Nicholson McLaren Aviation holds UK CAA, EASA Third Country & FAA Approvals


Superior XP series kit engines

If you’re looking for quality engines, contact Nicholson McLaren Aviation Ltd. We stock top-quality Superior XP series kit engines.

Superior XP Series Kit Engine

At Nicholson McLaren Aviation, our roots have come from our founding company Nicholson Mclaren Engines world renowned for designing and developing Formula 1 and various other race engines. When it comes to an experimental aircraft engine, Nicholson Mclaren Aviation can utilise all of the professionalism engineering expertise from our sister company Nicholson Mclaren Engines to create a bespoke engine to your requirements.

We thoroughly enjoy working with high performance and experimental engines. We have carried out work and developed engines for Red Bull Air race engines and various other aerobatic and display pilots. All our experimental engines are released to service after a full test on our Schenk Dynamometer with a log book certificate. We are now proud to be appointed and to be able to offer the Superior XP series kit engine.

Superior XP Series Engine Kit Nicholson McLaren Aviation Aviation

Experimental XP-320

  • Displacement: 320 cubic inches
  • BHP: standard 160 hp (150 hp and 165hp available)
  • Compression ratio: 8.5:1 standard (7:1 and 9:1 available)
  • Engine mount types: type 1 or 2 dynafocal or conical
  • Propeller drive: direct, AS127 type 2 modified
  • Propeller type: fixed pitch or constant speed
  • Weight: 285 – 290 lbs depending on model
  • Engine dimensions: 24.6″ H x 32.3″ W x 32.8″
Superior XP Series Engine Kit Nicholson McLaren Aviation Aviation

Experimental XP-360

  • Displacement: 360 cubic inches
  • BHP: standard180 hp (170 hp and 185 hp available)
  • Compression ratio: 8.5:1 standard (7:2 and 9:1 available)
  • Engine mount types: type 1 or 2 dynafocal or conical
  • Propeller drive: direct, AS127 type 2 modified
  • Propeller type: fixed pitch or constant speed
  • Weight: 288 – 297 lbs depending on model
  • Engine dimensions: 24.6″ H x 33.4″ W x 32.8″
Superior XP Series Engine Kit Nicholson McLaren Aviation Aviation

Experimental XP-400

  • Displacement: 400 cubic inches
  • BHP:  standard 215 hp
  • Compression ratio: 8.9:1 standard
  • Engine mount types: type 1 or 2 dynafocal or conical
  • Propeller drive: direct, AS127 type 2 modified
  • Propeller type: fixed pitch or constant speed
  • Weight:  310 pounds
  • Engine dimensions: 24.0″ H x 34.3″ W x 32.8″
Better features, benefits and value from Superior XP engine series


Each factory new XP-Engine is created from the most advanced designs and manufacturing techniques then individually hand assembled by experienced engine craftsmen using many of the same FAA certificated parts used to build the FAA certificated vantage engine.

The components used to create Superior’s XP-Engines are the culmination of literally hundreds of individual design and manufacturing improvements we have made to our array of FAA PMA-approved parts and components over the last 40-plus-years.

Today, the fit, finish and quality of all of our parts and components are of the highest possible quality and consistency. Our parts and components are not painted or alodined to hide blemishes or manufacturing shortcomings.

The only reason we paint our millennium cylinder barrels or alodine finish the cylinder heads, crankcases, sump, cylinder heads and assembly drives on the XP-Engine is for corrosion protection.

Why? The reason is simple: we have the best looking parts in the business and we don’t have to cover up any manufacturing flaws with paint.

The obvious quality of the XP engine is just the beginning of the many performance and quality advancements it brings to piston-powered, experimental aircraft and helicopters.

Other examples of the XP’s many standard features and benefits include:

Reinforced crankcase

  • Direct lubrication available to the thrust face greatly reduces crankcase and crankshaft wear.
  • Balanced oil system provides uniform lubrication to both sides of the crankshaft and camshaft. This reduces pressure fluctuations while equalizing oil flow through the entire engine, including the filter.
  • Reinforced cylinder deck strengthens key areas against crankcase pressure and helps eliminate cracking.
  • Precision machined to accommodate cooling nozzles for high-compression piston and turbocharger applications.

Proprietary ESR crankshaft

  • Electro Slag Remelt (ESR) process removes many more metal impurities than the standard Vacuum Arch Remelt (VAR) process used in the production of most prior-generation crankshafts.
  • Oil journals are polished and coated to virtually eliminate the corrosion and pitting issues that were prevalent in many VAR produced crankshafts.
  • Each crankshaft is balanced within exacting tolerances to ensure the smoothest engine operation throughout the power operating range.

High flow oil sump

  • Smoother intake manifold and plenum reduces aerodynamic turbulence for better breathing for all four cylinders.
    Unique plenum turbulator improves air fuel mixing.
  • Tuned intake tubes balance the intake runner length to further improve airflow and engine breathing
  • Polished, stainless steel tubes minimize rust and corrosion.
  • Horizontal cold air induction system (optional).
  • Air plenum is separated from the main sump body to keep inlet air cooler to provide more horsepower.
  • Horizontally mounted fuel injection system allows builders to create more aerodynamic cowling designs.
  • Lighter weight than conventional sumps.
  • Machined to allow for installation of inverted oil systems.



Millennium Cylinders

  • Through hardened steel barrel provides uniform hardness all the way through the barrel walls, ensuring even wear while withstanding extreme temperature and pressures.
    Very high quality casting creates aerodynamically smoother surfaces to improve overall airflow and cooling.
  • Exhaust and intake ports are volumetrically matched for maximum output and performance.
  • Computer-generated head fin configuration for more efficient heat transfer and fewer “hot” spots.
  • Increased port wall thickness eliminates issues with warping and cracking.
  • Manufactured from the most advanced alloys available to exceed industry standards for strength and porosity.

Computer Optimized Camshafts

  • Superior’s camshaft is designed for better cruise economy, lower valve train loads and smoother idle and power operation.
  • Lower valve train loads reduce camshaft and lifter spalling while decreasing wear and friction to the valve train and guide.
  • Precisely timed camshaft lobe valve events eliminate re-ingestion of exhaust gasses, improving economy and overall performance.
  • Idle and power vibration characteristics are also computer optimized to “passenger car” standards to reduce vibration, pilot fatigue and component wear.

Roller Lifters

Our roller lifters were developed to provide a smoother running engine and to help reduce wear between the camshaft lobe and the roller face, minimizing the occurrences of cam-lifter spalling.

Superior Exclusive

A unique feature of our roller lifter design is that they can be removed without opening the engine case, which reduces costly maintenance and repairs.

Connecting Rods

  • Precision machining of the entire connecting rod surface a better finish and more consistent weight and balance.
    Forged VAR 8740 steel per AMS 6325.
  • Individual connecting rods are statically and dynamically balanced.
  • Tongue and groove design reduces shear loads.
  • Component balancing and matching.
  • Connecting rods are individually statically and dynamically balanced.
  • Crankshafts are balanced to within ¼ ounce-inch
  • Connecting rods, pistons, piston pins, connecting rods and bolts are all weighed and balanced as a set to closely match the weights of all opposing components results in smoother engine operation.

Tri-Metal Bearings

  • Tri-Metal Bearings are 40% stronger than conventional aluminium bearings.
  • Superior’s machined parts versus the competition’s cast parts.
  • Superior has elevated the production of many seemingly simple parts to a higher art. For example, instead of using lower cost and quality processes including casting and painted, or plastic (filler tube) processes, and materials like our competitors, we have machine numerous parts from billets and then Alodine these parts against corrosion.

Superior billet-machined parts include:

  • Oil filler tube and level gauge
  • Vacuum pump drive
  • Oil filter adapter
  • Prop-governor drive

*NOTE: Superior XP engines are approved for 100LL Avgas per ASTM D910, 91/98 (lead optional) and motor gasoline with a minimum antiknock index (R=M/2 method of 91 per ASTM D4814 (European EN228). Use of auto fuel blended with alcohol (ethanol) is forbidden.

Superior XP Engine Build Specialists. For details, call us on
+44 (0) 118 973 8011