NADM new class- 2.5 pending.

Sledpuller

Comp Diesel Sponsor
2.5’’
The 2.5 street legal class is designed for daily-driven, on the road pickup trucks (full-bodied
diesel pickup trucks). Valid DOT registration and license plates are mandatory. The vehicle may
be two or four-wheel drive.
Designation: 2.5” followed by competition number
Weight breaks: 8000 lbs. Weight is with driver
REGULATIONS:
Ballast: Ballast is permitted. Hanging front weights are permitted but can’t exceed 60” to the furthest most point of the ballast from the center line of the front axle. Ballast may be added in the
bed of the truck. If used, ballast must be securely fastened to the bed. Final decisions rest with the
DIESEL MOTORSPORTS Technical Department.
Batteries: The batteries must be securely mounted. They may not be located in the driver
compartment or forward of the radiator core support.
Body: The body must be the OEM truck body, including the full bed floor. The body must retain
full sheet metal. Metal after-market hoods are permitted. Fiberglass is prohibited. The hood must
be closed and securely latched while the vehicle is hooked to the sled. The complete OEM
firewall and OEM floor pan is mandatory. A factory installed pickup bed or commercial style aftermarket bed must be installed.
Brakes: Four-wheel hydraulic functional brakes are mandatory.
Chassis: The OEM chassis is mandatory. The engine must be in the OEM location for the body
used. The vehicle must retain the full OEM chassis. Wheel tubs, back-half conversions, tube
chassis, etc., are prohibited.
Cooling System: Radiators must be in the stock location and be of at least stock size.
Credentials: All drivers must have a valid state driver’s license.
Driveline: An OEM transmission and transfer case are mandatory. They must have been an
option on a one-ton or smaller pickup.
Driver Restraint System: The OEM restraint system is mandatory and must be worn.
Engine: The engine is limited to a stock-appearing, OEM make-specific compression ignition
Engine. The engine block must have been available as a factory option on a one ton or smaller pickup truck. Cubic inch limit of 444 CI. Blocks must circulate coolant freely. No hard filled blocks. Water pumps may be factory or electric powered. All factory driven accessories, excluding the air conditioning compressor, must be retained and powered VIA the crankshaft by a standard serpentine or “V” belt. Electric cooling fans are permitted.
Exhaust: All vehicles must be equipped to direct exhaust upward. The exhaust must exit
rearward of the driver’s compartment. Stacks exiting through the hood or fender well are
prohibited. If the muffler or catalytic converter have been changed from stock, two 3/8 inch
diameter, minimum grade 5, bolts must be installed through the exhaust pipe in a cross pattern
within one inch of each other as close to the turbo as is practical.

Fire Extinguisher System: A fire extinguisher is mandatory. A fire extinguisher system is
permitted.
Fuel: The fuel must be pump #1/#2 diesel only. Soy/Bio-diesel fuel is permitted. Fuel must be commercially available. Off-road diesel
fuel is prohibited. . NITROUS OXIDE is prohibited along with other oxygen extenders as
well as the use of PROPANE is also prohibited. All system components MUST be removed
from the truck.
Fuel Injection Pump: The fuel injection pump is limited to a stock-appearing, Cylinder number specific(IE: 6 cylinder pump on a 6 cylinder engine) OEM engine
model-specific pump only. The use of multiple high-pressure common-rail fuel pumps is
permitted. Powerstroke engines with a single factory turbo may utilize a second HPOP. Pumps
from different years in the same engine model may be interchanged. Ag govenors are prohibited. Sigma or 12 cylinder pumps are prohibited.
Fuel System: The OEM fuel tank is mandatory and must be used. Racing fuel cells are prohibited
and must be removed from the vehicle.
Harmonic Balancer: All engines turning 4500 RPM and higher must be equipped with a
harmonic balancer or damper meeting SFI Spec 18.1.
Hitch: The hitch must be a receiver-style hitch; reinforcements are permitted. Reinforcements
must not extend forward of the centerline of the rear axle or to the axle housing itself. Trick
hitches are prohibited. The hooking point must be the rear-most point on the vehicle and
must be rearward of the stock location of the tailgate. The hitch must be horizontal to the
ground and stationary in all directions. Bumpers may be notched or removed. The hitch’s height
from the ground may not exceed 26 inches on 4wd units and 30 inches on 2wd units. The
hooking point must have a minimum 3.750-inch inside diameter opening for the sled hook. The hooking point must be a minimum of 44” from the centerline of the rear axle, to the to the end of the hole where the hook touches metal to be pulled from, this is the hooking point.
Inter coolers: Factory style or aftermarket air-air coolers are permitted. Water-to-air coolers are prohibited. Any means of cooling the air before the engine, except the air-air cooler is prohibited.
Interior: A complete interior, including dashboard, door panels, headliner, etc., is mandatory.
Two matching front seats are mandatory. Aftermarket seats are permitted; they must be fully
upholstered. All factory controls (lights, signals, horn, windows, wipers, etc.) must be retained
and be operative. The use of hand-throttle controls is prohibited.
Kill switches: It is recommended to have a air shut off on all trucks.
Rear End: Non-OEM rear-end housings are prohibited. It must have been an option on a one-ton
or smaller pick up. Rear axle bolts must be covered by a cap or shield.
Steering: The vehicle must retain the full, original OEM steering gear. The vehicle must retain
the original OEM power steering assistance, if it was so equipped. Additional stabilizers are
permitted. Non-OEM power assist methods are prohibited.
Street Equipment: Complete headlight and taillight assemblies (all) are mandatory and must be
operative. Complete OEM windshield and windows are mandatory. Windows must be operative
per factory specifications; that is, they must open and close via OEM electrical or mechanical
means.
Suspension, Front: The upper mounting point for strut assemblies must be in the factory
location. Adjustable caster/camber pillow ball mounts are permitted. The lower control arm may
be strengthened provided factory-mounting points to chassis are maintained. The lower mounting
point for the strut assembly may be modified for improved caster or camber. Strut tower braces,

lower tie bars, sway bars, and limit straps are permitted. Traction bars and devices are permitted.
Final decisions rest with the DIESEL MOTORSPORTS Technical Department.
Suspension, Rear: An OEM-style suspension is mandatory. Lowering or raising the vehicle
height with suspension modifications is permitted. Traction bars and devices are permitted; they
must be bolt-on only; welds are permitted for attachment to frame or axle housing. All OEM
suspension mounting points must be retained and used. Sway bars, limit straps, and camber kits
are permitted. The rear suspension must maintain a minimum compression shock travel of one
inch; compression stops must be adjustable. All rear suspensions must use at least one working
shock absorber per wheel. Airbag spring assistance is permitted; airbag compressors must be
disconnected.
Tires: The tires must be DOT street tires. Cut tires are prohibited. Dual wheels will be permitted on factory equipped trucks only. Trucks utilizing dual rear wheels will be limited to a tire with maximum width of 8’’ of tread per tire.
Tow Vehicles: Tow vehicles are prohibited.
Transfer Case: Non-OEM transfer cases are prohibited. The transfer case must have been an
option on a one-ton or smaller pickup truck.
Transmission, Automatic: Non-OEM transmissions are prohibited. Aftermarket torque
converters, valve bodies and internal components are permitted. Transmission brakes are
prohibited. Any non-OEM floor-mounted automatic transmission shifter must be equipped with a
spring-loaded positive reverse lockout device to prevent the shifter from accidentally being put
into reverse gear. A functional neutral safety switch is mandatory. All transmission lines must be
metallic or high-pressure-type hose. All vehicles with engines running 4500 RPM or more and
using an automatic transmission must be equipped with a transmission shield meeting SFI Spec
4.1 and must be labeled accordingly. A blanket-type shield is permitted; it must be
appropriately labeled as meeting SFI Spec 4.1 and it must extend from the rear of the block to
the front of tail housing with a minimum six inch overlap where it is fastened. All non-blankettype
shields must incorporate two (or one, per manufacturer’s instructions) 3/4 inch by 1/8 inch
straps that bolt to the shield on each side and pass under the transmission pan unless the
transmission pan is labeled as meeting SFI Spec 4.1. All vehicles with engines running 4500
RPM or more and using an automatic transmission must be equipped with a flex plate
meeting SFI Spec 29.1 and be covered by a flex plate shield meeting SFI Spec 30.1.
Transmission, Manual: Non-OEM transmissions are prohibited. Aftermarket internal
components are permitted. A clutch meeting minimum SFI Spec 1.1 or 1.2 is mandatory on
all vehicles with engines running 4500 RPM or more. All manual transmissions must be clutch
assisted. Sequential shifters are prohibited. All vehicles with engines running 4500 RPM or
more and equipped with a manual transmission must have a flywheel shield labeled as
meeting minimum SFI Spec 6.3 or greater. Applications for which an SFI Spec flywheel
shield is not available may use a properly attached SFI 4.1 or 4.2 blanket that completely
covers the bell housing; it must be attached to the block and extend rearward to the transmission
with a minimum six inch overlap where it is fastened.
Turbocharger: 2.50 Turbocharger: The vehicle is limited to a single turbocharger. The inducer bore on the compressor housing may be no larger than 2.500”. The inlet will be measured using a 2.550'' plug or internal calipers. Bushing of any larger turbo size down to a 2.500 turbo is PROHIBITED. Inducer bore must be non-removable. Turbo compressor covers must be a true-bore inlet. Stepped/ Tapered covers are prohibited. Clipping/ trimming of the compressor wheel is prohibited. The turbo wheel must measure no larger than 2.500'' in front of and behind the MWE. The turbo may utilize a stock map width enhancement (MWE) groove, but is to be no wider than .250” maximum. No MWE alterations will be allowed. All provisions allowing air to the wheel other than via the bore and the MWE groove are prohibited. Exhaust manifold/ Pedestal bolt pattern shall measure no larger than 3.500" x 2.750" (t-4 flange). Altering of the turbo housing to accommodate a smaller foot or base will not be permitted. 6.4 liter Powerstroke/ 6.7 liter scorpion engines may utilize the factory turbo configuration. The driver will be responsible for making the compressor wheel and bore accessible for Tech Officials to measure bore and inspect the compressor wheel.

Water Injection: Water injection is prohibited. All system components must be removed from
the truck.
Wheelbase: The vehicle must retain the original factory wheelbase and track width.
 
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This may be a good class for the guys that want a built motor in a truck they can still use to tow and drive on the street . I would be interested when my bottom end leaves me and I am forced to build it .
 
Interesting class. We tried to make a class like this in nw Missouri for next season but didn't get it done cause we didn't have a good set of rules but this is exactly what we were lookin for.
 
I didn't have time to look, but how close are these to the 2.5 classes that exist in the midwest? I can't remember the sanctioning body...
 
Discussion point for the MWE and wheel size:

I have two late model compressor covers, one Garrett and one Holset.

BOTH have the MWE ever so slightly up into the contour and not 100% on the straight section of the wheel. It's tricky to measure but the wheel would be several thou larger than the inducer at the rear edge of the MWE. Thus we would have two stock turbos that would be illegal if judged to the letter of the law.

Just a suggestion to make this easier. Let the MWE be in whatever location, just limit the width. NO OEM is using a 0.25" wide MWE, not even close. Knock down the limit on the width (say 0.200" like others run) and let that be it.

I don't think you want tech people trying to figure the bore OD at the leading and trailing edges of the MWE, that's just annoyingly full of potential measuring erros, especially when one needs deep throat calipers to make the measurement accurate.

I mean, this class seems to be trying to encourage simplicity and using stock parts, not highly modded, high dollar cheater parts.

Or if you are saying you just don't want MWE's way up into the contour and you're not worried about 10-20 thou difference at the back edge, then fine. Just trying to keep things simple.
 
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correct me if I am wrong but wouldn't it be a pain in the a$$ to tech these turbos right . Or would you be able to see a cut wheel by looking from the outside .
 
A cut wheel is pretty obvious if you know how to look for it.

Measuring the diameter of both sides of the MWE groove in the compressor housing is a bit trickier.
 
These rules are the same as what we made up for the Darke County Tractor Pullers Assn.
DCTPA. That was a year ago. Did you copy from us?
 
No idea Gavin, 2.5 guys have been sending me rules/ideas for the past 2 years, this is what they came up with.The final copy will be layed out, in our normal rule form, these are basically highlights. If they are yours, nice job, they seem to be very popular.

That said, how are they working? Any tech issues?
 
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As far as i know we had no tech issues. But i wasn't at all the pulls. These rules were made by pullers for pullers. We had a meeting, and thats what we came up with. I think it's a very good set of rules. Very fair for everyone.
 
Water pumps may be factory or electric powered. All factory driven accessories, excluding the air conditioning compressor, must be retained and powered VIA the crankshaft by a standard serpentine or “V” belt. Maybe I'm missing it, but with the direction and intent of the class what is the reason for allowing electric water pumps, and even though some are gear driven, wouldn't they still be defined as a "factory driven accessory"? It looks like you are asking all (minus the A/C compressor IF removed) factory driven accessories to be factory driven, yet allow the water pump as an exception. Are that may guys daily driving with electrics?

The turbo may utilize a stock map width enhancement (MWE) groove, but is to be no wider than .250” maximum. No MWE alterations will be allowed.

If no alterations are allowed, and no stock MWE is .250 (going off of what Matt stated), if someone shows up with a .250" MWE (and I'm sure several will), will they be disqualified?

I think it's a great set of rules and will offer guys not able to jump up to 2.6 a chance to compete, just was looking and having dealt with rules/tech issues before, those two items stuck out.
 
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