Ultimate Guide to Parameter Monitoring?

[ANITIX87]

Hi, all.

With @Raider's blessing, this has officially become the "Ultimate Guide to Parameter Monitoring" thread.

Basically, I am a noob when it comes to using things like UltraGauge, DashHawk, AccessPort, Torque, etc. After ordering my first such tool (I went with the UG), I needed to decided what to monitor. I searched a ton and decided what parameters I wanted to track, but I couldn't very well know if the car was running normally if I didn't know what the normal range of values should be.

This thread is, therefore, a list of commonly monitored parameters and what their acceptable values are. Please add/modify as you see fit.

Boost: Should be in the negatives (vac) while at idle. With A/C on it will fluctuate a bit as the compressor turns on and off. As you accelerate it will raise closer to zero and eventually go in to positive numbers (building boost) if you continue to accelerate. Stock cars target 12PSI in gears 1-3, and 15PSI in gears 4-6. Most OTS "Stage 1" maps target 17PSI across the board, but it's generally accepted that you should be running upgraded HPFP Internals before aiming for numbers this high.

Engine Temp (Coolant Temp): Normal operating temps are between 180-200 but people have seen as much as 220 sitting in a parking spot and as low as 160 cruising down the highway on a cold night.

Intake Temp (IAT): When moving, these should be at (or within a few degrees of) ambient temperature. When stopped, obviously, you're sucking in hot engine bay air so it will raise considerably but will return to ambient quickly when moving again.

Fuel Pressure: At idle, fuel pressure will be around 420, give or take 30psi. With A/C on it will fluctuate a lot. If you ever see under 100 chances are there is something wrong with the fuel pump and you are running off in-tank pressure only. At WOT it should never drop under 1600, if it does there is an issue with the HPFP, period.

Air-Fuel Ratio (AFR): Stoichiometric is 14.7 and that is what your car is always trying to achieve under normal driving. Stock cars run notoriously pig-rich (as low as 9.0AFR in some cases) in order to protect the engine OTS maps generally target 11.4-11.8 and some tuners run even leaner than that successfully. When you lift your foot off the gas and coast most gauges will show a value of 29.xx since the fuel injectors turn off (the true value is, technically, infinity).

Mass Air Flow (MAF): Very basically, how much air the car is sucking in (shown in grams/second). This changes all the time as you move and unless you are tuning, not really something you have to monitor. Larger intakes (SRI/CAI) and turbo-inlet pipes (TIP) will make huge differences here. Do not run these intakes without upgraded internals, especially in second-gen MS3.

Engine Load: This is a theoretical, calculated value that the ECU determines based on operating conditions. Generally, you want to consider this when doing load-based tunes or hybrid tunes. If using boost logic tunes, then load doesn't matter. Since this is a theoretical value, it's tough to outline acceptable parameters, but most people will never see higher than 2.7 (generally, you want to avoid high loads below 3,000 RPM).

Battery Voltage: With the stock battery mine is generally at 13.7. This shouldn't have any effect on tuning or driving unless you're having starter problems.

Knock Retard (KR): In an ideal world, this should always be zero but with engine noise, shitty roads, low-quality fuel, and a thousand other things you will almost always register something when driving. Generally as long as it is under 2.0*, not consistent, and not during WOT, ignore it.

Long-term and Short-term Fuel Trim (LTFT/STFT): Basically, how much fuel your motor takes and adds to reach your targeted AFR. These numbers vary but on an OTS map should be +/- 8 of each other, and on a custom tune will be generally be +/- 4. The closer these numbers are the better because your ECU is not going crazy trying to keep things in check. Environment, weather and fuel quality are just some things that affect the numbers. Any time you change fueling values or MAF values, the ECU will have to re-learn its fuel trims. When modifying any parameters that affect STFT/LTFT, drive nice and easy for a few days.

Boost Air Temperature (BAT): the temperature of the air as it is being ingested by the motor. For the most part, the colder the better. Upgrading intercoolers, shooting meth, and using insulation will lower this number. No real constant number because it depends on your mods.

Waste Gate Duty Cycle (WGDC): How long your boost control solenoid stays open. When your WGDC is at 100%, your boost control solenoid stays open, diverting boosted air away from the waste gate actuator, allowing boost pressure to increase beyond the waste gate actuator spring pressure. When your WGDC is at 0%, boosted air is allowed to continue into the waste gate actuator, allowing spring pressure to control boost (the wastegate starts to crack open when boost pressure overcomes spring pressure, venting excess boost). This inherent safety feature allows the turbo to revert to mechanical (spring pressure) boost should the boost control solenoid fail.

Everyone can feel free to list the parameters they monitor, what accepted values are, and maybe even what mods you have (or just include in Signature) so that anybody else thinking of adding a mod can know what to expect. I'll conglomerate the information in the OP for easy access.

TIS