Georgia FX4

I recently got a SF3 tuner for my 5.0 F150 and was wondering how much spark advance is safe with a stock engine on 87 and 91 octane gas? I have 87 in my tank and am waiting for it to run out so I can try out the 91 tunes. I have the spark advance set to +1 degree. I tried +2 degrees but decided to go with less.

jcain

Whatever you can run without knock...

Georgia FX4

Is there a limit that you can go though? I'd rather not have the engine knock to find out.

jcain

I imagine its a 5 point spread. Knock isn't lethal on an n/a setup if you take your foot out of it. Keep bumping it up til you get a ping, then back it off

mechanicboy

Adding too much spark advance can cause you to actually lose power on the top end so don't go too crazy.

Georgia FX4

Would 2 degrees be anything to worry about?

jcain

Hell no.

ClaySlayer

These engines are mass produced and thus are susceptible to a range of tolerances when built...aside from being put in different trucks (reg, ext, screw) with different gear ratios and a host of other variables. With that said, each engine will take a different amount of spark advance before it knocks. It takes a lot of driving/scanning/reading data and adjusting to get it right. On my last car, some guy on a forum put together an excel sheet that you could scan/log certain parameters and then dump the data into his sheet and it would spit out a "new" timing table. Talk about AWESOME! With that said, start out with a could degrees and go from there.

Georgia FX4

I've bumped up another degree to 2 and haven't heard any pinging and a little better gas mileage. I haven't really tested the power but it has sufficient power at a quarter throttle to get up to speed in traffic. I'm going to run this tank of 87 down and start going with 91 to see if I see any more mileage increase. I eventually want a 5 Star custom program but am still deciding on whether I want to get a cold air intake and if I do, what brand. Narrowed it down to the Airaid or Volant. I am leaning to the Volant but still can't decide if replacing the coolant tank is worth it or will I get the same gains with the Airaid. There a lot of threads to look through, still searching.

jonbar87

MBT is not always acheived at detonation. A lot of times it's acheived much before detonation occurs. Don't just blindly add timing. It's an excellent way to screw up your engine. I personally wouldn't add ANY timing as I've heard mine ping under load before. Not to mention, global timing advance is the worst thing you can do. Say for example, just because the engine may want 3* of advance at - 8 in hg doesn't mean that that's what it needs at WOT, and could actually need less. Unless you know how to tune engines, don't touch your ignition timing. Coming from a guy who's tuned N/A, supercharged, and turbo'd engines, timing is NOT something you mess with unless you're

1. on a dyno
AND
2. know EXACTLY what you're doing