres no warranty, no ?live? tech support, no company overhead, and no rent to pay. Conversely, if you burn it up, its up to you to figure out how, why, and how to fix it, if it doesn?t work in your application, you get to either forge ahead on your own and figure it out, or you can post specifics and others can make recommendations (of course you 2,7and 900 series people don?t have to worry about that
). So far that?s worked fine. And a little kernel for those of you who aren?t using electromotive or sds, the vast majority of EMS?s come from australia & europe, so tech support is a long distance call and potentially another language, away?
LH 2.2
Processor specs:
8-bit cpu
max memory of 4k
ram is either 64, 128, 256 (in volvos its 4k rom, and I *Think* 128 bytes of ram)
table size is 16x16
LH 2.4:
8-bit cpu
16x16 table
8k rom, 256 bytes of ram
20mhz max speed (not likely that it actually ran this)
Capable of addressing 128k of external ram (divided into two segments, 1 for storage one for ops) unlikely that bosch added external ram
MS ecu:
8mhz
32k rom, 512 bytes of ram
8x8 table for fuel and 8x8 table for ignition (currently)
8bit
Features: At least two programmable outputs that could be used as: e-fan control, intercooler sprayer/water injection, converter lock up, shiftlight, nos arming, almost anything that can be turned on.
With a code reflash you can have:
Distributorless ignition and fuel control ,along with the two mentioned outputs, A two step revlimiter has been implemented (think flat shift)
Ignition and fuel control with stock volvo components (doesn?t require fabbing of any triggers, not that this is difficult per-se)
Boost controller as well as an aditional injector controller (or additional injector controller along with water injection)
With the addition of a ?daughter board? one could feasibly have full sequential injection, at the very least one gets
Haltech (E6x):
Rpm increments of 500/1000 rpms
32 point maps based on coolant temp? (website was fairly vauge about that)
Features:
Boost control , Engine control (?) , Electric fan , Fuel pump , Nos arming , Turbo timer Anti-lag, vtec, shiftlight, air conditioning, converter lockup
Electromotive Tec3:
? PC programmable and configurable for 1, 2, 3, 4, 6, 8, cyl. engines and Rotories with a 12 cyl.and 6 cyl dual plug option
? Operate in Open or Closed loop
? Run True Sequential, Phased Sequential or Simultaneous Injection with individual cylinder trim
? Configurable for TBI, MPI, TPI and individual throttle bodies
? Additional Injector Output Drivers built-in.. Run Low or High impedance injectors
? Full 150 mJ of Spark Energy directly to the plugs without misfire
? New Dual Rev Limiters with ?Triple Smooth Technology?.. 1st step retards timing to a negative -12? degrees.. 2nd step cuts coil current in half.. 3rd step coil current and fuel are cut-off.. all three steps occurring within milliseconds!
? Waste Gate (Boost Control), Nitrous Control with up to 4 stage retard available
? Four Programmable GPO?s (General Purpose Outputs) to control or activate VTEC, Shift Lights, Water Pumps and Fans, A/C Compressor, Torque Converter and more.
? New Programmable Adjustable Electronic Tachometer Output
? Uses primarily GM type sensors
? Diagnostic monitoring with codes issued through Check Engine Light
? Easy to install bolt-on Trigger Wheel and Mag Sensor Kits available for many applications
Autronic SMC:
Sequential operation for 2 to 8 cylinder engines.
3D fuel and Ignition maps.
User defined up to 32 RPM and 16 Load sites = 512 sites.
Anti-Lag.
Flat Shift (ver 1.19).
Data Logging.
Software selectable trigger angle.
Support for multi-tooth or missing teeth triggers.
Auxiliary outputs other than fuel pump control
8 cyl engine = 1 (1 PWM output).
6 cyl engine = 3 (1 PWM + 2 On/Off)
4 cyl engine = 5(1 PWM + 4 On/Off)
Auxiliary outputs can be defined for boost control, nitrous oxide, camshaft timing, AC, fan control, idle valve etc...
Available with high current drivers if required.
AutoTune option available.
Motec:
Hard to say, couldn?t install their software (don?t ask) and the site doesn?t really do anything but blow smoke, however I?ve heard tell of something on the order of every 12 rpms
So, there we have a breakdown of the features of the stock fuel injection, megasquirt, and a couple other fairly common (at least in the us) aftermarket engine management systems(EMS?s). I really wish I could have gotten the chip specs for the other EMS?s, but I suspect that this would qualify as a trade secret, altho I?m willing to bet they?re just re-badged off the shelf processors. So what does this all mean? At a glance the stock stuff and ms both appear to be rather dated and minimally functional at best, and in the case of the stock ECU?s its hit or miss as to wether or not they?re programmable. As you can see from the above break down of 2.2 and 2.4, the two are fairly close to each other, and as the comment (note to self if you will) says, its not likely that bosch ran the 2.4 processor at its full speed, and the reason I say this is the 2.4 ecus are not ventilated (much like the 2.2 ecus) and even as late as 1990 a 20mhz processor would put out some decent heat. Also, when you look at what they were moving to and coming from, there really wouldn?t be any reason to run it that fast (altho they might very well have, I couldn?t find any specific info on that). Regardless of the clock speed, you?ve got two fairly limited ecu?s, not in power, but in memory, and its apparent why then volvo chose to use a 16x16 map. Why not larger? Bit math comes into play here, 16 * 16 gives you a map with 256 points on it (which many after market ems makers would scoff at?more on this later) The next largest easily divisible number is 32 (16 is 2^4, 32 is 2^5, by using numbers like that you get nice and very easily calculated numbers that greatly reduce the number of calculations the chip has to do just to look up a given point on a table, basically, you fiddle with the address space in a certain way and you get what you need without having to do anything fancy. This might sound silly to you non-software people, but trust me, it?s a common thing), which would net you a table size of 1024. Assuming a byte per point (it could be smaller, say half a byte) you?ve just soaked up ? of the space available on the 2.2 chip, now you?ve only got 3k within which to stick the runtime routine for the chip, the formulas required to interpolate, the coolant ref values, the rev limit, etc. Now, with megasquirt (and really I can only talk in depth about ms, because as stated before, none of the big ems people wants anyone to know whats under their hood), you?ve got a fair amount larger rom space, and twice the scratch pad the 2.4 processor has. The nice thing about the ms ecu is that the clockspeed=bus speed, so generally the processor doesn?t sit waiting for data to come back either from ram or rom (and I?m told there isnt any significant penalty for retrieving from rom vs ram), so things move on through in a fast mannor. With all this extra space, one might be tempted to ask ?Why only 8x8??. This is a good question (And don?t dare ask it on the mailing list unless you?ve got the very best asbestos on). There are a couple of reasons.. the formula megasquirt uses to interpolate between points on the map is fairly well documented as being ?correct? (and for those of you in the crowd that are going to bitch about it having to calculate in between points, understand your beloved LH has to do the same thing, along with every other EMS, and what sepperates the men from the boys is how well coded & what algorithm they use, again, more on this later). The short reason for this (aside from the stauch defense of the blasters ?it works damnit and I don?t want to have to mess with anything bigger?.. noobs) is at the time of implementation, they didn?t really need anything bigger. I?ll insert a bit of tuning theory in here: understand first, that the 8 rpms points and the 8 map points are not hard coded in the ecu, you pick them.. the idea being that you ?cluster? the rpm points around your torque peak (but but but what about the horsepower peak? F the horsepower peak? There is no such thing as horsepower, it?s a calculated number that has no relevance to engine tuning other than bragging rights), what you?re trying to do is mimic on the map what your dyno chart looks like, and for the area where its changing most (the torque peak) you want a couple extra points close together to get that ?good? tune. The points going up to the peak and falling away from the peak are generally linear, and as such don?t require as much attention. Despite this, I personally believe that a 12x12 or even a 16x8 (16 rpm, 8 map) would be nice, the latter probably becoming tiresome to tune. So why then, doesn?t everyone use this and make things easier on the end user. Couple reasons. Bosch didn?t because there?s a certain amount of overhead in calculating (at least in the mannor the ms guys do it, which is grabbing a certain radius of nearby points and working things out from there), and as one can see, theres a limited amount of space. Also, the larger the map the more accurate the interpolation is, and since the lh stuff got setup once, it wasn?t as big a deal to them to have a bigger map. Then there?s the PR factor (or the big dick factor) MY system has twice the map space of his system. What you should read into this is: I, the end user, now have to tune twice the number of points on the map when I change something. And then some of the systems (motec, iirc) have just an insane number of map points (I think e11 is like this as well), and also something many of the companies have to take into account is emissions, the modern motronics have data points ever 5 or 11 rpms (have fun tuning that, I think I?d rather have a carb).
When you start talking about extras, like programmable outputs, those are for the most part, side effects and or unused pins on the chosen chip, and the type and manor in which they function is related to what type of output on the chip that?s being used (basically its up to the engineers that work for a given company, they tend to use what they know best, so if you could get the info on the chips used, I suspect you?d find that they stick with the family of chips they know best, and anything beyond that is bonus). # of outputs has also started to turn into a pissing contest, in reality, you really only need a couple, Fan control is something I?d rather leave to the tried and true thermostat tied to a relay (and a switch on the dash to override the thermostat) NOS arming is also probably best left up to the organic matter behind the wheel (or maybe not depending..). And on a closing note, 8x8 is not limited to megasquirt, electromotive used to(and might still) use an 8x8 map, and it wouldn?t surprise me if others did as well, the methods employed in the megasquirt system are certainly not exclusive to it nor were they thought up exclusivly by its creators (contrary to what some of the zealots might tell you..).
So why is it so cheap would be the next question people ask and use to ?talk down? about it.. For the same reasons commercial systems are expensive.. theres no warranty, no ?live? tech support, no company overhead, and no rent to pay. Conversely, if you burn it up, its up to you to figure out how, why, and how to fix it, if it doesn?t work in your application, you get to either forge ahead on your own and figure it out, or you can post specifics and others can make recommendations (of course you 2,7and 900 series people don?t have to worry about that
). So far that?s worked fine. And a little kernel for those of you who aren?t using electromotive or sds, the vast majority of EMS?s come from australia & europe, so tech support is a long distance call and potentially another language, away?
, tuning my map was largly limited to following the boost across the map, and then trying to get the off boost stuff right in a similar mannor. I can see where some of the people who don't want to mess with it are coming from, it does get a little tedious after a while (but most of the time its fun). I've toyed with the idea of going through the code and doing it myself, the problem is in order to do so I'd have to re-write most of the ve table code in order to do so, and thats not really something that gets me pumped (its hard to get pumped over coding assembly tho). 
), i'm sure there was some reason (which left us with those bastard 37/9 pin parallel looking things). The board design might not be optimal, but I dont really see how that would precipitate failure, I'm curious to hear boris's thoughts on that.
