Slideshow: Do You Need a Turbo Blanket?
Are turbo blankets just racer stuff, or can they prove useful on a street-driven vehicle as well? And are they strictly for preventing fires, or can they help engines pump out more power? Engineering Explained and the University of Texas help us answer those questions and more.
Boogie Blanket
If you think about your turbo(s) at all it's probably either to: 1) fret repairs because something broke or, 2) ponder how you can use it to make your vehicle faster. You may have noticed something wrapped around turbos in photos showing modified and/or competition cars, which fits case number 2, but are they of any use on a bone-stock commuter? And what about case number 1? Will swaddling your turbo in a cloak incur more frequent or expensive repairs? With the help of Engineering Explained and a study done at the University of Texas, we'll look at what's going on with those turbo blankets, and whether they should be on your shopping list.
The turbo blankets on the market can be made from a variety of different materials including heat-resistant fabric, flexible metal forms, and even volcanic minerals. They wrap around the exhaust sides of turbochargers, can be easily installed by even a novice, and are designed to contain heat inside of the turbo rather than letting it dissipate under your ride's hood. But why would you want that?
Protection
The first and most obvious answer is that covering the turbo's super hot turbine protects the other engine components around it. Road and Track tells the story of automotive YouTuber Rob Dahm's three-rotor turbo RX-7—Dahm measured temperatures as high as 760 degrees Fahrenheit coming from his brightly-glowing turbo. Without the use of a turbo blanket, the paint on his hood wouldn't have survived, never mind the toll that kind of temps could take underneath it.
>>Join the conversation about turbo blankets right here on LS1Tech.
Feel the Burn
Jason Fenske of Engineering Explained and his fellow YouTuber Humble Mechanic used Humble's VW GTI, which put out an 'average' of 12 PSI of boost, as a testbed for their experiments. They used 4 sensors hooked up to a data logger to record results with and without a turbo blanket, and they found average temperature drops with the blanket in place of 12.7 degrees Celsius at the turbo's oil line, 14.9 degrees C at the turbo's coolant line, 3.4 degrees C at the air intake point, and 6 degrees C near the turbo's exhaust outlet. Their measurements were conducted on a below-freezing day, so the temperature drop in the footwell of the car wasn't quite as welcome since the GTI didn't have a functioning heater at the time.
They also borrowed a $50,000 Flir thermal imaging camera to produce the image you see here.
>>Join the conversation about turbo blankets right here on LS1Tech.
Pressure and Boost
The study conducted at the University of Texas used a 6.7-liter Cummins diesel engine hooked up to a dynamometer. Like the Engineering Explained guys, the study measured temperatures too, but in seven locations and using thermocouples rather than probes, with several of them underneath the blanket rather than outside of it. The study, which made no other changes, tuning or otherwise, other than the use of the blanket, found much hotter temperatures at and in the turbo, and at the exhaust exit pipe, with the blanket in place. More heat inside the turbo meant higher pressures, which meant faster turbo shaft speeds, which resulted in more boost.
>>Join the conversation about turbo blankets right here on LS1Tech.
Spooling Up
The U.T. test measured the differences in turbo performance during something they called "instantaneous load tip-in scenarios" which translates to instances of hard acceleration. The study showed that, at both low and higher rpm, the blanket-equipped turbo had a 200-250 rpm advantage after tip-in over the non-blanketed turbo, translating to 3-4 psi more boost at the same point in time after tip-in was initiated (after the pedal was put to the metal). On their Cummins engine, this added up to more than a 10 percent increase in torque—yielding as much as 100 lb-feet more. The test also found that peak power levels were virtually unchanged. The made power faster with the blanket, with less lag, but not greater maximum power.
>>Join the conversation about turbo blankets right here on LS1Tech.
Cooking with Oil
Critically, both the Engineering Explained test and the U.T. test found virtually no change in turbo exit oil temperature. In the words of the U.T. study: "Oil 'coking' was not a concern since the temperature difference of the oil with and without the turbo blanket was negligibly small." Humble Mechanic mentioned that, yes, if a turbo is run hard and shut off fast with a turbo blanket on, oil degradation could in fact occur, but that good turbo practice already dictates a proper cool-down period after any hard use.
>>Join the conversation about turbo blankets right here on LS1Tech.
Blanket is the new Black
So, back to our original questions. Does a turbo blanket improve performance? Yes. Even on a stock daily driver? Yes. Will it hurt reliability? Well, it will still oil properly and keeps under-hood temps down. With practically no downside, turbo blankets might just be the exhaust-side version of a cold air intake. The only cost we could think of is monetary. You know what they say: free power isn't free.
>>Join the conversation about turbo blankets right here on LS1Tech.
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