Ignition timing

[overlordsshadow]

What are the advantages, disadvantages, and limits to advancing or retarding ignition and spark. Basically its gettin colder here and I always use 91 octance and with an intercooler I figure if the roads are dry sometime I could get a good few extra hp by changing up the spark and cam timimg.

I have an adjustable cam gear and want to play with it:p Looking at the sprocket, which way do I turn it to advance it?

[cordes]

The biggest disadvantage I see with adjusting ign. timing is that if you add some or take some out, you do so across the board. That might be great at 0-5PSI, but it might be the straw that breaks the camel's back at 20PSI.

When looking at the cam sprocket from the front, if the cam stays in the same position, and the belt and gear move toward the firewall, that will advance it. If it moves toward the front of the vehicle that will retard it.

[moparzrule]

Basically you'll want to advance the ignition timing as much as you can without have ping. Advanced timing will give more power and better fuel mileage. Every single setup is different so it's not like we can tell you running 14 instead of 12 will be better for you because maybe you will se detonation at 14? Unlikely, but possible.

You don't really move the sprocket when adjusting cam timing, you move the cam. Loosen the 4 bolts holding the sprocket, and use the bolt on the cam and turn it clockwise to advance the timing and counterclockwise obviously to retard the cam timing. Oh and of course tighten the 4 bolts back down!

[overlordsshadow]

Thanks, but how do you check for/listen for ping. Even now that I have the muffler on my car it is just too loud. I do have a wideband to put in at some point but I assume a code reader to check the knock sensor output is better?

[moparzrule]

Raise timing until you crack a piston, then back off slightly :D

[cordes]

I know that Rob has a hold on his stuff until he gets moved, but I would think that getting a cal from him would be the way to go. He can get the CEL flash on knock going for you. I assume that your are running 92' electronics which should be SBEC II, so the cals in the code repository won't work for you I believe.

[overlordsshadow]

Running 88 engine bay wiring and a S5 once it gets redone.

[moparzrule]

Hmm, the stage 5 has a lot of timing advance already because it's meant for racing. You are definitely gonna need a scanner.

[overlordsshadow]

Yes I found out later that the stage 5 should have stock or less ignition timing and 93 octane. Gettin it reproged to be a bit more mild, or at least set to 91 octane.

[moparzrule]

A stage 4 will be milder on the timing and you can run just as much boost.

[overlordsshadow]

mmm, that may be what they will program it as then, basically I had a stage 5, now I am just gettin a custom cal from fwd.

[cordes]

By 88 wiring, I assume that you are also running a SMEC. I would run one of Rob's cals in the meantime which have CEL flash on knock.