[preludefan]

hi all,

just want to announce that i have had my 3rd gen running on megasquirt in full stand alone mode running wasted spark, using the stock honda vr sensors.


this is a basic how to for anyone else who wants to do it, this setup is compatable with most hondas, but more importantly its compatable with ALL PRELUDES from 2nd gen si to 5th gen, and can be done on a single cam lude that was carbed with the addition of a d series distributor housing with the three vr sensors in it- i have not tried this so how you get it to fit your engine is up to you, should you want to take this route.


DISCLAIMER, this post is designed to give people an idea of how i got my engine started and idiling, i am not resposible for anyone elses actions in any shape or form, undertake this at your own risk.


now lets get started.


first and foremost, make sure you are prepared to undertake this and allow time to fix any possible errors, with wasted spark, we will need to modify the 24 toothed wheel so this setup will not be backwards compatable with the stock ecu.

ok, to make wasted spark work the way i did it, we need two triggers to feed into megasquirt:

primary trigger and secondary trigger, in this instance well use the 4 toothed wheel as the primary trigger (orange blue (+) white blue (-)) and the single toothed wheel as the second trigger (orange(+) white(-))

now you need to remove your distributor unit from the cylinder head, then remove the cap,rotor and dust cover and then the stock coil and ignitor (4th gen and up),, now look at the trigger wheels and look at the vr sensors, what you need to do is observe the little metal bit stiking out of the vr sensor surrounded by a white square, that is where the point of contact with the trigger wheel occurs, take note of that.

now we 3rd genners also need to remove the exhaust cam sensor too and open the cover up on that.

now remove the 24 toothed sensor from your distributor and line it up with the single toothed sensor in the position so it will slide directly onto the drive spline, there will be one tooth that will line up with the single toothed wheel perfectly, mark that tooth with a twink pen, not find the tooth that is ecactly 180 degrees opposite to the tooth you just marked and also mark that.
those two marked teeth you need to keep, the rest, cut out with either a grinder or use a file like i did and carefully shave them all down.

once you have removed all other teeth, it the 4 toothed wheel back in its place and then your new custom 2 toothed wheel in the place of the single toothed wheel so that in one half turn (equivilant to one full crank turn) the sisnsors will put out two pulses on the primary 4 toothed wheel and one pulse from your secondary 2 toothed wheel.

now refit your distributor housing and put the old dizzy cap back on to protect the sensors or make your own cover and plug the distributor plugs back in.

now for the hardware side of megasquirt, you must follow the instructions here: http://www.msextra.com/manuals/MS_Ex...anual.htm#5cyl

this is for the output side of megasquirt using 4g63 coils and ignitor, you dont have to use these, just use what ever is available to you at a good price, you will also have to use the correct dwell settings for the ignitor you use- the mistubishi one is in that link somewhere close.


once you have set up your megasquirt like decribed in the manual i will now explain to you how to make a decoder for the vr sensors so that megasquirt can see the signal the vr sensors are sending out, basically a vr or varible reluctance sensor generates an ac wave form that megasquirt cant see, so this decoderwill take in the 400 millivolt ac signal from the vr sensors and spit out a 5 volt signal every time it gets a pulse from the vr sensor, that 5 volt signal will go directly into the megasquirt chip and give us our signal!

i use a v2.2 board that has no on board vr decoder whereas the v3.o board has a SINGLE vr deocder built in, however, we need TWO vr decoders so ill introduce a seperate vr decoder chip that can decode two vr sensors in one go, so in this case it does not matter what board your using, dont build the ignition input circuts on either boards as we will build an interface that takes care of all of the for us instead!.

the chip is called NCV1124 from on semiconductor and is available through farnell here is the link to the specsheet, http://www.onsemi.com/PowerSolutions...o?id=NCV1124DG

and here is a picture of the circut diagram for ho to build the interface:





here is my finished one:



now be warned, this chip is about half the size of one fingernail so much care is needed as being an SMD package its not easy to work with- i suggest surface mounting the ehire circuit on a piece of plastic then glueing it all in place.

now wire the primary trigger + orange and blue to r1 as your input one and the organge trigger secondary into r2, now ground the other two wires at the same point AT the megasquirt ground on the db37 plug to keep external interfarance as low as possible.
find a good 5volt source in megasquirt forthe chip i took my supply off one of the noise surpressors- and ground the chip to a good ground point- the 5v regulator ground for examle.

now run your primary trigger wire (no 4n25 circut needed to protect the chip as the signal cant exceed 5v in any case) to pin 14 on the megasquirt cpu and run trigger wire two to pin 11 and now your done hardwar wise!

now to software, i recomend running the megasquirtnspark- extra format available here: http://www.msextra.com/manuals/MS_Ex...nual_Index.htm

for ms1 chip and here:http://www.msextra.com/ms2extra/

for the ms2 chip.

once you have this all loaded on (you should know how to do all of this already, after all you read the manual right?) and you have megatune running, go to codebase and outputs and select "spark output a" as led 17 and "spark output b" as led 19, make sure no other spark outputs are set.
now also select generic wheel for your decoder.
close that and re open the menu and select "wheel decoder settings" set your base teeth as 2, then select second trigger enable and select "rising".

now for trigger position a type "1" and for trigger position b type "2" and thats it, make sure everything else is set to zero, then make sure your dizzy mode is set to normal, save burn and close that.

next you need to go into spark settings and type in "60" for your trigger angle and then select "time based" for cranking timing and punch in perhaps say "5" dregrees cranking advance, now go to the bottom and type in 15 in place of the "-10" in the fixed angle area, click burn and save.

your engine should now start, once you have it running, check your trigger angle with a timing light (the "60" you typed in up the top), it should be in the ballpark but you need to adjust this + or- a bit to get your timing perfect, once you have this spot on, change your fixed angle from "15" back to "-10" so megasquirt will start using the spark map, congratulations, your now ready to head to the tuners!

thanks for reading!


mike

[Rosko]

So you can't just configure Megasquirt to use the full 24th tooth wheel for more resolution?

[preludefan]

Originally Posted by Rosko

So you can't just configure Megasquirt to use the full 24th tooth wheel for more resolution?

you can but you will still need a 2 toothed wheel as your return trigger as you need one pulse per 360 degrees of CRANK rotation, the cams turn at half the speed of the crank, so you need double the teeth on the return trigger.

to be honest, i dont see the point in using the 24 (megasquirt sees it as a 12) toothed wheel for getting more resolution when megasquirt bank fires injectors and runs wasted spark, if you had sequential injection, like the pgmfi ecu does, then it would be needed.

the whole reason i used the 4 toothed wheel as the way to go here is you dont need to buy or hunt down a second 24 toothed wheel to cut up, you can simply use what you already have, which is what most of us will probably do.

[cygnus x-1]

Originally Posted by Rosko

So you can't just configure Megasquirt to use the full 24th tooth wheel for more resolution?

I was wondering that myself. I know it has direct support for quite a few different crank and cam sensor setups but it may not support the 24/4 Honda ones yet. This area of the code has been growing rapidly and I'm sure it will eventually be supported, although I doubt there's much demand for it so it could take awhile. From what I've seen (and I'm no expert) the Honda crowd tends to go toward OBD1 conversions instead of standalone ECUs like Megasquirt.

I think the 24/4 tooth wheels should theoretically allow wasted spark or full COP support (and therefore sequential injection) with the newer MS2/Extra code. But again, I'm no expert. The sequential support is very new and still being developed.

I'm planning to switch to sequential and full COP over the winter, however I'll be using a Ford 36-1 crank wheel and single tooth cam trigger. I'm already running EDIS so it's the easiest route for me.

C|

[Rosko]

Originally Posted by preludefan

you can but you will still need a 2 toothed wheel as your return trigger as you need one pulse per 360 degrees of CRANK rotation, the cams turn at half the speed of the crank, so you need double the teeth on the return trigger.

to be honest, i dont see the point in using the 24 (megasquirt sees it as a 12) toothed wheel for getting more resolution when megasquirt bank fires injectors and runs wasted spark, if you had sequential injection, like the pgmfi ecu does, then it would be needed.

the whole reason i used the 4 toothed wheel as the way to go here is you dont need to buy or hunt down a second 24 toothed wheel to cut up, you can simply use what you already have, which is what most of us will probably do.

Well my point was that you shouldnt need to modify anything unless megasquirt is that incapable. If you can run an unmodified dizzy/with a single coil in megasquirt (just like stock) than you should be able to run an unmodified dizzy with multiple coils. All you need is to tell it when to fire.

I've done the setup before, only not with megasquirt, with an aem ems. Just like a stock ecu you really dont even need the 4 tooth wheel, just the single and the 24. An engine cycle is 720 degrees so for every 720 degrees the crank rotates the dizzy rotates 360, so having one tooth as a cam sync always tells the motor when cyl #1 is on TDC ready to fire as it passes by once per 720 degrees of crank rotation. This alows you to run sequential injection and also individual cylinder trims. having a wheel with more teeth for crank position isnt neccesary bu tthe more the better and will give the engine a more accurate spark as it will always know where its at.

I'd be very surprised if you can't setup megasquirt to run this way.

[Rosko]

Heres what I was using for a the cam/crank pickups. Its the same parts you'd find inside a Honda dizzy, just mounted in my own custom case. I've also done the setup with actual crank trigger wheels (16 tooth, 8 tooth, 60-2 teeth) but found I couldnt get a clean signal off of them and that this worked the best. This turned out to be the easiest to setup as well as it used all the stock settings as far as inputs goes.

[Tim07]

I agree with you

[preludefan]

the single coil distributor based setup is actually closer to sequential coil on plug sequential as there is 4 spark events per 720 degrees where as wasted spark seems to need a reset every 320 cran degrees.


i agree you can use the 24 toothed wheel for any megasqurt setup but for wasted spark, i could not get it working without a 2 toothed wheel for a return trigger- because it seems that, with cam mounted sensors, you need two pulses per crank rev for it to work IF both of your sensors are cam mounted, if you have one mounted on the crank and one on the cam then you an use the 1 toothed wheel because you can manipuate the wheel settings in megatune because the sensors are turning at different speeds, as you know,but it failed to start with the single toothed wheel when i tried it, then i fitted the 2 to the wheel i made and it fired straight up with no problem.



the info in the megasquirt extra manuals back this up also - here is the link;

http://www.msextra.com/manuals/MS_Ex...l.htm#twotrigs




and even if megasquirt is not as sophisticated as an aem, microtech autronic... etc, it only costs 200 us bucks, its designed as essentially a diy ecu, with software freely available on the net programmed by people who do it in their own free time for the benifit of hobbyists and those who believe its crazy to pay 2 grand for an ecu- you cant expect to get a full standalone ecu that cheap that you dont have to do a little work on your hardware to make it work, for what i have payed and the features i now have, i think its amasing.

Originally Posted by Rosko

Well my point was that you shouldnt need to modify anything unless megasquirt is that incapable. If you can run an unmodified dizzy/with a single coil in megasquirt (just like stock) than you should be able to run an unmodified dizzy with multiple coils. All you need is to tell it when to fire.

I've done the setup before, only not with megasquirt, with an aem ems. Just like a stock ecu you really dont even need the 4 tooth wheel, just the single and the 24. An engine cycle is 720 degrees so for every 720 degrees the crank rotates the dizzy rotates 360, so having one tooth as a cam sync always tells the motor when cyl #1 is on TDC ready to fire as it passes by once per 720 degrees of crank rotation. This alows you to run sequential injection and also individual cylinder trims. having a wheel with more teeth for crank position isnt neccesary bu tthe more the better and will give the engine a more accurate spark as it will always know where its at.

I'd be very surprised if you can't setup megasquirt to run this way.

[preludefan]

are you running a 2nd gen?

the only thing i have against edis is its difficult to get a spark cut set up for it, there is a module available somewhere on the internet that cuts off the positive feed to the coil at a set rev limit, but i personally wanted to use stock honda sensors for ease of replacement and for reliability (edis stuff is rare in my country) and i also wanted everything programable via megatune.


megasquirt DEFINETLEY cant decode a 4 tooth as a second trigger, however there is like you said alot of devalopment going on with megasquirt, especially with the ms2 chip, its far more complex than the ms1 im running, it is now possible to run, with the ms2 chip, sequential injection as well as sequential coil on plug on a 4 cylinder, i personally wont go there for this particular engine as a, the engine does not rev high enough to take advntage of coil on plugs dwell benifits and b, i have a fuel system well capable of keeping fuel rail pressure up despite running bank fire injection, i did not want to complicate things, the other reason i dont want coil on plug is that they are wel known for failing due to heat soak, like the crappy obd-1 dizzy ignitors and coils of the b and d series engines.


i might convert to coil PER plug for my big engine build, as i can get ls2 coils very cheap which have very strong spark, far stronger than the stock evo coils but other than that im prettymuch sorted now!

Originally Posted by cygnus x-1

I was wondering that myself. I know it has direct support for quite a few different crank and cam sensor setups but it may not support the 24/4 Honda ones yet. This area of the code has been growing rapidly and I'm sure it will eventually be supported, although I doubt there's much demand for it so it could take awhile. From what I've seen (and I'm no expert) the Honda crowd tends to go toward OBD1 conversions instead of standalone ECUs like Megasquirt.

I think the 24/4 tooth wheels should theoretically allow wasted spark or full COP support (and therefore sequential injection) with the newer MS2/Extra code. But again, I'm no expert. The sequential support is very new and still being developed.

I'm planning to switch to sequential and full COP over the winter, however I'll be using a Ford 36-1 crank wheel and single tooth cam trigger. I'm already running EDIS so it's the easiest route for me.

C|

[cygnus x-1]

Originally Posted by Rosko

I've done the setup before, only not with megasquirt, with an aem ems. Just like a stock ecu you really dont even need the 4 tooth wheel, just the single and the 24. An engine cycle is 720 degrees so for every 720 degrees the crank rotates the dizzy rotates 360, so having one tooth as a cam sync always tells the motor when cyl #1 is on TDC ready to fire as it passes by once per 720 degrees of crank rotation. This alows you to run sequential injection and also individual cylinder trims. having a wheel with more teeth for crank position isnt neccesary bu tthe more the better and will give the engine a more accurate spark as it will always know where its at.

I'd be very surprised if you can't setup megasquirt to run this way.

In fact it can.

http://www.msextra.com/ms2extra/MS2-Extra_Dual.htm

This allows for COP ignition and sequential injection.

C|

[cygnus x-1]

Originally Posted by preludefan

are you running a 2nd gen?

Yep. Mine started out carbed though with an all mechanical distributor that I really wanted to get rid of. At the time I didn't know anything about Honda FI distributors or even MSExtra code so EDIS seemed like the obvious choice. It's simple and does work quite well.

Originally Posted by preludefan

the only thing i have against edis is its difficult to get a spark cut set up for it, there is a module available somewhere on the internet that cuts off the positive feed to the coil at a set rev limit,

MS1 doesn't have any spare programmable outputs? If it does you could just have it drive a relay to cut the coil power. And does it really have to be a spark cut and not just a limit? Just curious.

Originally Posted by preludefan

but i personally wanted to use stock honda sensors for ease of replacement and for reliability (edis stuff is rare in my country) and i also wanted everything programable via megatune.

Good points there. EDIS parts are common as dirt over here.

Originally Posted by preludefan

megasquirt DEFINETLEY cant decode a 4 tooth as a second trigger,

Actually you're correct here. As a secondary it wouldn't work. You need a single tooth secondary on the cam.

Originally Posted by preludefan

however there is like you said alot of devalopment going on with megasquirt, especially with the ms2 chip, its far more complex than the ms1 im running, it is now possible to run, with the ms2 chip, sequential injection as well as sequential coil on plug on a 4 cylinder, i personally wont go there for this particular engine as a, the engine does not rev high enough to take advntage of coil on plugs dwell benifits and b, i have a fuel system well capable of keeping fuel rail pressure up despite running bank fire injection, i did not want to complicate things, the other reason i dont want coil on plug is that they are wel known for failing due to heat soak, like the crappy obd-1 dizzy ignitors and coils of the b and d series engines.

Honestly I'm not that interested in sequential injection either. I'm going to be switching to ITBs with the injectors by the throttle bodies, so no point in it really. Individual fuel trim might be cool, but I'm not sure if it's in the MS2 yet. MS3 it is for sure.

And the only reason I want COP is because I don't like plug wires. But thanks for the heads up on the heat soak. I'll have to address that when I get there.

However, what I do want is the new sequential MAP sampling. It lets you time the MAP sampling to the intake valves, making for a much more stable signal. This is a HUGE benefit for ITBs and other setups with lumpy cams.


C|

[preludefan]

Originally Posted by cygnus x-1

Yep. Mine started out carbed though with an all mechanical distributor that I really wanted to get rid of. At the time I didn't know anything about Honda FI distributors or even MSExtra code so EDIS seemed like the obvious choice. It's simple and does work quite well.


oh yeah in that case edis is supereasy, its almost like plug n play!



MS1 doesn't have any spare programmable outputs? If it does you could just have it drive a relay to cut the coil power. And does it really have to be a spark cut and not just a limit? Just curious.

ms1 does have programmable outputs and they are rpm based and you could use that but to make an output work with the official rev limiter that has soft and hard cut settings as well as launch contol and flatshift, you have to be up with the play in c programming language to make it work, that im certanly not, but will be in future maybe, id like to write a code unique to my car!










Honestly I'm not that interested in sequential injection either. I'm going to be switching to ITBs with the injectors by the throttle bodies, so no point in it really. Individual fuel trim might be cool, but I'm not sure if it's in the MS2 yet. MS3 it is for sure.

And the only reason I want COP is because I don't like plug wires. But thanks for the heads up on the heat soak. I'll have to address that when I get there.

However, what I do want is the new sequential MAP sampling. It lets you time the MAP sampling to the intake valves, making for a much more stable signal. This is a HUGE benefit for ITBs and other setups with lumpy cams.


C|

i hear you on the ht leads, but trust me they are far more durable and cheap than the cop units, ive seen people pay out almost 200 each for one! the best option for you if you mind me making a suggestion is coil per plug which means you can have remote coils on your firewll etc and run a lead to each plug from each coil and that would give you cop advantages without disadvantages- thats what i want to be doing with the ls2 coils, otherwise if your not fussed, stick with your edis coils, use your trigger wheel to give megasquirt a signal, and run your coils direct from megasquirt.

also there is a way to tune itbs well with the current megasquirt, by using tpsdot, which means you use the tps to activate the acceleration enrichments instead of the rate of change of the map sensor, then run a hose from each runner to a plenum similar to the black thing we have near our stock honda map sensors, and also plug your map hose into that and it will even things out real nice!

or you could just use rpm based enrichment but youll have to read that, i dont know too much about it, but i eventually want to run my civic with itbs so ill be looking at it someday!

[Rosko]

Originally Posted by preludefan

the single coil distributor based setup is actually closer to sequential coil on plug sequential as there is 4 spark events per 720 degrees where as wasted spark seems to need a reset every 320 cran degrees.


i agree you can use the 24 toothed wheel for any megasqurt setup but for wasted spark, i could not get it working without a 2 toothed wheel for a return trigger- because it seems that, with cam mounted sensors, you need two pulses per crank rev for it to work IF both of your sensors are cam mounted, if you have one mounted on the crank and one on the cam then you an use the 1 toothed wheel because you can manipuate the wheel settings in megatune because the sensors are turning at different speeds, as you know,but it failed to start with the single toothed wheel when i tried it, then i fitted the 2 to the wheel i made and it fired straight up with no problem.



the info in the megasquirt extra manuals back this up also - here is the link;

http://www.msextra.com/manuals/MS_Ex...l.htm#twotrigs




and even if megasquirt is not as sophisticated as an aem, microtech autronic... etc, it only costs 200 us bucks, its designed as essentially a diy ecu, with software freely available on the net programmed by people who do it in their own free time for the benifit of hobbyists and those who believe its crazy to pay 2 grand for an ecu- you cant expect to get a full standalone ecu that cheap that you dont have to do a little work on your hardware to make it work, for what i have payed and the features i now have, i think its amasing.

Thanks for that link I'll read up on that when I get a chance.

From what you just said about the motor not starting with a single cam pickup, and then starting right up with the dual sounds like the settings may be off for the number of crank teeth. Did you try and manipulate that at all? If it works with two cam pickups that makes me think that you've got the setting for the number of crank teeth twice what it should be. I know this aspect was confusing in the aem because sometimes it wants values per 360 degrees and sometimes per 720 degrees. For example an obd1 h22 has a 24 tooth wheel in the distributor, and an obd2 h22 has only a 12 tooth wheel, except that its mounted on the crank. Like you said since they are spinning at two different rpm's the ecu still see the same number of pulses so it doesnt know the difference. There may or may not be any advantages to a sequential setup but it sounds like you were very close to having one.

You can still run sequential with wasted spark as well. All wasted spark means is that you are firing two cylinders at once, and one cylinder is always the "dead' cylinder. It doesnt neccesarily mean that you cannot run individual cylinder trims (at least in the aem anyways) but the ecu has to only have one cam pickup per 720 degrees so it knows where its at as far as TDC#1.

My setup considted of an aem ems with two coil outputs to an msd dis-4 (dis-2 would have also worked) and 4 honda cbr coils running in wastefire (wired in series) The setup was great but every once in awhile the signal would break up and it would miss spark events. At the time I blamed it on the MSD box and just figured it was going bad. i switched back to a distributor and later on ended up having the same problem. After spending several nights working on it and rewiring various sensors and trying different distributors I found out that it wasnt the wiring itself, but that I was routing the wires too close to the main harness and the interference was breaking up the signal, even with good quality shielded wire. Now everything is routed away and the signal is perfect. Ever since then I've wanted to give it another shot.

BTW I wasnt trying to talk down megasquirt, I know its a cheap system and I can understand why a guy would want to use it. What really makes it fun is figuring out stuff like this and getting it to work when many others can't. It really makes you learn the ins and outs of how all the behind the scenes stuff works in an ecu, so a big thumbs up to you for figuring it out.

[preludefan]

hey rosko,

yeah i did try to work the numbers in megatune but no joy, it seems as though it keeps trying to fire 4 induvidual spark outputs even though i only have two outputs set- that is if i set four four teeth as the primary wheel decoder- it will splutter but the engine wont run under its own power, it seems that, for two coil outputs, you must have two teeth per return only when your sensors are turning at half the speed of the crank- its hard to understand i know, im struggling to work out why fully too!

that obd-2 crank trigger is news to me- does it still have a return trigger, or have they gone to missing tooth now?
im trying to work out how the k20 works as it has cop and a mate of mine wants to turbo his!

i think in that sense, honda probably did not want to change its ecu triggering system (if it aint broke dont fix it right?) so i guess your right that they put it on the crank so it appears to the pgmfi as a 24 toothed wheel.

to this day i still struggle to understand why honda and many other leaders in technology, didnt go to coilpacks when they started dicking with fuel injection- the distributor is like the one single primative thing that stayed with the prelude its entire life - perhaps our cars were a prelude to cop!


also, its good to hear that you got the noise sorted out, i also recomend running say a 47pc capacitor in paralell with each vr sensor where it connects to your ecu or vr decoder- i had horrible noise but as soon as i fitted those, the signal was perfect, i recon you should give it another go!


sorry about over reacting a bit too, its sometimes hard to see where people are coming from over typing!
there have been heaps of people giving megasquirt shit- mainly these guys in europe who think they are the biggest and best of everything and claim they can do way better, but all a lot of them do is copy the original and say they have improved it, like this guy:

http://www.turbosport.co.uk/showthread.php?t=135721



though i dont put you in with them at all!!!!!


mike

[cygnus x-1]

Originally Posted by preludefan

i hear you on the ht leads, but trust me they are far more durable and cheap than the cop units, ive seen people pay out almost 200 each for one! the best option for you if you mind me making a suggestion is coil per plug which means you can have remote coils on your firewll etc and run a lead to each plug from each coil and that would give you cop advantages without disadvantages- thats what i want to be doing with the ls2 coils, otherwise if your not fussed, stick with your edis coils, use your trigger wheel to give megasquirt a signal, and run your coils direct from megasquirt.

$200 for a COP module? F#$% that! I'll get some from the junkyard (or ebay) for $20 each and take my chances.

I haven't really decided yet. I have to relocate the coil anyway to make room for a *distributor* again, so I figure I might as well make the switch to COP. An EFI distributor is the easiest way to get a cam signal for the sequential MAP sensing (below). I don't want to do it but I don't want to engineer another solution either.

Originally Posted by preludefan

also there is a way to tune itbs well with the current megasquirt, by using tpsdot, which means you use the tps to activate the acceleration enrichments instead of the rate of change of the map sensor, then run a hose from each runner to a plenum similar to the black thing we have near our stock honda map sensors, and also plug your map hose into that and it will even things out real nice!

Actually, I've already seen most of this movie.

Over the summer I put together my own ITB setup using GSXR-1300 throttle bodies. To make the manifold easier to build I spaced out the TBs to match the Honda cylinder spacing. This caused major issues with throttle synchronization, which means they mostly just didn't work for S#!%. You can read all the specifics here if you're interested.

http://preludepower.com/forums/showthread.php?t=287583

Anyway, for fueling I ended up using SD/Alpha-N blend, which means that under low MAP conditions it used the MAP sensor for fuel calculation and under high MAP conditions (greater than about 8% throttle) it used throttle position for fuel calculation. This worked pretty well. For acceleration enrichment I tried both TPSdot and MAPdot, but neither ended up working right. MAPdot was just all over the place, mostly I think due to the badly synchronized throttles. So to keep from getting random extra fuel added I had to set the threshold so high that it never added extra fuel at all. TPS might have worked but I had some noise in the signal (probably from having the ignition and injector wires bundled with the sensor wires, bad I know) that kept it from being effective too. Pretty much I just seriously underestimated how sensitive the whole setup was going to be. Even though the project was ultimately a failure I learned a TON about how to setup ITBs. So when I tackle it again I'll be ready.

Oh, one thing I wanted to mention about the MAP signal. Tapping from each runner into a vacuum can does smooth out the signal, but it also adds a bit of delay. This delay causes a momentary lean spike on throttle open events because the ECU is getting old information about the pressure in the manifold. The other problem with combining the MAP lines is that it tends to average together all the pressures in the runners at the particular time when the MAP sample is taken. This average pressure is not really representative of the actual pressure in the one *active* (has it's intake valves open) runner at the time that sample is taken because each runner is essentially its own manifold, and the pressure in each one is wildly different depending on how long it has been since it was last *active*. The runner pressure during a single cycle can vary by as much as 40kPa. The solution to this (as devised by the REALLY smart MS guys) is to sample each runner independently and only use the signal that represents the lowest pressure, because that signal will be from the *active* runner. There is some really interesting reading about it here:

http://www.synchromap.com/index.html

The synchromap board described here will likely never be mass produced because someone found a simpler circuit to do it with, but I tried the simplified version and it makes an unbelievable difference in the dynamic range and signal to noise ratio of the MAP signal. With (relatively) huge 45mm ITBs on my wimpy 2.0L the idle pressure was 35-40 kPa. With a simple combined runner signal it probably would have been 70kPa at best.


Ok, well I'm rambling now so I better stop. It's just really exciting when you find other Honda guys interested in Megasquirt!

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[cygnus x-1]

Originally Posted by preludefan

to this day i still struggle to understand why honda and many other leaders in technology, didnt go to coilpacks when they started dicking with fuel injection- the distributor is like the one single primative thing that stayed with the prelude its entire life - perhaps our cars were a prelude to cop!

Seriously. Ford figured it out in the early '90s. Distributors are retarded. WTF took everyone else so long? Nissan put a distributor in the Frontier up until at least 2004.

Originally Posted by preludefan

also, its good to hear that you got the noise sorted out, i also recomend running say a 47pc capacitor in paralell with each vr sensor where it connects to your ecu or vr decoder- i had horrible noise but as soon as i fitted those, the signal was perfect, i recon you should give it another go!

Oooh, that's nice tidbit there. I'll remember that one.

Originally Posted by preludefan

there have been heaps of people giving megasquirt shit- mainly these guys in europe who think they are the biggest and best of everything and claim they can do way better, but all a lot of them do is copy the original and say they have improved it, like this guy:

http://www.turbosport.co.uk/showthread.php?t=135721

Interesting read there. It's annoying but pretty much inevitable. Look at it this way; the fact that people are copying it means that they (B&G) must be doing something right. And ultimately all that matters to me is that it works for me. Everyone else should use what works for them, be it Megasquirt or something else. (but hopefully not an illegal copy)


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[preludefan]

mitsubishi still put them in their l300 vans- i think they are called the express in the usa- even today, im positive its strictly so they can sell parts, which sucks as i need to buy one sooner or later because im an electrician- but hey why worry when you can megasquirt it!!!!

[preludefan]

just to let everyone know, i swapped to a 24 toothed wheel, with the 4 toothed wheel being cut down to a 2 tooth, it now runs a bit better- although there is no difference in high rpm performance, the acceleration enrichments come in alot faster with more teeth!

[cygnus x-1]

Originally Posted by preludefan

just to let everyone know, i swapped to a 24 toothed wheel, with the 4 toothed wheel being cut down to a 2 tooth, it now runs a bit better- although there is no difference in high rpm performance, the acceleration enrichments come in alot faster with more teeth!

Interesting. Are you using an MS1 chip? I think that was one of the upgrades from MS1 to MS2; a faster processor so the calculations run faster.

Pretty soon here I'm going to be pulling my MS out to do the sequential/COP conversion. Going to use the existing 36-1 EDIS wheel and add a single tooth pickup for the cam using a hall sensor and magnet on the cam pulley. Just got some LS2 coils with built in ignitors so I won't have to add any to the MS. Just need to add some new injection transistors and a hall input circuit for the cam sensor.


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[preludefan]

fuck yeah man, the ls2 coil setup is my dream setup!, though id run them in wasted spark mode on mine but they are great bcause they have such a strong spark!

correct me if im wrong but cant you juyst use the 32-1 wheel on your crank without needing a second trigger?

and yes im running the ms1 chip, its resolution is pleanty for my lude now!

Originally Posted by cygnus x-1

Interesting. Are you using an MS1 chip? I think that was one of the upgrades from MS1 to MS2; a faster processor so the calculations run faster.

Pretty soon here I'm going to be pulling my MS out to do the sequential/COP conversion. Going to use the existing 36-1 EDIS wheel and add a single tooth pickup for the cam using a hall sensor and magnet on the cam pulley. Just got some LS2 coils with built in ignitors so I won't have to add any to the MS. Just need to add some new injection transistors and a hall input circuit for the cam sensor.


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[cygnus x-1]

Originally Posted by preludefan

fuck yeah man, the ls2 coil setup is my dream setup!, though id run them in wasted spark mode on mine but they are great bcause they have such a strong spark!

correct me if im wrong but cant you juyst use the 32-1 wheel on your crank without needing a second trigger?

and yes im running the ms1 chip, its resolution is pleanty for my lude now!

You can use just a crank wheel for wasted spark but for sequential injection and/or individual coil ignition you need some sort of cam sensor so it can tell which half of the 720 degree cycle it's on.

For awhile I've been waffling back and forth about whether or not to do the individual coils. But I've been wanting to change the wiring to get rid of some electrical noise it's been having and also get ready for another shot at an ITB setup. So I finally decided that if I'm going to bother changing anything I might as well just do it all the way I want, even if it's more work. I expect the sequential injection will smooth out the idle and low RPMs a little but the individual coils will likely make no difference in how it runs. Really it's the sequential injection I want. But by the time you have that, the extra work to do individual coils is almost trivial. The hardest part with the individual coils will be figuring out how to mount them to the engine. With the built in ignitors the electronics are easy.


EDIT: Incidentally I found my LS2 coils on ebay for $18 (US) each. Pretty hard to beat that kind of price. I still need the plug wires and coil connectors but I can get the connectors from the local junk yard and plug wires from the pars store.



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[Dexter]

You don't need this to run single coil with MS correct?

[preludefan]

Originally Posted by Dexter

You don't need this to run single coil with MS correct?

no, if you are just running the single coil distibutor setup,use the 4 tooth wheel in the dizzy on msnspark mode, tha will ensure you get your spark timing sorted and ms1 will run its bank fired injection off the same signal.

you will however need to run a single vr conditioner for that 4 tooth wheel if you are using ms1.

[cygnus x-1]

Preludefan, you were asking over on the msextra board about using the Honda MAP sensor with megasquirt. You certainly can but the calibration is different. In TunerStudio, under Tools -> Sensor calibration, for the MAP sensor you want -4.0% at 0 volts and 179% at 5.0 volts.


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[preludefan]

thanks buddy