More Timing or Less Timing? That is the question

[n8dogg]

So in theory more timing advance equals more power right? Depending on who I ask some say yes, more timing to get more power until MBT. Some say the more efficient your engine is the less timing you need. I understand you don't need as much timing when your engine is efficient, but if its not at MBT wouldn't advancing a touch help?

My car is consistently advancing at 22 deg. WOT. Room for more advance seeing there is no KR?

[WeathermanShawn]

Dogg:

I don't think it is necessarily that simple. I don't know the technical MBT references as much, but here is what I do know. Many have found on higher CR heads you do not need that much timing. I run 22-25 max, and make better power than running 26-27 degrees of Spark.

On another forum a very reputable tuner stated he rarely saw a LS1 with the LS6 intake make additional power using over 25 degrees of Spark Advance at WOT.

You can probably run 24-25 degrees with no problem. You can flat-line it ( I do) or do the rolling spark curve. Thats where you go for more spark advance from 2800-4000 Rpm's, then decrease it at peak TQ (4400-5200), then increase it again.

Check out the 98-02 LS1 Spark Curves (Holden Crazy). You will see a few examples. Personally, on your car 22-25 degrees should be about the sweet spot..:)

[5.7ute]

How are you measuring whether you are at MBT?
Timing is all about getting the peak cylinder pressures working when they will have the most effect on the piston. Nothing more, nothing less.

[odd boy]

From little experience on dyno, small engines love more timing than big ones. Sometimes, you gain 3 hp of adding 1~2 deg which is considered negligible for 8 cylinder engines. For example:

a car makes 330 hp with 25 deg, then u go 2 steps (27deg) and it makes 333 hp, the difference is not considered at all (0.9%) and could be because of cooling between dyno pulls.

Any ways it differs from engine to engine & setup to another, if you are specifically talking about 5.7L i would say ~27 for some setups, with 4.8 L you can add more and make more power..................... my point of view

[The Alchemist]

[QUOTE=WeathermanShawn;126855]Dogg:



On another forum a very reputable tuner stated he rarely saw a LS1 with the LS6 intake make additional power using over 25 degrees of Spark Advance at WOT.

>On good quality fuel at 6200rpm maybe... I find most standard engines knock at peak torque with timing over 18 to 19degs at 4800/5200rpm and 22 to 23deg at 6000rpm. I definately would not run 25 deg at peak torque...ever ...with pump gas.
.
You can probably run 24-25 degrees with no problem. You can flat-line it ( I do) or do the rolling spark curve. Thats where you go for more spark advance from 2800-4000 Rpm's, then decrease it at peak TQ (4400-5200), then increase it again.

>"Rolling" is best AND needs to be set on a dyno for best accuracy. The reason you pull out timing through to peak torque area is because the motor has higher cylinder pressures at this point and is more prone to knock
. As engine efficiency drops off and RPM increases you can ramp timing back in to keep up with the engine (higher rpms = less time to burn so you ignite earlier with more timing). Tuning with KR can be used as a guide with caution but is NOT good practise


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