Exhaust Heat Wrap, how hot & how much

[AndyG]

Am looking at wrapping the exhaust to reduce heat next to transmission and my leg: ( Defender)

Starting from the first join from the manifold, what's the likely max temperature in this area. I see tapes go up to 1500 C, but that must be for manifolds/ turbos on performance vehicles. 500 C should be enough for the next section?, or 850 C ?

By my calcs, invoking the 200 mm circumference and 100% overlap, then i should get 2.5 m wrap out of 20 m tape ?

Finally thinking of removing these sections of pipe to wrap them, this will be a first for me. How hard ?

thanks
Andrew

[Rickoz]

Am looking at wrapping the exhaust to reduce heat next to transmission and my leg: ( Defender)
Starting from the first join from the manifold, what's the likely max temperature in this area. I see tapes go up to 1500 C, but that must be for manifolds/ turbos on performance vehicles. 500 C should be enough for the next section?, or 850 C ?
By my calcs, invoking the 200 mm circumference and 100% overlap, then i should get 2.5 m wrap out of 20 m tape ?
Finally thinking of removing these sections of pipe to wrap them, this will be a first for me. How hard ?
thanks Andrew
I was going to do the same after doing a bit of reading on here went to a real exhaust shop not the local Franchise types asked about Wrapping they suggested ceramic coating rather than Wrapping so off i go to it to the place they recommend (can't recall name ATM) that's the way i'm going now but will wait till after Winter is over coz ATM i'm still needing the zircon on all the time to stay cool in the box;) & figured the heat will be welcomed in mid Winter.
If u think this is the way u'll go too then PM me & i'll look for the card & FWD details to ya.

[steveG]

Not sure what engine you've got, but I'd say 850deg would be higher than a turbo-diesel would normally get.

I've never got around to doing the one on my county (wrap is still sitting on the shelf), but one tip I did pick up was to wrap from the rear towards the front as the overlaps are facing away from the direction of airflow/mud etc.

Steve

[Dougal]

Ceramic coatings are to make things pretty. There is no insulation value.

Post turbo you won't see more than about 650C unless a complete muppet has tuned your engine.

[camel_landy]

Ceramic coatings are to make things pretty.
...not if you've got a decent ceramic coating!!!

You can use the zorst wrap stuff but it's horrible to work with and it'll only last for a few years before it falls apart. I'm also not sure how it will cope with the the kind of crud thrown up off-road.

Ceramic coating is a neater option for channeling the heat but can get quite expensive.

FWIW - I've been jumping through these hoops with my TVR as the heat from the manifolds can damage the chassis rails. I looked at the wrap option but discounted it for the above reasons. Instead, I've gone for a thin ceramic coating on the manifolds, to take some of the heat and used gold reflective tape on the chassis to reflect the rest of the heat.

M

[Dougal]

...not if you've got a decent ceramic coating!!!

3mm of ceramic coating might give usable insulation. But I'll bet most coatings are only microns thick.

[AndyG]

Thanks all,a good wrap is $100 , will give it a go & consider it a consumable, as I will do things to the exhaust in time.

[chook73]

Thanks all,a good wrap is $100 , will give it a go & consider it a consumable, as I will do things to the exhaust in time.

This is the stuff that was recommended to me, I bought it ages ago but its still sitting in the shed waiting to be fitted.....

TAN Exhaust Heat Wrap Titanium Fibre 30M L X 50mm W 10 X S Steel Zipties | eBay (http://www.ebay.com.au/itm/TAN-EXHAUST-HEAT-WRAP-TITANIUM-FIBRE-30M-L-X-50mm-W-10-X-S-Steel-ZipTies-/181376851322?pt=AU_Car_Parts_Accessories&hash=item2a3ae71d7a)

[Toxic_Avenger]

exhaust wrap (eg the kevlar type) will attract mud, retain water, and can lead to rusting of a mild steel exhaust system. If you've got full stainless, go nuts.
Many factory options use steel pipe with a heat shielding clamshells around them, but this is not easily fabricated at home.

Ceramic coatings can work. its common in racing applications, as its light, prevents heat soak and heat dissipation, and can even assist turbo operation through retaining as much heat energy pre-turbo (more gas volume) for more extracting more boost peer m3 of gas thru the exhaust turbine. Doing a whole exhuast would be cost prohibitive though.

In all honesty, if its just a hot trans tunnel that you are experiencing, then just get a heat shield, mould it to the system, make a few brackets and fix it up. Reflecting back all that radiant heat is probably going to drop temps by half alone.
Somethign like this: http://www.aclperformance.com.au/prod_heatshield.htm

[incisor]

exhaust wrap (eg the kevlar type) will attract mud, retain water, and can lead to rusting of a mild steel exhaust system. If you've got full stainless, go nuts.

really, lasted 8 years on my shorty...

never heat wrap stainless steel.... you will anneal it and it will twist, crack, warp and generally go to crap in no time flat.

[Ancient Mariner]

really, lasted 8 years on my shorty...

never heat wrap stainless steel.... you will anneal it and it will twist, crack, warp and generally go to crap in no time flat.:eek:

I don`t think so

AM

[incisor]

:eek:

I don`t think so

AM

i know so... but feel free...

anything above about 440 deg c will cause grief...

[simmo]

Some good comments , exhaust wrapping is hard to beat on a cost basis , a 30 meters costs between 80 -100$ if you go to the industrial insulation shop. I posted the contact details of one shop in Brisbane yesterday on the thread about new exhaust pipe for my defender. ( 30 meters 60$ +GST). If it lasts 5 years no problems.

I think it would be easier to do a neat job if you took the pipe off. I'l be doing mine in a few weeks and can send a couple of pictures of how it comes out.

Stainless steel (304), exhaust pipes are easier to damage than you might think, it's more prone to cracking than mild steel, one of the problems with lagging it is the lagging can hold salt and contaminants close to the surface. SS 304 suffers from intergranular corrosion in this circumstance. For you that means a crack.

SS 304 is fine for decorative work and items that are low stress, kept clean, & away from salty atmospheres. I use SS 304 bolts & nuts everywhere on my motorbikes and cars for brackets, attachments etc because they're cheap don't rust and look good, and if they break it's not important. SS304 should not be used in stressed bolts positions, (suspension, brakes, steering, recovery points) if there's any chance they could become exposed to salty conditions or salt water etc. Their failure can be unpredictable, intergranular corrosion is not always obvious. SS 304 bolts and tube fitting are prohibited, by most offshore & marine operators, in case they are fitted by accident in place of SS-316. :eek: something to consider anyhow.

[simmo]

You can use the common industrial insulating fiberglass tape, (up to 500 degrees C) for landrover exhaust after the turbo. After the turbo is quite a lot cooler than before the turbo. cheers simmo.:)

[rick130]

really, lasted 8 years on my shorty...

never heat wrap stainless steel.... you will anneal it and it will twist, crack, warp and generally go to crap in no time flat.

What Inc says.

People tell all sorts of dire stories about wrap with no practical experience what so ever.

Six years or so now with the wrap still looking as new and the (mild steel) exhaust still in one piece.

Who would've thunk it ?

321 stainless is the best for high temp exhausts, but it's damned near impossible to get in Oz.

[Dougal]

Do they really use 304 stainless for exhausts? I thought 400 series was usual. It's easy to tell, 400 series is magnetic, 304 is only very weakly magnetic.

[Ancient Mariner]

After nearly 30 years of installing diesel generators with exhausts from 2"x10' long to 14 "x13 stories high with the stainless lagged with 2" of either 650c rockwool Fiberfax or calcium silicate Stainless was either 316 ,316l or 321 with a 304 sometimes depending on the spec 321 was readly available in spiralweld but all bends had to be fabricated.You would think after all this time I would have noticed such catastropic failures:( Just looked at my Sanvik cat there are 15 different grades listed for elevated temps up to 1150c:eek:

AM

[Samblers]

Since we're being slightly philosophical/ on a scientific tangent...

I've thought about exhaust wrapping in the past when ive been towing and its a 45deg day and we're all burning up even with the aircon on, BUT

i'm always mindful that wrapping/ heat-shielding wont strictly speaking "reduce heat" but just make it go somewhere else other than the cab.

Where it goes exactly, i'm not sure - some out the back, yes, but the rest into the mechanicals/ lubricants etc., and that bothers me ...

[Dougal]

Since we're being slightly philosophical/ on a scientific tangent...

I've thought about exhaust wrapping in the past when ive been towing and its a 45deg day and we're all burning up even with the aircon on, BUT

i'm always mindful that wrapping/ heat-shielding wont strictly speaking "reduce heat" but just make it go somewhere else other than the cab.

Where it goes exactly, i'm not sure - some out the back, yes, but the rest into the mechanicals/ lubricants etc., and that bothers me ...

It all goes out the back. A wrapped exhaust has no temperature bearing on the engine upstream.

[AndyG]

It is claimed, that keeping the exhaust gases hot improves extraction, & more power.
So with a nugget air box and a wrapped exhaust to improve efficiency I am looking forward to an eye numbing 92 kW :p

[rick130]

It is claimed, that keeping the exhaust gases hot improves extraction, & more power.
So with a nugget air box and a wrapped exhaust to improve efficiency I am looking forward to an eye numbing 92 kW :p


My finely calibrated bum dyno couldn't tell the difference ! :D

I found a 4mm mig bead protruding inside the dump where the flange was welded on so ground it out plus port matched the cast dump to the flange, etc on my 300Tdi and.........Nothing !

Couldn't even pick a difference in EGT's in use.

An engine dyno may have told a different story when you add a bunch of little things like that together though, but in and of itself, no change. ;)

[AndyG]

how many times have i tried to flick that annoying insect reading one of Rick130's posts;)

[simmo]

I mentioned dyno in another thread, I was quoted $200 for 30 mins drive on drive off no adjustments etc. That seems a bit steep for 30 mins.:( maybe just I'm not in touch with costs etc. But when I'm done with new turbo , some fuel pump tweeking, bigger exhaust it would be good to know what the end result is.
cheers simmo

[AndyG]

I suppose they are not cheap gadgetry, plus mechanic, manager etc.
hopefully someone can provide the stock profile for comparison when the time comes.

[Dougal]

I suppose they are not cheap gadgetry, plus mechanic, manager etc.
hopefully someone can provide the stock profile for comparison when the time comes.

I can dry hire a $200k excavator for under $100/hour. Dyno's are cheaper than excavators.