Map Switching - Lag?

General Topics for configuring, operating and tuning the Megajolt. Also see the <a href="http://www.autosportlabs.net/MJLJ_V4_Operation_Guide">Operation Guide</a>

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Funky Diver
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Map Switching - Lag?

Post by Funky Diver »

OK, might sound like a daft question, however, to clarify, I haven't actually GOT anything yet (waiting on my shiney package arriving full of bits n pieces, it is shiney right Brent?) and my car is FAR off ready being completed.

When on the move, is there any lag between map switching? The reason I ask is that I'm looking at hooking up my map switch using electronic means - ie Arduino - so that if the mean velocity is above say 40mph for a period of time, say on a motorway / freeway / longer stretch of road combined with the lack of variation in RPM, it switches to a more economical map for that style of driving. When it gets back to up n down MPH, RPM, the system knows we're back in town for a more.... err... agressive style of driving. Sure you get the picture... :P

There will be an over-ride in the system anyways, so that if I wanted to go economy in town, I can... and vice versa.

So, is there any lag in the switch over? I kinda feel that I already know the answer as it's all software generated, but would like it conclusive before I start looking at coding.

Cheers,
Rich

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brentp
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Post by brentp »

The check to switch maps occurs every ignition event, and if it needs to, it happens immediately. We haven't timed it but it takes about as long as it takes to copy about 200 bytes of memory. and it happens before the next ignition event is processed.

i.e. it's as immediate as you can get. :)
Brent Picasso
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DannyP
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Post by DannyP »

I think you're making it too complicated. If you have some sort of load sensing(MAP or TPS) you can dial some economy into the curve. Less load, more advance kind of thing.

I have two maps loaded in but I haven't touched the map switch in a year. Once you get it right and it runs really well you won't need to switch maps.

I just recorded 23.5 mpg for my car, with big Webers on a good-sized VW motor. I used to get way worse, like 17-18, until i did the 'Jolt and fine-tuned it.

Funky Diver
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Post by Funky Diver »

DannyP wrote:I think you're making it too complicated.
Possibly... but then that's the fun of it :D

If life were "simple" I'd be sticking with my stock VW Scirocco (Mk2) however, it's getting the works. It's a GT model and apparently so was the spec in 1989. GT's have come a long way since, and so has my idea for the whole car. Sheep in Wolfs clothing? Possibly, Wimp in Drag... definitely not!

Funky Diver
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Post by Funky Diver »

OK, my information quest deepens.

Is it possible to switch to configuration of the programmable outputs withthe Map change? I'm guessing no, but I do ocnstantly keep getting surprised at this kit!

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brentp
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Post by brentp »

Hi,

Yes: actually, the whole ignition configuration changes- map, bins, user defined outputs, shift light and rev limiter settings.

Gobal settings, like cranking advance, trigger wheel offset and TPS / Aux Input channel calibration do not change.
Brent Picasso
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Funky Diver
Posts: 133
Joined: Tue Jun 08, 2010 7:06 pm

Post by Funky Diver »

WOOOHOOOOO, that's exactly what I wanted to hear (see?)

Cheers Brent!

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