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Author: Subject: Odd fire engines with megasquirt n extra
NS Dev

posted on 16/11/06 at 02:37 PM Reply With Quote
Odd fire engines with megasquirt n extra

anybody know anything about running odd fire engines with megasquirt n extra type setups?? (i.e. ignition and injection control)

I guess the basics are a setup that can use 2 trigger inputs, the crank trigger and a single point cam trigger to give phase.

anybody done it?





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benji106

posted on 16/11/06 at 03:20 PM Reply With Quote
never heard of a fire engine running megasquirt, what constitutes an odd one anyway?
would you call this an odd fire engine?

Description
Description


I'll get my coat

[Edited on 16/11/06 by benji106]

[Edited on 16/11/06 by benji106]

[Edited on 16/11/06 by benji106]

[Edited on 16/11/06 by benji106]





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benji106

posted on 16/11/06 at 03:33 PM Reply With Quote
the comedy effect was lost somewhat due to the lack of picture.





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NS Dev

posted on 16/11/06 at 06:47 PM Reply With Quote
quote:
Originally posted by benji106
never heard of a fire engine running megasquirt, what constitutes an odd one anyway?
would you call this an odd fire engine?

Description
Description


I'll get my coat

[Edited on 16/11/06 by benji106]

[Edited on 16/11/06 by benji106]

[Edited on 16/11/06 by benji106]

[Edited on 16/11/06 by benji106]


LOLOLOLOL





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NS Dev

posted on 16/11/06 at 07:08 PM Reply With Quote
Well.........

I've looked, read lots of abbreviations, and come to the conclusion that nobody has yet run megasquirt with ign control on an odd-fire engine.

Plenty have run fuel only on them, and plenty have run megasquirt and sparks, but none on an odd-fire engine as far as I can see on those forums, and in 2 days nobody has answered my basic question on the Msextra forum either!

I am reading lots of posts asking detailed questions and getting loads of detailed answers on the easy bits that I didn't even mention in my question, such as the fact that not only is the engine odd-fire with 2 VR sensors for phasing, but it also has twin plugs per cyl and is coil per plug too. I assumed all that bit was easy, its the timing that I assumed would be harder, and nobody can answer the question it seems.

One answer I read suggests that "microsquirt" may deal with 2 VR inputs on one engine, but current systems can't.

Another section then talks about twin VR inputs, but makes no mention of ignition!

I'm confused!





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carnut

posted on 16/11/06 at 08:00 PM Reply With Quote
Are you trying to build a "big bang engine"? Maybe you could just trick it by thinking it has more than the number of cylinders that it has. ie just ground the spark for the cylinders that arent really there.
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MikeRJ

posted on 16/11/06 at 08:21 PM Reply With Quote
quote:
Originally posted by carnut
Are you trying to build a "big bang engine"?


Don't think so, but Nat is running V twins which naturaly have odd firing intervals.

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carnut

posted on 16/11/06 at 08:58 PM Reply With Quote
Whats the V angle and is there a crank pin offset for the 2 cylinders?
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NS Dev

posted on 16/11/06 at 09:11 PM Reply With Quote
60 degree vee, common crankpin, I make the firing intervals 420deg then 300deg





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paulf

posted on 16/11/06 at 09:24 PM Reply With Quote
Cant you just run the standard ignition system?.Would there be much advantage using megasquirt for the ignition? it can fuel oddfire engines with no problem so surely this would be the way to go to get it up and running.
Paul.

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Chippy

posted on 17/11/06 at 12:03 AM Reply With Quote
I am in the process of constructing Megawhatsit for my V6, and that uses the original Hall effect dizzy to regulate the spark interval, could you not do something like that. Sorry if this idea is duff, but not too clued up on the why's and wherefores. Regards Ray.
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NS Dev

posted on 17/11/06 at 07:58 AM Reply With Quote
The Aprilia has integrated ignition and injection, so can't run the std ignition, it all comes from the same box!

Can't run a dizzy as it doesn't have one, the crank and cam sensors give the reference triggers.





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NS Dev

posted on 17/11/06 at 10:15 AM Reply With Quote
That is the plan at the moment, complicated by the fact that I am short of the ECU's.

The engines were bought as running kits, but the difficulty is that the keys are coded to the ECU's on the later bikes, and no keys = no ecu.

I'm awaiting the ECU's but none have turned up yet.

I am supposed to be getting a pair of ECU's and looms from the USA where they apparently don't have the key coding issue (Mal on here is organising that for the chap I got the running kits off, but is stuggling to source them at the moment)





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NS Dev

posted on 17/11/06 at 12:36 PM Reply With Quote
cheers Calvin!

I am pretty familiar with the basics of engine management (probably more so that I come across as ! ) but always with 4 cylinder setups, and as with anything, you get used to the way of doing things, and then new things seem odd!

The problem with reading and learning is just (as I guess is the case with yourself as well) just lack of time!

I am trying to get all the tiny finishing jobs sorted on the locost before I start the grasser, but then I have to strip the grasser donors, which takes time too.

I spent 2 hours reading up last night and gained very little after using up that time net-trawling, which put me in very poor mood when it came to getting anything done on the 7 afterwards!

I'll keep you up to date, Bill Shurvington is investigating for me!

I hasten to add, the wiring and hardware is straightforward for me, its the code that worries me as I haven't a clue and have no time to learn!

[Edited on 17/11/06 by NS Dev]





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Syd Bridge

posted on 17/11/06 at 04:09 PM Reply With Quote
Nat,
Look at the problem from this angle....you have two cylinders in a 60deg. V.

This is 1/3 of a V6. You just have to work out which cylinders of the 6 that yours uses.

Obviously, the first to fire is no.1, and the second is either 60deg or 420deg. further on. Which cylinder of the V6 is it????

Cheers,
Syd.

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NS Dev

posted on 20/11/06 at 09:03 AM Reply With Quote
Cheers for the U2U Syd!

Very good point on the V6, running my v twin will indeed be the same as running a coil-on-plug v6 with 4 cylinders deleted.

The input requirements are the same though in that two triggers will be required in order to do the ignition, but I have read up on this (see I do read sometimes Calvin lol ) and Philip Ringwood et al manual on various things msextra is actually both readable and understandable....hurrah!

Basically, yes, I can run two VR inputs on version 3 quite easily, and I can also drive 4 coils per engine for the twin plug coil on plug setup that the Aprilia uses.

So far so good, but I don't think I can build the standard board myself, let alone one with a number of fairly serious modifications (even though they are well documented in the manual) so to that end I have now emailed Philip Ringwood, as he sells systems, to see what he can tell me about prices!

If anybody on here has the time and inclination and confidence to have a look at it for me then I am interested, needless to say!!!





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NS Dev

posted on 20/11/06 at 07:39 PM Reply With Quote
hmmmm, been investigating further!

The v6 conection is not straightforward (as usual! )

The v twin fires with alternating 300 degree and 420 degree intervals, the v6 fires with even 120 degree intervals.............................

I can't then resolve the intervals required by the v twin using the v6 setup, cos I need to resolve to 60 degrees to do that.

Edit..............

argghhh think I am being stupid, my brain is cooked!!!

My bro has just come in an pointed out that the spark events are 120 degrees apart in both cases so it should work...................its just a case of how!!!!!

[Edited on 20/11/06 by NS Dev]





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Syd Bridge

posted on 21/11/06 at 09:20 AM Reply With Quote


There's a smart arse know all in every crowd. Where's that paddy got to?

Syd.

Without the u2u you don't know what transpired 'tween me and Nat, anyway.

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NS Dev

posted on 21/11/06 at 09:40 AM Reply With Quote
Had a reply from Philip Ringwood now (who sorted most of the decent manuals on tinternet on megasquirt with the "extra" code) and he says he doesn't know either!!!!

Looks like I may be on my own on this one!!!!!

Still not sure why I can't just use 2 seperate trigger points, one for each cylinder, a bit like running 2 linked 1 cyl engines using a common crank wheel????????????????????????

The triggers are in the right places on the wheel

Am I missing something here?





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Syd Bridge

posted on 22/11/06 at 11:50 AM Reply With Quote
This should only need a change in a number in the raw code, to tell the system to fire at no.1, and then 60deg or 420deg later.

The unit measures where it is from the toothed wheel, either by tooth count, or more likely, tooth count and time between tooth signals.

So, a four fires every 180, a 6 every 120, an 8 every 90. (for even fire anyway.)

Should just be a number change in the code, then recompile and apply!

Cheers,
Syd.

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MikeRJ

posted on 22/11/06 at 02:50 PM Reply With Quote
The problem is the stock MS only knows the position of the crank, it doesn't know if number one is on the compression or exhaust stroke. Not a problem for an even firing engine using a wasted spark system, but for an odd fire engine it needs to know if it should be firing now and in 60 degrees, or wether it should be waiting for another 420 degrees. The only way to do this is with a cam sensor, which the V3 MS does not natievly support.

The MicroSquirt system currently under development does support two engine position sensor inputs. I've not followed the progress of the uSquirt, so I don't know how close it is to a useable release.

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Syd Bridge

posted on 22/11/06 at 03:30 PM Reply With Quote
Wasted spark fires the cylinders on power and exhaust. Shouldn't be any different. All you need to do is shift the spark event time.


A cam based sensor would be ideal though.

Cheers,
Syd.

[Edited on 22/11/06 by Syd Bridge]

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Syd Bridge

posted on 22/11/06 at 04:30 PM Reply With Quote
OK. Been trawling the MS stuff 'tween coats of 2pack clear.

I see mention of 12 cylinder engines. These fire every 60deg for even fire!

So, Nat's engine IS two cylinders of a 12!

Now, which two?

Cheers,
Syd

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NS Dev

posted on 22/11/06 at 05:05 PM Reply With Quote
Yep, that's the conclusion we came to on the Msextra forum, V12 has the right resolution, I've emailed Philip for a cost, he's not got back to me yet, and I'm not sure about being the guinea pig on something that is to race not play with, but its a definite possibility!

cheers folks!





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MikeRJ

posted on 22/11/06 at 05:42 PM Reply With Quote
quote:
Originally posted by Syd Bridge
Wasted spark fires the cylinders on power and exhaust. Shouldn't be any different. All you need to do is shift the spark event time.


I see what you mean, it won't hurt to fire each cylinder twice per cycle like a wasted spark system, but obviously it would have two separate coils rather than one double ended one.

Done a bit of digging in the MS&S Extra code and an odd fire wheel decoder seems to have been in place from version 026f and is still in current version (029t) BUT no reports of wether it works or not!

http://megasquirt.sourceforge.net/extra/setup-oddwheel.html

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