andenbre

iTrader: (4)

If anybody knows how the 9 utilizes its multiple ignition maps I have an open ear.
where the 8 has one high and one low octane map the 9 has three of each. the high octane are all very similar but do have differances. the low octane maps are also very similar to each other.
The only theory I have at the moment is that different maps are used for different mivec ranges, and it is just that, a theory.

the-moss

iTrader: (3)

I have been thinking about this also and haven't come up with any good reasoning on it. The Mivec theory sounds better than any I have come up with at this point.

jcsbanks

I just increment or decrement the same zones by the same amount on all four high octane maps on my JM8857-08. You could of course set the timing maps to something different to see which one it is accessing with a logger, same for load zones.

MalibuJack

iTrader: (5)

I think its relative to the MIVEC stuff, Shiv posted a really good thread in the Vishnu forum last year about what those maps meant and whatnot.. I never digested the info completely because I never expected to need it..

Its pretty obvious though that altering the cam timing would shift the engines VE and you would likely need different maps for different levels.. I mean, MIVEC does alter cam overlap and that definitely would force a typical Evo8 to do a slight retune for different cam gear settings.

andenbre

iTrader: (4)

i will search for shivs thread and if I dig up any good info I will post it here

jcsbanks

From previous reading I've not found any details of which of the ignition maps do what.

I don't see the need for more than a high and low ignition map simply because of MIVEC. The Denso ECUs, or MoTeC or other standalones don't need lots of ignition maps because of the operation of VVT. Since the MIVEC table is load and RPM referenced then you should be in steady state operation in a given fuel or timing map zone.

MalibuJack

iTrader: (5)

I have to disagree, bt only from a logical perspective (I have not yet tuned an Evo9)

If you shift the cam, you shift the cam timing and overlap, therefore, you shift the power band, you may not necessarily shift the load on the engine, but you will need to alter timing slightly to compensate for higher RPM operation with basically a different bit of Cam Overlap.. Logically I've tuned cars with adjustable cam gears, and although you don't always have to alter the tune, you will reap the most benefit if you do..

I don't think the existing maps make the best use of the power that multiple ignition maps gives you, their obviously being used.. You will see this feature invaluable when you start seeing larger cams become available where altering the overlap will have a more significant effect on the engines Tune..

jcsbanks

At one particular load and RPM point the cam timing has a target. So you just need one fuel and timing map also referenced by the same load and RPM points to have a satisfactory map. I'm not saying you don't tune for the cam changes, just that you only need a single load vs RPM map to tune for any given instance. Further maps will be for different operation conditions such as octane changes, sensors out of range etc?

the-moss

iTrader: (3)

I see what you are saying jcsbanks.

Basically that for any given load/rpm cell the cam timing is known so the required ignition timing is also known, so why do we need multiple maps for ignition timing?

jcsbanks

Yes.

andenbre

iTrader: (4)

oh ok you opened my eyes there you would only need multiple ignition maps for mivec if there were multiple mivec maps being used.

I see said the blind man

Blak94GSX

Ignition map 1 is used exclusively until the coolant reaches over 149F. Ignition map 2 is used exclusively once it is warmed up, and Ignition map 3 is used in limp mode when there is a major DTC triggered like the MAF is disconnected.

Basically map 2 is the primary map.

andenbre

iTrader: (4)

that is great info Blak94gsx. thank you very much. so in my case with a stock car with no injector, air intake, or turbo mods I will concentrate on map 2 and leave the others alone for safetys sake. even with the turbo back I will be installing i dont think its neccecary to mess with any thing other than 2

burgers22

Is this the same theory for other multipule maps, like target boost ( not just on the IX) ?

MB

jcsbanks

Makes sense, I was told that #2 is the one it usually runs so that agrees there.

I wonder what the high octane #4 does in my JM8857-08?