Stand alone ECU project
07-01-2014, 07:15 PM
#61
Three Wheelin'
Thread Starter
I've downloaded the latest release of VEMStune and loaded up an example configuration and map to have a play. It does look very well put together. As a non expert I could pretty much find everything I would need.
Here's a video of one of the two built in VE tuning mechanisms. This method involves running the engine through the cells on the ve table, on the road or dyno, you can log to sd card so plenty on memory. Once you have some data it analyses the corrections required (using the wbo2 logged compared to the target afr) and makes it simple to apply them. Skip past the annoying music at the start.
Here's a video of one of the two built in VE tuning mechanisms. This method involves running the engine through the cells on the ve table, on the road or dyno, you can log to sd card so plenty on memory. Once you have some data it analyses the corrections required (using the wbo2 logged compared to the target afr) and makes it simple to apply them. Skip past the annoying music at the start.
07-02-2014, 09:23 AM
#63
Three Wheelin'
Doczilla,
I've only just spotted this. Obviously I don't understand much of it but would be interested in following up once we see how it plays out on your car! What kind of cost are you looking at in parts..roughly?
I've only just spotted this. Obviously I don't understand much of it but would be interested in following up once we see how it plays out on your car! What kind of cost are you looking at in parts..roughly?
07-02-2014, 09:54 AM
#64
Three Wheelin'
Thread Starter
Mapping depends on how much you can do yourself. If you can work a computer or, cough, know a man that can
, it looks like VEMSTune will help you map the VE table fairly easily which takes car of the fueling (the two videos above). You only need a dyno for "hard to reach places" on the rpm vs map table that you only pass through quickly on the road.Speed density tuning, which should work for you and me, requires setting up a Volumetric Efficiency (aka VE) table - this tells the ecu the "pumping" efficiency of the engine at different RPM and different pressures in the manifold as measured by a MAP sensor.
Once you have the VE table you setup another table with your target air fuel ratios; for optimum economy at idle and cruise, and optimum power under load (best power AFR=13.0 ish for a 964 - leaner than most cars) again the table is a grid of columns for RPM vs rows for MAP values.
Finally you set a table which sets the ignition advance, again its a grid of columns for RPM vs and rows MAP values (FYI 964s run low ignition compared to most due to the twin spark, which makes the fuel burn more quickly, which is good in all sorts of ways) the goal here is to make the best torque (without causing knock) pretty much everywhere except on idle where you want a sort of middling amount of advance that lets the ecu advance or retard timing to control the idle rpm. This really needs a dyno as you want to do a "spark hook" test where you hold the car at a given load and rpm and advance the timing until it either knocks (in which case you back off a few degrees and leave it) or the torque stops rising (which is known as MBT).
The ignition map is critical (it's the magic in a SW chip) and makes a big difference to part throttle, throttle response and "tip-in" so is worth doing and is almost impossible on the road, so you need a good dyno and a friendly mapper. There is a bit of back on forward as when you change the timing you need to go back and check the AFRs.
I'm getting the man that maps my Skylines to do the ignition for me on his hub dyno (he maps all sorts, N/A, SC, Turbo, ITBS, Drag, Race, Road - Link/VIPEC, Motec, ECUTEK etc, etc). It will probably cost me a £300-400 in dyno time depending on how good the ignition map Peep supplies is and how long it takes to figure the software out the first time.
07-02-2014, 10:08 AM
#65
Three Wheelin'
About a grand in parts plus mapping (fitting myself obviously). So you can spend the difference compared to a 9m Motec on a s/h supercharger kit, or some Jenvy throttle bodies and a nice exhaust system!
Mapping depends on how much you can do yourself. If you can work a computer or, cough, know a man that can , it looks like VEMSTune will help you map the VE table fairly easily which takes car of the fueling (the two videos above). You only need a dyno for "hard to reach places" on the rpm vs map table that you only pass through quickly on the road.
Speed density tuning, which should work for you and me, requires setting up a Volumetric Efficiency (aka VE) table - this tells the ecu the "pumping" efficiency of the engine at different RPM and different pressures in the manifold as measured by a MAP sensor.
Once you have the VE table you setup another table with your target air fuel ratios; for optimum economy at idle and cruise, and optimum power under load (best power AFR=13.0 ish for a 964 - leaner than most cars) again the table is a grid of columns for RPM vs rows for MAP values.
Finally you set a table which sets the ignition advance, again its a grid of columns for RPM vs and rows MAP values (FYI 964s run low ignition compared to most due to the twin spark, which makes the fuel burn more quickly, which is good in all sorts of ways) the goal here is to make the best torque (without causing knock) pretty much everywhere except on idle where you want a sort of middling amount of advance that lets the ecu advance or retard timing to control the idle rpm. This really needs a dyno as you want to do a "spark hook" test where you hold the car at a given load and rpm and advance the timing until it either knocks (in which case you back off a few degrees and leave it) or the torque stops rising (which is known as MBT).
The ignition map is critical (it's the magic in a SW chip) and makes a big difference to part throttle, throttle response and "tip-in" so is worth doing and is almost impossible on the road, so you need a good dyno and a friendly mapper. There is a bit of back on forward as when you change the timing you need to go back and check the AFRs.
I'm getting the man that maps my Skylines to do the ignition for me on his hub dyno (he maps all sorts, N/A, SC, Turbo, ITBS, Drag, Race, Road - Link/VIPEC, Motec, ECUTEK etc, etc). It will probably cost me a £300-400 in dyno time depending on how good the ignition map Peep supplies is and how long it takes to figure the software out the first time.
Mapping depends on how much you can do yourself. If you can work a computer or, cough, know a man that can
, it looks like VEMSTune will help you map the VE table fairly easily which takes car of the fueling (the two videos above). You only need a dyno for "hard to reach places" on the rpm vs map table that you only pass through quickly on the road.Speed density tuning, which should work for you and me, requires setting up a Volumetric Efficiency (aka VE) table - this tells the ecu the "pumping" efficiency of the engine at different RPM and different pressures in the manifold as measured by a MAP sensor.
Once you have the VE table you setup another table with your target air fuel ratios; for optimum economy at idle and cruise, and optimum power under load (best power AFR=13.0 ish for a 964 - leaner than most cars) again the table is a grid of columns for RPM vs rows for MAP values.
Finally you set a table which sets the ignition advance, again its a grid of columns for RPM vs and rows MAP values (FYI 964s run low ignition compared to most due to the twin spark, which makes the fuel burn more quickly, which is good in all sorts of ways) the goal here is to make the best torque (without causing knock) pretty much everywhere except on idle where you want a sort of middling amount of advance that lets the ecu advance or retard timing to control the idle rpm. This really needs a dyno as you want to do a "spark hook" test where you hold the car at a given load and rpm and advance the timing until it either knocks (in which case you back off a few degrees and leave it) or the torque stops rising (which is known as MBT).
The ignition map is critical (it's the magic in a SW chip) and makes a big difference to part throttle, throttle response and "tip-in" so is worth doing and is almost impossible on the road, so you need a good dyno and a friendly mapper. There is a bit of back on forward as when you change the timing you need to go back and check the AFRs.
I'm getting the man that maps my Skylines to do the ignition for me on his hub dyno (he maps all sorts, N/A, SC, Turbo, ITBS, Drag, Race, Road - Link/VIPEC, Motec, ECUTEK etc, etc). It will probably cost me a £300-400 in dyno time depending on how good the ignition map Peep supplies is and how long it takes to figure the software out the first time.
07-02-2014, 02:56 PM
#66
Instructor
Join Date: Nov 2013
Location: Crawley, West Sussex, UK
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About a grand in parts plus mapping (fitting myself obviously). So you can spend the difference compared to a 9m Motec on a s/h supercharger kit, or some Jenvy throttle bodies and a nice exhaust system!
Mapping depends on how much you can do yourself. If you can work a computer or, cough, know a man that can , it looks like VEMSTune will help you map the VE table fairly easily which takes car of the fueling (the two videos above). You only need a dyno for "hard to reach places" on the rpm vs map table that you only pass through quickly on the road.
Speed density tuning, which should work for you and me, requires setting up a Volumetric Efficiency (aka VE) table - this tells the ecu the "pumping" efficiency of the engine at different RPM and different pressures in the manifold as measured by a MAP sensor.
Once you have the VE table you setup another table with your target air fuel ratios; for optimum economy at idle and cruise, and optimum power under load (best power AFR=13.0 ish for a 964 - leaner than most cars) again the table is a grid of columns for RPM vs rows for MAP values.
Finally you set a table which sets the ignition advance, again its a grid of columns for RPM vs and rows MAP values (FYI 964s run low ignition compared to most due to the twin spark, which makes the fuel burn more quickly, which is good in all sorts of ways) the goal here is to make the best torque (without causing knock) pretty much everywhere except on idle where you want a sort of middling amount of advance that lets the ecu advance or retard timing to control the idle rpm. This really needs a dyno as you want to do a "spark hook" test where you hold the car at a given load and rpm and advance the timing until it either knocks (in which case you back off a few degrees and leave it) or the torque stops rising (which is known as MBT).
The ignition map is critical (it's the magic in a SW chip) and makes a big difference to part throttle, throttle response and "tip-in" so is worth doing and is almost impossible on the road, so you need a good dyno and a friendly mapper. There is a bit of back on forward as when you change the timing you need to go back and check the AFRs.
I'm getting the man that maps my Skylines to do the ignition for me on his hub dyno (he maps all sorts, N/A, SC, Turbo, ITBS, Drag, Race, Road - Link/VIPEC, Motec, ECUTEK etc, etc). It will probably cost me a £300-400 in dyno time depending on how good the ignition map Peep supplies is and how long it takes to figure the software out the first time.
Mapping depends on how much you can do yourself. If you can work a computer or, cough, know a man that can
, it looks like VEMSTune will help you map the VE table fairly easily which takes car of the fueling (the two videos above). You only need a dyno for "hard to reach places" on the rpm vs map table that you only pass through quickly on the road.Speed density tuning, which should work for you and me, requires setting up a Volumetric Efficiency (aka VE) table - this tells the ecu the "pumping" efficiency of the engine at different RPM and different pressures in the manifold as measured by a MAP sensor.
Once you have the VE table you setup another table with your target air fuel ratios; for optimum economy at idle and cruise, and optimum power under load (best power AFR=13.0 ish for a 964 - leaner than most cars) again the table is a grid of columns for RPM vs rows for MAP values.
Finally you set a table which sets the ignition advance, again its a grid of columns for RPM vs and rows MAP values (FYI 964s run low ignition compared to most due to the twin spark, which makes the fuel burn more quickly, which is good in all sorts of ways) the goal here is to make the best torque (without causing knock) pretty much everywhere except on idle where you want a sort of middling amount of advance that lets the ecu advance or retard timing to control the idle rpm. This really needs a dyno as you want to do a "spark hook" test where you hold the car at a given load and rpm and advance the timing until it either knocks (in which case you back off a few degrees and leave it) or the torque stops rising (which is known as MBT).
The ignition map is critical (it's the magic in a SW chip) and makes a big difference to part throttle, throttle response and "tip-in" so is worth doing and is almost impossible on the road, so you need a good dyno and a friendly mapper. There is a bit of back on forward as when you change the timing you need to go back and check the AFRs.
I'm getting the man that maps my Skylines to do the ignition for me on his hub dyno (he maps all sorts, N/A, SC, Turbo, ITBS, Drag, Race, Road - Link/VIPEC, Motec, ECUTEK etc, etc). It will probably cost me a £300-400 in dyno time depending on how good the ignition map Peep supplies is and how long it takes to figure the software out the first time.
Regarding the ITBs and drivability, it's like putting Webber carbs on - if you use too big choke sizes you get good top-end and poor low/mid; too small and you get good mid-range and poor top-end....
BTW, did you get the email address I PM'd you?
07-02-2014, 03:14 PM
#67
Three Wheelin'
Thread Starter
Alex, if you've already bought the SW chip, then I'm sure there are no copyright issues about using the Ignition maps from it. You can very easily blend the the Part and Full-throttle maps into one. Also, on NA engines, the ignition is engine-configuration dependent, i.e. compression, and spark plug position. Load and volumetric air-flow are not exactly the same, but you might be able to measure the relationship between the 2 in an intermediate ECU config where you have both sensors active.
Regarding the ITBs and drivability, it's like putting Webber carbs on - if you use too big choke sizes you get good top-end and poor low/mid; too small and you get good mid-range and poor top-end....
BTW, did you get the email address I PM'd you?
Regarding the ITBs and drivability, it's like putting Webber carbs on - if you use too big choke sizes you get good top-end and poor low/mid; too small and you get good mid-range and poor top-end....
BTW, did you get the email address I PM'd you?
I was think of just using the SW and stock chips as references for the shape of the ignition map and the high and low points etc. I think the optimum ignition advance is dependent on the VE and with the cam in the car that will have changed possibly quite alot. I was reading a post by Geoffrey or Steve Wong i think that was saying once one of these engines has been rebuilt even stock the stock calibration can be quite a long way out.
yup I got your email address alright, i just need to get off my **** and find the chips in the garage now!
07-02-2014, 04:22 PM
#68
Three Wheelin'
There are no driveability issues with ITB's once they are properly tuned.
Here's a vid of 993 engine with GSXR1000 ITB's, 200cell cats and VEMS, other than that, engine is completely stock:
And that is not even fully tuned yet, I was just trying to cover as much cells as I could.
Regarding ignition, it is not a rocket science, just a matter of getting maximum cylinder pressure to occur ~15 degrees ATDC
Knowing a given engine, there are no big variables when engine is normally aspirated and runs pump fuel... Some may disagree though..
Here's a vid of 993 engine with GSXR1000 ITB's, 200cell cats and VEMS, other than that, engine is completely stock:
And that is not even fully tuned yet, I was just trying to cover as much cells as I could.
Regarding ignition, it is not a rocket science, just a matter of getting maximum cylinder pressure to occur ~15 degrees ATDC
Knowing a given engine, there are no big variables when engine is normally aspirated and runs pump fuel... Some may disagree though..
07-02-2014, 05:24 PM
#69
Three Wheelin'
Thread Starter
07-02-2014, 05:28 PM
#70
Three Wheelin'
07-03-2014, 01:43 AM
#71
Three Wheelin'
It's a different Motronic connector, a 88pin vs 55pin on 964 and early 993.
And it is MS3 fitted into Motronic enclosure, not entirely new ECU design.
I have made 88pin Motronics also, though not for Porsches, but for BMW M3 3.2 with dual vanos control etc.
And it is MS3 fitted into Motronic enclosure, not entirely new ECU design.
I have made 88pin Motronics also, though not for Porsches, but for BMW M3 3.2 with dual vanos control etc.
07-03-2014, 02:16 AM
#72
Three Wheelin'
Thread Starter
Have you guys looked at this ECU project from the 993 board
Clearly a guy that knows what he is doing and gets on with it. Also shows how long it takes to properly develop this sort of thing even when you are starting with a ready made microcontroller and code base.
I have looked at MS a few times over the years and it always seemed to have random limitations and shortcomings, as if the features that worked were the ones the developers were interested in, not the ones that would be most useful to people tuning cars. It also seems to be geared towards people who are more interested in a challenging electronics project than having something that works out of the box. As far as I can tell you really need MSextra in addition to MS3 to build a decent system, which raises the price and still leaves a lot of work to do.
07-03-2014, 03:00 AM
#73
Three Wheelin'
There are no driveability issues with ITB's once they are properly tuned.
Here's a vid of 993 engine with GSXR1000 ITB's, 200cell cats and VEMS, other than that, engine is completely stock: Porsche 993 countryside road driving and tuning - YouTube
And that is not even fully tuned yet, I was just trying to cover as much cells as I could.
Regarding ignition, it is not a rocket science, just a matter of getting maximum cylinder pressure to occur ~15 degrees ATDC Knowing a given engine, there are no big variables when engine is normally aspirated and runs pump fuel... Some may disagree though..
Here's a vid of 993 engine with GSXR1000 ITB's, 200cell cats and VEMS, other than that, engine is completely stock: Porsche 993 countryside road driving and tuning - YouTube
And that is not even fully tuned yet, I was just trying to cover as much cells as I could.
Regarding ignition, it is not a rocket science, just a matter of getting maximum cylinder pressure to occur ~15 degrees ATDC
Knowing a given engine, there are no big variables when engine is normally aspirated and runs pump fuel... Some may disagree though..Probaly the first post on the thread I understand!
Interesting stuff though
07-03-2014, 05:26 AM
#74
Three Wheelin'
Sounds like you're really going to start modding the car Alex.. are you planning to remove the ABS at any point? I have no use for it as hardly ever drive in the rain.. and if I do not fast enough to care. Was thinking it would def save a few kilos. Would it be complicated?
Last edited by jack.pe; 07-03-2014 at 06:26 AM.
07-03-2014, 05:43 AM
#75
Three Wheelin'
^^ no - not complicated at all. Just remove the brain & pump and fit a few short sections of brake line. I can't imagine the warning light would take too long to overcome either. Irrespective of your ability, and conditions you normally drive in, unless a dedicated track I think its beneficial to keep the ABS.
