Hey guys, I know that there are a few of you out there that are like me and want to learn as much as possible. That way when something goes (hopefully it doesn't) wrong, you know where to look. I have the Haltech platinum on my 06 350z, and I am currently running about 7.5-8psi with a turbo. I have my fuel dialed in, and it sits at about 11.5:1 throughout the entire WOT while in boost.

The timing is conservative, at peak torque it sits at about 11deg. It then start to climb to a max of 14deg at 6000rpm, and stays there to red line.


Now, what is considered "aggressive"? It is not a place where I want to be, but I am curious. I know that every car/setup is different too, and that there are other factors.

Any constructive input welcome

 

I'd say anything more than 17* or so would start to get aggressive and warrant a careful ear on the dyno

 

I am assuming that this is the highest one would go in the critical areas (peak torque).

Don't get me wrong I am not looking at going to 17*, but rather get an idea of how conservative my tune is and how much room I have.

 

The only way to find out how much room you have is to get it on a dyno, and see how much timing your motor wants. Otherwise, you're just guessing and not getting the most from your setup. Boost pressure, octane, compression ratio, etc, all play a factor into how much timing you can run before you start to knock. But if you want a number, I'd say 18-20* on a stock motor and pump gas is pretty "aggressive".

 

So what happens when you run too little timing, besides lost power etc.. High EGR? Can very low timing values lead to preignition?

 

Yes, high EGT's and chances of detonation are increased.

 

You need to be on a dyno to tune timing. There are a no set "aggressive" values etc, as every setup is different - especially yours

Overly advanced has obvious downsides (blown motor) but overly conservative will do damage as well as rob power.

 

Yeah I put a call in this morning to get the ignition timing tuned on a dyno. I am just stumped with the A/F readings at WOT, with them being off by .4a/f on average. Bank one richer than bank two.

 

So without getting into a full blown tuning discussion (becuase I know those are out there), in a nutshell, what do you guys look for when tuning timing on a dyno?

Do you advance until gains start to diminish, then pull back a few degrees for safety, or is that dangerous? What is the basic approach?

 

On a forced induction car on pump gas, you're most likely never going to get to the point where power starts to diminish before running into knock; therefore you're knock-limited. If you are running race fuel and everything else is in place (cool intake air, proper a/f ratios) to where knock isn't going to be a problem, then yes, I would advance until the power starts to flatten out, then pull back a couple of degrees. The ultimate goal in ignition timing is achieving MBT (minumum best timing or minimum advance for best torque)