There is a separate engine cranking timing that it uses below a set RPM, usually around 400, but is adjustable in both timing and RPM crossover, so hard to crank over is easily remedied without even changing the idle.
Every time I build an NA pump gas engine for a toy, I leave the knock sensors off, all they are going to do is retard my timing, and I use premium fuel because I usually have the compression to need it, I don't want my timing retarded from where I set it. If I hear ping I'll fix it myself, I don't want the computer doing it when I don't know it, I want to know it.
The knock sensors pick up random crap all the time, if I can't hear it, I'm not worried about it. Yes there are tiny stuff that is minor pinging you can't hear the knock sensors can, but I am not worried about that.
There are a few limiting factors to timing
- It pings. I think we have that covered
- You get past the point of peak torque - i.e. further advancing makes less power
- It's hard to crank the engine over.
Most likely, all 3 of these things will play into your tune, but in different areas of the table. This is part of why electronic timing control is so advantageous. How do you tune for #2?
Basically, you increase timing until the power stops increasing (or it pings), then back it off just a bit. A street car needs to be more conservative than a race car because it's going to see various ethanol blends and weather. Modern cars do trigger the knock sensors all the time and do a lot of timing adjustment based on that, but that's typically happening outside of the WOT range. You really don't want to ride the knock sensors to set your WOT timing. I can't comment on how effective the Holley system is in turning knock feedback into proper timing, but the OEMs do it with a ton of factors specific to that engine. I would aim for only small blips of a couple degrees occasionally on transients.
It also makes sense to scale knock in your plots so the max is like 10-15 counts/degrees. That way you'll notice some burst knock or whatever. You're never going to detect a knock level of 100 (or you have bigger problems!) and it's never going to retard 50 degrees.
See, the reason I tried to turn them on is at WOT when the windows are up, I thought there was a pingy knocky sound. Almost like lifter rattle.
But that's the only way I hear it.
So I turned them on and only gave em a sensitivity of 1.
And I'm seeing knock as high as 15 at idle.
When sensitivity was at 10, it was basically pegged at a knock level of 80-100 at idle.
But idle sounds great.
So I looked into the knock sensors in the help index, and the 24 tooth LS base tune has them set wrong to start with.
My engine has two 1 wire sensors. Which are resonant sensors, and according to them, need to be set at around 11khz. But have to be adjusted for your engine. Mine are set at 2k.
They claim a sensitivity of 50 is best.... If I did that now I'd be pegged at 100.
So I guess I'm just not going to run them, because I'm not a freaking engineer lol.
As for adjusting timing till power stops going up, and such.....
That's why I'm thinking dyno.
All I have to test this is make a change, go out on a busy highway and risk my license, come home, check a log that really doesn't tell me much about power, and try again.
This is a VERY uneconomical system. Especially when I can make 5 runs at the same time and be .5 second in either direct different on 0-60.
Then go make changes, and do 5 more, and be in the exact same 1 second range.
Which that equates to at least 6-10 runs, which could take me 3-4 days to accomplish. Due to traffic and such.
If I can stop making power before I ever hit ping, then there's no way I'm going to get it right with this current testing system I'm using
Tuning for 0-60 is hard anyway since it shifts at like 55. So I try to do 0-100. And 5 pulls at 0-100 is just asking for a loss of license.
