Title says it all. Is there a list of acronyms and definitions available? This is pretty funny, I work in Telecom where we practically invented the TLA and I find some of the "Tuner Terms" a bit baffling. Any pointers would be appreciated!
Cheers,
Mark
I'll start off with some of the ones I know:
BOV = Blow off valve
Mounts between the turbo and the throttle body, allows excess boost pressure to be released when the throttle plate closes when you let off to shift or slow down.. makes that nice sound, and prevents compressor damage from a sudden wave of high pressure smacking into the turbo trying to force it backwards.
BPV = Bypass valve
Same thing as a BOV, only the air isn't vented to the engine bay, it's vented to PAST the throttle body. Not only does it not make a noise, but it's needed for cars using a MAF sensor, so that all "air in the system can be explained" Cars that use MAF and BOV's stutter/stall when the BOV goes off.
W/G = WasteGate
Limits maximum boost by allowing some exhaust gas to bypass the turbo, can either be external to the turbo (looks like a BOV) or internal (is a flapper door). Externals generally allow for higher boost levels without "creep" where maximum boost slowly get's higher.
MBC = Manual Boost Controller
A simple twist valve normally, that changes the amount of boost pressure required before pressure is sent to the wastegate, thus opening it. this is used to actually SET maximum boost.
EBC = Electronic Boost Controller
Just like a MBC, but computer controlled. All stock turbo cars after the mid eighties have these.
I/C = Intercooler
A "radiator for air" that absorbs intake air heat to cool down the hot air charge from the turbo. There are several types of I/C's but this isn't the pace to discuss them.
MAP = Manifold Air Pressure sensor
Measures the pressure OR vacuum of the intake air. These are used as the primary means of measuring air in "Speed density" style fuel injected cars, like j-bodies.
MAF = Mass AirFlow sensor (note, our cars don't use these, yay!)
the "modern alternative for MAP's, this actually measures the amount of ACTUAL air entering an engine via weird technical voodoo you don't want me to explain. You don't have this, forget you heard of it.
IAT = intake (or incoming) air temperature
Measures the temperature of the intake air, is used in fueling calcs by the ECM
E/M = Exhaust Manifold
Bolts to the head, directs exhaust air out. duh.
T/M = Turbo manifold
Bolts to the head, directs exhaust air into the turbo. duh.
I/M = Intake manifold
Bolts to the head, directs air from the T/B to the head. derrr duh.
T/B = Throttle body
Do I have to explain this?
D/P = DownPipe
Bolts to the turbo, then to the exhaust. it's the "intermediate" usually it's cast iron.
Cat = Catalytic Converter
Scrubs excess emissions causing chemicals from you're exhaust and excess fuel via more voodoo you don't need to know.
Vac = Vacuum
What you're engine is under, when it isn't boosted ;-)
DIS = Distributorless ignition system
A ignition system without a distributor, a fully computerized ignition system. Digital if you will. all j-bodies after like 90ish are DIS
Tach = Tachometer
Measure engine RPM.
WBO2 = Wide Band Oxygen sensor
0-5 volts range, linear scale, for measure A/F ratios very accurately, Dynos and serious tuners and smart people use these ;-) can be found stock on some uber-low emmisions cars (read honda's toyotas, etc). Costs about 100 bucks per sensor :-O
NBO2 = Normal Band O2
What j-bodies normally have. these measure a/f on 0-1 volt scale, and it's very UNLINEAR, that is to say it gets very unaccurate when measuring anything other then perfect A/F
EGR = Exhaust Gas recirculation system
Takes a small amount of exhaust gas from combustion, at high throttle, and feeds it back into the intake, to "cool" the combustion temp off so that NoX (nitrosomething of Oxygen aka Greenhouse Gas) cant' form. J-bodies after 2K don't have these (thank god). It also reduces detonation when the engine is stock (there are better ways to fight it).
PFI = Port Fuel injection
Generic name for MPFI. All j-bodies after 90ish have some form of MPFI.
MPFI = Multiport fuel injection
Generic name for PFI, lol. I don't want to cover injection types sorry.
SFI = Sequential fuel injection
Another type of MPFI, again, blah about this.
TBI = Throttle body injection
You don't have this ;-) Only pre 90ish j-bodies do. It's like a carb with a single fuel injector.
Adv. = Advance (timing)
Someone else handle timing I'm getting sleepy. bah
Ret. = Retard (timing)
see above
FPR = Fuel Pressure Regulator
Regulates fuel pressure to a constant level to maintain fuel rail pressure for the injectors. it's the little can on your fuel rail.
AFPR = Adjustable FPR
A FPR you can change the pressure setting of. Also, some factory boosted cars (like mine) have a vacuum line running to their FPR that raises fuel pressure based on Boost pressure. Also called a "rising rate" FPR then.
FMU = Fuel Management unit
A piggy back FPR or sorts that raises fuel pressure based on boost. It's a handicap for turbo cars with improper fuel systems for running happy amounts of boost.
ECM = Electronic control module
THE BRAIN! This baby does it all! and I refuse to call it anything other then a ECM. That's what my fuse box says for it ;-)
ECU = Emissions control unit (same thing as an ECM, or a PCM)
If you call an ECM this you are gay.
PCM = Powertrain control module
if you call a ECM this you are gay AND a ford lover! that's like 2x the gay.
F/P = Fuel Pressure
Um, the pressure of fuel in the rail.
P&P = Port and Polish
To smooth the ports in a cylinder head, to enlarge them slightly, to make the air enter the combustion chamber smoother, and to put a mirror polish on the exhaust ports and a rougher one on the intake ports. WHy? That's another lesson.
LSD = Limited Slip Differential
Locks both tires when accelerating in a straight line, so that not just one tire is gripping the road. Better ones even lock in turns at lower speeds. These give you better traction.
T/C = Torque Converter
The automatic tranny equivilent of a clutch (damn I'm oversimplifying)
BAR = Unit of pressure 1 bar = 1 atmosphere, 2 bars about 15 PSI of boost
^^
PSI = Unit of pressure (american)
If you don't know this you can't even fill your tires. Get out of here.
Kpa = Unit of pressure (metric)
Canadian eh?
LTFT = Long Term Fuel Trim
LTIT = Long Term Idle Trim
STFT = Short Term Fuel Trim
STIT = Short Term Fuel Trim
2.4L Twin Cam Cavalier Z24 | T3 Super 60 @ 9 PSI | FMIC | TurboXS RFL | Greddy Profec B Spec II | Custom HO Intake Manifold | 2.5" Charge Pipes | 2.5" Downpipe | HP Tuners | 5 Speed Swap | Team Green LSD | SPEC Stage 3 Clutch | Fidanza Short Shifter | Prothane Control Arm Bushings | Carbon Fiber Hood
STIT = Short Term Idle Trim (air flow PID)
Quick adjustment to control engine speed and prevent stall. Not stored in NV RAM.
LTIT = Long Term Idle Trim (air flow PID)
Long term adjustment to cover myriad operating conditions. Is a stored value in NV RAM
NV RAM = Non-Volitile Random Access Memory - doesn't lose it's memory when key is turned off.
TT = Twin Turbo (usually)
RAF = Base RUNNING AIR FLOW
How much air in lbs/hr or grams/Sec (g/sec) needed to keep the engine idling without stall/surge.
DFCO = Deceleration Fuel Cut Off
Fuel is cut off when at medium RPM and closed throttle settings. Used to lower emissions and improve fuel economy. Can also simply reduce fuel during decreasing throttle transients.
TM = Torque Management
Used to control wheel spin or slip (think icy roads or TT vehicles) in conjunction with the anti lock brake system (ABS). Reduces engine power by reducing torque output of the engine usually by reducing spark advance considerably or closing the throttle on ETC vehicles. Also used to prolong transmission life (at least through warranty...) by reducing engine output (reducing spark advance) during shifts.
ETC = Electronic Throttle Control
Drive by wire throttles. No cables. ETC encompasses a stepper motor drive to open and close the throttle and two TPS sensors. On one the voltage output increases as the throttle is opened the other decreases as the throttle is opened. If the sensors do not agree then the throttle is closed.
APP Sensor = Throttle pedal on ETC vehicles
Works in the same way the ETC TPS sensors work: Voltage goes up on one sensor as you press the pedal and goes down on the other. As with the ETC the sensors must agree or the throttle goes closed.
TAC = Throttle Actuator Control Module
Translates between APP Sensor and ETC to create the proper throttle opening. Interfaces with ECM to provide torque management and current throttle position. Also used on *some* cable actuated cars for torque management by relaxing the throttle cable when torque managment is requested.
EGR = Exhaust Gas Recirculation -The valve everyone loves to hate.
Introduces exhaust gas into the intake system to reduce NOx (Oxides of Nitrogen and Nitric Oxide - NO -- Very poisonous BTW!) emissions. Achieved by cooling the combustion with inert gas (exhaust). Some systems now cool the exhaust gas before introducing it to the intake system for further NOx reduction. A side benefit (minor) is that pumping losses in the engine are reduced with a slight improvement in gas mileage. Previous statement applies *mostly* to Linear EGR valves and systems.
Always Support Our Troops!
FUBAR = f***ed up beyond all repair
:P
Mike Horist
00 WS6 (TA) | 04 WS6 (GTP Comp G)
Mike \\#at&\\ horist \\&dot$\\com
BOTH cars HP Tuners Tuned
Perfect! Thanks guys! Now, is there such a thing as a class to "learn" how to tune with HPT? I have a very good understanding of the internal combustion engine and it's internals, it's just the computer systems and tuning I need to learn. Any pointers would be greatly appreciated!
Cheers,
Mark
Originally Posted by horist
I was pretty much in the same boat tuning wise (at least you understand the combustion engine...LOL) and I'm still learning. These forums are great. The amount of information provided by the members and by the HPT crew is invaluable.
For the class, you are attending it each time you logon. Post a question, and someone will answer (pretty quickly too, i might add).
I am a noob, what is KR ?
Knock Retard
Always Support Our Troops!
does it change the sensativity of the KS ?
Also what is a PID ?
No. It changes the timing of your spark. The timing is retarded in an effort to reduce the knock. To change the sensitivity of your knock sensors you have to use another table.Parameter Identifier.Also what is a PID ?
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