Glossary of Common Terms

Here are a few of the most common terms associated with a turbocharger system. Im not going to go crazy and define everything as most of you probably have a good understanding as to what everything already is. If you would like something added feel free to contact me and i will see that it gets put in. I will be adding additional segments over time.


A/R -A/R means area/radius. It is a formula to determine the size of the compressor and its turbine-housing confiruration. Sounds like a lot but to make it simply put, the smaller the A/R the faster your spool up time and the better your throttle response. But the down side is that the top end will suffer and choke off. If you have a large A/R you will be able to flow more air but you will experience a longer spool up time and poor response also known as turbo lag.


Blow Off Valve or BOV -A BOV is simply a valve between the turbocharger and the throttle plate that bleeds off extra boost pressure. Under certain conditions like when you shift gears or when you back out of the throttle the turbo keeps spinning yet the throttle plate is closed and the air is trapped. This will lead to the air pressure getting so great that it will actually force air backwards through the turbo causing what is known as compressor surge. This will cause a huge lag the next time you hit the gas or if you are boosting high enough it can actually bend compressor blades or even break the turbo shaft. A BOV will release this excess pressure. Another name for a BOV is a compressor bypass valve.


Compressor Surge - Compressor surge is when the air pressure in the charge pipes becomes so great that it forces air backwards through the turbo.


Intercooler -An intercooler is a heat exchanger in the intake tract that is used to cool the air that has been heated by a turbocharger or supercharger. There are several types including air-to-air and water-to-air intercoolers of which each has its pros and cons.


Trim -Trim is simply the size of the compressor wheel. There are many different variations and they are not only diameter but also height, weight, curvature, fin shape and several other factors. Just remember this, in general the larger the wheel the more more volume the turbo is capable of flowing. Whether it is on the intake side which will allow higher boost levels or on the exhaust which will create less back pressure in the exhaust system.


Volumetric Efficiency or VE -VE is the volume of the intake charge on the intake stroke versus the volume of the cylinder. This is always expressed in a percentage and the higher the percentage the better.


Wastegate -A wastegate is a devise that is used to regulate boost pressure. It is done by controlling the speed at which the turbocharger spins. The easiest way to do this is to route the exhaus tthe exhaust gases around the turbine whether it be back into the exhaust or vented to open air. Also by doing this a properly sized turbo will remain in its most effective speed range. A wastegate can be set to any boost level and will remain closed until that level of boost is reached. By doing this the turbo can use all of its available exhaust energy to reach maximum boost pressure.

Here is list of popular sites. Let me know if you want something added or if something is not right.


DRAG ? if anyone knows let me know

Revhard www.Revhard.com

F-Max [url=http://www.F-Max.com]www.F-Max.com

Greddy www.Greddy.com

Innovative Turbo Systems www.Innovativeturbo.com

Inline Pro www.Inlinepro.com

JG Engine Dynamics www.JGenginedynamics.com

AEM www.AEMpower.com

Spearco www.Spearcointercoolers.com

Turbonetics Inc. www.Turboneticsinc.com

HKS USA www.HKSUSA.com

Clutch Masters www.Clutchmasters.com

ACT www.Advancedclutch.com

Vortech www.Vortechsuperchargers.com

Moroso www.Moroso.com

Redline Oil www.Redlineoil.com

Skunk2 www.Skunk2.com

JE & SRP www.jepistons.com

Fluidyne www.Fluidyne.com

Summit Racing www.Summitracing.com

Apex Integration www.Apexi-usa.com

Quaife America www.Quaifeamerica.com

Total Seal Inc. www.Totalseal.com

Crane Cams www.Cranecams.com

Crower Cams & Equiptment Co. www.Crower.com

EFI Systems www.efisystems.com

ARP Automotive Racing Products www.ARP-bolts.com

RC Engineering www.RCENG.com

MSD www.MSDignitions.com

Heres a quick look at how the drag strip is comonly laid out.

GLOSSARY OF DRAG TERMS

After Market - Generally, the replacement parts and high performance products market.

Air Dam - Used to direct or block air flow. Used in front to prevent air flow to undercarriage,
intended to prevent turbulence and lift.

Air Foil - Stabilizer, generally used to create down forces, increasing stability and tire-to-track
adherence at high speeds.

Arm Restraints - Restraining straps to restrict arm movement in a car accident.

Ballast - A controlled amount of weight, functionally positioned, used to help car meet class weight
requirements.

Belly Pan - Generally, a skin of aluminum or fiberglass used to cover the under carriage of vehicle,
assisting in preventing turbulence and air drag.

Blueprinting - The meticulous matching to factory specifications all parts and/or components.
Dressing parts to absolute design callout or manufacturer's specifications.

Bleach Box - Section of track before the starting line where cars spin the tires in water.

Breakout - (Run Under) When your elapsed time is quicker than your dial-in, causes you to be
disqualified.

Burned Piston - When a cylinder runs lean (too much air in the air-to-fuel mixture) and excessive
heat burns or melts the piston.

Burn-Out - Spinning of rear wheels at high RPM in water to heat and clean drive tire rubber prior to
a run, resulting in increased traction.

Bye Run - A lone run given to a randomly chosen car, because of an unequal number of cars in the
round.

C.C. - Cubic Centimeter, a metric unit of volume measurement, equal to approximately 0.061 cubic
inch.

C.F.M. - Cubic Feet per Minute. A measure of volume.

C.I.D. - Cubic Inch Displacement. A measure of volume.

Camber - Tilting of the top of the wheels from the vertical. When tilt is outward, camber is positive.

Caster - Tilting of steering axis forward or backward to provide directional steering ability. Positive
caster recommended for drag racing.

Catch-Can - A container used to catch liquid overflow, preventing spillage on race track. Also
known as catch-tank.

Christmas Tree - An electronic starting device incorporating calibrated lights displaying a visual
countdown for each driver, activated by a designated official.

Chromoly - Also Chrome Moly. Short for Chromium Molybdenum steel. A very strong and light
tubing highly adaptable for race cars.

Chute - Short for parachute or drag chute. Used to assist high-speed braking.

Clutch Can - Bell housing, the bell-shaped housing used to encase clutch and flywheel.

Clutch Lockup - The progression of the clutch-disc engagement controlled by an air-timer
management system.

Competition Area - The staging lanes and race track surface.

Deep Staging - When the racer inches his car forward, not completely passed the starting line
(staging line) so much as to turn off the staging light.

Dial-Ins - Driver's predictions of E.T.'s their cars will run in their first eliminations.

Dialing Under - Allows competitors in Stock and Super Stock the option of selecting a time faster
than the National Index. Applied in handicap elimination racing where breakout is in effect.

Diaper - A blanket made from ballistic and absorbent material, often Kevlar, that surrounds the oil
pan and serves as a containment device during engine explosions.

Displacement - In an engine, the total volume of air/fuel mixture an engine is theoretically capable of
drawing into all cylinders during one operating cycle.

Dropped Cylinder - When a cylinder becomes too rich (too much fuel in the air-to-fuel mixture) and
prevents the spark plug (s) from firing.

Dry Hops - Process of spinning your tires on dry pavement.

E.T. - (Elapsed Time). The total time it takes to get from the starting line to the finish line.

Eliminations - When cars are raced two at a time, resulting in one winner and one loser
"eliminated". Winner continues to race in a tournament-style competition.

F.I.A. - International Federation of Automobile Clubs. Sole international body governing motoring
sport.

Final MPH Light Beam - Shuts off MPH computer.

Finish Line - Line which determines winner and computes Elapsed Time.

Finish Line Light Beam - Light beam to shut off elapsed time computer and signals win indicator
and elapsed time.

First MPH Light Beam - Light beam to start MPH computer.

Foul Start - Leaving the starting line before the green light starting signal.

Fuel Check - A tech station used to inspect fuels to insure content is within limits allowed for that
particular class. Analysis of fuel.

Fuel Injection - (F.I.)A system replacing conventional carburetion which delivers fuel under
pressure into combustion chamber of air flow prior to entering chamber.

Full Tree - The method used to start cars at the starting line. The method used is one yellow light is
used at a time, then the green light. As opposed to all yellow lights are lit at once then the green light
(Pro-Tree). The reaction time used in full tree is .500.

Guard Beam - Light beam to alert officials if driver starts to race before the green light appears.
Often called a foul start.

Gusset - A reinforcement addition adding web-like or triangulation reinforcement to car structure,
usually welded in place.

Halon - Special Freon Fire Extinguisher. Generally a 3% to 5% concentration will extinguish fire.

Handicap - When one car is faster than the other, the slower gets a head start. Headstart depends
on previous elapsed times or dial ins.

Hole Shot - Starting-line advantage achieved by the quicker reacting driver.

Hydralic - When a cylinder fills with too much fuel, thus prohibiting compression by the cylinder and
causing a mechanical malfunction, usually an explosive one.

Index - Elapsed time assigned by NHRA or IHRA to allow various classes to race together with an
equitable handicap starting system.

Inline - Cylinders in a single row, valve stems in a single row.

Interval timers - Interval timers are part of a secondary timing system that records elapsed times,
primarily for the racers' benefit, at 60, 330, 660, and 1000 feet.

Length of Track - 1320' 1/4 mile distance from start to finish.

Lexan - A trade name of General Electric used for a durable thermal resistant plastic material used
where transparent material is required (i.e.., face plates, goggles, windows, etc.)

M.I.G. - Metal Insert Gas Arc welding. Uses a continuous-feed filler rod material pulled through the
torch from a roll of wire.

M.P.H. - Miles per hour.

Magnaflux - The process of using a special electromagnet and magnetic powder to detect cracks in
iron which may be invisible to the naked eye.

Methanol - Technically pure methyl alcohol CH3oh(toxic) produced by synthesis.

Minimum Weight - The lowest allowed weight for the vehicle in it's class.

Nomex - Trade name of DuPont, a fire-resistant fabric used in the manufacture of protective
clothing.

O.E. - Original Equipment (as originally produced and installed by factory manufacturing
automobile.) Originally equipped.

O.E.M. - Original Equipment Manufacturer. Original Automobile Manufacturer.

O.H.C. - Overhead Cam.

Otto Cycle - The four operations of intake, compression, power, and exhuast (4-cycle engine).
Named for inventor Dr. Nikolaus Otto.

Permanent - Pre-assigned, registered competition numbers assigned by NHRA or IHRA.

Pilot Chute - A spring-loaded device which pulls the braking chute from its pack.

Pits - Where the race cars are worked on.

Pre-Staged Light Beam - Light beam used to warn drivers they are inches away from starting line.
This beam when broken by front wheels sets off pre-staged bulb on top of the Christmas Tree.

Port- The opening in an engine where the valve operates and through which the air-fuel mixture or
exhaust passes.

Protest - A complaint filed against a competitor, investigated by officials.

Pro-Tree - The method of starting cars from starting line, using the Christmas tree. Method used is
all three yellow bulbs light then green as opposed to one yellow light at a time then green (full tree).
Also uses a reaction time of .400.

R.P.M. - Revolutions per minute.

Rake - Bottom of body not parallel to ground (lower in front).

Reaction Time - Computed in thousandths of a second and is the time how quickly you moved off
the starting line after the go signal.

Return Road - Road which leads from shutdown area back to the pits or staging lanes.

Round - When all cars in a bracket (class) have made a run.

Shutdown Area - Area located after finish line for racing cars to slowdown.

Speed Trap - The final 66 feet to the finish line, known as the speed trap, where speed is recorded.

Staging Director - A person who directs the flow of traffic from the staging lanes to the race lanes.

Staging Lanes - Lanes where drivers line up and wait to make a run down the track.

Staged Light Beam - Light beam used to warn drivers they are on the starting line ready to race.
This beam when broken sets off staged bulb on top of the Christmas Tree.

Tech Area - Area where Drag Officials inspect tires, steering, brakes or anything that might be a
safety hazard before time trials.

Time Slip - Printout of Elimination information.

Time Trials - Practice runs.

Timing Booth - Printouts of Elimination Elapsed Times are located here.

Traps - The two beams of light at the end of the drag strip which compute mile per hour.

Water Burnout - Process of spinning your tires in water to get the tires hot and sticky for
better traction.

Wheelie Bars - Bars attached to the rear of the car to prevent excessive front wheel lift

This is very important. If you do machanical work on your car invest the money and get your self a set of these for your model and year. They will run you roughly 36.00 for the shop manual and if you choose (recommended) another 40.00 or so to get the electrical troulble shooting guide.

www.helminc.com

or call them directly at 1-800-782-4356