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Month: May 2011

“Speed Lab” 501-T .21 Nitro Engine

“Speed Lab” 501-T .21 Nitro Engine

By TQ Racing – Oct 10Posted in: 1/8th Scale


This Italian-made mill is a race proven design, capable of maximum usable-horsepower.  It is produced by one of the most renowned engine companies in the world, with former World Champion Rody Roem at the helm! The parts used for this engine are made from the finest materials available, and are compatible with the previously GRP branded engines.  However, this engine is more than a re-badged GRP. The 501-T includes a re-designed connecting rod for increased strength and lifespan, re-designed carburetor needles to help improve fuel mileage, and a lighter 9-fin cooling head to lower the center of gravity.

 Other Important Information

  • The 501-T’s all-aluminum carburetor has a longer Low Speed Needle (LSN), which allows for smoother power transition and increased fuel economy.  The carb also features a heavy duty slide-boot for long life and consistent idle and tune.
  • After extensive testing, the factory’s dynamometer shows that the most linear and usable power can be achieved by using the TQ tuned pipe.  The updated version of this pipe, the 003XS will soon be introduced, with increased body strength and a re-enforced stinger.  See the Specifications below for other pipe recommendations.
  • The ideal operating temperature range is 180-220F.  Until the first few quarts are run through the engine, temps may be slightly higher.  We suggest the user try to keep below 220F.  After complete break-in, the engine will naturally run cooler.
  • The TQ glow plugs really work best for this engine, and so are strongly recommended.  The stock TQ H6T fulfills the needs for most conditions.  The TQ H7T is best for hot weather conditions.  Other manufacturers’ plugs that will suffice in a pinch are the O.S. P6 and O’Donnell 99T.  Hotter plugs may cause pre-detonation and overheating.
  • Works great on both off-road buggy and truggy classes.
  • Run times average 9-10 min. in buggies, and 10-12 min. in truggies, when tuned properly.
  • A Modified version is in the works for future release (2011).

Type: Off-Road
Size: .21 (3.5cc)
Bore: 16.27mm
Stroke: 16.80mm
Crankshaft: 14mm SG
Cylinder: ABC 5P
Carburetor: Aluminum Cast 9mm w/ 7mm Venturi
Cooling Head: 60mm; 9 fins; Drilled
Glow Plug: Turbo; Conical H6 Included

Pipe Recommendations: EFRA 2069 (TQ), 2053, 9901, 2060, JP3


TQ Racing manages warranty and service issues right here in the US, so there’s no need for a customer to have to ship their engine to Italy. 

There are several internet forums that offer advice and support for these engines online, from TQ Racing team drivers and current customers.

We have an in-house engine specialist with over 30 years of nitro model engine experience to help customers who need extra support after purchase.