NEBRASKA BUSH PULLERS
Super Farm - Limited Super Stock - Modified
Tractor Pulling

2008 RULES
(These rules are for reference only.  Official NBPI rulebook will be used in case of discrepancy.)

SECTION 7

SUPER STOCK, SUPER FARM EQUIPMENT RULES

7-1 ENGINE HEAD AND HEADERS

(1)     No headers allowed on 8200 lb. or 9200 lb. diesel tractors.

(2)     Engine head must be OEM agricultural-type for that brand engine

(3)     OEM stock intake and exhaust manifolds for that series engine for 8200 lb. and 9200 lb. diesel tractors only.

(4)   505 cid limit on new alcohol tractors built. 650 cid limit on new diesel tractors built.

 7-2 FUEL INJECTION PUMP

One fuel injection pump, any make, any size and location. Water  injection with multiple nozzles  allowed. No sigma pumps are allowed and there is a limit of one plunger per cylinder. Tractor models manufactured exclusively with diesel engines must use injection pump and nozzles. Fuel requirements/specifications, will mirror / be the same as Outlaw  Super Farm fuel regulations.

 7-3 FIRE SHIELD

All tractors must have a metal fire shield between engine and operator. Shield may be a one, two, or three piece shield, secured every two inches at the seam with a minimum of 1/8” fasteners; if openings are necessary, keep as small as possible and seal opening with high temperature sealer or equivalent. Shield may be constructed of sheet metal and/or aluminum, minimum thickness of .060.

 7-4 TURBOCHARGER

Turbocharger limitations(general): One turbocharger is allowed(EXCEPT AS NOTED).                                                6500/7500 Super Stock classes only: It must have the same specifications, or be equivalent to, a Holset H5, 4.120 inlet, with or w/o  MAP ring.

(1)   SUPER STOCK 6500 lb. and 7500 lb. classes: Any make or model of turbocharger will be allowed with a maximum of 4.120 inch inlet. Inlet to be measured at the face of the wheel. No " custom design" MAP rings. Hybrid turbos that are smaller than 4.120 are allowed. No hybrid 4.120 chargers will be allowed. Any configuration or size on the outlet/exhaust housing. Sleeving of intake allowed. Tractors with a factory cid of 410 or less are allowed to use two turbochargers.

(2)   SUPER FARM 8200 lb. and 9200 lb. classes: Turbo will be the Garrett GT42, with no modifications, with the following part numbers:
712402-5008 Garrett GT42 Std. CHRA
451888-5011 Garrett GT42 Ball Bearing CHRA
446397-0460 V-Band
446401-5795 V-Band
447884-0041 Intake Compressor Cover (Band Clamp Outlet)
757708-0002 Intake Compressor Cover (Band Clamp Outlet) with Clamps Kits
712340-0033 Intake Compressor Wheel (Fits Both Std. & Ball Bearing CHRA)
714470-0001 Exhaust Turbine Wheel (Std.)
714470-0007 Exhaust Turbine Wheel (Ball Bearing)
740659-0006 Overhaul Kit (Std. Only)
757707-0001 Exhaust Turbine Housing 1.01
757707-0002 Exhaust Turbine Housing 1.15
757707-0003 Exhaust Turbine Housing 1.28
757707-0004 Exhaust Turbine Housing 1.44
No waste gates, or waste-gated exhaust housings.

 7-5 SUPERCHARGER

No superchargers allowed unless factory equipped.

 7-6 TIE BARS/FRAME

Tractor must have either: 1. Safety tie bars mounted to rear axle housing with at least 4 axle housing bolts and extending forward of flywheel area and fastened to side of block or main frame with at least two 5/8 inch bolts; OR 2. A one-piece frame extending from front of tractor to rear axle housing mounting bolts.

 7-7 SCATTER BLANKET

A scatter blanket is required and must cover 360 degrees around the flywheel housing. Overlap goes to the bottom.

 7-8 TRACTOR LENGTH

Maximum length of tractor wheelbase can be 114 inches from center of rear axle to center of front axle. Engine block may be repositioned a maximum of 1” forward of original. Maximum length  of tractor can be 13 feet from center of rear axle to futhermost point of the front weights. 

 7-9 EXHAUST

Cross bolts are required in exhaust outlet. Bolts are to be a minimum of 5/16” diameter. They are to be positioned at a 90 degree angle to each other and at a maximum of 1” apart vertically in the exhaust outlet. Bolts must be at least a grade 5. Exhaust must discharge vertically; no rain caps, no curved outlets on pipes.

 7-10 BLOCK REQUIREMENTS

Must use OEM transmission, rear end, and engine block. Only OEM adapters or mounting plates are allowed. No aftermarket adapters, with the exception of originally independent mounted coupled components. Must not cross manufacturer’s lines. Any questionable combination will be addressed by the board members.

 7-11 TRANSMISSION COVER

Transmission cover must be made of steel at least 1/16 of an inch, or factory equipped.

 7-12 KILL SWITCH

All tractors must be equipped with a kill switch. For diesels, it must be an air shutoff; for spark-ignition engines it must be a complete ignition system shutoff. Kill switch must be located a maximum of 4 feet above the drawbar, 6” in any direction.

CONSTRUCTION

Kill switch cable must be enclosed, so that if tractor unhooks from sled, cable can be separated from tractor without obstruction from the tractor. Ignition and/or air must be able to be killed from operator’s seat.

 7-13 DEADMAN THROTTLE

A dead man throttle is required. Spark ignition engines must utilize a return spring on the butterfly shaft. Diesel engines must utilize a return spring on the fuel injection pump, speed control lever. Return springs utilized must function in such a manner that if the operator's control cable and/or linkage fails or comes unhooked, positive return to low idle position will occur.

7-14 DRAWBAR HEIGHT & DRAWBAR CHECK

Drawbar may be 20” maximum from ground to top. Drawbar height check will be done at the beginning of the track before each pull attempt. Rule applies to all classes, all tractors. Measurement will take place in the same location for each tractor.

7-15 DRAWBAR CONSTRUCTION AND PLACEMENT

Drawbar will be 18” minimum length from center of rear axle to hook point, maximum of 1 ½” from back of hole to rear of drawbar. Minimum specification: 1” wide and 1” thick material around 3” drawbar hole hook point. All hooks must drop in from the top. Overall construction to be at discretion of rules officers. Drawbars must be rigid in all directions.

7-16 ENGINE SIDE SHIELDS

Engine side shields are required. They may be constructed of aluminum or steel and must be a minimum thickness of .060” The shielding must extend from the top of the cylinder head casting down to 2 inches below the centerline of the crankshaft main bearing journal.

7-17 FENDERS

Fenders are mandatory and must be a minimum of 2” above the top of the tire. They must extend outward 2” over the tire, with a minimum fender length of 30”.

7-18 TIRE SIZE

Super Stock          6,500 lb. and 7,500 lb. classes: 30.5 x 32 or less size tires.

Super Farm       8,200 lb. and 9,200 lb. classes:   24.5 x 32 or less size tires.

No duals. No 4-wheel drive. No front wheel assist engaged.

7-19 TRACTOR FRONT END

All tractors must have a wide front end.

7-20 ALUMINUM AND FIBERGLASS

Aluminum may be used in construction, except for restrictions as noted here.

Rule 7-10 Block Requirements

Rule 7-11 Transmission Cover

NO wood allowed anywhere.

7-21 CAMS AND VALVE HEAD

No overhead cam(s) or 4 valve head(s). No aluminum cylinder head(s). 

7-22 FLYWHEEL AND PRESSURE PLATE

Flywheel must be steel or aluminum. No cast iron flywheels allowed. No cast iron or gray iron pressure plates. Floater plate must be steel. ( SEE 7-31 ALSO)

7-23 WHEELIE BARS

Wheelie bars are required and must support the weight of the tractor. Bars are to be 32” back from the center of the axle, 25 square inches each pad; 10 inch maximum height from pad to ground. Wheelie bars must be constructed as to not interfere with hook or chain of sled. Wheelie bars and weight brackets must be separate from the hitching device.

7-24 ALCOHOL INJECTION

Alcohol injection will be allowed in the 6500/7500 lb classes only.

7-25 WATER INJECTION

Water injection will be allowed.  No alcohol based substance, additive  and /or formula containing alcohol or any kind or manner may be used or allowed in water injections in the 8200/9200 lb classes. Water pump lubricants are allowed 

7-26 FUEL ADDITIVES

No fuel additives, such as nitrous oxide or nitro methane allowed. No onboard pressureized containers, other than fire extinguishers allowed in the 8200/9200 Super Farm Classes. Example: NOS, oxygen, CO2, ect bottles.

7-27 INTERCOOLERS

OEM intercoolers will be allowed. No aftermarket intercoolers. Engine coolant only must be run in intercooler.

7-28 SHEET METAL CHANGES

Updates are allowed. However, mere changes in sheet metal do not allow for changeover of mechanical components to coincide with new sheet metal. Sheet metal upgrades cannot cross manufacturers lines.

7-29 OPERATOR’S PLATFORM

All tractors must be equipped with an operator’s platform and proper shielding to prevent operator’s feet from contacting tires.

7-30 ELECTRONIC FUEL CONTROL

No electronic fuel control and/or air metering devices allowed.

7-31 ELECTRONIC CLUTCH

No electronic clutch control devices allowed.

7-32 FUEL SHUT OFF

Manual or electric fuel shut off to fuel injection pumps on diesel tractors is required. Must be controlled from the driver'’ seat.

7-33  CUBIC INCH LIMIT . 8200/9200 SUPER FARM CLASSES

Back to the Top