"Standback Tuning For Dummies Guide" The Official Q&A...

[AutoXRacer]

OK, so regarding MAF and Timing tables... Why would one modify/adjust these...?

Am I correct to assume that if you want to adjust your AFRs, then you modify the MAF table, while if you are getting Knock, then you adjust the Timing tables?

Basically, how do you know when to adjust/mody the Timing table?
Do you only adjust the Timing table when you get Knock?

***Edited 2:17pm:***

What PIDs should we be logging? I know Laloosh uses the following:

-RPM
-AFR from sensor
-Timing Advance
-Knock Retard
-Boosted Air Temp

I understand all the PIDs except for the Boosted Air Temp. What does that tell you?

[Haltech]

If you guys like, i can do a PDF for it as well that will sit attached on the first post. Just let me know when you have everything posted and ill extract it.

[www.cp-e.com]

Originally Posted by AutoXRacer OK, so regarding MAF and Timing tables... Why would one modify/adjust these...? Am I correct to assume that if you want to adjust your AFRs, then you modify the MAF table, while if you are getting Knock, then you adjust the Timing tables?

That's exactly right.

Yep, we're scaling the voltage from the MAF sensor in order to adjust fueling. What we're essentially doing is lying to the car about how much air the engine is processing. So for instance when you "add fuel," we're basically lying to the computer and telling it that we're getting more air than we actually are. So we scale the voltage "up" which increases fuel delivery. So we're just tricking the car into injecting more fuel, and we use the MAF sensor to accomplish that.

Although knock can be affected by many variables, timing is most closely coupled to knock. Ignition timing dictates when the plug fires, and typically it'll fire just before the piston reaches top dead center on the compression stroke. As you can imagine, if you start the combustion event too early then the piston will be trying to compress an expanding air/fuel mixture. If the event starts early enough the pressure in the cylinder gets really high, and the air/fuel mixture burns uncontrollably and auto-ignites. This is what we want to avoid. The game here is to balance how much cylinder pressure we run. Cylinder pressure increases the most with boost and timing increases.

Originally Posted by AutoXRacer Basically, how do you know when to adjust/mody the Timing table? Do you only adjust the Timing table when you get Knock?

The reason why timing is so tricky to tune is because it isn't the only factor that affects knock, and the tuner needs to understand minimum best timing, and that more timing isn't necessarily better even if there is no knock present. Typically when I'm doing tuning off of the dyno I stick to removing timing in critical regions, which I'd be happy to discuss.

Originally Posted by AutoXRacer ***Edited 2:17pm:*** What PIDs should we be logging? I know Laloosh uses the following: -RPM -AFR from sensor -Timing Advance -Knock Retard -Boosted Air Temp I understand all the PIDs except for the Boosted Air Temp. What does that tell you?

RPM- We need to know this to understand "when" we're making changes.

AFR - Good feedback for air/fuel tuning. Gives some indication as to how much fuel should be added/removed.

Timing Advance - Timing advance tells a lot about how the car is running. Low timing advance (before tuning) could indicate that there's a problem, and that the ECU is pulling timing for some reason. It's also important to have some indication as to how much advance the engine is running.

Knock Retard - The more knock retard the ECU registers, the more knock there is. The amount of timing the ECU pulls in response to knock is proportional to the knock event. You can use the KR to indicate how hot (or poor) a tune is.

BAT - This one isn't as important, but it can help explain weird knock events, or issues with the turbocharger.