GCAP Performance are one of London's premier supercar, performance and tuning workshops. We specialise in bespoke tuning packages and general maintenance of all sports, performance and supercars.

Owner and founder Gary Conway is a car enthusiast before all things. He has owned and built a number of high performance track and show cars, featured in many automotive magazines and even appearing on television (see our PRESS section).

Gary Conway comes from a family of well respected automotive figures. His father being a well known name in the automotive industry. His business, Air and Sound, went from a small garage in West London fitting car alarms, to building demo vehicles for some of the biggest car audio manufacturers in the world, including Clarion. With this wealth of knowledge behind him it was inevitable Gary would follow suit in the automotive trade. After several years studying Motorsport Engineering and equipped with experience working with a major racing company within the BTCC, Gary founded GCAP Performance.

GCAP's humble beginnings began with installing bolt on performance upgrades from the London workshop. As the company grew, so too did the services offered by the company. GCAP now offer full bespoke tuning packages ranging from basic bolt on parts to custom performance parts made exclusively for the company, in house and by some of the worlds biggest tuning manufacturers.


Based in Notting Hill, West London, GCAP Performance has an extremely well equipped, state-of-the-art and uniquely clean facility which gives you peace of mind, knowing that your vehicle is going to be looked after from the minute it arrives, to the moment you collect it.

We have a customer waiting room where we invite you to sit back and relax whilst we work on your pride and joy. We have free Wifi, Selection of movies and TV shows and magazines to make your wait enjoyable. On display we have a vast range of products we stock so customers can be hands on with the items to help them plan their next step with their vehicles.

We have a huge parts department dedicated to keeping a vast array of parts in stock to ensure all web orders are dispatched as quick as possible.

We are minutes away from the world famous Portobello Market offering a vast array of shops, stalls and restaurants. We are also a stones thrown away from Westfields should you wish to indulge in some proper retail therapy, enjoy a movie at the cinema or treat yourself to some great food.


For your car's protection, and for ours, we are fully insured for all cars that enter our workshop.. Our policy covers us for all cars; be the value low or extremely high (many millions of pounds). We have a 24 hr recorded CCTV system and a full workshop alarm system, it's safe to say that your car's security is of our prime concern. We pride ourselves on our clean, safe and modern premises and are confident you will be happy to leave your pride and joy in our hands.


​Alongside Gary, the team consists of an ex-Holden race engineer from Australia, a leading auto-electrician who specialises in can-bus wiring and diagnostics and a Royal approved Jaguar engineer.  Between the team we have over 100 years experience in the automotive trade. We can cater for all vehicles from basic hot hatches to high end million pound supercars. With our unique set of skills each of the team members provide, we can ensure no matter the problem, the modification or build - we have the ability to deliver every time.


With the ever increasing demand for high output BHP cars we have ensured that we can tune your vehicle safely and efficiently with exclusive use of a 4WD dynometer at the Dyno Developments HQ.

Here we can tune your vehicle to its full potential using the latest tools and technology to monitor knock, AFR, Boost, timing, intake temps and more. All customers have the choice to have their vehicle road tuned or on the dyno.

The dyno we use boasts the following features:

  • Rated for up to 2400 BHP at the wheels

  • Runs Front Wheel Drive, Rear Wheel Drive, Four Wheel Drive

  • Test Cars, Trucks, RV, Go Karts, Quad Bikes and Motorcycles

  • Measure HP, Torque Time, Tractive effort rpm etc

  • Measure AFR / Lambda

  • Automatic weather station Air Temperature Correction

  • Measure vacuum / Boost

  • Thermocouple / EGT channels

  • Built in Knock detection

  • Measure RPM direct from engine / Roller speed

  • Ramp Mode for Power Graphing

  • Steady State mode for fine engine tuning

  • Fine syncronisation of  road speed between front and rear rollers

  • Optional 4WD Belt to lock rollers together (also enables 2wd cars to be tested with no ABS or Traction Stability faults)

  • The Dyno uses Intelligent Adaptive load control and will hold load perfectly every time, very useful for engine mappers



GCAP Performance

6 Powis Mews

Notting Hill


W11 1JN