Timing???

[02Z0h6]

I am lost when it comes to timing How do you guys ballpark a timing table for your cars? I see very little written on ignition timing and would like to know generally where to start. I would think the best place to do wot timing is on a mustang dyno so you know when the car stops increasing in power to back it off a bit and leave it. (I really don't like the wait till it knocks and back it off idea) What about part throttle? Advance it X* and see how the car reacts? I don't want to break anything guys.

Thanks for any insight.

[02Z0h6]

Helloooo out there.

[animuL]

If you have the resources the best way is definitely to put the car on the dyno and run as much timing as makes peak hp or peak torque. When you do logs on with this make sure you log airflow in grams/cylinder since this value shows up on the timing tables. You'll see exactly what range on the timing tables your car is using at WOT. Also there are lots of parameters that can modify timing, like Engine temps, intake temps, and knock retard so keep in mind that those can make yourtiming numbers different than expected. The other thing is you have a high and low octane table. The way that works is that your VCM will interpolate a value in between those two tables based on knock. So if you go a long time w/o knock the VCM will bump timing up until either it sees knock or it hits the number on the high octane table. Many people, choose to make the high and low octane tables the same to make things easier to work with and to make your engine runmore consistant. When cruising the main thing is how the timing effects fuel economy, in general more timing = more mpg, but of course you never want to be seeing kr on a normal basis. Its nice to be able to display the Knock Retard Histogram as you cruise around to see where it gets KR. On some cars you will actually hear KR before you see it on the scanner, in order to turn that around you would have to adjust the knock retard setting to be more sensitive. But really its easier just to add to the entire table until it starts to ping for cruising, and then tune in the WOT after the overall table is adjusted.

[WS6FirebirdTA00]

Helloooo out there.

it isnt easy to explain, you need to find out what works best for your setup with something that can give results of changes, either in logging or dyno.

[02Z0h6]

Thanks animul and WS6 for the responses. So, in general there is no rule of thumb for a NA LS1. For example, LS1's don't do much over 24* of advance at wot. Or cammed LS1's like about 8* of timing added in idle zones. These are things that can get a novice like me started in the right direction.

Thanks.

[WS6FirebirdTA00]

Depending on the setup, WOT can go up around 30*, depending on the cam size, idle timing can be stable between 24*-32*

[02Z0h6]

Depending on the setup, WOT can go up around 30*, depending on the cam size, idle timing can be stable between 24*-32*

Excellent. That's the kind of stuff I'm looking for.

NICE NUMBERS BTW! I'd be estatic if my car made anywhere near that.

[WS6FirebirdTA00]

thanks I am happy but always wanting more

[GMRACIN]

My stock 02 Z06 did not like much more timing at WOT than what was in it stock. I saw KR on a dyno with very little added timing.

[02Z0h6]

Should my base and main spark tables match in idle regions?

[WS6FirebirdTA00]

all my timing tables are the same

[Main_One]

Depending on the setup, WOT can go up around 30*, depending on the cam size, idle timing can be stable between 24*-32*

My high octane table tops out around 25*. Now that outdoor temps are dropping, between cooler IAT, 160* thermostat, and PE added advance, I've been seeing up to 32.5* WOT advance in the scanner. Should I be backing off of my timing table in cooler weather?

[02Z0h6]

OK, I don't have my laptop here right now so correct me if I'm wrong. The main spark table is added to the base and that is your total timing? If I go ahead and match my base and main spark tables I would be raising my total timing by 9* in some areas right off the bat. Correct?
Why not just advance the main and then you don't have to worry about the base? Just wondering why I would to touch the base timing at all?
Thanks for setting me straight on this guys.

[WS6FirebirdTA00]

My high octane table tops out around 25*. Now that outdoor temps are dropping, between cooler IAT, 160* thermostat, and PE added advance, I've been seeing up to 32.5* WOT advance in the scanner. Should I be backing off of my timing table in cooler weather?

where does this happen at? unless you have some odd corrections, you should have the same timing.

[WS6FirebirdTA00]

OK, I don't have my laptop here right now so correct me if I'm wrong. The main spark table is added to the base and that is your total timing? If I go ahead and match my base and main spark tables I would be raising my total timing by 9* in some areas right off the bat. Correct?
Why not just advance the main and then you don't have to worry about the base? Just wondering why I would to touch the base timing at all?
Thanks for setting me straight on this guys.

do you mean the idle tables? No timing tables are added except the correction talbes.

[02Z0h6]

do you mean the idle tables? No timing tables are added except the correction talbes.

Sorry WS6. I've got Editor open now and I was thinking of the Idle Spark Advance and see that it is predominatley used for idle with the selector in gear or neutral. The In Drive and In Park tables already match eachother. Should I be making sure that the Idle Spark Advance In Drive and In Park tables match the main spark table?
BTW, what the hell is total timing? I've heard people mention it and figure it must be the sum of at least two values, what are they?
Thanks again.

[Main_One]

where does this happen at? unless you have some odd corrections, you should have the same timing.

On the same page that gets me to the high and low octane tables, in the middle of the page, there are sections for Spark Correction, and under that there is AFR Correction Base and Mult, IAT Spark Base and Mult, ECT Spark Base and Mult, as well as the same type of thing for Cat Lightoff, EGR correction, and startup flare control. My current settings for these are what my truck came with from the factory.

For instance, timing starts getting pulled above IATs of 77*. I'm now seeing IATs below that during my scanner data logs for the first time in about 6 months. In PE, if I'm adding 35% extra fuel at 4200 rpm, I'm adding up to 10* of advance. In reading in what timing people are running, I'm left wondering if what they are quoting is just what is in their timing tables, or if that is what they are seeing in the scanner for what the engine is actually doing. Sometimes people will state that they have zeroed these things out, but often they don't mention whether they have or not.

[Main_One]

BTW, what the hell is total timing? I've heard people mention it and figure it must be the sum of at least two values, what are they?
Thanks again.

In my mind, total timing is the timing that the engine sees after the corrections that I noted above have been applied to the high/low octane tables.

[Russ K]

My high octane table tops out around 25*. Now that outdoor temps are dropping, between cooler IAT, 160* thermostat, and PE added advance, I've been seeing up to 32.5* WOT advance in the scanner. Should I be backing off of my timing table in cooler weather?

My cam/header ZO6 wot timing peaks at ~25.2* @ 3200 rpm, then to 23*
by 4800 rpm till 7000 rpm. This is at .76 g/cyl and a 13.0 AFR with 92 octane.
Once the IAT temp is 98*F the timing starts reducing by 1* for every column warmer air. Any more timing and I get audible spark knock. And the ECT timing tables have been changed so there is no spark retard when the engine is warming up.

If your AFR is too rich, the engine will tolerate more spark timing which is a bad idea.

Russ Kemp

[Main_One]

My cam/header ZO6 wot timing peaks at ~25.2* @ 3200 rpm, then to 23*
by 4800 rpm till 7000 rpm. This is at .76 g/cyl and a 13.0 AFR with 92 octane.
Once the IAT temp is 98*F the timing starts reducing by 1* for every column warmer air. Any more timing and I get audible spark knock. And the ECT timing tables have been changed so there is no spark retard when the engine is warming up.

If your AFR is too rich, the engine will tolerate more spark timing which is a bad idea.

Russ Kemp

Are your timing numbers from a table, or are they what the scanner shows?