Can exhaust wrap damage headers? Short answer: no. Correctly fitted exhaust wrap does not damage extractors or headers in normal use.

Two situations do cause damage, and you can prevent both. Moisture held against mild steel speeds up rust. Thin-wall headers under sustained extreme race heat can crack or fatigue. This guide explains both risks, how to avoid them, and when a heat shield or coating is the better choice. For materials and ratings, see the Kool Wrap exhaust heat wrap range.

Risk 1: Moisture and rust on mild steel

Exhaust wrap is a woven fibre, so it absorbs water. On a car you drive often, the exhaust gets hot enough to drive that water out.

The trouble comes when wrap stays damp for long stretches:

• A weekend car parked in a cold, damp shed
• A 4WD after a creek or river crossing
• A car that only does short trips, where the pipe never gets fully hot
• A boat, or a work vehicle hosed down every week

Wet wrap keeps bare mild steel damp, and rust takes hold faster than it would on an open pipe. You will not see it until rust stains come through the wrap or a hole opens up underneath.

If your 4WD crosses water often, check the wrap after each trip. Wrap that stays wet for days should come off, and the pipe should be dried, checked and re-wrapped.

Risk 2: Heat fatigue on thin-wall headers

Wrap keeps heat inside the pipe, so the pipe wall runs hotter than it would bare. On a street car, that is well within what the steel can handle.

Race use is different. Under sustained extreme heat, thin-wall headers can crack or fatigue. Kool Wrap cites endurance racing as the example, where the pipes run for hours at full load with no chance to cool.

Street cars, towing 4WDs and daily bikes do not see that kind of sustained load. If you run a track car, ask your header builder about wall thickness and material before you wrap.

For a sense of how hot pipes run in different setups, read how hot your exhaust gets.

Mild steel vs stainless steel headers

Stainless handles wrap better than mild steel on both counts.

If you are wrapping stainless headers on a street car, the main job is a clean pipe and a tidy fit. If you are wrapping mild steel, the paint step matters most.

How to prevent damage

1. Inspect the pipes first. Fix cracks, leaks and blown gaskets before they disappear under wrap.
2. Clean the pipe of oil, dirt and loose rust.
3. Coat mild steel with high-temperature exhaust paint and let it dry fully.
4. Fit the wrap dry, or only lightly dampened. If you dampen it, run the engine soon after so the heat dries the wrap out. Do not leave damp wrap sitting on the pipe.
5. Keep the overlap at about 6mm per turn. Heavy overlap builds thickness that holds more heat and more water.
6. Fit one layer. It is the standard fit in the Kool Wrap install guide, and extra layers build thickness that holds more heat and takes longer to dry.
7. Optionally seal the finished wrap with high-temperature exhaust paint to lock down loose fibres.
8. Leave O2 sensors and flex joints bare. Leave catalytic converters bare unless the vehicle maker allows wrapping them.
9. Re-wrap if the wrap stays wet or gets oil-stained.

Our step-by-step exhaust wrap install guide covers each of these in detail, including how much wrap to buy.

When to use a heat shield or coating instead

Wrap is not the only way to control exhaust heat. If moisture or sustained race heat is your bigger worry, consider these options.

Embossed semi-rigid heat shields

Embossed semi-rigid heat shields are multi-layer embossed aluminium panels. You fold and form them by hand and mount them with brackets or hose clamps. There is no adhesive. They cut radiant heat by up to 90%, and the panels are designed for up to 650°C. Because they are metal, they do not hold water against the pipe.

DCI exhaust pipe shields

These are pipe-specific shields rated at 600°C or 1,000°C. They suit 2in to 3in pipe, come in 300mm and 600mm lengths, and fit with hose band clamps. You trim them with tin snips. Undo the clamps and you can inspect the pipe underneath.

Ceramic coating

Some owners have their headers ceramic coated by a specialist coating shop. There is no fibre to hold moisture and the pipe stays visible for inspection. Kool Wrap does not offer a header coating service.

Which to choose

Inspection checklist

Check these at every service, or before each race meeting:

• Rust stains or orange streaks on the wrap
• Wrap that still feels damp days after the last drive
• Soot marks near joints, or a ticking sound on cold start that points to a leak
• Loose, broken or missing ties
• Oil-soaked, brittle or frayed wrap
• Wrap rubbing on the chassis, engine mounts or heat shields
• On race cars, cut back the wrap at welds and flanges between events and look at the metal

If the wrap shows wear, read how long exhaust wrap lasts for the signs that it is time to replace it.

Header damage FAQs

Can exhaust wrap damage headers?

Correctly fitted wrap does not damage headers in normal road use. Two situations do cause damage. Moisture held against bare mild steel speeds up rust, and thin-wall headers under sustained race heat can crack or fatigue. Painting mild steel before wrapping and keeping the wrap dry prevents the first. Talking to your header builder prevents the second.

Does exhaust wrap cause rust?

Wrap does not cause rust. Water does. Wrap absorbs water and holds it against the pipe, so bare mild steel rusts faster under damp wrap than it would in open air. Coat mild steel with high-temperature exhaust paint before you wrap and the problem largely goes away.

Is it safe to wrap stainless headers?

Yes. Stainless resists both of the risks better than mild steel. Clean off oil and dirt, then wrap as normal. You do not need to paint stainless first.

Will exhaust wrap crack my extractors?

Not on a street car. Cracking is a thin-wall, sustained-race-heat problem. If you run endurance or track events, check wall thickness with your header builder and inspect the metal at welds and flanges between meetings.

Should I wrap or use a heat shield?

Wrap goes on the pipe. A heat shield goes on the part you are protecting. If the problem is a hot floor, firewall or fuel tank, the shield does more. If the vehicle often sits wet, a semi-rigid shield avoids the moisture issue entirely. Plenty of builds use both.

Need help choosing?

Tell Kool Wrap what your headers are made of and how you use the vehicle, and we will help you choose between wrap, a shield or both. Call 1300 44 33 34, or compare wraps and ratings in the exhaust heat wrap range.

How to Install Exhaust Wrap: Step by Step

A good wrap job comes down to three things. A clean pipe, even tension and a consistent overlap. Get those right and the wrap stays tight, looks neat and lasts.

This guide shows you how to install exhaust wrap from start to finish, from working out how much to buy to what to expect on first start. It suits car extractors, dump pipes, 4WD exhaust sections and industrial pipe. Choose your material and roll size from the Kool Wrap exhaust heat wrap range before you start. Wrapping a bike? Our motorcycle exhaust wrap guide covers the bike-specific details.

Tools and materials

• Exhaust wrap in the right width and length
• Stainless steel locking ties. Rolls include 4, 6 or 10 ties, and you can buy more from the stainless steel ties range
• Gloves, long sleeves and safety glasses
• Degreaser, rags and a wire brush
• High-temperature exhaust paint for mild steel pipe
• Spray bottle of water (optional)
• Sharp scissors
• Pliers to pull ties tight, and side cutters to trim the tails
• Tape measure and marker
• Drop sheet to catch loose fibres

Set aside an unhurried afternoon for a four-cylinder extractor set on the bench, and longer if you are wrapping in place.

How much exhaust wrap do you need?

Use this formula:

Metres of wrap = metres of pipe x pipe circumference (mm) divided by (wrap width minus overlap, mm)

For round pipe, circumference is the diameter multiplied by 3.14. Then add about 10% for bends and tie-offs.

As an example, 1m of 50mm pipe with 50mm wrap at 6mm overlap needs about 3.7m of wrap. The table gives rounded figures per metre of pipe, all at 6mm overlap. They run slightly above the bare formula to allow for the wrap’s own thickness.

Worked example: four-cylinder extractors

Say your extractors have four 38mm primaries, each about 0.8m long. That is 3.2m of pipe. At 2.9m of 50mm wrap per metre, you need about 9.3m, or about 10.2m with 10% added. A 10m roll falls just short, so buy 15m. Measure your own pipes before you order.

Roll lengths available

• Standard fibreglass: 25mm and 50mm widths, in 4.5m, 7.5m, 10m and 15m rolls
• Vermiculite coated fibreglass: 50mm width, in 7.5m and 15m rolls
• Titanium basalt fibre: 25mm width in 4.5m and 10m rolls, 50mm width in 7.5m, 10m and 15m rolls

Choose the right width

Use 25mm wrap on pipes up to about 37mm (1.5in) diameter and 50mm wrap on anything larger. Narrow wrap follows tight bends more neatly, but the table shows it needs more than twice the length of 50mm wrap on the same pipe. The last row in the table shows what 25mm costs you on a 38mm pipe, which is why 50mm is the default at that size.

What not to wrap

Plan your start and finish points around these before you begin:

• O2 sensors and their bosses
• Flex joints, which need to move freely
• Catalytic converters, unless the vehicle maker allows wrapping them
• Anywhere wrap would rub on a mount, crossmember or chassis rail

How to install exhaust wrap

Prepare the pipe

1. Let the exhaust cool completely. Remove the pipes or extractors if you can. Wrapping on the bench is faster and neater.
2. Inspect the pipe for cracks, rust holes and blown gaskets. Fix them now, because wrap will hide them.
3. Clean off oil, dirt and loose rust with degreaser and a wire brush.
4. Coat mild steel pipe with high-temperature exhaust paint and let it dry. Stainless pipe only needs to be clean.

Wrap the pipe

1. Dampen the wrap if you like. Kool Wrap wraps do not need wetting, but a light spray makes the wrap easier to pull tight and keeps loose fibres down. Soaking is optional. If you dampen it, run the engine soon after so the heat dries the wrap out. Do not leave damp wrap sitting on the pipe. Gloves and long sleeves go on now, because fibreglass fibres irritate skin.
2. Start at the narrowest end of the pipe. Fold the first few centimetres of wrap back on itself, lay it on the pipe and lock the fold under the first turn. The cut end stays hidden and cannot fray.
3. Wind the wrap with firm, even tension and about 6mm overlap per turn. Kool Wrap’s guide allows 5 to 8mm. On bends, the inside of the bend overlaps more on its own. Keep the outside of the bend fully covered with no gaps.
4. When you reach the finish point, trim the wrap and hold the end tight while you fit the tie. On extractors, wrap each primary separately and stop short of the flanges so you can still reach the gaskets and bolts.

Secure it

1. Fit a stainless steel tie at the start and the finish. Pull each one tight with pliers, then trim or fold the tail so it cannot snag. For extractors, a four-cylinder set needs about 4 to 8 x 200mm ties plus 1 x 400mm tie. Double that for a V8.

Finish and refit

1. Seal the wrap with high-temperature exhaust paint (optional). This locks down loose surface fibres. Kool Wrap’s heat proof paint range includes a silica ceramic exhaust spray paint rated 704 to 1,093°C.
2. Refit the pipes. Wrap adds thickness, so check clearance to chassis rails, mounts, steering, wiring, fuel lines and heat shields.

How to wrap exhaust headers and extractors

Headers need a bit more planning than a straight section of pipe. If you are wrapping headers, use the same basic process as any exhaust header wrap installation, but pay particular attention to the bends, flanges and collector.

• Wrap each primary on its own, starting at the head end, which is the narrowest, and working out towards the collector.
• Stop short of the head flange. You want to reach the gaskets and bolts without cutting wrap off.
• At the collector, tie off each primary before you start on the collector itself.
• Tight bends are where gaps appear. Pull the outside of the bend tight, let the inside gather, and check for daylight before you move on.
• On a V8, do one bank completely before you start the other. It is easier to copy a finished side than to remember what you did.

This approach works whether you call it header wrap, header heat wrap, heat wrap for headers or exhaust header heat wrap. The important part is consistent tension and coverage.

First start: why exhaust wrap smokes

Expect light smoke and a smell the first time the wrap gets hot. Makers use binders and starches to hold the fibres in their woven pattern. Heat burns them off, and the smoke clears after the first few heat cycles. It does not harm the wrap or the pipe.

To get through it cleanly:

• Do the first start outdoors, or with the shed door open.
• Idle the engine, then take a gentle drive. Let it cool and repeat.
• Keep anything flammable away from the exhaust during the first run.

Look further if smoke continues after several heat cycles, smells of burnt oil or fuel, or comes from one spot. That points to oil or fuel on the wrap, or an exhaust leak. Find the source before you keep driving.

A new turbo blanket smokes on its first heat cycle for the same reason. See how to fit a turbo blanket for blanket-specific steps.

Final checks

• Ties tight, with tails trimmed or folded away
• No gaps on the outside of bends
• O2 sensors, flex joints and catalytic converter left bare
• Clearance to wiring, fuel lines and brake lines
• Ties rechecked after the first few drives, once the wrap has settled

Note the date you fitted the wrap. Quality wraps typically last 2 to 5 years, and our guide to how long exhaust wrap lasts lists the signs it is due. To protect the pipe underneath, read whether exhaust wrap can damage extractors.

Exhaust wrap installation FAQs

How much exhaust wrap do I need?

Multiply the pipe length in metres by the pipe circumference in millimetres, then divide by the wrap width minus the overlap. One metre of 50mm pipe wrapped with 50mm wrap at 6mm overlap needs about 3.7m. Add about 10% for bends and tie-offs. A four-cylinder set with 38mm primaries about 0.8m long works out near 10.2m, so a 15m roll is the safe buy.

How long should you soak exhaust wrap?

You do not have to soak it at all. Kool Wrap exhaust wrap does not need wetting. Some installers give it a light spray because damp wrap pulls tighter and sheds fewer fibres. If you do dampen it, run the engine soon after so the heat dries it out, and never leave damp wrap sitting on the pipe.

How much overlap should exhaust wrap have?

About 6mm per turn. Kool Wrap’s install guide allows 5 to 8mm. More overlap than that builds thickness, holds more heat against the pipe wall and holds more water.

Do you wrap from the top or the bottom of the pipe?

Start at the narrowest end, which is usually the head end on a header and the front on a straight section. Fold the first few centimetres back on itself and lock that fold under your first turn so the cut end cannot fray.

Can you install exhaust wrap without removing the exhaust?

You can, and plenty of people do on a hoist. It takes longer, the tension is harder to keep even, and you cannot inspect the far side of the pipe. Take the pipes off if the job allows it.

Why does new exhaust wrap smoke?

Binders in the wrap burn off during the first heat cycles. Light smoke and a smell are normal and clear after the first few runs. Smoke that keeps going, or smells of oil or fuel, means contamination or an exhaust leak.

Need help choosing?

Not sure how much wrap your system needs? Send Kool Wrap your pipe sizes and lengths, or call 1300 44 33 34. Wraps, ties and paint are all in the exhaust heat wrap range and related categories.

Motorcycle Exhaust Wrap: Why, Which Wrap and How to Fit It

On many bikes the headers run right past your leg, boot and side covers. Motorcycle exhaust wrap cuts the heat that radiates off those pipes. You feel less of it at the lights, nearby plastics and wiring run cooler, and the bike gets the wrapped look plenty of riders are after.

This guide covers why riders wrap, the pros and cons, which wrap and colour to pick, how much to buy and a seven-step fitting method. You will find every material and roll size in the Kool Wrap exhaust heat wrap range.

Why riders wrap their exhaust

• Leg and boot heat. A wrapped header radiates less heat onto your leg, which you notice most in slow traffic on a hot day.
• Fairing and side cover heat. Plastics and painted panels near the headers see less radiant heat.
• Nearby parts. Wiring, sensor leads, hoses and fuel lines routed near the pipe run cooler.
• Looks. Wrap comes in black, white, natural and graphite black finishes.

Pros and cons of bike exhaust wrap

Two points matter more on a bike than a car. First, bikes get wet. Rain, washing and dew all soak into wrap. After a wet ride or a wash, ride long enough to get the pipes fully hot and dry the wrap out. Second, wrap is not a burn guard. The outer surface still gets hot enough to burn skin, so do not rely on it to protect a pillion’s leg or a child’s calf.

Which wrap and which colour

Standard fibreglass

Standard fibreglass exhaust wrap is rated to 540°C continuous and 980°C intermittent. It comes in black, white and natural (light tan) at 1.5mm thick, in 25mm and 50mm widths. It is a good fit for road bikes that see normal riding.

Vermiculite coated fibreglass

Rated to 650°C continuous and 1,090°C intermittent, in graphite black. It comes in 50mm width only, so it suits bikes with larger pipes.

Titanium basalt fibre

Titanium basalt fibre exhaust wrap is rated to 980°C continuous, the highest in the range. It comes in natural and black, with 25mm rolls in 4.5m and 10m for pipes up to about 37mm, and 50mm rolls in 7.5m, 10m and 15m for larger headers. Choose it for high-performance bikes and track use.

Picking a colour

Black suits blacked-out and dark bikes. Natural gives a classic, retro look. White looks sharp when new but shows road grime and oil quickly.

Picking a width

Use 25mm wrap on pipes up to about 37mm (1.5in) diameter and 50mm on larger pipes. Narrow wrap follows tight header bends more neatly.

How much exhaust wrap for a motorcycle

Measure the length and diameter of each pipe you plan to wrap. Then use the wrap formula in our step-by-step exhaust wrap install guide and add about 10% for bends and tie-offs.

Here is how that works on a bike with 38mm headers, each about 1m long. At 38mm the pipe is just over the 37mm boundary, so 50mm wrap is the default.

Smaller pipes at or under about 37mm take 25mm wrap, which follows tight bends more neatly. It uses a lot more of it, roughly 7m per metre of pipe against 3.2m for 50mm, so budget for that if you choose the narrow wrap.

Roll lengths differ by material. Standard fibreglass has a 4.5m option, while vermiculite and 50mm titanium start at 7.5m. Measure the length and diameter of your own pipes before you order, because header runs vary a lot between bikes.

Allow at least two stainless ties per pipe, one at each end. Rolls include ties, and you can buy extra from the stainless steel ties range.

How to fit motorcycle exhaust wrap in 7 steps

1. Remove the headers. Let the bike cool completely, then undo the header nuts and hangers and take the pipes off. Wrapping on the bench is far neater than wrapping on the bike. If your bike has an O2 sensor in the header, remove it or mask the boss so you can leave that area bare.
2. Clean and paint. Degrease the pipes and wire brush any loose rust. Coat mild steel pipe with high-temperature exhaust paint and let it dry. Stainless pipe only needs to be clean.
3. Prepare the wrap and plan the route. Put on gloves and long sleeves. Dampening is optional, since Kool Wrap wraps do not need wetting, but a light spray makes the wrap easier to pull tight and keeps fibres down. If you dampen it, run the engine soon after so the heat dries the wrap out. Do not leave damp wrap sitting on the pipe. Mark where hangers and brackets sit so you know where to stop and restart.
4. Start at the narrowest end of the pipe. Fold the first few centimetres of wrap back on itself and lock the fold under the first turn. The cut end stays hidden and will not fray.
5. Wrap with even tension and about 6mm overlap. Pull firmly on every turn. Keep the outside of each bend fully covered. At a bracket or hanger, tie off on one side and restart on the other.
6. Tie off with stainless ties. Fit a tie at every start and finish point and pull it tight with pliers. Turn the lock to the back of the pipe, away from your boot, and trim the tail. Optionally seal the wrap with high-temperature exhaust paint to lock down loose fibres.
7. Refit and heat cycle. Refit the headers, using new exhaust gaskets if the old ones are crushed. Check the wrap clears fairings, side covers, the frame and the rear brake. Start the bike outdoors. Light smoke and a smell on the first ride are normal as binders in the wrap burn off, and they clear after the first few heat cycles. Recheck the ties after the first few rides.

Smoke that continues after that, or smells of oil or fuel, points to contamination or a leak. Find the source before you ride on.

Heat shields and heat sleeves near wiring

Wrap works on the pipe. For parts that sit close to it, use a product made for the part.

• Heat sleeves protect wiring, sensor leads, hoses and fuel lines. They come in open seam and closed seam versions, so check the product pages for the one that suits your loom.
• Fibreglass-backed aluminium tape suits the inside of motorcycle fairings. It reflects 95% of radiant heat and withstands up to 454°C radiant heat. Stick it on the panel, never on the pipe.
• Adhesive heat shields cover larger panels near the headers. Never stick an adhesive shield directly onto an exhaust pipe.

Motorcycle exhaust wrap FAQs

What does exhaust wrap do on a motorcycle?

It keeps heat inside the header instead of letting it radiate onto your leg, your boot and the panels around the pipe. Riders notice the difference most in slow traffic on a hot day. It also keeps wiring, sensor leads and fuel lines routed near the pipe cooler.

Why wrap a motorcycle exhaust?

Three reasons. Leg and boot heat in traffic, protecting plastics and wiring that sit close to the headers, and the wrapped look. On a bike the first reason is the one most riders act on.

How much exhaust wrap do I need for a motorcycle?

On typical 38mm headers about 1m long, allow around 3.2m of 50mm wrap per pipe once you add 10% for bends. A single cylinder takes a 4.5m roll, a twin about 6.4m and an inline four about 12.8m. Narrow 25mm wrap on smaller pipes needs roughly double that length. Measure your own pipes before you order.

How do you install exhaust wrap on a motorcycle?

Take the headers off, clean and paint mild steel, then start at the narrowest end with the first few centimetres folded back under the first turn. Wrap with even tension and about 6mm overlap, tie off with stainless ties at each end, and refit with fresh gaskets. Expect light smoke on the first ride.

Does motorcycle exhaust wrap cause rust?

Wrap does not cause rust, but it holds water against the pipe, and bikes get wet. On bare mild steel that speeds up rust. Paint mild steel headers with high-temperature exhaust paint before wrapping, and after a wet ride or a wash, ride long enough to dry the wrap out.

Will exhaust wrap stop my leg getting burnt?

No. Wrap lowers the radiant heat you feel from the pipe, but the outer surface still gets hot enough to burn skin on contact. Treat a wrapped pipe exactly like a bare one, and do not rely on it to protect a pillion.

Need help choosing?

Want to check how much wrap your bike needs, or which colour and width suit your pipes? Call Kool Wrap on 1300 44 33 34. For car and 4WD systems, and the full calculation method, see the step-by-step exhaust wrap install guide. Rolls, ties and paint are in the exhaust heat wrap range.