Factory 4AGE spark advance

[Vertigo]

There are a few maps floating around the net with the spark advance for 4AGE, including one derived from a detailed factory ECU analysis, which suggests it goes as high as 48 degrees advanced. Is this true? Anyone know how high the stock ECU spark advance goes at its maximum?

[jondee86]

This is the ignition table I derived from the information provided
by Jeremy Ross in his analysis of the MK1 MR2 ECU...



The very high values are at closed throttle on the overrun, so they
are basically meaningless. However, the WOT values look to be in
line with conventional practice.

The one thing I could not figure out when I was looking at this data
was why the values in the idle area are so high ? Observed advance
at idle on a warm engine is around 16-17 deg, whereas this table
would indicate low 20's.

Cheers... jondee86

[Vertigo]

Thanks for that. Unfortunately I think thats just muddied the waters even more! I think the only way to verify these values is to measure them directly, which I cant do without a dyno..

[QikStarlie]

all those numbers seem too high. 35degrees at wot is too much.

[touge_ae101]

We ran 36deg on my old blacktop so it doesn't seem too ridiculous

[matt dunn]

We ran 36deg on my old blacktop so it doesn't seem too ridiculous

36 deg at full load is where we aim for on NA cars,

We used to do a lot of mechanical advance modification on old points and electronic dist's,
and we always used to set them so 36 deg was where they ended up.

[QikStarlie]

is there any power gains though? we never gained any power past 27 degrees on my 16v 4age. not stock engine though.

[Lith]

is there any power gains though? we never gained any power past 27 degrees on my 16v 4age. not stock engine though.

I was going to add something to that effect, too - and this is why we don't use a flat ignition map for every engine, if we could then tuning would be much much easier As you squeeze more and more air and fuel into the same volume you need less and less timing to ensure the pressure build through the power stroke is optimal and safe, I have gone into the 30s on stock NA motors on 98 octane and had it be worth it - but I have also run as low as mid 20s on cars with higher compression and high lift cams and made way more torque at equivalent rpm than an equivalent stocker version of the same motor running way more timing.

Strange numbers in the map though, makes it seem like they may not be necessarily aligned to TDC.