Timing un-retard... How far can we go?
02-12-2007, 07:31 PM
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Timing un-retard... How far can we go?
In the month or so since I got my DO kit installed and working I've more or less sorted out the fuel situation and have started to focus on the timing. Thus far I've just been incrementally adding equal amounts of advance (or reducing the retard) across the whole boosted area of my map, which itself is based on BGRacer's work.
Thus far I've added six degrees back into the lower half of my timing map, and no discernable ping as of yet. I'll probably try another two degrees this afternoon on the way home. Does anybody have a good feeling for what sort of limit on ignition advance (or un-retard) I should safely expect to reach?
I've attached a screenshot of my current IGN map. (remember, these are relative advance/retard numbers, not actual timing) This is on a stock (10 BTDC) base timing, intercooled 1.6 Greddy, with D.O. injection. Currently reaching about 11PSI boost maximum. AFR is typically running an indicated 12.5 to 13.0, though I believe it's actually just a bit richer than this (based on observing the WBO2 as I switched the WI on and off manually). Fuel is California 91 (R+M/2) octane. I'm injecting about 50% Methanol and water.
Thus far I've added six degrees back into the lower half of my timing map, and no discernable ping as of yet. I'll probably try another two degrees this afternoon on the way home. Does anybody have a good feeling for what sort of limit on ignition advance (or un-retard) I should safely expect to reach?
I've attached a screenshot of my current IGN map. (remember, these are relative advance/retard numbers, not actual timing) This is on a stock (10 BTDC) base timing, intercooled 1.6 Greddy, with D.O. injection. Currently reaching about 11PSI boost maximum. AFR is typically running an indicated 12.5 to 13.0, though I believe it's actually just a bit richer than this (based on observing the WBO2 as I switched the WI on and off manually). Fuel is California 91 (R+M/2) octane. I'm injecting about 50% Methanol and water.
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02-12-2007, 08:39 PM
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I think that you can add in a lot more timing than what you have now. I am at 8-9psi, and I am only pulling 3 degrees from a base of 12 degrees. I have absolutely no knock either, my only problem is that the fueling is a little lean, and the clutch is slipping.
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02-13-2007, 11:33 AM
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Well, added another two degrees in last night, and still no pinging. This morning I also increased the boost to 12PSI, with initial surges to 14. (Yes, even the fancy TurboXS HPBC permits spikes...)
I'm now at +8 degrees vs. my old ignition timing map, which was right on the verge of detonation. I don't know why, but my engine loves to ping. And yes, I verified that the crank pulley hasn't slipped. I know there's a point of diminishing returns on ignition advance, not sure where it is for my engine yet. Add that to the list of things to figure out on the dyno...
So I guess this is one very happy DevilsOwn customer so far.
Now all I need is a bigger tank. The washer bottle ain't cutting it.
I'm now at +8 degrees vs. my old ignition timing map, which was right on the verge of detonation. I don't know why, but my engine loves to ping. And yes, I verified that the crank pulley hasn't slipped. I know there's a point of diminishing returns on ignition advance, not sure where it is for my engine yet. Add that to the list of things to figure out on the dyno...
So I guess this is one very happy DevilsOwn customer so far.
Now all I need is a bigger tank. The washer bottle ain't cutting it.
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02-13-2007, 12:41 PM
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Joe
your running similar boost to mine ,and youve seen my map
So maybe you can go a bit more, i was happy to push it as far as i could -since i had a decent Knock monitoring/sensing system and my CR ratio is i think a little lower than yours.
your running similar boost to mine ,and youve seen my map
So maybe you can go a bit more, i was happy to push it as far as i could -since i had a decent Knock monitoring/sensing system and my CR ratio is i think a little lower than yours.
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02-13-2007, 01:06 PM
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Al, I don't see a single "-1" anywhere in the 4500 RPM column, so I'm not sure wtf you're talking about 
He's running a piggyback, so I believe this chart shows the advance or retard of the stock total timing table (base timing plus advance). If his base timing is 10°, his stock ECU might add ~17° advance at, say, 4500 RPM, for a total timing of 27°, then his e-Manage is pulling ~10° at 11.5 PSI, for a total of 17°.
That's what the graph looks like to me.
He's running a piggyback, so I believe this chart shows the advance or retard of the stock total timing table (base timing plus advance). If his base timing is 10°, his stock ECU might add ~17° advance at, say, 4500 RPM, for a total timing of 27°, then his e-Manage is pulling ~10° at 11.5 PSI, for a total of 17°.
That's what the graph looks like to me.
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02-13-2007, 01:16 PM
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Joe, I have Emilio's (of 949Racing fame) e-Manage timing map which shows non-intercooled timing and water-injection timing, both at 8 PSI and 10° base on a '99 motor...not sure what octane gas, but I would guess it's either 91, 94 or a mixture of both to achieve ~93.
He's pulling less timing than you non-intercooled, FWIW.
Also, I'm pulling ~5.5-6° of timing, intercooled, at ~8 PSI, FWTW.
He's pulling less timing than you non-intercooled, FWIW.
Also, I'm pulling ~5.5-6° of timing, intercooled, at ~8 PSI, FWTW.
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02-13-2007, 01:54 PM
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He's running a piggyback, so I believe this chart shows the advance or retard of the stock total timing table (base timing plus advance). If his base timing is 10°, his stock ECU might add ~17° advance at, say, 4500 RPM, for a total timing of 27°, then his e-Manage is pulling ~10° at 11.5 PSI, for a total of 17°.
Those numbers are advance or retard done to whatever the stock ECU is putting out. The data we have for the stock timing is one-dimensional (advance vs. RPM) whereas the stock ECU takes load into account, by comparing airflow to RPM. And since I don't have the CAS hooked up, it's impossible for me to say what the actual ignition timing is in the less-then-boosted areas. But that's a more or less academic problem, not a practical limitation...
BTW- *VERY* nice chart, Brian.
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02-13-2007, 07:36 PM
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Ladies and Gentlemen, I present the Smartass of the Year Award:
Yeah, pretty much like that.
Seriously, I'm amazed by this wealth of information. And also that there's not a sticky labeled "Everything Brian knows for some mysterious reason but hasn't shared with the rest of us until just recently."
Would you happen to have the original table that generated that chart?
Yeah, pretty much like that.
Seriously, I'm amazed by this wealth of information. And also that there's not a sticky labeled "Everything Brian knows for some mysterious reason but hasn't shared with the rest of us until just recently."
Would you happen to have the original table that generated that chart?
Last edited by Joe Perez; 02-14-2007 at 01:44 AM.
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