Forced Induction Total Timing under boost

[Dontknowchit]

I was going to resurect an old thread, to get clarification. I opted to start a new one. I was watching a video from Leech motorsports about tuning, he flashed this timing table on the screen:

WOT vs advance timing table
5000 rpm+= 26deg
3500 rpm = 22deg
2600 rpm = 22.5
2150 rpm = 21.5
1800 rpm = 18.5
1000 rpm = 8

This seems to jive with what the older thread was saying, but others disagreed. I was under the impression it was base +commanded so that max WOT timing would be 10 (factory base) plus 26 for a total of 36

What I think I understand now is it is actually base increase (like 12-14 as most of us do) + 26
so if I'm running 12 base (up 2 from factory), then my max at WOT is 2+26=28

Is that a proper understanding?

Just trying to ball park set my MSD BTM to a safe total timing retard without giving up too much. (92 GT w/vortech v3 sci@10psi)

Right now I have it set to start pulling timing at 2.5-3 psi, and pull 1.5deg/psi resulting in a WOT of ~15deg

I have heard that 17-18deg should still be safe with stock heads if IATs are good, so thinking of switching it to start pulling @5 psi and pull 1.75deg/psi for a total timing of~17deg @6000

Do I have this correct?
Any wisdom on pulling timing later after making some boost and pulling more agressivley per psi vs pulling timing more gradually and starting at 0psi?
What is the tribal knowledge on safe total timing for 10psi on stock heads?

Thanks in advance, I know this is old tech but I have a old school build.

 

[FastDriver]

You're on the right track. The table in the Leech video is the WOT table and looks close to or exactly what an A9L's table is, stock. That's total timing, and yes, if you bumped base by 2*, the computer will take you to 28*.

15* is super conservative, but the right way to get aggressive is on a dyno or at the track reading plugs & ET/Traps. You haven't mentioned an intercooler, which will lower IAT & allow more timing. You didn't mention AFR, which is first and foremost before messing with timing.

From what I'm reading, folks with V3 blowers @10 psi tend to end up in the 21* ballpark with aluminum heads, though stockers are likely to end up perhaps a couple-few degrees down from that, but the right way to get there is incrementally while attempting to measure power output.

I think you're well researched and ready to head to the track or a dyno.
You're also right to question where to ramp from, and again right to start pulling later and getting more aggressive with the ramp rate, i.e. 2* instead of 1.5* or whatever gets you back to your desired total timing, while looking for ETs to drop at the track, or for the tq curve to pick up down low on a dyno. If you dont get a positive response, then you've waited too late.

 

[Dontknowchit]

Great, thank you. My AFR is right at 11.0, it is not innercooled but will have a "chemical innercooler" installed soon for that very purpose. The stormin Norman hood did help my engine temps considerably so I'm sure with ambient blowing directly over the charger and discharge pipe it's "better than it was". This makes so much sense why it felt like such a dog before, I was maxing out the BTM from 0 and pulling 15deg, so was maxing at 11.........well i guess it was safe lol.

I have not made a WOT pull yet with the new 10 psi pulley, wanted to get in the ballpark first. Thanks for confirming. There is ALOT of conflicting data on this fact both on this site and others.

Once it is in it's "final state" I will see how much the local shop charges for dyno time. From the chatter I've heard, it may be trying to do it at the track.