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Hey all, I was just curious on what the deal is with turbo blankets and exhaust wraps. I don't have them on my engines and doubt I even need them, but I like to learn as much as I can about marine diesels. Thanks

You may need them if the turbo exhaust is near the box top.
They usually are. Sometimes too close, due to space scarcity.

If you cannot find or do not want to pay for exorbitantly priced turbo blankets, make your own by wrapping the exhaust with that white fire repellant fabric and securing it in place with thin, very thin, cable.

It lasts forever.

Turbos-

Turbos that are cooled with the motors antifreeze/coolant do not need Turbo Blankets.

Turbos not cooled run so hot they can start a fire so a heat protective blanket in put on to contain the heat.



Exhaust
Stock exhaust is usually setup with an exhaust elbow. This elbow is a tube within a tube. The inner tube is where the hot exhaust travels. The outer "jacket" is cooled by the seawater. It flows in at the top, flows around the inner pipe and ejected in a spray around the exhaust at the end of the elbow. The water cools the exhaust enough so as not to burn the exhaust hose. This system does not have the outer pipe get ht enough to burn anything.
Down side here is that is that outer jacket with salt water corrodes through the inner pipe, water could make it way back t the turbo. to the motor...not good.


Sometimes the turbo outlet is too close to the waterline...that could allow water back up into motor...not good. So a custom exhaust pipe is made to raise the motors exhaust outlet higher. This is often done without the aid of a a cooling outer jacket as if the inner tube developed a leak it is almost a guarantee the water is going back into the motor. So that single dry section of pipe can get red hot...for that reason the pipe needs to be insulated not to cause a fire. Hence...heat wrap or heat blanket.

Thanks Carl. Like I said I just like learn everything I can.

I hear you...always good to get familiar with everything you can.

Lots of great info here so ask away and please share were you can.

...and if you wondered why turbos and exhaust pipe in cars and truck do not need to be covered with wraps or blankets its because the vehicles engine bays have a ton of air being pushed through them when moving, where in a boat they sit is a covered hole surrounded by fiberglass, wood and...

Although vehicles do have heat shields and deflectors in various spots.

My DD 8.2s are over the road motors marinized by J&T--referred to by Capt. Pat as "junk and trash." They have dry turbos and exhaust blankets. The turbos are mounted high on the motors (like most) and are thus right under the engine box. The turbos get pretty hot, but you can put your hand on the blankets