Timing Advance

[J Fennell]

Anyone know what the actual timing advance numbers are supposed to be at idle for the 4.0L? I'm seeing around 15 deg at 740 RPM with the current tune.



I have an SCT Xlacibrator and Auto Enginuity's software and am playing around with a couple of custom tunes for mileage and I cannot find that spec anywhere.



Actually, I'd like to optimize the timing settings at idle and under load, air/fuel at idle, part throttle and full throttle, etc.



Been a long time since I've posted here (I've been off fiddling with my '06 STang for about the last three years so I'm a little behind). I see some of the old crowd are still hanging around, so I thought I'd send up a flare.



UB10

 

[J Fennell]

Anyone help out a Trac'er from way back...??



UB10

 

[Richard L]

Timing is not manually adjustable. All ignition timing is controlled by the ECM Computer. The only way to alter the timing is to get something like an XCal unit to reprogram the ECM computer.



...Rich

 

[Dreman]

I don't know the spec, but can you change the timing with the setup you have there?

 

[J Fennell]

I have an XCal (1st gen) and it will adjust timing in the ECM tune. I've had it set all the way from 5 degrees to 20 degrees advance-at idle. I just need to know what the tolerance is before it begins to engage the knock sensors.



UB10

 

[Todd Z]

That actually depends on the gas grade, engine condition, spark system, plugs wires, temperature, air pressure, intake, all those factors can change what the engine can tolerate....



You may be able to run 20 and not have an issue and some one else may be able to only run 10...



So unfortunately i would play wit it, listen to the motor and read what the 02 sensors are saying...



Todd Z

 

[J Fennell]

 

[J Fennell]

Okay. Todd you're right.



Here's the latest testing info for what it's worth.



2001 SportTrac 2WD

53K

4.10 LSD Auto



88 degree ambient temp (humid GA day)

87 Octane Racetrac pump gas (no additives)

Idle is set to 720 RPM

Timing advance = 24 degrees at idle



That seems to be about the limit before it starts to ping a little during hard acceleration. Feels very strong at that setting. I'm going to try it for a tank of gas at these settings and I'll post mileage figures afterward.



Thanks for everyone's input.



UB10

 

[Todd Z]

Also need to know what A/F your running..... You can run all,the timing advance you want but at 14.7 to 1 you will damage the motor.....



At wot on 93 I run around 12.7 on race gas over 100 i run 12.3 On my 93 street tune I run it about 13.2.......



Todd Z

 

[J Fennell]

I have not changed any of the mixture settings. The program does allow you to lean or richen the mixture, but my scanner software does not measure the A/F reading so I left them alone. If anything, they're probably set rich from the factory.



All the MAF, IAT, fuel trim and the O2 sensors are right on the money.



UB10

 

[Todd Z]

Cool...



Todd Z