GMR — Graham Martin Racing
Throttle Body Kits

Bespoke ITB Kit — any engine

from £350.00 per cylinder

£420.00 inc. VAT per cylinder · the full price is quoted on your engine

Bespoke — request a quote

Your engine not on the list? We design and build complete individual throttle body systems for engines we have never seen before — that is where every kit we sell came from. Talk to us.

Tell us about the engine

Answer what you know — we’ll fill the gaps on the call. Only your name, email and the starred questions are needed.

No obligation, and the first conversation is free. We’ll tell you honestly if a listed kit does the job for less.

What’s included

Every bespoke kit is quoted individually — this is the shape of one.

Typically in the quote

  1. Intake manifold designed to your cylinder head and port outline
  2. Throttle bodies in your chosen size and spacing
  3. Airbox built for your engine bay, with integrated velocity stacks and filter
  4. Throttle quadrant kit and linkage
  5. TPS and mounting hardware
  6. 3D proof to approve before manufacture

Quoted separately

  1. Injectors, fuel rail and blanks
  2. Vacuum and idle manifold provision
  3. Idle valve, MAP and air temperature sensors
  4. Mapping, if you want it done here

What we can make

Everything we sell started as a bespoke job for somebody. We design in SolidWorks and have it made in the UK — carbon composite by Direct Digital Manufacturing, with CNC work where it needs it — so a one-off costs us a design, not a tooling programme. That is the whole reason we can quote a single part at a sensible number.

A complete system, not a box of parts

A bespoke kit is specified the same way our listed kits are: intake manifold to suit your head and port shape, throttle bodies in the right size and spacing, an airbox built for your engine bay with integrated velocity stacks, the throttle quadrant and linkage, a TPS, and the hardware to bolt it on. Injectors, fuel rail, vacuum and idle provision are specified around your management rather than assumed.

We have built for four-cylinder road and race engines, bike-engined cars and kit cars. If it breathes through four ports and there is room, it is usually possible.

What we need from you

  1. Engine and chassis, and what the car is used for
  2. A traced outline of your cylinder head ports — or the head, or a spare, sent to us
  3. Throttle body size and pattern if you have already chosen; otherwise we will specify it
  4. Injector, fuel rail and sensor requirements
  5. Ideally a detailed 3D scan of your engine bay. It is the single most useful thing you can send — it turns clearance from a guess into a measurement, and it is usually the difference between one design iteration and three. If you cannot scan it yourself, we can do it for you; ask when we speak.
  6. Failing that: bonnet clearance, bulkhead, strut tower and anything else in the way, with photographs and measurements
  7. Target power, and the induction you are running now

How a bespoke job runs

  1. Talk to us first — free. Tell us the engine, the chassis and what the car is for. We will tell you honestly whether we can improve on what you have, and whether an existing kit gets you there for less.
  2. We quote. Design and manufacture, itemised, before anything is committed.
  3. You approve a 3D model. You see the actual part in your browser, from every angle, before a gram of material is used. Nothing is made until you have signed it off.
  4. We make it. The manufacturing lead time starts at design approval, not at the order date — so the clock only runs once you are happy.
  5. We support it. Fitting questions, sensor and fuelling advice, and mapping if you want it done here.

Start the conversation — tell us what the engine is and we will tell you what is possible.