Writing a map...

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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Edwardatherton
Posts: 30
Joined: Sun Jul 01, 2007 9:50 am
Location: Manchester, England
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Writing a map...

Post by Edwardatherton »

Even though I have data on RPM/vacuum advance settings, is it better to...

1)run the engine at a certain speed then advance the ignition till the I find the highest revs.

2)Repeat the above for different RPMs.

???

or not?
Land Rover 1957 S1 88" 2.5 petrol/LPG

MartinM
Posts: 433
Joined: Sat Aug 27, 2005 12:08 pm

Post by MartinM »

That might be a rather simplistic way if you only had 2D control, but when you say "run the engine", I assume you mean in the garage, so you will not be seeing any realistic load settings that equate to
- foot in the carpet at low rpm, i.e. lower rpm, higher kPa
- foot off the throttle at high rpm, i.e higher rpm, lower kPa
...because you won't be able to reproduce them.

If getting a map was that easy, all the rolling road tuners would be out of business!

You've got at least three options:

- do the above, note which cells you are covering and work out the best values for the other cells using the general features of all maps ie more rpm = more advance, more vacuum (lower kPa) = more advance, and any specific features you can find about your engine (max advance, idling advance, amount of vacuum advance at different rpms etc etc)

- keep increasing the advance everywhere and drive around listening for knocking; back off the advance where the knocking occurs - this is undoubtedly an option, but I would never recommend it - it could wreck valves an/or pistons 8)

- get it done properly on a RR

Martin

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