Thermoquad tuning on 318
Idle timing is a compromise? No it is not. There will be a correct amount for each engine.
I beg to differ.
I can set my t-slot exposure and sync it to the mixture screws, to eliminate the Tip-in sag, and then vary the timing anywhere between 5* to 20* just with my dial back electronic module, from the driver's seat, and with a manual trans drive it like this, without a tip-in Sag.
If I want to, I can mess the exposure up, and if the tip-in sag is not too bad, I can still drive it. Or
If I want to, I can fatten up the Idle mixture until my eyes cry uncle , and still drive it like that.
> at idle, you can mess the heck out of these adjustments, and still get it to idle.
Driving it is another matter totally.
With an automatic, the Tip-in sag has got to go. And if you use pump-shot to do it, or a rich mixture-screw setting, you will pay for that choice every time you fill the tank. Just bite the bullet and give the engine the Idle timing that the T-slot sync dictates.
Idle-timing is ALWAYS a compromise because,
the tuner is always trying to get to>>>>>>> whatever the maximum Power-Timing might be for your combo, as early as possible without getting into detonation .................. from; whatever your Idle Timing is.
If your Idle Timing is 10 degrees and your earliest Max-timing is 36* at 3600 rpm, then you mod the distributor to connect the dots. This comes to a curve of about @26* in 2600 rpm = 1*per 100, thus 10+8=
18 measly degrees of power-timing, and with this curve, the low rpm power might really suck.
The tuner might be able crank the idle-Timing up to 18 degrees, and now the curve is going to need to be, still 1*per 100, which means at an 1800 rpm stall, the engine will see 18+ 8=
26 magically delicious degrees.
But if this new number causes detonation, then back to the distributor machine you go, and with less Idle-Timing to start with.
This is how compromises are made.