V3.X firmware for ms2 - differences

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Fred
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V3.X firmware for ms2 - differences

Post by Fred »

Hi Jean,

I know that it does sequential, and knowing you, it probably does siamese port stuff too, but what else does it do/not do compared to 2.0 or 2.1?

In particular, what abotu staged injection?

Could you run 4 sequential injectors at idle and bring in staged injectors at a later date? Can you have the staged ones be sequential and the idle ones run in bank/batch mode? What are the staged options with your 3.X code?

Fred.
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jbelanger
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Re: V3.X firmware for ms2 - differences

Post by jbelanger »

It does have a few siamese port options. And there are a lot of additions, bug fixes and changes (small and not so small) which would be quite long to list here: they are listed in the different threads for each public version.

Since there are only 4 injector channels, the only way to have staged injection is to run semi-sequential with two primary injectors and two secondary injectors. And that's only for a 4 cylinder engine (obviously). The table at the top of this page shows all the different combinations available.

Jean
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Re: V3.X firmware for ms2 - differences

Post by Fred »

Great, thanks :-)

I'll make sure the guy asking finds out about this. I somehow have more faith in your alpha than in other release code... even though I've not seen it. Something tells me that it'll be good stuff :-)

Fred.
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Re: V3.X firmware for ms2 - differences

Post by spencer »

Hi Jean

Specifically what I am trying to do is run outboard injection on a 2l NA 4cly engine like something like this

Image

Now idealy I would want sequential with 8 injector drivers, but with your 4 drivers and semi sequential I could at least get it running on my MS2 and play around.

My question is with the staging code. It doesn't seem to cater for what I want to do. How this setup would run is two sets of injectors of similar size. Under low revs you run under full inboard injectors, as the revs increase you slowly phase in the outboards. Until your running around 80% outboard 20% inboard, if you go to much fuel to the outboards you end up with fuel fogging issues (= fire hazard). Am I missing something with the staging code?
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Re: V3.X firmware for ms2 - differences

Post by jharvey »

Hmmm, looks like ITB's. You might find this interesting.

http://batchpcb.com/index.php/Products/32945

I have modified this design for a 4 cyl version, but I haven't talked much about it because the 12 cyl version is currently in round 2 of the prototyping process. Once it's confirmed as a good design, I'll post more about it some where.
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Re: V3.X firmware for ms2 - differences

Post by jbelanger »

Staged injection runs the same pulsewidth for the primary and the secondary except during the transition from primary to primary+secondary. So with identical injectors, you'll always get 50% fueling from each.

There is now a table where you can adjust this percentage as a function of rpm and load but the maximum you can have is still 50-50 (that's what the 100% means in the table). The values in the table are in percentage of fully staged.

For full sequential and staged injection on a 4 cylinder, you'll have to go with an MS3 (or something other than Megasquirt). They may change the staging code to allow different staging strategies which would allow you to do what you state.

But the best place for asking this would be on the msextra forum.

Jean
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Re: V3.X firmware for ms2 - differences

Post by Fred »

Could you trick it by setting RPM cut in point to 0 and hooking the outers as the inners and vice versa and adjusting the percentage backwards? I guess you'd have 50% at idle on the outboards, then, though, which would suck.

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Re: V3.X firmware for ms2 - differences

Post by jbelanger »

The way to get more fueling out of the secondaries is to use larger injectors (or smaller primaries). However, to get 80% of the fueling out of the secondaries, you'd need to have a 1:4 ratio between the primaries and secondaries which might not be practical.

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Re: V3.X firmware for ms2 - differences

Post by Fred »

I was talking to Spencer in chat and suggested a couple of other dubious things too :

A switch between the banks at some RPM with four relays - probable transition stutter.
B run injectors so large that the fuel is only flowing during the inake 1/4 of the time - should eliminate fogging.

Fred.
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Re: V3.X firmware for ms2 - differences

Post by spencer »

Cheers guys

I like the idea of that map board, is there a website? I've tuned many throttle body cars now and stable map readings is always an issue.

The idea of large injectors may work, I'd love to try it. My fuel rails and throttle bodies are from a 09 CBR1000RR and are well sized for my engine/power requirements. New 1000cc injectors to fit my fuel rail would put me into new ECU territory $$ wise

Regarding the MS3 and the source not being open, this could mean the code to run staging as I desire could never come out?

I'll bring this up on the MS/extra forum once I'm signed up cheers
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