Insulation on exhaust hoses

[Mich7920]

Hi All,
Is this one of the solutions to have less heat into the car ?
Is there any inconvenience ?
Mich

[christopher storey]

It can probably do no harm . However, it needs to be borne in mind that energy is indestructible, and all this will do is transfer the heat downstream, probably to the silencers which are right underneath the passenger compartment ......

[Mich7920]

Purhaps not the best idea I had...

[johnetype]

I've done exactly the same on my car and it works well. Yes the heat has to go somewhere but into the exhaust boxes where there's good airflow on the move and then on out the back is better than into the engine compartment.

So you did have a good idea

[Mich7920]

Hi John,
One think made me stop is that I thought about the rain on the Hose and the possibility to have smog from the evaporated water.
Any experience ?
Mich

[johnetype]

Yes, I have had that but the insulation only retains a small amount of moisture if you get it wet and it steams off so quickly as the pipes warm up you don't notice it so I'd say it's not a problem.

[PeterCrespin]

Exhaust wrap is an excellent way of cutting down underbonnet and cabin heat - especially with six long pipes.

It is also a fractionally effective tuning aid in that hot exhaust is less dense and the longer you can keep it hot the easier it is to expel - again particularly useful on multi branch headers. I took a set I wrapped off one tuned E and am saving them for the next.

[Mich7920]

Thanks for all these answers.
I'm goig to keep it and we'll see.

[Mich7920]

Christopher,
I deside to put insulation also on the silencers...
Mich

[chrisfell]

I knew a motor engineer who insulated the whole system on his car, manifold to tail pipe (not an E). He claimed two benefits: 1. It kept heat inside the system until out from under the car; 2. The hotter system resisted rusting (mild steel) for much longer. I wasn’t sure whether his theory was based on sound engineering principles or that he was a bit of a crank. Given that the car was a 1970s Volvo, I’m going with crank.

[PeterCrespin]

Actually worse rust is reportedly one of the weaknesses. I read of someone (possibly a motorcyclist) who took the wrap off and found the exhausts rotted almost totally away up near the head at the first bend. His theory was something like the extra heat did it, or the moisture held in the wrap during prolonged standing.

[rfs1957]

Hi Michel,
I've been running this wrap (from GT2i) for nearly 10 years on the down-pipes in an attempt to quieten the slightly tinny noise from the stainless, the cooling benefits being incidental, and it has been a fit-and-forget modification.

[Mich7920]

Hi,
The rust isn't my problem as my exhaust is full inox but the heat is !
In summer it's very very warm inside and I can't support this now.
As I restor the front, I have put reflexion heat on the bulmhead and stop stop heat inside.
I hope I must used heating in August...
Mich

[Joe Burghard]

I have done this to both of the down pipes which are carbon steel and was warned that a process which the writer called "mummification" would occur. This "process" supposedly resulted in the relatively rapid loss of metal beneath the wrap - some form of corrosion that affected the carbon steel as a result of it being kept at higher temperatures than allowed for this material. Sounds consistent with the motorcyclist's experience.

Wrapping does keep the engine bay temperature noticeably lower and I added additional half-pipe heat shields over the mufflers to keep the cabin from getting hot. The exhaust temps ex-tail pipe are reasonable. I haven't removed the wrap to inspect the down pipes but they appear sound when squeezed.

Joe

[rfs1957]

Metallurgical fears about the "Mummification" of exhaust pipes is the kind of nonsense that we were spared before the Internet became the great level playing field, where all of a sudden everyone's an expert and a metallurgist.

Given the number of vehicles I've seen and owned with wrapped pipes, and my modest grasp of metallurgy, yours will be just fine, Joe.

Accelerated rusting through sustained dampness is another issue, but it's bikes left out in the rain that get that.

[cactusman]

I did my MGB down pipes. Made a modicum of difference. Pipes fine. Do be aware though that the insulation is very coarse woven fibre glass and is extremely uncomfortable to handle in my experience. Wear stout leather gloves when handling and wrapping

[PeterCrespin]

I'm no metallurgist either Rory but not all stainless is rot proof.

As I write, I have a Jaguar saloon fitted with the OEM factory stainless system including two badly holed rear silencers. At 22 years I'm not complaining - it sounds quite rory, sorry, rorty,

I expect the jag system was 410 or some such. In my time as a salt-roads rider I saw other stainless bits rot noticeably. I'd struggle with mummified 304.stainless wrapped headers, say. But extreme heat degradation of insulated mild steel, or lowest grade stainless versions, around the flame impinging area doesn't require a huge leap of my imagination?

[MikeMilton]

An alternative that might be worth exploring is a ceramic coating. In addition to excellent heat blocking, this can be quite attractive.

[Bobb]

Actually worse rust is reportedly one of the weaknesses. I read of someone (possibly a motorcyclist) who took the wrap off and found the exhausts rotted almost totally away up near the head at the first bend. His theory was something like the extra heat did it, or the moisture held in the wrap during prolonged standing.

That was likely me in the Jag Lover's forum a few years back. My front one fell off one morning and I had to limp noisily home. I discovered that it had rotted almost completely away. The rear one wasn't far behind. I assumed it was the moisture trapped in the wrap. I now use a stiff but bendable aluminium backed stuff wired a few cm away from the metal to allow a bit of air circulation.

[66an]

Wrapping is nice to reduce the heat. I have tried it on stainless pipes. The stainless pipes will be a bit ugly of it but that is probably a minor problem for most of us.
Downside, it increases the risk of fire. A leakage of oil on the wrapping is enough to start a fire. I have lost a car with wrapped headers because of that. In my case because of a clutch hydraulic failure that sprayed out hydraulic oil.
Just my own experience.