At what point do I need to worry about advancing ignition?

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Jun 17, 2004 | 07:53 PM

#26

j9fd3s

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From: https://www2.mazda.com/en/100th/

Quote:

Originally posted by slvr7
Base ignition timing has the leading plug firing 5 (measly) degrees before TDC. As rpm builds, timing advances significantly so the the leading plug is firing well _before_ TDC. The resulting flame front takes time (milliseconds) to propogate enough to make the big 'push' on the rotor - with the rotation of the rotor also occurring during those milleseconds, it should all happily occur at or just after TDC.
You can see the problem if you over-advance, or have a fast burning (low octane) mixture - and the push happens before TDC

the problem is on the stock ecu is that you can only move the whole curve, instead of parts of it. so if you set the timing for w.o.t. it might be over or under advanced at part throttle, or idle.

Jun 17, 2004 | 08:34 PM

#27

ajsuper7

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From: Houston, Texas

i believe the mdrace chip that was developed a long time ago advanced the timing a signifigant amout through the low and mid range and dropped off at high rpms for the best spread of power. supposedly it made a huge difference in mid range power...well as big as you can get with a ecu chip on a n/a. i do not believe that these chips are made anymore or were sold to superchips or some generic ecu company but i dont know if im making stuff up or if thats how it was. im sure some ecu experts can correct me if im wrong. im not sure if there is any way besides a standalone to achieve what i think mdrace did but i have no experience with these matters. anyone want to comment on this?

Jun 17, 2004 | 10:36 PM

#28

Tofuball

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From: Silver Spring, MD

Quote:

Originally posted by RETed
Um, I'm a bit confused on your question...
Did I mentioned anything about doing this?

-Ted

When you said "If you move the CAS, this means ALL ignition timing will be moved this amount."

I thought "ALL" ment the trailing and leading together, as in, you would want to advance them seperately (Whitch confused the heck out of me, thus I asked for more info)

But now that I re-read it, I realise that you ment under different (load, throttle, whatever) situations :-p

Last edited by Tofuball; Jun 17, 2004 at 10:40 PM.