Exhaust Heat wrap

[Rick Kral]

I am building a custom exhaust for both my diesel engines. I was hopeful one of the engine savy faithful had some input/experience on the best exhaust wrap system to use around the exhaust pipe prior to the shower head. I have a couple of 90 degree bends and obviously a tight fit under the engine hatch.
Thanks,
Rick Kral

[Kevin]

Rick,
I am familiar with the rolls of heat wrap since I have done the turbo exhaust on my car. I would think you could use the same wrap with stainless wire ties to hold it in place. The stuff is fairly easy to work with. I have never messed with it on the diesels. You can just about touch turbos on the boat when they are running without the wrap. I can hold my hand on the turbo down pipe while running on the car with the wrap on it so the stuff works very well. Hope this helps.

[CaptPatrick]

Rick,

The two principle componebts are the thermal wrap and the thermal wrap coating. The over all thickness needs to be at least 3/4" thick and I've seen it built up as thick as 2". Naturally, the thicker the build up the lower the exposed surface temerature will be. The thermal coat is 2" wide x 1/16" thick, so that's 12 wraps for 3/4" finished thickness. By my calculations, you'll need at least 25' of the thermal wrap to do a 10" section of 6" pipe at 3/4" thickness. that's 2.5' per 1 linear inch of exhaust pipe.

Here's a couple of sources to begin your material search:

Thermal wrap 2" x 1'16" x 50'



Thermo-Tec 12001 Exhaust Coating

[Tony Meola]

Capt. Pat

Is it better to go with custom insulation, similar to what Tony Athens sells or just wrap the pipes? I was leaning towards the wrap but was not sure how will it would work.

[CaptPatrick]

Tony,

As far as I know, the main difference between what Athens does and what one of us might do is the degree of professionalism and finesse... The materials are pretty much the same. I've never done it myself, but have be planning on it for quite a while on a set of motorcycle exhausts.

[Rick Kral]

Gentlemen,
Thank you for the feedback. I have been researching a product made by Heatshield Products (good website). The company has a marine product line. The company does show the tape that Cpt. Patrick mentions but also lists a product called "Armor exhaust". The product comes .5" think with an insulation backed heat reflective material. There is also a matching tape. The product is rated for up to 1800 degrees and would appear to have more of a custom finished look than the conventional heat wrap. I am going to order some of the material next week. I will let you know how things turn out.

Thanks,
Rick Kral

[bob lico]

Carl get ready we are about to reach down into that bag of tricks again this post is getting close to the topic .Remenber Tony when I told you to put that stronger (cuminns factory reman. Comes with a Dyno. Sheet to help you ) on the starboard side ,well along with this post subject you have a revealing clue.lets sit back and think about this .this trick along with all the rest that Carl exposed in prevous fuel economy post makes you 31' Bertram have the same economy as twin 150hp on 26' regulator.

[Harry Babb]

Hey Bob........what's the rest of the story????

What trick are you talking about???

hb

[bob lico]

When you lay out the exhaust to go from turbo to " hot pipe " instead of directly to sprinkler head you will gain horsepower above 2000 rpm range.a layman would call this the fireplace effect basically a horsower gain by way of savaging effect from hot temperature at turbo output to cooler insulated pipe. The port engine gains a lot more because the exhaust gas travels much further thru the hot pipe before hitting sprinkler head on opposite side of engine.that is why you go up and over with exhaust in addition to no surge tube needed.i had four hp. Differance on Dyno. But gain a few on weak side ( port) thru exhaust gain.

[bob lico]

Harry I have a photo somewhere of a 1962 vette I had with the heat wrap on headers years before it became popular 331" small block shifted 1st to second at 8500 rpm Way back in 1965 . My Bertram is also heat warped but I have blanket around for appearance as well as physical protection.

[Harry Babb]

That makes good sense Bob........thanks

hb

[bob lico]

I know some people want me to be exact with my post so to avoid the pm's . Here is the tecnical answer ;The savaging effect increases the volemetric effientcy by removing 100% of the exhaust out of combustion chamber rather then a less desired exaust expulsion from just the exhaust valve opening on a naturally aspired engine. This effientcy at the combustion chamber will increase fuel economy/ hp.my 62 vette had the first long tube headers in the area jere Stal made them and ship them from CA. A big improvement with long tube headers and thermal wrap compare to Hedman short headers Big hp. Gain above 5000 rpm.on 315 hp cummins along with 6" exhaust all the way from sprinkler head to output flange a nice gain at 2300 rpm .

[Tony Meola]

Tony,

As far as I know, the main difference between what Athens does and what one of us might do is the degree of professionalism and finesse... The materials are pretty much the same. I've never done it myself, but have be planning on it for quite a while on a set of motorcycle exhausts.

I am also sure we can do the wraps ourselves cheaper. I jsut wasn't sure if thestuff from Athens and others was somthing special. Heck no one seas it until I open the engine box, just needs to be clean looking and work.

[bob lico]

Tape the start then go completely around the circumference then half lap with constant pull to keep tight all the way to end of pipe then a complete circle and half lap again to start tape start you will have a 45 degree wrap one way and a 45degree the opposite direction stop ,cut ,and wrap with heat tape. The surrounding blanket can be purchase separately and you just stagger wrap with SS. Wire around loops done!

[Rick Kral]

Bob,
Thank you for technical support. I have also read that is better to soak the tape in water as you wrap the exhuast pipe. The water helps stretch the tape a bit and when it drys you have a tight fit that is almost bonded together. Have you had any experience wetting the tape before application?

Rick Kral

[CaptPatrick]

Rick,

Yes, soak the tape first, wrap it wet, and once finished, let it dry thoroughly by assembling on the engine and running the engine up to temperature for about 15 - 20 minutes. Going to be a fair amount of steam and smoke during this step as the starch in the fabric burns off.

The wrap must be thoroughly dry before applying the exterior silicone coating. That'll mean that you will have to un-assemble to apply the coating. While not mandatory, It's also a good idea to use a high heat paint on the bare metal before wrapping...

[bob lico]

Yes wet it but I was assuming you would be wrapping stainless steel or in automotive ceramic coat in that case do not paint.

[tds8268]

Bob L

Got a question for you. Would you mind giving me a ring.

Dan
717-682-1530

[conchy joe]

I'm very glad I found this post..... I had to have replace my turbos (4BT's/28' FBC) because I used the factory wet elbows and over time salt water rusted the exhaust housing horribly...anyhow I bought 316L stainless tube and created my own dry exhaust that utilized all of the engine room height before down turning and adding a wet exhaust bell. The problem was I only used one layer of wrap to cover the dry exhaust and immediately realized that was not safe (too hot).

I had been wrestling with having custom blankets made but I don't think based upon the very tight room I have to work with that would have been the best option. I was then researching ceramic insulation blanket material or mineral wool insulation, wrapping that and then coating with a extreme temp epoxy.

Bottom line, it seems that I was creating a "Rube Goldberg" when all I need to do with a crap load of exhaust tape wraps and paint.

Any other advice or input would be greatly appreciated.

[scenarioL113]

I'm very glad I found this post..... I had to have replace my turbos (4BT's/28' FBC) because I used the factory wet elbows and over time salt water rusted the exhaust housing horribly...anyhow I bought 316L stainless tube and created my own dry exhaust that utilized all of the engine room height before down turning and adding a wet exhaust bell. The problem was I only used one layer of wrap to cover the dry exhaust and immediately realized that was not safe (too hot).

I had been wrestling with having custom blankets made but I don't think based upon the very tight room I have to work with that would have been the best option. I was then researching ceramic insulation blanket material or mineral wool insulation, wrapping that and then coating with a extreme temp epoxy.

Bottom line, it seems that I was creating a "Rube Goldberg" when all I need to do with a crap load of exhaust tape wraps and paint.

Any other advice or input would be greatly appreciated.

I would love to see pictures of your exhaust setup on that 28. I have the same boat/same engines and am considering redoing the exhaust system. Could you post a few pic or PM me?
Frank V