The term “turbo blanket” seems almost oxymoronic the first time you hear it. If you know anything about turbos, you know that they use wasted exhaust gases to turn a turbine which spins another turbine connected to it via a shaft to produce boost. But in this process, exhaust temperatures get extremely high as back pressure caused by the turbine in the exhaust stream causes a restriction. More restriction, more heat.
So why would you want to put a blanket on something that is already incredibly hot? For the answers, we turned to the guys over at Design Engineering, Inc (DEI) to give us the low down on why every turbo out there should be using one.
Is It Getting Hot In Here?
So, first things first. Why would anyone us a turbo blanket in the first place? “Blankets keep the heat in to save engine components and add to their life (and your hood paint), help with faster spool up times on larger framed turbos, protect the racers who use them when they need to work in the engine bay between runs, and they improve the looks in the engine compartment,” said Dan Stark of DEI. “Think of all the rubber products under the hood and how they can dry out and become damaged by long-term heat. This can all be prevented by wrapping your pipes and by using a turbo shield or blanket.”
In essence, there is relatively no reason not to use them. But how does making something that’s already hot, hotter help with spool times as Dan mentioned before? Well, that has a lot to do with thermal dynamics and the process that is occurring to spin the turbocharger.
“Hotter gasses flow easier and this helps the engine when the turbine housing is insulated,” Dan explained. “This helps with exhaust scavenging and it helps with getting the exhaust out of the pipes easier due to the hot gasses moving easier than cold dense gases.”
On top of the improved scavenging effects of hotter exhaust gasses, keeping the energy in the exhaust pipes and turbine housing until they reach the turbine means that the heat energy is being directly transferred to the wheel sitting in the exhaust stream, instead of to the air as ambient heat. In essence, heat wraps and turbo blankets ensure that as much energy as possible is reaching the turbine.
As you may know, hot gases expand. The hotter the gases, the more they expand. Thus the more heat you can keep in the exhaust, the better the thermal efficiency of the turbo since it’s that very expansion that’s spinning the turbo and creating boost on the other side. An added bonus to this improved efficiency is cooler temperatures under the hood. As Dan mentioned earlier, this can not only degrade other components under the hood, but that heat can be transferred to charge pipes heating the air charge as it moves from the intercooler to the engine, thus reducing the efficiency of your intercooler and resulting in increased intake air temperatures (IATs).
Built for Success
Taking into consideration just how hot the turbo and exhaust pipes are getting, what ever sits on them —especially in a turbocharged vehicle — has to be pretty heat resistant. We’re talking temperate up to 1,300 degrees Farrenheight! Needless to say, this is not one area you want to cheap out on. Materials not rated for the proper heat index could actually catch fire and burn your build to the ground. That’s why DEI uses proprietary materials to manufacturer all of their heat wraps and turbo blankets, just like the one we used on Project Corn Star.
“Our shields are made from high-grade materials that are rated well over the maximum temperatures a turbo will see,” Dan said. “Many of the shields on the lower price levels contain glass fibers. These are only rated for around 1,000 degrees F. Since turbo heat can go past that level, we offer a thick Silica pad to take the maximum heat levels and block the heat transfer. The inner layer that makes contact with the housing can also take over 2,000 degrees F of abuse. While our outer Titanium and Onyx material can also take the abuse of high heat, most of the heat is already held back by the core padding. This gives a great result and a durable product.”
Don’t Be a Fool, Wrap Your Spool
If improved efficiency, decreased under-hood temperatures, increased component life, and better looks aren’t enough to convince you that you probably need a turbo blanket, then we really don’t know what else to say. However, we’ve been running one on Project Corn Star for six months now and can personally attest to the lowered temperature and decreased spool times.
If you are in the market for one, check out what the guys over at DEI have to offer. Remember kids, respect your turbo and your turbo will respect you… and use protection.