What is the best method to use a gtech to tune spark advance?

do you run like a 0-60 time as a base then increase the advnce in the main spark table by a degree and then run another and see if there is an improvement? How do you decern if the sparks at individual rpms is optimal.

Some one that has used a gtech to tune their spark advance could you give me some help please.......................

 

Well now thinking about it 0-60 times would not probably work because i would be in PE mode......

Suggestions.......

 

Scannin and data logging are fastest and easiest.

You want to tune tune the spark timing in the higher gears so you have the engine fully loaded, tuning in 1-2 gear will give you way too much timing.

At DIY-EFI.org, at the FTP, is an article called tuning tips that might help.

 

You can tune spark in PE. I recommend putting a lot of load on the engine when tuning spark tables as grumpy said. Try to find a very steep hill or do it in higher gears.

 

I have read the tuning tips before and again, however, I still seem to be ambiguous about the best way to tune the spark. You say scannin and data logging are fastest, what should I be looking for in those high load high gear situations?

How do I know when I have it right? I have read that you do not want to keep advancing the timing until you get detonation and then back off 2 deg, because there may be more spark than you would need.

Also, I have been lookin at my MSA for my 305 and I noticed that the numbers are considerably higher than a 350 bin. From what I have read it is due to the combustion chamber shape. Typically how much more room is there to increase/ improve. Are there situations that it acutally would be better to lower the spark advance to get better performance or is this just in situations where you may have a large cam and in the low rpms you have special situations.

I know that I am asking alot of questions, however, the VE tuning was straight forward, this spark thing...I have not yet come across an article that did a nice clean conscice job of explaining what to do.... I wish Traxion would have compleated his part 2 tuning where he eluded to spark tuning. Have I just been missing the articles/posts that clearly explain spark tuning??

Thanks,
Tom

 

There is no quick and easy way to get the spark right. using a scanner and data logging will tell you when you've gone past the liit and hit the knock sensor, which will help to limit the extremes of the timing settings.

The whole process for a street car is running as little timing as possible constant with best performance. ie you can tune with the WOT spark at 34d and maybe be a little faster then 28d, but you might be adding alot of fuel to keep the motor out of detonation. The extra fuel loading and timing aren't going to be good for engine life, and your wallet.

With fuel you can be pretty safe at 14.7 idle cruise, and 12.5 WOT, but idle timing can be 14-24d, cruise timing 28-42, and WOT 26-38. There is just more room for error with timing. And fueling errors can mask timing problems.

Until someone comes up with a combustion chamber pressure or driveline torque sensing, system, timing is going to be more difficult then fuel.