Dual Map Tables

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Old Grey
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Dual Map Tables

Post by Old Grey »

I assume you can do single IGN and INJ maps with offset, like table plus 10%, but can you do two full separate IGN/INJ maps activated with a switch.

I was wondering if I can have a full economy mode - needs more advance because less fuel is less volatile - and press a switch to go to full power mode - needs more fuel - when I need to get in front of someone at a set of lights.
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Re: Dual Map Tables

Post by AndreyB »

Not at the moment. The firmware is at the border of RAM usage at the moment so I am reluctant to add a second set of maps - in order to do it right I would first need to reduce memory usage, that's definitely doable just requires time.
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Re: Dual Map Tables

Post by AndreyB »

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Re: Dual Map Tables

Post by Dial0 »

I am sure you already know this, but you can move all the static strings from ram to flash, and that would free up a lot of ram.
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Re: Dual Map Tables

Post by AndreyB »

Actually what I need to do is to give up on 4-byte 16x16 maps and retreat to 2-byte 16x16 maps, that would give me dual map tables with same exact memory usage. As much as love my native float numbers, these tables are just using too much RAM :(
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Re: Dual Map Tables

Post by Old Grey »

Currently I would say that dual tables is a luxury item, as I could get away with single tables and a button offset, so don't go to too much trouble on my part.

I was also thinking that a hand button is too slow, and would want a full throttle button that would automatically switch to power mode for say 1 min after full throttle and then switch back to economy.
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Re: Dual Map Tables

Post by Dial0 »

What would be the difference between the power tune and the economy tune?
You should be able to achieve both with a single table, without sacrificing the other.

Dual maps are generally for different fuels, high octane fuel tune vs lower octane fuel tune for example
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Re: Dual Map Tables

Post by stefanst »

I run two different timing maps and EBC maps- one each for track use and street use. Since track is more demanding I dial down boost and go a little more conservative with timing. On the street where you rarely see high boost I go more aggressive. Fuel maps are the same though.
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Re: Dual Map Tables

Post by Old Grey »

Dial0 wrote:What would be the difference between the power tune and the economy tune?
You should be able to achieve both with a single table, without sacrificing the other.

Dual maps are generally for different fuels, high octane fuel tune vs lower octane fuel tune for example
Dual fuels is a good reason for dual tables, but if you had the sensor it would be better as I think it can differentiate mixes of the two fuels on the run.

Economy uses reduced fuel and can possibly use a more advanced ignition table, because the lean mixture burns more slowly so can handle more advance. This can only be used in low load part throttle - part throttle reduces the VE - because lean with high advance and high load can burn pistons.
Power needs extra fuel, even excessive fuel for cooling incoming air to increase its' density, with a touch less advance.

I'm no EFI expert but do the bigger units (MS) have a multi table feature. I'm pretty sure Motec, etc have multi table because you see it in racing.
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Re: Dual Map Tables

Post by stefanst »

What would be the reason not to run the higher fuel efficiency settings in part throttle? If you always go with high efficiency, the need for a second table goes away.
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Re: Dual Map Tables

Post by Old Grey »

True, if you don't mind the compromise like with transients.

Most new sports cars have mode select, and the racing industry uses it, so I thought it would be quite a good idea if there is no down side.

How about street tuning - some people can't afford dyno time -.

Remember the old days when you did an accel test, pulled over, changed the timing, and did another run totally forgetting what the other run felt like.
Now you can do A-B-A etc testing with the push of a button multiple times just on part of a table, fast enough that you can feel something.
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Re: Dual Map Tables

Post by stefanst »

Street tuning works much better than its' reputation suggests. I've used Virtualdyno, combined with detcans quite successfully to tune spark. All you need for fuel is a wideband anyway. And then, after you have a perfect street tune, get the last 0.5% on a dyno.
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Re: Dual Map Tables

Post by AndreyB »

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Re: Dual Map Tables

Post by Simon@FutureProof »

I believe some of this is going to be covered by the changes needed to support flex fuel.

It is my understanding that as part of that change the ability to define a modifier map and a trigger to have it applied to the main tables will be implemented.

This will mean that spark additions or VE alterations can be made in the sub map and a simple switch used to trigger the application of those changes to the main table.

It is required for flex fuel as we will need to be able to blend between two operating conditions depending on the ethanol percent sensed at the flex fuel sensor.
To use it as a switchable map the flex sensor could simply be replaced with a switch.

To use it for ignition timing back to backs it would be as simple as making the +- alterations in the modifier table and then flicking the switch would apply them and return to the base table.

It is my understanding that this is the most RAM efficient way, more flexible than simple map switching and the way some of the more high feature stand alone ECUs have chosen to do it.
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