QSM11 Ceramic Coating of Exhaust Manifold

[Will]

On the QSM11 Dry Exhaust manifold, is there any reason not to have the exterior portions of the exhaust manifold and exhaust side of the turbo coated w/ JetHot’s extreme heat 2500 degree ceramic coating to help push that heat on out of the exhaust system into the mixer instead of so much heat staying in the engine compartment?

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[Steve]

I wonder why this wasn’t thought of initially? Money, perhaps? Ceramic coating exhaust systems is very common in the motorcycle world when trying to manage heat. Especially on air cooled engines like those found in Harley Davidson’s. But ceramic coating is also used in automobile exhausts, too. The thing these two applications have in common with the QSM11 is that they are all dry exhausts. I can’t imagine that ceramic coating these manifolds would not have lessened the problems that occurred from excessive heat in the exhaust and allowing them to get more power out of the engine, safely?

And while ceramic coating isn’t cheap, it’s far less than the cost of replacing or rebuilding these engines. But cheaper still ( for Cummins) is not doing anything at all. Surely ceramic coating would be a lot less expensive for Cummins than designing in a new wet exhaust system?

[Tony Athens]

Removed 4.5″ of pitch? Now that is a very positive move in reducing EGT.. Meaning all the temps inside are would be measurably less

Got before & after numbers on the EGT?

If the super-high tech extra coating retains more heat in the manifolds, then would that be an extra layer of insulation (correct) , or did you remove factory shields?

As to all the rest– To me all sounds really is good..

Tony

[Will]

Well, for what its worth, I decided to try some things after reading about what all hasn’t worked on this forum and other forums before I put new manifolds on it which I plan to do eventually anyway. I just had the jethot 2500 ceramic put on the exhaust manifolds and exhaust side of the turbos on twin qsm11s (Had the manifolds machined true in a jig) and put back on w/ Remflex gaskets, and some custom heat shields I had made from a specialty shop — so far I’m not certain the heat shields are even needed w/ the ceramic coating on there, but then you wouldn’t get to buy a 2 set of $1100 each Cummins heat shields every few years. I took 4.5″ of pitch out of the props based on your articles and by getting feedback from others w/ the same boat. We are still sorting out a few voltage and gauge issues and other things so have not spent much time above 1100 rpms so far, but heated up more than enough to set the fuchs 762 on the turbo-to-riser connections. After running a few hours you can still get right up on those exhaust manifolds w/ your hands and w/ very little radiant heat. I did bring it up to about 2100-2200 rpms last test run and kept it there a few minutes, jumped 40,000lbs up on the plane to 35mph w/ some throttle left, still almost no heat coming from exhaust or turbo, so at this point I disagree with you about helping with the heat in the engine room. I do agree the engine compartment needs more ventilation and we are ciphering on the best way to handle that.
I posted a separate question about how long would one expect it to take for a slip joint to “soot”/seal up. I got some soot initially but it is difficult to tell where it came from and seems that it may have quit. Just haven’t been able to get the boat back out in decent conditions to run it longer and harder. We’re going to clean it up and do some more test runs to look for exhaust leaks, but unless there’s a reason not to ceramic coat those manifolds and exhaust side of the turbos, I’m a believer at this point and would be inclined to ceramic coat new manifolds when I get them. I’ll keep you posted. Thanks for the reply, And thanks for the help with the Aftercoolers and Heat Exchangers a few months back, y’all were great.

[Tony Athens]

QSM Dry manifolds & heat

I do not think doing that will help the heat in your in your engine room-The factory heat shield does a good job that way ( maybe too good)…That why they “cook” under the heat shields–The system sucks for a “marine engine”…….. IMO, you need to increase positive cool/dry air flow to the engine room to help that..

Tony

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