Timing tips

I have never tuned an EFI car, and am only familiar with carbs,
And there are several FABO members that considerably wiser than me on these matters.
But
I offer you this:
I cheat.
I have a stick-onto-the-window, accelerometer, that has data-logging capabilities. Mine is a G-tech-Pro-SS. With it, you can do a test run at any load setting and over what ever rpm range you want. It plots acceleration over time. Then I go home and play it back, looking for anomalys.
I also have a dash-mounted, dial-back, timing box with a range of 15 degrees; so I can change the timing on the fly, from the driver's seat.
It shows up on the SS as faster or slower acceleration thru the speed or rpm window.
The two tools cost me less than $500, and have paid for themselves many
times over.
Oh yeah, I had to make a throttle-stop early on, for Part-Throttle runs, for repeatability.

I've actually got something like that. I have an old Beltronics GX2 or something like that. The trick is getting all the suspension settings dialed in for it to be accurate, though I guess for a back to back comparison that wouldn't really matter much. And by "suspension settings", I mean the accelerometer has values for pitch and roll per G that you put in so it can cancel out the gravity it measures as the car tilts. But again, as long as I don't change those settings I should be able to do back to back plots, even if the actual values aren't "correct".

What vehicle is this engine in? You talk about wot tuning and cruise timing and then mention 87 octane and blowing the tires off all in one paragraph. Is this a truck? A hot rod? A cruiser? What’s the goal here? And are you stuck on the low octane gas requirement?

Sorry, it's a 67 Dart street car basically. Stock suspension, just a modern drivetrain (2006 5.7 Hemi and a Viper T56). 8 3/4 rear end with a posi unit and 3.55 gears. Former setup was a dual computer affair with a standalone MSD running ignition and a Megasquirt running fuel. Ran well and had some good pull, though I'm fairly sure not fully tuned to the engine's ability. A hard hit in first gear at low rpm would light up street tires and chirp my DOT drag tires with that setup in that it just hit hard and fast, though it did feel like it ran out of breath fairly early. New setup is a Megsquirt 3X running both fuel and ignition, fully sequential. I thought I put a similar timing map in it compared to what was in my MSD, but the car just didn't respond the same and felt lazy everywhere. It would cruise around town and idle nicely, but the most noticeable issues were the lazy full throttle stabs and the high speed high gear cruising. I've always run the car on 87 octane. I'm not forced into it by any means as I have the freedom to tune to whatever I'd like to put in it and 89 or 91 is readily available to me, I just never really wanted or tried to push the envelope. I can actually run a switch to swap between tables if I really wanted to as another option, though I doubt there's a whole lot to gain between 87 and 91 compared to something like pump gas and race gas.

As for the knock, no, I don't have any sensing capability at the moment. The Megasquirt can't take them as direct inputs (and I'm kind of running out of inputs already anyway). I need a conditioner board to handle the factory sensors, and I just haven't really messed with them yet. I have thought about adding them in one of these days, but I also know if I have a good tune in it with a little room for error I shouldn't really need them. Always nice to know though, so I may still get around to it one of these days.

Do you have a picture of your set up on the engine. Does this have injectors in the manifold runners?

Here's about the best I could find on the internet. The injectors do point more or less at the back of the valves. They shoot maybe just a little more inboard than down, but it's still more or less at the valve, not a throttle body style injection setup.
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