Ordering the wrong hose is one of the most common — and most avoidable — problems in an intake or cooling project. This guide walks through the four decisions that matter: diameter, shape, length and reinforcement.
Step 1: Measure the outside diameter of the pipe
Silicone hoses are specified by their inner diameter (ID), and that ID should match the outside diameter (OD) of the pipe or spigot it slides onto. Measure the pipe OD with a vernier caliper rather than a tape measure, and measure at the point where the clamp will sit. A hose that is slightly too large will not seal properly even with a tight clamp; a hose that is too small is hard to fit and can split.
Step 2: Different diameters? Use a reducer
If the two parts you are joining have different ODs — for example a turbo outlet and a larger intercooler pipe — use a reducer hose instead of forcing one hose over both. Reducers are available as straight transitions or as reducing elbows, which combine a size change and a bend in one part.
Step 3: Choose the shape
- Straight hose / coupler — joins two pipes in line.
- 45° elbow — a gentle change of direction, good for airflow.
- 90° elbow — the most common bend for turbo, radiator and intercooler connections.
- 135° elbow — routes the pipe back on itself in tight spaces.
- 180° U-bend — fully reverses direction in a single piece.
- Hump hose — adds flexibility to absorb engine movement and vibration.
- T-piece — adds a branch for a blow-off valve, sensor or heater line.
Fewer joints mean fewer potential leak points. If a route needs several elbows and straight sections, consider a custom-moulded hose that replaces the whole assembly with one part.
Step 4: Check leg length and overlap
For elbows, measure the length of each leg from the centre of the bend. Make sure each end of the hose overlaps the pipe enough for a clamp to sit fully on the pipe, ideally behind a bead or flare on the pipe end. Leave a small gap between the two pipe ends inside a coupler so the hose can absorb movement.
Step 5: Choose the reinforcement
Reinforcement plies stop the hose from expanding under pressure. Low-pressure coolant and breather lines need fewer plies; turbo and intercooler hoses that see boost need more. Tell your supplier the application and the maximum pressure the hose will see, and they can recommend the construction.
Step 6: Pick the right clamps
Use clamps sized for the hose OD, and avoid sharp-edged worm-drive clamps that can cut into silicone. Many buyers prefer hose kits supplied with matching clamps so there is no guesswork at installation.
Checklist before you order
- Pipe OD at both ends (mm)
- Shape and angle
- Leg lengths or total length
- Application: coolant, intake, boost, vacuum
- Color and any branding
- Quantity
Send this information — or simply a drawing, sample or photos — to our team and we will confirm the right specification. Request a quote.