2012 E-Mod (Economy) Rules

[South Texas Speedway]

2011 STS E-Mod Rules

PREFACE: All equipment is subject to approval by South Texas Speedway track officials. It is the racer’s responsibility to keep his/her car legal at all times. Equipment having passed through inspection unobserved will not be considered as approved. South Texas Speedway officials may assess weight penalties for cars and/or parts deemed as not in compliance with these rules. It is ultimately the obligation of each participant to insure that their conduct and equipment comply with all applicable rules, as they may be amended from time to time. No expressed or implied warranty of safety shall result from publication of, or compliance with these rules.

FRAME: 1978-1987 OEM midsize GM metric full frame only. Minimum wheelbase 107-inches, maximum 109-inches, both sides. Frame must be full and complete, cannot be widened, narrowed, shortened, lengthened, or be cut, bent, or altered to change suspension brackets, except upper control arm brackets on front end. All frame bolt holes must remain in OEM location. Front frame horns may be removed in front of steering box. Front frame may be cut for radiator clearance. Frame may be notched for seat clearance. Transmission crossmember mounts may be removed, no further forward than frame welds. Rear of frame, behind upper shock mounts, may be replaced with round, square, or rectangular tubing. No part of frame can be lower than five inches from ground except front crossmember. No other frame alterations allowed.

 

ROLL CAGE: Must consist of continuous hoops, minimum 1.5 inch O.D. tubing, with a minimum wall thickness of.095 inch for main cage. Cages must be steel or chrome-moly. Main cage no further forward than rear of engine and no further back than front edge of rear tire. Four bars, two per side, may extend from main roll cage to main frame points in front of the upper control arms. These bars may have two additional braces per side to the main frame. Six bars may extend from the main cage to the rear. X-bracing is allowed. Driver’s head must not protrude outside cage with helmet on. Roll cage must be securely supported and braced with minimum one cross bar in top halo. All bars forward of cage must be lower than hood.

 

DOOR BARS: Minimum three driver side door bars required, minimum 1.5 inch O.D. and .083 inch wall thickness, must be parallel to ground and perpendicular to driver, and welded to front and rear of roll cage. Minimum two passenger side door bars required, must have at least one cross door bar, horizontal or angled. Steel door plate, 18 gauge or .049-inch.

 

BODY: (See diagram) Must be same width, front to rear, and parallel to OEM frame. Cooling holes allowed. Nose panel may be no wider than 2 inches outside of front frame horns and no lower than 4 inches. Nose panel must remain within confines of front bumper. No plactic nose pieces. Engine compartment must remain open (no side panels). Aluminum or fiberglass hoods allowed, must completely cover top of radiator and engine, extending from nose to interior deck and enclosed at rear. Must have front and rear roof supports. Roof must be fiberglass or aluminum, full size and rounded down in all directions. No dished roof allowed. Driver roof hatch allowed. No plastic body panels or filler panels allowed. Must have complete interior deck from side to side, must be aluminum or sheet metal. Quarter panels must remain 90-degrees to ground, maximum 45-degree bend 4-inches from bottom and 2-inches from top of doors and quarters.

NO Spoiler allowed. Sail Panels must extend from the roof to the back of the car, no short sail panels allowed. Sail panel height at rear of car maximum 3”.

 

BUMPERS/RUB RAILS: Steel only. Two bar front bumper and single bar rear bumper must be used on car at all times and welded, or bolted securely using minimum 0.375 inch bolts. Must be maximum 1.50-inch O.D. tubing, .095-inch wall thickness on front and 1.75-inch tubing, .095 wall thickness on rear. Maximum 1.50-inch O.D. tubing, .095-inch wall thickness fuel cell protection bar required, must cover rear and extend past both sides of cell, may be welded to rear bumper. See diagram for bumper heights. Rear bumper may be maximum 6-inches beyond rear deck. All bumpers and rub rails must be capped with no sharp edges. Single bar rub rail from front to rear wheel allowed on each side, no center supports allowed, maximum 1.50-inch O.D. tubing and .095-inch wall thickness, must be mounted to cage at front and rear of rub rail.

DRIVER COMPARTMENT: Must have minimum three 5/16 inch O.D. windshield bars in front of driver. Aluminum cowl panel in front of driver can be no wider than cockpit. Aluminum high-back seat only, must be securely bolted, using minimum 0.375-inch bolts, to roll cage and support system. Floor pan must be metal or aluminum and cover entire driver compartment. Bottom of seat can be no lower than bottom of frame rail. Driver must be sealed off from track, driveline, engine, fuel cell, cannisters and pumps. No oil coolers allowed in driver compartment. No devices that would enable driver adjustment to alter wheelbase or for weight jacking while car is in competition. No mirrors of any kind.

 

FRONT SUSPENSION: All components must be steel, unaltered OEM, in OEM location, and match frame. No jack bolts allowed. Adjustable spring buckets are allowed. May use IMCA stamped tubular upper or may use OEM upper. Lower A-frames and mounts must remain OEM. Upper A-frame mounts may be modified and moved for caster and camber adjustment, but must remain OEM material. Lower A-frame mounts and bolt holes on frame must be in OEM location, mount may be notched for clearance. All A-frame bushings may be aftermarket, but no OFFSET or bearing/heim type. OEM or OEM replacement ball joints allowed, may be tacked in. No Sway bars allowed.

 

STEERING: All components must be steel, unaltered OEM, in OEM location and match frame. No grinding, lightening or welding on any steering parts. Spindle may be reamed and bolt on spindle savers are allowed. Steel steering shafts and knuckles only. Steering quickener (optional), steering wheel and quick release (required) may be aluminum. Power steering pump and reservoir must remain one unit, serpentine belt system will be allowed. Driver compartment steering may be modified, must be kept on left side. No rack and pinion.

 

SHOCKS: One steel shock per wheel only. Only Stock Shocks, AFCO, Pro, and QA1 (EC series) street stock shocks will be allowed. No rebuildable shocks allowed. Shock must be in OEM mounts and location. Mounting spacers are allowed. One or all shocks may be claimed per event for $50 each, any car finishing on the lead lap can claim shocks from any one of the top 5 cars. A single driver can only claim 4 shocks in one season.

 

SPRINGS: One steel spring (racing allowed) per wheel only. Minimum 4.5-inches O.D., non-progressive coils only. No torsion bars or air bags.

 

REAR SUSPENSION: All control arms and mounts must be steel, unaltered OEM, in OEM location, and match frame. No jack bolts allowed. Adjustable spring buckets allowed, may be dropped as long as they remain in OEM location. If upper spring cup uses all thread, it must be securely welded to chassis. Lower spring cups must be centered on housing. Control arms may be reinforced, but cannot be shortened or lengthened, must remain OEM length. All control arm bushings may be aftermarket, but no bearing/heim type. Bushings cannot be drilled. No suspension parts may be altered or lightened. No aluminum parts allowed, other than bushings.

 

REAR END: Must use OEM 7.5-inch GM 10 bolt rear end (bracing optional), must remain stock width. No Ford or floater rear end allowed. Steel components only. OEM mounts on lower control arms must remain in OEM location on original 7.5-inch tube housing. Aftermarket axles, mini-spools and C-clip eliminators allowed. Locked rear ends only, no torque dividing differentials allowed. No full or aluminum spools allowed. Pinion angle can not be changed.

 

TIRES/WHEELS: Southwest Speed Spec tire will be the only tire allowed. This tire is 26x8x15.

3” or 4” offset wheels only. No Bead Lock allowed. No bleeder valves. Must use minimum 1-inch O.D. lug nuts and 0.625-inch studs are recommended. Wheel spacers are allowed but not with OEM studs. Wheel adapters are treated as spacers and may be aluminum, maximum 1.50-inches thick.

 

BRAKES: 4 wheel brakes are mandaroty, drum or disc. Must maintain minimum OEM dimensions for hubs/rotors and calipers, cannot be lightened. Bolt pattern may be changed. 0.625-inch studs allowed. Single or dual aftermarket master cylinders allowed. Adjustable dual pedal brake bias assembly allowed but may be adjusted by driver. Rear rotors may be aftermarket, minimum 0.810-inch thickness, maximum 12-inch O.D. Vented rotors only, no scalloped, ceramic coated, single phase or drilled rotors allowed. Rear caliper brackets must be welded to housing. Additional proportioning valve (in-line type) allowed to be in car but is not allowed to be used, must be out of driver reach.

 

EXHAUST: Stock exhaust manifolds only. 2" maximum exhaust pipe off the manifold at a minimum of 36” long. Pipes may not tie together in any way.

 

FUEL SYSTEM: Racing fuel cell required, maximum 22 gallon capacity, must be in minimum 20 gauge steel container. Must mount with minimum two solid steel straps around entire cell, two inches wide and 0.125 inch thick, between frame rails in trunk area only. Fuel cell vents, including cap vent, must have check valves. If fuel cell does not have aircraft style positive seal filler neck/cap system - a flapper, spring or ball type filler rollover valve is required. No part of cell can be lower than protective tubing. OEM mounted, mechanical push rod fuel pumps only. No regulators, bypass fuel systems, pressurized, or return lines allowed.

 

CARBURETOR (one only): Holley(unaltered) #4412 500 cfm two barrel may be used on any engine (float bowl must face forward).circle track floats may be installed. No other carburetors allowed. Any one piece adapter allowed, maximum 1.250-inches thick, including gaskets. No throttle bore adjustable carburetor spacers. No cool cans. Any air cleaner allowed. No cold air boxes or ducting of any kind between engine and hood.

 

FUEL: Gasoline only. Racing fuel allowed. No E85, No Methanol. No performance enhancing additives or scented additives. Fuel must pass both dielectric meter and chemical tests. Fuel sample may be taken from any car at any time

 

WEIGHT: Minimum weight limit of 2,500 pounds with Maximum of 55% rear weight after race with driver in car. Ballast must not be used in driver compartment or outside body. All ballast must be securely mounted and painted white with car number on it. No titanium, magnesium, stainless steel or carbon fiber components. Solid steel fasteners only.

 

BATTERY/STARTER: One 12-volt battery only. Must be shielded and securely mounted. Aftermarket starter allowed, must bolt in OEM location. Must have capability of starting without being pushed or pulled. Must leave initial staging area on demand, unaided, or go to rear of that race.

 

GAUGES/ELECTRONICS: ***All Engines will be required to run an MSD soft touch rev control part # MSD-8728 with a 6000rpm chip**** No unapproved cameras, transmitting or listening devices, timing retard controls, or digital gauges (including tach). No electronic monitoring computer devices capable of storing or transmitting information except analog tach. OEM style ignitions only. GM: HEI distributor (must remain one unit) or point distributor allowed. Any module may be used that fits inside the distributor with no alteration. Vacuum advance may be removed and pick-up coil locked. No external coils allowed, unless using point distributor. No GM or aftermarket ignition boxes allowed. OEM type alternator with internal regulator allowed. No electronic traction control devices.

 

TRANSMISSION/DRIVE SHAFT: Only OEM production turbo 350 transmissions allowed. No aftermarket transmissions allowed. No ‘in and out’ boxes or quick change devices allowed. With engine running and car in a still position, must be able to engage car in gear and move forward, then backward. Functioning shift levers must be in OEM location. Transmission fluid coolers allowed. Flexplate and converter must be steel. Minimum 10-inch diameter steel torque converter. No direct drives, couplers, valved pumps, or bleeder style valve bodies. Must have at least one forward gear and reverse gear, gears must function. Must have an approved scattershield constructed of .125-inch by three-inch steel, 270 degrees around top of flexplate. Steel OEM style flexplate only, must be bolted directly to end of crankshaft.

Drive Shaft: Minimum 2-inch diameter, white, steel drive shaft only. Steel slip-yokes only. 360-degree drive shaft loop required, constructed of at least 0.125-inch by 2-inch steel, or 1-inch tubing, mounted 6-inches back from front U-joint.

 

 

ENGINE COMPARTMENT: Rear of engine (bellhousing flange) must be mounted at least 70-inches forward from centerline of rear axle. Minimum 11-inch engine height from ground to center of crankshaft. One radiator allowed, steel or aluminum, 27-inches by 19-inches maximum in size, must be mounted in front of engine. Racing cap and electric fans allowed. No sprinklers. Catch can required. Power steering pump and reservoir must remain one unit and mount in front of engine. Side engine mounts only (OEM or 45-degree style) must be steel, aluminum mid-plate allowed.

 

ENGINE SPECIFICATIONS: All engines must be able to be used in conventional passenger car without alterations. External engine casting and threaded holes cannot be altered. No aluminum, titanium or carbon fiber components allowed. ***All Engines will be required to run an MSD soft touch rev control part # MSD-8728 with a 6000rpm chip. Rev Limiter may not be located within reach of the driver.****

BLOCK: Must use OEM steel passenger vehicle production block only. No GM bowtie, Ford or Chryslers allowed. Approved blocks are: GM (Chevy only): 283, 302, 305, 307, 327, 350. Maximum cubic inch limits: GM 364 no tolerance. No 400 or larger cubic inch parts allowed. 4 valve relief pistons only, no gas ported pistons. 3.48-inch maximum GM stroke. Maximum 160 lbs. per cylinder compression, no tolerance. Compression checked with one spark plug removed, turned five engine compression revolutions. Engines may be balanced and block decked. Oil filter system must remain OEM. ‘Wet’ sump oiling system only. No accumulators. OEM stock or OEM replacement steel crankshaft only – cannot be lightened (no aeroing, bullnose, knife edge, undercut or drilling of second or third rod throws allowed. OEM stock or OEM replacement steel rods only - GM must use maximum 5.7-inch rod. No cap screws. No splayed main caps. Racing oil pans allowed. (One inch inspection hole required.). No obstructions to crank and rods. If obstructions are present, must remove pan for inspection. Engine bolts may be aftermarket. Fluid dampener balancer allowed. No roller bearings allowed. Clarification: OEM Replacement means Cast only.

 

CYLINDER HEADS: Only GM OEM approved head numbers are (last 3 digits): 126, 185, 336, 441, 445, 487, 493, 598, 624, 862, 882, 920, 993, 997, with valve no larger than 1.94-inch intake and 1.50-inch exhaust. Valve sizes can not be changed. No porting, polishing, or unapproved alterations to ANY cylinder head. No vortec, bowtie, or aftermarket heads allowed. Flat milling allowed. Guide plates, screw-in shouldered studs (0.375-inch max) and polylocks allowed. No stud girdles. Stamped steel, OEM style, stud mounted (0.375-inch max) rocker arms only. Any length push rods allowed. OEM diameter springs (GM – 1.250 inch maximum O.D.) must match heads. No beehive valve springs allowed.

 

 

INTAKE: Unaltered, approved OEM cast iron low rise, two- or four-barrel only! No OEM hi-rise, marine or bowtie intakes. All intakes must have unobstructed 0.250-inch vacuum fitting. Belt driven, OEM style water pumps only, no aluminum water pumps on Chevy engine.

 

CAMSHAFT: Non-roller hydraulic cam/lifters only. Lifters must remain UNALTERED OEM you can not alter lifter bore. OEM firing order cannot be changed (GM 1-8-4-3-6-5-7-2). All makes of engines must pull 15-inches of vacuum at 1000 rpms. Vacuum must be pulled on intake vacuum fitting, not carburetor. No alterations of any kind may be made at time of tech. Track equipment being used for tech is final. Lifter bores cannot be altered. Must be chain driven, no gear/belt drives.

OFFICIAL RULINGS: Officials reserve the right to make final decisions in the interpretation of any rules or race procedures at any time. No equipment will be considered as having been approved by reason of having passed through inspection unobserved. If you have any questions regarding the rules set forth, contact Owen Pittman at 361-548-0669. We reserve the right to make adjustments in total car weight.

[dirtracer58]

Is there a body diagram for these? Or one close we can go off of?