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Should I Coat or Wrap My Exhaust?

Ending the debate of High Temp Coatings Vs Exhaust Heat Wrap

Contributed by: Enginebasics.com

We received a question recently from a reader asking us the question of “if he should have his headers hi temp coated or he should wrap them in a high temp exhaust wrap?”  We thought this would be an excellent time to write an article explaining which one is better, and why coating your exhaust components like headers, downpipes, and turbo turbine housings is a good thing.

Why you should consider coating or wrapping your hot parts?

We all know that engines get quit hot.  Take your car or truck on a spirited drive and pop the hood afterward.  You will be smacked right in the face with a blast of hot air from the engine compartment.  The real question is, does this matter?  Well, the answer is yes and here is why.

Increased efficiency from the radiator, oil cooler, transmission cooler

Engines have a specific temperature range where they are most efficient.  Most engines like to operate between 180 degrees F and 205 degrees F.  While they do operate at colder and warmer temperatures, this is the ideal range of operation.  If we do a better job of keeping the heat of the engine in the exhaust manifold, downpipes, headers, and so on, than we can have that exhaust escaping out the back of our exhaust pipe instead of escaping into our engine compartment.  By removing excess heat from under the hood we will allow our car or trucks radiator to not have to remove as much heat from the engine.  This is also true for oil coolers and transmission coolers as well.  By keeping the engine in an environment that is cooler, we can bring our operating temperatures down much easier.

Better Exhaust flow

When you coat or wrap your exhaust, not only are you keeping the heat inside the exhaust so that it exists out of the vehicle, but you are also increasing the flow of that exhaust.  By keeping the exhaust gas heat in the exhaust gas itself, it will keep the exhaust moving at a high velocity.  As the hot exhaust gasses cool, their velocity actually slows and you loose flow.  So not only is coating your exhaust good for under hood temps, but it also has a power benefit as it helps increase exhaust flow.

Exhaust coating and wrapping adds horsepower and torque

It’s true.  We know that cold air is denser air, and the more air we can shove into the motor the more horsepower and torque we can make.  By keeping our under hood temps down, we are able to keep our intake tract and potentially our intake manifold cooler.  This allows us to shove denser cool air into the motor.  Also with the exhaust retaining its heat/energy, it will have a higher velocity and flow better.  This also helps us make more horsepower and torque.

Does wrapping a turbo header and turbo blanket decrease turbo lag?

Yes.  A turbos ability to “spool up” and produce boost is based on its ability to extract the hot exhausts energy and spin up its turbine wheel.  The more energy/heat you can keep in the turbo exhaust header, the more energy you will have to spin the turbo up.  On large turbo set-ups, owners have reported an increase in spool by wrapping or coating the manifold and the turbo turbine housing.

On a dyno it is easy to see the importance of heat retention.  When you do the first dyno pull on a car and establish where the car makes full boost, you will notice that if you do several pulls immediately afterward, that the car will make full boost even faster.  This is because you have now built up a bunch of heat into the manifold and turbo.  Because of this built up heat/energy, the exhaust gasses will loose their heat much slower allowing all of that energy to be spooling the turbo.  By wrapping or coating your exhaust, you will essentially be doing the same thing by helping to trap that heat in the exhaust flow.

Turbo Blankets.  Again, anything you can do to keep the exhaust heat from escaping will help not only the under hood temps, but the boost response as well.  Anyone that has seen a turbo car on an engine dyno knows that a turbochargers turbine housing can get so hot that it glows orange.  In fact the whole turbo header can get that way, but you will notice that the turbine housing glows first.  This means that there is a TON of heat located there.  If we are able to retain that heat in the turbine housing than we will be able to drive that energy towards our turbine wheel much better.

Should I hi-temp coat my exhaust or heat wrap it?

Yes.  No really the answer is yes, because both of them are great.  If someone was going for maximum heat retention and performance than doing a hi grade coating and exhaust wrapping would be best.  You would get the benefits of a coating as well as an exhaust wrap. 

Are their any negatives to coating an exhaust?

Yes.  The coating cannot be welded on, so if you have a manifold or downpipe coated and it cracks and needs repair, than repairing becomes a lot more difficult.  If the manifold or pipe has been coated not only on the outside, but the inside as well it can make it almost impossible to repair since it is very difficult to get the coating inside off to do a full penetration weld. 

Are their any negatives to wrapping an exhaust?

Yes.  When wrapping an exhaust you have to be very careful that you are wrapping the exhaust as tight as possible.  Because of the constant heating up and cooling down of the pipe, the wrap can work its way loose over time and loose its effectiveness.  If the wrap job is done properly (so every 8-12” re-enforced with a stainless ziptie to keep it tight) than it will do fine.

The other negative is getting the wrap wet.  If the exhaust wrap is wet it can trap moisture and cause rust problems on the exhaust.  For this reason we strongly suggest that you are wrapping stainless steel exhausts, and also not wrapping the exhaust down under the car where it has the potential to get wet if the car or truck is driven daily. Hopefully on a performance car or truck your using at a minimum stainless 304 for all your exhaust needs.  If you are doing an all out build and don’t want to worry about cracking or exhaust performance, than putting up the money for stainless 321 is a great choice.

Last, high temp exhaust wrap is AMAZINGLY effective.  So effective in fact that it can trap so much heat in the exhaust that it can cause cracking of the pipes or tubes if not properly welded or stressed.  If you have a cheap knock off manifold or exhaust piping, than I would not spend the money for wrap or coatings.  I would first start by getting a quality made exhaust or manifold.  You will see many people that won’t wrap their exhausts because it “caused the manifold to crack”.  Understand that a properly designed and welded manifold should be able to handle the heat, and if the part is cracking because of wrapping it, than there already was a quality issue with the part.

Which one is better, high temp exhaust wrap or coatings?

If you had to choose just one than high temp exhaust wrap is hands down the clear winner.  Even on the most expensive hi temp coatings on the market today you would never reach in a grab the exhaust manifold on the dyno.  That would be asking for severe burns and a nasty smell of skin.  On the other hand, you can see videos all over the Internet of owners grabbing their exhaust headers that are hi temp wrapped with a good hi quality exhaust wrap.  As more proof, place your hand next to a manifold or turbine housing that has been hi temperature coated and you will still feel heat radiating off.  Now do the same test with an exhaust manifold or turbine housing that is wrapped or has a turbo blanket and you can barely notice much heat radiating off at all. 

Which high temp exhaust wrap is good quality?

DEI seems to be one of the leaders in heat control and their lava wrap exhaust wrap and turbo blankets do not disappoint. 

They are very easy to use and don’t cause irritation and cut into skin like some of the old fiberglass wraps.  Please don’t cheap out when it comes to wrapping something as hot as an exhaust.  These wraps are already very affordable as is, so there is no reason to risk a fire hazard by choosing an inferior product. 

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