Exhaust Wrap - Information
Information about exhaust wrap
- Exhaust wrapping
- Stainless steel cable ties
- Wrap exhaust manifold
- Wrap downpipe
- Change of color
- Smoke at start-up
- How much is needed?
Installing exhaust wrap is usually done on exhaust parts such as manifolds and exhaust pipes for cars, motorbikes, ATVs, and more to counteract radiant heat and keep the temperature in the engine compartment down. Apart from age, radiant heat is one of the biggest reasons why hoses and cables go bad. In addition, a manifold that does not have any heat protection raises the temperature in the engine compartment and nearby components and makes service of engine-related parts unbearable or impossible due to the high heat, even some time after the engine has been switched off.
An exhaust wrap solves all its problems and gives a nice look.
The material in exhaust wrap is usually based on fiberglass fabric, which is available in many variants. In addition, depending on the quality, the fabric is also treated in different ways and at various stages during manufacturing. These two points determine how good the quality of the exhaust wrap gets.
Installation can be done dry and wet, but a damp exhaust wrap is usually easier to install because you can stretch it out a little more so that it has a tighter fit when installed. However, when first starting up / warming up the exhaust wrap, it smokes a bit and works like laying a plaster. This is because the fibers in the wrap "harden" and stay in place well, but if you have to dismantle it, it breaks easily when the stiff fibers break in the opposite direction. In other words, the exhaust wrap can be considered used when it has been wrapped and heated once. However, it is sometimes possible to use it again but then with an "overstretched" wrap as the fibers have already been stretched out once before.
Consumption of exhaust wrap can be easily calculated if you know what is to be wrapped and you are clear about how. Otherwise, many factors come into play to get a sensible result, such as overlap, bends, stretch, extraction, etc. A roll of 10-15 meters is often enough for a "normal" manifold. The rule of thumb is to use 25mm width for the manifold and 50mm for the exhaust systemm eller för att säga det annorlunda, 25mm där skarpa böjar förekommer och 50mm på raka rör eller med svaga böjar.
Stainless steel cable ties
Stainless steel cable ties are used when installing the exhaust manifold. There are two known steel cable ties: stepless cable ties and cable ties with a click function. These cable ties are available in different lengths and widths.
The stepless cable ties work precisely as they sound. They are tightened steplessly and pinched in place.
The stainless cable ties with the click function are easy to assemble and have about 1mm between each step/click, so it is almost "stepless."
Which cable tie you choose is of no great importance but is a matter of taste.
When attaching the exhaust wrap with stainless steel cable ties, wrap one lap, then lock it with a cable tie. This tie is then covered over, and the exhaust wrap can be locked in place every 10cm. The last cable tie will be visible at the end of the winding. If it is a long stretch to be wrapped or very tight bends, several stainless steel cable ties can be used with advantage as this only gives a better result, and the exhaust wrap is held in place better.
Wrap exhaust manifold
Exhaust wraps are usually wound on manifolds and so-called extractor manifolds where the manifold is not cast but is made up of pipe parts. It is generally made up of tight bends, so a 25mm (1") exhaust wrap is easier to work with and gets a good result than a 50mm (2"). But, first, it is radiant heat from the manifold that you want to get rid of as this heats the entire engine compartment and can damage nearby parts such as hoses from the turbo and cables pulled nearby.
Wrapping exhaust systems with exhaust wrap is done for the same reason as manifolds, as you want to lower the temperature in the engine compartment and prevent radiant heat from aging and damaging nearby hoses and wiring. When winding a downpipe, a 50mm (2") exhaust wrap is usually used as there are typically extended bends, and broader exhaust wraps provide a more durable installation as fewer revolutions on the same stretch are used compared to a narrower exhaust wrap.
Change of color
An exhaust wrap is black or yellowish when new due to the mix of materials it is. When these get hot, and the fibers solidify, the color also changes. It becomes lighter / whitish and can vary depending on where it has been the hottest. This is normal and applies to all types of exhaust wraps that should insulate the heat.
Smoke at start-upA new exhaust wrap is treated to be flexible and not collect as much dust. This facilitates installation. When you start the car for the first time, the wrap fibers burn-in and begin to smoke. Therefore, stand with the engine hood open outdoors or in a well-ventilated area when starting up.
How much is needed?
Exhaust wraps are often sold in rolls of around 15 meters, so we take that as an example. The examples are with 50% overlap, as straight parts often have less overlap and bends have more overlap.
50mm wide exhaust wrap with 50% overlap
2" pipe is enough for about 2.3 meters
2.5" pipe is enough for about 1.8 meters
3" pipe is enough for about 1.5 meters
3.5" pipe is enough for about 1.4 meters
4" pipe is enough for about 1.2 meters
25mm wide exhaust wrap with 50% overlap
1.67" (42.4mm) pipe is enough for about 1.4 meters
1.9" (48.3mm) pipe is enough for about 1.2 meters
2" (51mm) pipe is enough for about 1.15 meters
2.12" (54mm) pipe is enough for about 1.1 meters
2.36" (60mm) pipe is enough for about 1 meter
2.5" (63mm) pipe is enough for about 0.95 meters
More overlap = more heat protection = more consumption = better durability
Anything from 25% to 75% overlap is used when an exhaust wrap is clad.
Whether 25, 50, or 75% overlap is used on a straight pipe does not matter as much as in a bend. If you want to insulate the tube more, use a 75% overlap. If you're going to minimize consumption, use a 25% overlap.
The overlap outside of the pipe bend is what determines how a bend is wound. For the winding not to be too thick, approx. 25% overlap is used on the outside of the bend; thus, the inside overlap is automatically determined by the angle of the bend.