Not legal2 parts
Prohibited. DD.7
- Aftermarket supercharger · Forced induction
- Supercharger internals, clutch and pulleys · Forced induction
IHRA · drag
Drag, Turbo No Nitrous
IHRA2026, DD.7. A closed-list class. The craft must stay stock except where the rules allow otherwise, so anything unlisted is not permitted.
Places where the rulebook contradicts itself, or where a figure could not be settled. Nothing in this list is decided, and it sits here rather than in a footnote because it is what you would want before spending money.
- The same DD closed-list problem applies, and this class is where it is most visible. The section states what is banned and nothing about what is allowed, while the preamble says anything unlisted is illegal. Together they describe a class in which a compliant craft cannot be built.
- The 68mm inducer limit is stated without a measurement method.
Confirmed absent by a targeted read rather than merely unnoticed. In a closed-list class an absent article is why a part reads as not permitted; in an open class it is why one reads as open.
- No class criteria.
- No engine, fuel composition, ignition, pump or hull article beyond the five bullets.
What the rules say (65 parts)
21 permitted outright, 40 answered by our reading of the class rather than by a quoted rule, 0 the rules do not settle. Grouped by the answer, because an open class gives one answer to most questions and printing it once per part would say the same sentence forty times.
Not permitted, not listed in the rulesOur reading, not a rule we can quote at you. This class requires the craft to stay stock except where the rules allow otherwise, and this part is not on the list.
Not legal1 part
Bolts, nuts and washers may not be substituted with titanium unless originally equipped. Locking mechanisms are allowed. J.7
- Titanium fasteners · Engine
Not legal1 part
No nitrous, no spraying. DD.7
- Nitrous oxide system · Forced induction
Not permitted, not listed in the rules40 parts
On a closed list an unlisted modification is not permitted. A.2.2, J.1
- Aftermarket head pipe and exhaust manifold · Exhaust
- Aftermarket or modified waterbox · Exhaust
- Relocated or aftermarket through-hull outlet · Exhaust
- Exhaust restrictor plate removal · Exhaust
- Aftermarket intake manifold · Fuel
- Aftermarket flame arrester · Fuel
- Aftermarket air intake or cold air system · Fuel
- Airflow sensor modification or removal · Fuel
- Aftermarket throttle body · Fuel
- Aftermarket electric fuel pump · Fuel
- Aftermarket or substituted fuel tank · Fuel
- High-pressure fuel line and fittings · Fuel
- ECU reflash or reprogramming · Ignition
- Aftermarket or standalone ECU · Ignition
- Aftermarket or lightened flywheel · Ignition
- Aftermarket boost sensor · Ignition
- Aftermarket wiring harness or connectors · Electrical
- Aftermarket pistons · Engine
- Aftermarket or modified crankshaft assembly · Engine
- Aftermarket connecting rods · Engine
- Cylinder head work (4-stroke) · Engine
- Engine block substitution · Engine
- Aftermarket camshafts · Engine
- Aftermarket valves · Engine
- Aftermarket valve springs and retainers · Engine
- Aftermarket or thicker head gasket · Engine
- Aftermarket intercooler · Forced induction
- Aftermarket pump housing and stator vanes · Driveline
- Aftermarket or bored pump nozzle · Driveline
- Aftermarket driveshaft and couplers · Driveline
- Titanium driveshaft · Driveline
- Adjustable or rider-controlled trim tabs · Driveline
- Aftermarket or modified top deck · Hull and handling
- Aftermarket hood · Hull and handling
- Aftermarket bulkhead · Hull and handling
- Flotation foam removal · Hull and handling
- Ventilation tubes and vent sealing · Hull and handling
- Aftermarket seat · Hull and handling
- Aftermarket seat cover · Hull and handling
- Aftermarket cooling lines and fittings · Cooling
Legal, within limits1 part
Limits: max injectors 4. DD.7
- Aftermarket fuel injectors · Fuel
Legal, within limits1 part
Gauges may be modified or removed provided no hazard is created and any resulting hole is sealed. Section J permits modification and removal and never addresses adding an aftermarket instrument. J.15
- Aftermarket gauges and data logging · Electrical
Legal, within limits1 part
Must fit the original battery box and be securely fastened. J.9
- Aftermarket or relocated battery · Electrical
Legal, within limits1 part
Repairs are allowed for a crack or puncture, but only one damaged area affecting one cylinder bank. No other modification. J.11
Legal, within limits1 part
Watercooled only. No hot headers. Limits: max inducer 68 mm. DD.7
- Aftermarket turbocharger · Forced induction
Legal, within limits1 part
May be modified or replaced with an aftermarket part. The original diameter must be maintained in Stock class, and the rulebook never defines which classes that is. J.18.2
- Aftermarket impeller · Driveline
Legal, within limits1 part
May be replaced within OEM specifications. J.18.3
- Replacement wear ring · Driveline
Legal, within limits1 part
Aftermarket or modified, full-length type with at least one bar parallel to the driveshaft, dropping no more than 12.00mm (0.47 in) below the flat plane of the pump intake. J.18.1
- Aftermarket intake grate · Driveline
Legal, within limits1 part
Aftermarket or modified. An extension may not exceed the width of the original plate, and on a ski may not extend more than 100 mm (3.94 in). J.18.1
- Aftermarket ride plate · Driveline
Legal, within limits1 part
Replacement trim plates may be used provided they mimic the handling characteristics of the stock plates. J.18.2
- Replacement trim plates · Driveline
Legal, within limits1 part
Braking devices may be disabled for safety, and reverse buckets and trim motors may be removed or modified to disable them, provided no hazard is created. J.18.4
- Reverse bucket or brake removal · Driveline
Legal, within limits1 part
No lightened hulls. No gutted hulls. DD.7
- Aftermarket hull · Hull and handling
Legal, within limits1 part
Aftermarket, modified, repositioned or removed. Up to two, each no longer than 36 in (91.45 cm), protruding no more than 3.94 in (100 mm) horizontally, at least 6 mm thick with radiused leading edges, and not attached to a planing surface. J.16
- Aftermarket sponsons · Hull and handling
Legal, within limits1 part
Replacement bumpers and side rails may be used provided they create no hazard. A permanently affixed nose bumper remains required. J.13, I.17
- Replacement bumpers and side rails · Hull and handling
Legal, within limits1 part
May be added to adjust handling. Constant mass only, and no other part may be modified to carry it. J.19
- Ballast weight · Hull and handling
Legal1 part
Named in the general maintenance allowance along with wiring, hoses and clamps. J.7
- Spark plugs, wiring, hoses and clamps · Electrical
Legal1 part
May be replaced. J.8
- Replacement starter motor · Electrical
Legal1 part
May be replaced, as may starters and oil injection systems, with the oil injection system removable or disconnectable. J.8
- Replacement engine mounts · Engine
Legal1 part
Grips, throttle and cables may be modified or aftermarket. The bar must be padded at the mounting bracket or the crossbar padded. J.17.1
- Handlebars, grips and controls · Hull and handling
Legal1 part
Steering shaft, holder, handlebar holder and cables may be aftermarket, and quick-turn modifications are allowed. J.17.2
- Steering shaft, holder and cables · Hull and handling
Legal1 part
The bilge pump may be modified or disconnected and aftermarket bilge draining systems are permitted, provided they create no hazard. J.10
- Aftermarket bilge draining system · Cooling
IHRA 2026, DD.7, read from the rulebook on 2026-09-11, not verified by a racer. Read the rule yourself, Drag, Turbo No Nitrous. Every IHRA class · where the rulebooks differ.
This is one class. Every part below also has a page of its own showing where it stands across every class this body runs, and legality by part is the index of them.
65 parts read · 21 permitted outright · 2026 rulebook