Fitting Megasquirt
Discussion
stevieturbo said:
The main thing that put me off MS in the first place, was having to build the damn thing
Fully built, tested and guaranteed Megasquirts have been available for quite a while now. In fact there is a version which all surface mount, which is aimed for low-volume (non diy) production.eliot said:
Not sure I follow you.
The AFR table isn't the "map" - its the AFR you expect to be running at a particular axis
I'm talking about the VE table, not the AFR target table.The AFR table isn't the "map" - its the AFR you expect to be running at a particular axis
Although it's called the VE table, it doesn't actually contain pure VE - it combines the volumetric efficiency and the target AFR.
Megasquirt Tuning manual said:
VE = (actual air mass)/(theoretical air mass)*AFRstoich/AFRactual
http://www.msextra.com/manuals/MS_Extra_Tuning_Manual.htm#veI think they are showing the ego correction within the formula - TBH i'm not quite sure without reading it more.
MS1 is just a straight VE map - you 'artificially' increase the VE's to richen the mixture up at a certain points. The AFR table is for the EGO correction routine to adjust the pulsewidth to your desired AFR - after the fact if you like - hence why I want to capture the amount of correction and get that back into the original VE table, so it doesn't need to correct it dynamiclly (ideally).
But with either system, you start with a relatively flat map and drive around increasing the areas until you get your desired AFR - Then use closed loop AFR once the map is getting close. Its not really for sorting out a very rough table, its quicker to get an assistant to help you get the basics done. As I said, I've not used any other system - so my experience is limited, but I haven't found it do be difficult so far. Tens of thousands of other people with little or no knowledge have built, installed and tuned their own cars by following the documenation and using the forums - so it cant be that bad!
If you need more clarification on it, post a question on MSEFI.
Eliot.
ETA,
Are you saying why dont you have a true VE map, then a seperate map that represents the fueling increase over stoic for that particular bin, rather artifically increasing the VE bins? If so, I understand what you mean now - but I guess thats the way it is!
MS1 is just a straight VE map - you 'artificially' increase the VE's to richen the mixture up at a certain points. The AFR table is for the EGO correction routine to adjust the pulsewidth to your desired AFR - after the fact if you like - hence why I want to capture the amount of correction and get that back into the original VE table, so it doesn't need to correct it dynamiclly (ideally).
But with either system, you start with a relatively flat map and drive around increasing the areas until you get your desired AFR - Then use closed loop AFR once the map is getting close. Its not really for sorting out a very rough table, its quicker to get an assistant to help you get the basics done. As I said, I've not used any other system - so my experience is limited, but I haven't found it do be difficult so far. Tens of thousands of other people with little or no knowledge have built, installed and tuned their own cars by following the documenation and using the forums - so it cant be that bad!
If you need more clarification on it, post a question on MSEFI.
Eliot.
ETA,
Are you saying why dont you have a true VE map, then a seperate map that represents the fueling increase over stoic for that particular bin, rather artifically increasing the VE bins? If so, I understand what you mean now - but I guess thats the way it is!
Edited by eliot on Saturday 29th December 09:33
Eliot,
What would be the best, quickest most efficient path to a well mapped engine for a newbie then.
Lets assume the ecu is in there and working and no work is required to any hardware at all and the engine is a nice basic n/a with single tb plenum, where would you start and go from there with the mapping?
What would be the best, quickest most efficient path to a well mapped engine for a newbie then.
Lets assume the ecu is in there and working and no work is required to any hardware at all and the engine is a nice basic n/a with single tb plenum, where would you start and go from there with the mapping?
[quote=ihatesissycars]
I'm going to need an ms or emerald ecu to go in my project 944 but I'm going to be running a high c/r and boost so I wasn't very confident with the mapping isde of things and wanted someone else to do it.
quote]
Have you decided what crank trigger you are going to use yet? The 944 has 2 sensors, 1 measures TDC, the other one looks at the ring gear. No aftermarket ECU is capable of reading this setup. A converter pcb has just been released for megasquirt - http://www.jbperf.com/dual_VR/index.html he other option is to mount a new trigger on the front of the crank. All the conversions I have seen on 944's look awful, usually with bits of timing cover hacked away or modified pulley's that don't line up properly.
I'm going to need an ms or emerald ecu to go in my project 944 but I'm going to be running a high c/r and boost so I wasn't very confident with the mapping isde of things and wanted someone else to do it.
quote]
Have you decided what crank trigger you are going to use yet? The 944 has 2 sensors, 1 measures TDC, the other one looks at the ring gear. No aftermarket ECU is capable of reading this setup. A converter pcb has just been released for megasquirt - http://www.jbperf.com/dual_VR/index.html he other option is to mount a new trigger on the front of the crank. All the conversions I have seen on 944's look awful, usually with bits of timing cover hacked away or modified pulley's that don't line up properly.
ihatesissycars said:
Eliot,
What would be the best, quickest most efficient path to a well mapped engine for a newbie then.
Lets assume the ecu is in there and working and no work is required to any hardware at all and the engine is a nice basic n/a with single tb plenum, where would you start and go from there with the mapping?
Try to find someone local who can give you run-down and help with mapping.What would be the best, quickest most efficient path to a well mapped engine for a newbie then.
Lets assume the ecu is in there and working and no work is required to any hardware at all and the engine is a nice basic n/a with single tb plenum, where would you start and go from there with the mapping?
Do it in stages, add the turbos later.
I was going to copy this or machine away some of the teeth on the flywheel/pressure plate and see if that will work.
Eliot, no not my engine just a "in general this approach is easiet, base map pinched from someone else, get it running a decent idle, turn of ae, start driving keeping revs low with assistant watching the lambda readout adjusting as necc, thro the log thru megatune etc etc"
ihatesissycars said:
base map pinched from someone else, get it running a decent idle, turn of ae, start driving keeping revs low with assistant watching the lambda readout adjusting as necc, thro the log thru megatune etc etc"
That's basicly correct. I would study, rather than copy other peoples maps - and then only use the map, not the entire MSQ settings file - otherwise you could inherit someone elses mistakes or assumptions.Have you got any more photos of the engine? Wouldn't my technique of machinng 2MM from a pulley allow you to sandwich in a ford 36-1 pressed steel wheel?
http://www.mez.co.uk/ms11.html
Sorry to the OP, we seemed to have gone way O/T - perhaps we should continue this on your thread.
Edited by eliot on Saturday 29th December 10:54
My engine's out at the mo so I'll take some pics of the front pulley later on.
It might prove tricky though!
The belt pulley goes on first then another toothed pulley goes on to drive the balance shafts, this is hard up against the first puley then the alternator pulley goes onto the balance shaft pulley. You can't mount anything between these two as that would interfere with the covers which leaves mounting it like the above one, on the front of the alt drive pulley but if you have Ppower steering the pulley to power the pump goes where the trigger in that picture goes which leaves. . . . . No where! Especially seeing as I need to drive a blower which may need its own pulley too if I can't drive it off the alternator belt. . .
I'll post some pics later in my supercharger thread so you can see.
It might prove tricky though!
The belt pulley goes on first then another toothed pulley goes on to drive the balance shafts, this is hard up against the first puley then the alternator pulley goes onto the balance shaft pulley. You can't mount anything between these two as that would interfere with the covers which leaves mounting it like the above one, on the front of the alt drive pulley but if you have Ppower steering the pulley to power the pump goes where the trigger in that picture goes which leaves. . . . . No where! Especially seeing as I need to drive a blower which may need its own pulley too if I can't drive it off the alternator belt. . .
I'll post some pics later in my supercharger thread so you can see.
Thats the first one I've seen that looks good! Doesn't appear to has a pas pulley on it though.
Eliot - the crank pulley is quite odd on a 944, it is quite deep with just the ribbed section poking out of the plastic covers (to drive the alt) and in the middle of it fits the pas pulley which is a cone shaped affair. You can't mount a trigger on the outside of the pas pulley as it's not rigid enough (and quite often out of true), it may be possible to machine down the alt pulley and mount it between the 2 - but it has a damper.
Eliot - the crank pulley is quite odd on a 944, it is quite deep with just the ribbed section poking out of the plastic covers (to drive the alt) and in the middle of it fits the pas pulley which is a cone shaped affair. You can't mount a trigger on the outside of the pas pulley as it's not rigid enough (and quite often out of true), it may be possible to machine down the alt pulley and mount it between the 2 - but it has a damper.
ihatesissycars said:
Damper? My alt drive pulley mounts solidly to the balance shaft pulley. . . .
The pulley has a rubber vibration 'damper' between the outer ribbed section and the inner that you bolt to the crank. All 944's have the alternator driven from the crank - unless yours has been modified?? The balance shafts are hidden beneath the plastic covers...
Had a quick look at the clewett website, they do some interesting stuff.
BB-Q said:
Vixpy, you own a rolling road, don't you? What's your opinion of Megasquirt for those of us who're financially embarrassed? It's the only system I've any experience with too.
I'm sure loads of people on here would like a pro's opinions on the various systems and their cost/effectiveness ratio.
I'm afraid i've never even looked at the interface on the MS, let alone used one.I'm sure loads of people on here would like a pro's opinions on the various systems and their cost/effectiveness ratio.
No mines standard. I've just removed my old engine and replaced all the belts, pullies, water pump and so on on the replacement engine. Neither have a rubber damper between the alternator drive pulley and the balance shaft pulley.
Both though are the first incarnation of the 2.5 and porsche constantly updated the engiens so maybe that damper was added to the 2nd variant of the 2.5?
Both though are the first incarnation of the 2.5 and porsche constantly updated the engiens so maybe that damper was added to the 2nd variant of the 2.5?
stevieturbo said:
Looks like plenty of room up top for a camshaft mounted trigger if there isnt any down below.
Although there is always room for something.
A cam trigger is perhaps an easier if less accurate option. You would have to ditch the dissy cap and run wasted spark or coil on plug.Although there is always room for something.
http://www.clarks-garage.com/shop-manual/eng-10.ht... has some good info on the belt arrangement. If you scroll down there is a photo showing the crank pulley, the inner part runs the alt / ac, the outer does the pas.
bertelli_1 said:
stevieturbo said:
Looks like plenty of room up top for a camshaft mounted trigger if there isnt any down below.
Although there is always room for something.
A cam trigger is perhaps an easier if less accurate option. You would have to ditch the dissy cap and run wasted spark or coil on plug.Although there is always room for something.
http://www.clarks-garage.com/shop-manual/eng-10.ht... has some good info on the belt arrangement. If you scroll down there is a photo showing the crank pulley, the inner part runs the alt / ac, the outer does the pas.
A cam only trigger should also be able to run sequential too with the right trigger.
Slap on a trigger from a Nissan 200 or some Skylines. They have a dual path optical trigger that runs off the front cam pulley, that covers crank and phases triggering.
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