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Australian Ford Member
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1,120 Posts
Discussion Starter #1
If I advance timing, say a couple of degrees before the ignition mark used for base timing on my 3.9mpi, will the ECU treat that as a base and keep timing the same amount advanced throughout the range? If so, what's the best amount to advance it for maximum acceleration?
 

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T5 Expert Operator
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6,540 Posts
EA S,

In the EA's my guess is the timing will stay constant through the rev range. Ie if you have 2 degree's advance before TDC, it will stay that way right up to 4900rpm.

About what is the best advantage for acceleration, the rule of guide about timing advancing as i understand it is if you advance your timing and run a higher octane fuel you'll get abit more power and response. So if you plan to run the 98Ron fuels you'll be able to advance the timing more than running on a lower ron fuel.
 

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Australian Ford Member
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1,120 Posts
Discussion Starter #3
After starting this topic and getting the reply, I stumbled on a statement in the factory manual which confims the reply. If base timing is out by x degrees, the ECU will be out by x degrees throughout the range, so timing can be advanced.
 

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Australian Falcon Member
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865 Posts
Yep, the timing will end up advanced by that much right thru the range - the ECU controls timing on a purely arbitrary basis which assumes the base settng is 10 degrees BTDC.

I've buggered about heaps with timing on my machine (used to carry a ratchet with long extension and 1/2 inch socket in the side pocket). It ends up being a trade off in that any advance improves response (and power?) thru the bottom and midrange up to a point (ie. the point where there's too much advance - at which point you get very obvious pinging even when accelerating quite gently off the line). The trade off is that any advance beyond maybe 2 degrees will impact negatively on top end.

Because I do a fair bit of open highway driving I now just leave mine at the std 10 degrees, but if you're in the city and want to improve responsiveness and make the old beast a bit more lively in the 60 and 80 zones, then it's well worth cranking it around a bit.

For town driving, you'll also find that advancing the std cam one tooth will make the car feel much livelier and improve fuel economy HEAPS - but forget about acceleration above about 130kph. Sort of makes it feel like a really hotted up V6 Commodore in other words.
 
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