What's the correct way to tune the timing? Do you keep on advance little by little until it knocks/pings and then back off a little? btw, I'm trying to do this with the Hondata.

 

timing gun

 

That's pretty much how it's done. It's not the only way or the best way, but it's the most practical for those that don't have sophisticated test equipment to measure in-cylinder pressures (and temperatures) as a function of crank angle.

The trouble is that once you have detonation or pre-ignition (esp on high strung motors), it's already too late. Sometimes the signs of warning aren't evident enough and/or happen too quickly. If you're doing this on a loading dyno (which is recommended), the heat loading from steady-state load tuning is greatly increased, which often exacerbates the problems with pre-ignition and detonation.

So, aside from knowing that, I'm pretty much stuck where you are.

I'm considering the usefulness of the MSD knock alert or using a VAFC2 with knock sum monitoring to maybe see if that can help me on determining how much ignition advance to dial in. I think the Hondata unit I'm using can also monitor knock sum, but I'll have to check on that when I start datalogging.

 

Even if it's not knocking, there's no sense in advancing ignition past the point where it's improving power. You need a dyno (or a good senstive G-sensor & datalogging) to tune ignition maps properly.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Daemione &raquo;</TD></TR><TR><TD CLASS="quote">Even if it's not knocking, there's no sense in advancing ignition past the point where it's improving power.</TD></TR></TABLE>

That's definitely true.

It's kind of like AFR's. There's a term....actually two terms...lean most power and rich most power that describe those boundaries where power remains the same but the AFR's are different. There's probably an analogous term for ignition advance, but I don't know it yet. Anyways, you usually want the least amount of timing for the same power output to be on the safe side.

 

I'm trying to figure this out as well. I'm looking to get an EGT sensor to datalog but I'm not quite sure whether its benefits justify the cost. Some people say that the temperature spike up when denotation occurs so maybe this is a better device than a knock sensor. Has anyone done this with success?

 

I'm not so sure teh EGT will pick it up until much later, or if it would even be that evident since it has to go through 2 cycles (combustion and exhaust) before the heat spike shows up. I dunno.

Ben

 

just bought the VAFC 2....and I aslo am trying to set my timing...
Do you know if the VAFC 2 retards when fuel is added, like the VAFC 1?

 

Yes. If you understand how the ECU interprets the MAP voltage into engine load, and how and why the fuel and ignition maps are the way they are, then you'll understand why the answer is yes no matter which VAFC version you use.

 

The best way to tune your VAFC, assuming you have enought mods, is to save your money and go to a dyno

 

The VAFC has lots of usefulness in cars where the ignition isn't controlled by the ECU. I don't think it can synth a crank signal (reluctor signal in our case) to force the ECU to advance or retard timing either.

For the price of it you'd be better to get a chipped ECU and get someone to tune a chip for you. Chipping the ECU in my opinion is far better because you can remap for different injectors, lift the speed limit, do full throttle shifting, tune the entire ignition map etc etc etc.

For your question about tuning ignition. A knock sensor with an amp and a set of headphones. I use a laptop with a mic input so I can record it. You can hear teltale pinging long before you'd hear it with your bare ears.

-Michael