These terms are often used interchangeably. OE refers to a piece ofOriginal Equipment on a production car. OEM refers to the OriginalEquipment Manufacturer. For instance, Chevrolet would be the OEM, butthe fuel pump on a Chevrolet would be an OE part.
The rollcage. This is a structure made of steel tubing that is welded tothe chassis. Its primary purpose is to protect the driver. Its secondarypurpose is to stiffen the OE chassis for handling purposes. A thirdpurpose is to prevent some chassis damage in a crash. The term 'cageoften includes the front and rear bracing of the main 'cage.
This term refers to a General Motors intermediate-size car's chassis.These cars are the '79 to '86 Chevy Monte Carlo, Pontiac Grand Prix,Buick Regal, and Olds Cutlass. All are almost identical under the skin.OE engines may vary with several sizes of V-6s and V-8s. These are sonamed because of the beginning conversion of GM to the metric system.However, both metric and standard fasteners are found on these cars.
A weight jack consists of several parts. As seen, the rod is threadedthrough a nut that is
They may be found an all four corners of the car. A weight jack consistsof a rod threaded through a nut that is welded to the chassis. A plateis affixed to the bottom of this rod. The plate rests on top of thespring. Screwing the rod up or down raises or lowers that corner of thecar, thus affecting the weight carried on that corner.
This is a term commonly given to any fuel tank other than an OE unit.Most aftermarket fuel tanks are made of a cross-linked polyethylene,rotationally molded plastic. These are seamless plastic fuel containers.A fuel cell, more accurately described, is one of these tanks encased ina steel box. This offers much more puncture protection in a crash.High-end fuel cells have a rubberized bladder inside. These are able tosustain major damage without leaking.
A quick-steer unit speeds up the steering ratio. This allows the drivera quicker response.
This is a small box containing either a set of gears or a chain withsprockets. It is placed in the steering shaft between the steering wheeland the steering box. Its function is to speed up the steering by aratio of usually 2:1. This quicker action allows the driver to respondfaster by not having to turn the steering wheel as far to produce thesame result.
A quick-release steering wheel hub is actuated by a means of pulling apin or squeezing a collar. A quick release is needed when the wheelposition and the driver's seating position require a quick removal ofthe wheel for the driver to enter and exit.
This is a picture of a lower A-frame. It has somewhat the configurationof the letter A, th
There are upper and lower A-frames, one of each on each front corner ofthe car. These A-frames are attached to the chassis in such a way thatthey can hinge up and down. At the outer end, they are connected to thespindle with ball joints. The wheel hub rides on the spindle bearings.Usually, the spring is placed between the chassis and the lower A-frame.This is the way the weight of the car is supported. The A-frame pivotpositions are often moved to improve handling.
The steering box is mounted toward the front of the chassis. A shaftfrom the steering wheel turns its gears. At the bottom of the steeringbox is a pitman arm. This transfers the rotational motion of the box toa linear motion. The pitman arm attaches to a drag link that runs acrossthe front of the car to an idler arm. The drag link, supported now onboth ends, is attached to the tie rods, which are secured to thespindle. The drag link is necessary to maintain wheel alignment when thesuspension cycles up and down.
A sway bar is, more or less, a straight spring running from wheel towheel on one end of the car. Its function is to keep weight fromtransferring from one side of the car to the other during cornering.Sway bars are seldom used on dirt track cars. With the less tractivesurface of dirt, weight must transfer to the outside front corner,adding traction to help the car enter the turn. Paved track cars runningon a higher tractive surface often use sway bars to keep weight on theinside tire, otherwise the outside tire can be overloaded.
This diagram illustrates the crossweight of a typical dirt track StreetStock. Crossweight
These terms are often used interchangeably. Wedge is a term dating backto the '30s, when Ford-based race cars had only one spring on each endof the car. It was installed from side to side. A wedge could beinserted in the spring mount. This would tilt one end of the car,affecting weight placement. The more correct term is crossweight becauseit affects the amount of weight adjusted across the car. More precisely,this refers to adjusting the weight the car carries on opposite wheels.The term usually refers to a percentage of the total weight of the carthat is carried by the right-front and the left-rear corners.
FRONT STEER/REAR STEER
These terms apply to the location of the steering mechanism, such as thesteering box, drag link, tie rods, and so on. These can be located infront of or to the rear of the chassis crossmember, which goes under theengine. There can be advantages to each location. Stock cars using theGM Metric chassis are front-steer cars.
Race cars use many different types of rear suspension to keep the axlein the desired position. They are four-link, three-link, Z-link, andtruck arm, to name a few. These are found on upper-level stock carswhere rules allow considerable modification. Usually, coil springs willbe found as the springing medium. At the Street Stock level, the rearsuspension is generally stock or near stock. This is most often afour-link style where the links do not run parallel to the chassisrails. This holds the side travel of the suspension in check whileallowing up and down movement. In a suspension where the links, alsoknown as trailing arms, are all parallel to the direction of travel, itis necessary to have a track bar (also called a Panhard bar) mountedfrom one side of the axle housing to the other side of the chassis. Theheight of the mounting points of the track bar can drastically affectweight transfer during cornering.
Leaf-spring rear suspensions are sometimes used. They are similar to aZ-link being attached to the chassis at each end and the axle bolted inthe center. Leaf springs work better on dirt tracks than on pavedtracks.
This is a rear-axle unit that has been modified so that the rear-axlehousing, rather than the axle, carries the weight of the car. In a stockrearend, the axle runs in a bearing inside the housing. If the axlebreaks, the wheels fall off.
With the floater design, the bearing is on the outside of the housing.The wheel bolts to a hub that fits over the bearing and carries theweight of the car, even if the axle is removed. This unit is strongerand safer than the OE part.
The center section of a 9-inch Ford rearend holds the rearend gears. Itis known by several
The removable center part of a 9-inch Ford rearend is known by these andother names. This center section carries the gears that determine therearend gear ratio. These sections are often fitted with different ratiogear sets. They are often changed at the track for varying conditions.
FINAL DRIVE RATIO
This is the ratio where engine rpm is compared to wheel rpm. It takesinto account any gear ratio reduction in the transmission and multipliesthat by the ratio of gears in the rearend. This makes the final driveratio. For instance, a transmission used in low gear with a 2.52:1 ratiocould be multiplied by a 2.73:1 rearend ratio. The resulting final drivewould be 6.88:1. Therefore, the engine would turn 6.88 times for thewheel to turn only one revolution.
The master cylinder generates the pressure that is sent to the brakes atthe wheel. Many times, OE master cylinders are used on stock cars. Theseare adequate much of the time. However, different front-to-rear brakingpressures are sometimes desired. This can be accomplished with anaftermarket proportioning valve or by using two different sizes ofmaster cylinders attached to the same pedal. When this is done, anadjustable balance bar is used.
This is a device used to adjust the balance between front brakes andrear brakes. With two master cylinders, this bar can be adjusted to movethe leverage of the master cylinders. This affects the pressure to thebrakes on one or the other end of the car.
This is used when the master cylinder is mounted on the floor below thebrake caliper. This valve keeps the fluid from flowing back to themaster cylinder when the brakes are at rest. A 10-psi residual valve isused for drum brakes while a 2-psi piece is used for discs.
Stock car brakes are of two types: drum and disc. Each has its owncharacteristics. A drum brake has a pair of shoes that fit inside adrum. A hydraulic cylinder expands these shoes so that they rub on theinside of the drum. It is this friction that stops that wheel fromrolling. Drum brakes can fade with heat because the heat will expand thedrum away from the reach of the shoes. On the other hand, due to thelocation points of the shoes, there is a self-energizing effect thatreduces braking effort. Under light braking, this can be an advantage.
Disc brakes are essentially C-clamps. A rotor, much like a flat plate,turns with the wheel. A caliper is the clamp. It contains ahydraulically operated piston. The piston pressure clamps the rotor.There are friction pads between the two to prevent metal-to-metalcontact. Disc brakes have little tendency to fade, since the rotor doesnot expand away from the caliper. Discs often operate at highertemperatures than drums.
If you have questions about this story, contact Sleepy at: firstname.lastname@example.org