Ign Timing - Couple questions

[Fanged03]

Guys,

I'm working on making a tune for E85, car is currently on the stock timing map. Bare with me, I've never really dealt with timing before, not even on a distributor.
1. I'm wondering if the timing numbers in the tables are based on a zero point of TDC or from the programmed timing offset?
2. As far as I'm aware the timing curve should be inverse to the load curve, correct? or can you just flat line the timing pas a certain rpm?
3. SAFTOT is the correct pid to datalog?

Thanks guys

[jsa]

1. From TDC
2. LOAD and rpm
3. Yes

[Fanged03]

Thanks for the reply John. Where abouts in Oz? I spent some time in Queensland last year and got to experience the Northern Nats, loved it up there, even with the high concentration of animals that want to you kill you.

Reading my #2 question over, it was pretty vague. Let me rephrase/clarify.

I know spark is determined by rpm/load. Lets say during a WOT run, how do you typically set up your timing curve for the WOT area of the table? I read an old mustang and ford magazine article where they put timing at 23* everywhere from 3000 to 6500 rpm. I don't plan to go that far, I'd like to get to 18-20* then get to a dyno for further dialing in. But does that seem right, flat lining the timing?

Another question I'm wondering about, going to e85, should I just add some timing to the entire table right off the bat? say 2*s?

Thanks.

[jsa]

I am in Brisbane. Glad you enjoyed your stay and didn't fatten up the wildlife, lol.

I wouldn't take much notice of magazines that say flatline advance over a broard range. Tuning is about finding what the engine wants. Certainly e85 wants more advance, so take it up a little at a time and see what gets best power for least advance. Do you know what detonation sounds like?

I don't have experience with your engine, so I won't give you any magic numbers to plug in.

[Fanged03]

JSA, me too haha

I've never dealt with detonation, but have seen it on youtube. Jar full of marbles sounds is pretty nasty. Problem is, doubtful to hear it over the eaton screaming. I added a little timing only to the WOT load area, definitely made a difference. Will wait to add anymore til I get it on a dyno.

[decipha]

its pretty difficult to detonate on alcohol. If its a stock 03/04 cobra which it sounds like it is you can shoot 23 degrees to it with no problem

keep it around .7 lambda for max power

[Fanged03]

Thanks Decipha. When you say 23, does that mean across the board or ramped up to 23? Whats the general rule for correlation for timing vs load and rpm?
Its all bolt on, 2.93upper/4#lower, ported eaton/elbow/TB, return fuel.

[decipha]

check out the spark write up