Can someone help me discover why my timing is diving so much under throttle?

[cjsgarage]

I've been messing with the spark tables/knock retard to try to get timing up when I goose the throttle. No go so far. If I manually command it at 17*to 28*, it doesn't dive. Not sure what the issue is here and I've been searching and researching to no avail. Any helpers out there?

It's an early LS1 running a 224/228 .581/.588 114LSA cam, 243 heads and an LS6 intake.
timingdive.hpl
ErikFreeman64SkylarkSDTuning2.hpt

Any advice or tips?
Josh

[cjsgarage]

i've tried to get this thing to display spark commanded by ECT, IAT, idle advance degrees, burst retard, and torque management advance, but they dont display on the chart. any other ideas on where i might find this gremlin?

[LSXtreme]

The timing is doing exactly what its supposed to do at that RPM/g/cyl and IAT. Your IAT is 124* (which is pretty warm) so its pulling 3* out of your base table. Without a stall your going to hit low timing numbers at that RPM and WOT. For starters, with that cam you should be idling around in gear 750-850 rpm and 18-20* of base timing. I know it seems high but without a stall and no tq that low its going to fall flat on its face (like its doing) idling around 700 and hammering it to the floor. Plus it will idle a little cleaner. Smooth your High Timing map so there isnt any peaks or valleys. It should have smooth transitions. Once you have the High table cleaned up, copy your high table to your low, select the whole map and remove 3 degrees out. Copy your low table up to 4800rpm and paste it in your In Drive and In Park Idle Spark advanced tables. Select the whole table on both and take another 2 degrees out. This way your spark only has a 5 degree window everywhere.

Try to not let the car sit and heat soak before you test again so the IAT isn't pulling any timing out from it being too hot.

[cjsgarage]

The timing is doing exactly what its supposed to do at that RPM/g/cyl and IAT. Your IAT is 124* (which is pretty warm) so its pulling 3* out of your base table. Without a stall your going to hit low timing numbers at that RPM and WOT. For starters, with that cam you should be idling around in gear 750-850 rpm and 18-20* of base timing. I know it seems high but without a stall and no tq that low its going to fall flat on its face (like its doing) idling around 700 and hammering it to the floor. Plus it will idle a little cleaner. Smooth your High Timing map so there isnt any peaks or valleys. It should have smooth transitions. Once you have the High table cleaned up, copy your high table to your low, select the whole map and remove 3 degrees out. Copy your low table up to 4800rpm and paste it in your In Drive and In Park Idle Spark advanced tables. Select the whole table on both and take another 2 degrees out. This way your spark only has a 5 degree window everywhere.

Try to not let the car sit and heat soak before you test again so the IAT isn't pulling any timing out from it being too hot.

I tried that, too. I'll do as you say on the timing tables. I am running 17* right now because that's where it idles the smoothest and the customer wants the cam to be as indetectable as possible. I'll try 19* and see if I can get it to stabilize there.

I ended up setting minimum spark advance to 17* up to 3200. That way, during any knock retard event, it wont go any lower than that. I am just a tiny bit of knock detected when I gas it(though i dont hear or feel it). Is there a safer way to do this, or am I going to have to run octane booster? It's running premium now. The histrogram is showing -9* of spark due to knock retard. Is there a way to soften this punch without altering the minimum spark advance so aggressively?

There's no way to keep IAT down. The intake is forced into the engine bay with the battery and accessories in place. Should I zero the IAT tables?

[Road]

Try raising your min spark advance vs rpm table to 10*?

[LSXtreme]

Try raising your min spark advance vs rpm table to 10*?

That would only work if he was seeing a very low commanded spark. He is still seeing 11* as the lowest. Here its only pulling 3* off the commanded 14-17* in that area from the heat.

I would not zero out the IAT Spark because its a useful tool. Just need to adjust for your application. If it is going to consistently run in that temp range then setup your base timing to something safe, which 16-17* at that temp is still ok if you have good fuel. I would zero out the 104-131* range then start your IAT retard at 131*.

Also adding timing isnt going to make the cam seem more noticable... if anything less timing is going to make it run more rough.

Have you even tuned the MAF or VE with the new cam? what your seeing is prolly not ignition knock but AFR knock from a lean tip or rich tip at WOT.

[cjsgarage]

The VE and MAF tables were tuned. Adjusting the timing tables as you suggested worked great. I was also running speed density because I was waiting on my 5 wire MAF connectors to come in (I've made so many harnesses lately, I sold out). Once I had the MAF installed and the fail frequency set back to normal, the car stopped jumping down in the the really high cylinder volumes under tip in. I think SD overshoots it a little bit. Anyway, after that, the timing stayed way up here on the cylinder airmass tables where it's much more advanced. That fixed it completely. I was able to return the min spark retard back to zero without any issues. I did set the timing a little bit higher at idle. It didn't really seem to make a difference on how smooth it idled. It left yesterday, and the guy seemed pretty happy with it. I certainly was. It rained a little bit here and it was hard to keep traction unless you really babied it off the line.

I did, however, suggest a longer intake pipe and a stall converter. He said he'll order that next. What's weird is, the Knock Retard shown on the Charts was only like .4*. When I ran the histogram though, I could see that it was pulling up to 9* out. What multipliers are those? This is the first car I've had to mess with the timing on, so I'm learning a lot.