Will exhaust wrap work in reducing the under-hood heat?

Richdownunder

Richdownunder

New Member
Joined
Jul 25, 2021
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Location
Noosa, Queensland, Australia
Hi guys,

Just coming into summer here in Oz, and my first summer with the 2004 TJ 4lt manual (90,700km) .

So, today I had my first taste of what I imagine is 'heat-soak' - was quite hot, around 30 Celsius and 96% humidity - and after highway driving, I experienced the dreaded cough n splutter....

I read, with interest, the forum section on heat-soak, and there's a heap of good stuff, but I do have a question;

I have a full roll of header wrap left over - can I wrap the fuel rail and injector bodies with it, or am I wasting my time? Surely the accumulated heat transfer that builds up under the hood, would simply 'soak' through the wrap....?

Anyway, I am certain there are many in the forum with higher expertise with heat and it's transfer that can answer this for me.

Cheers,

Rich
 
Yes, you can absolutely do that. It will help to some extent. The best thing I did was put heat shielding on my fuel line where it runs passed the exhaust on its way up to the engine. Made a huge difference…

I will tell you this, and I am sure you already know, that much cutting and handling of the heat wrap creates a lot of dust and debri. If it’s a fiberglass based product wear some gloves at least. The Lava heat wrap I ended using this last time around isn’t fiberglass based and it still makes a bit of a mess…
 
It stays hotter than that all summer here with 100% humidity and I've never experienced heat soak. A hood louver might work better.
p.s. Is this Fishtaco's cousin? ;)
 
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sycboi said:
Yes, you can absolutely do that. It will help to some extent. The best thing I did was put heat shielding on my fuel line where it runs passed the exhaust on its way up to the engine. Made a huge difference…

I will tell you this, and I am sure you already know, that much cutting and handling of the heat wrap creates a lot of dust and debri. If it’s a fiberglass based product wear some gloves at least. The Lava heat wrap I ended using this last time around isn’t fiberglass based and it still makes a bit of a mess…
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Hi sycoboi,

appreciate the response - and the good advice re the handling of the wrap - I wish I had known that the first time I used the stuff, many years ago, it would've saved a lot of skin-rash, to say the least ;-)

Rich
 
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TheBoogieman said:
It stays hotter than that all summer here with 100% humidity and I've never experienced heat soak. A hood louver might work better.
p.s. Is this Fishtaco's cousin? ;)
Click to expand...
Hi TheBoogieman,

Have to admit, I had to google C-Ville VA - had no idea it got that hot for such long periods, there - looks very nice, though.

Not sure what you mean by Fishtaco's cousin, but I have watched Spongebob Squarepants..... hahahahah

Stay cool.

Rich
 
This is the problem i have. Would auxiliary fan/fans work? There is an american who putted a small fan on top of fuel rail and covered with metal. Would an aux extra electric fan before A/c radiator work? These are the methods i am talking about

 
Turdworlder said:
This is the problem i have. Would auxiliary fan/fans work? There is an american who putted a small fan on top of fuel rail and covered with metal. Would an aux extra electric fan before A/c radiator work? These are the methods i am talking about

Click to expand...
The best thing you can do is put heat shielding between your fuel lines and the exhaust. I have used heat sleeves, heat wrap and split length heat sleeving all with good success. Any of those would make a dramatic difference in solving a heat soak issue…

They even sell specific kits for Jeeps that have a heat shielding wrap for the fuel rail and each fuel injector…

I personally wouldn’t bother with adding fans and all the extra wiring and load on the electrical system that would entail…
 
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Richdownunder said:
Hi TheBoogieman,

Have to admit, I had to google C-Ville VA - had no idea it got that hot for such long periods, there - looks very nice, though.

Not sure what you mean by Fishtaco's cousin, but I have watched Spongebob Squarepants..... hahahahah

Stay cool.

Rich
Click to expand...
Fishtaco is a member here from Oz. Perth I believe. 👍
 
The heat wrap will work, but I don't think it's the way to go here. Many will point out how it will accelerate rust greatly. I won't debate the finer points of that argument, but there is an element of truth to it. At the same time, your exhaust isn't going to rust off in a year either.

There is a factory solution utilizing a heat shield produced by Jeep for exactly your issue. That plus injector and fuel rail heat wraps will be better in your case me thinks.

https://www.summitracing.com/parts/...OTfK7v65nwOs1heM2OVBTZekQJzGvO_hoClLwQAvD_BwE
https://www.summitracing.com/parts/...2NMgcaMVRSjCI8t5y1i3prJ-fJFCEGUhoCgnYQAvD_BwE
 
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As others have said, 30ºC isn't very hot, even by North American summer standards. Humidity doesn't have an appreciable impact on the liquid side of a a liquid-to-air heat exchanger. I suspect you're having other issues...

Are you running the factory air box?
 
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Richdownunder said:
I have a full roll of header wrap left over - can I wrap the fuel rail and injector bodies with it
Click to expand...
Wrapping the fuel rail is a great idea, you can see from the links that @SkylinesSuck posted that's what some of the kits do. I used a Thermo-tec product to wrap mine and it works. Carefully wrapping the injector body is the most important part, the fuel rail next. I wouldn't wrap anything else beyond that other than maybe the fuel line like @sycboi suggested. I think the exhaust manifold heat shied is also a good idea but even with it I had heat soak problems until I wrapped the injectors.
 
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SkylinesSuck said:
The heat wrap will work, but I don't think it's the way to go here. Many will point out how it will accelerate rust greatly. I won't debate the finer points of that argument, but there is an element of truth to it. At the same time, your exhaust isn't going to rust off in a year either.

There is a factory solution utilizing a heat shield produced by Jeep for exactly your issue. That plus injector and fuel rail heat wraps will be better in your case me thinks.

https://www.summitracing.com/parts/...OTfK7v65nwOs1heM2OVBTZekQJzGvO_hoClLwQAvD_BwE
https://www.summitracing.com/parts/...2NMgcaMVRSjCI8t5y1i3prJ-fJFCEGUhoCgnYQAvD_BwE
Click to expand...

I like this. Would it help with exhaust heat entering the cab, or do you know of any other products for that? I've noticed how very hot my floorboard can get, right above parts of the exhaust.
 
Some ass hat removed my factory heat shield without telling me when it was at one of several shops. Without realizing that was probably the issue causing my floor mats to melt, I ordered a strap on heat shield for my flowmaster muffler. It's just stamped steel that places an air gap between it and the muffler. That worked shockingly well. I also later installed a "muffler blanket" from DEI which helped more. It's basically fiberglass insulation backed formable metal. Still waiting for the burning candle smell to go away.

Once you get the floor cool enough not to melt stuff, interior insulation does wonders.
 
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I might recommend a different brand of muffler wrap though. It says it's rated to 700 degrees while other brands are 2000+. The muffler blanket stuff is on top of the metal heat shield so if it rots anything, it'll be that.

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Richdownunder said:
Hi guys,

Just coming into summer here in Oz, and my first summer with the 2004 TJ 4lt manual (90,700km) .

So, today I had my first taste of what I imagine is 'heat-soak' - was quite hot, around 30 Celsius and 96% humidity - and after highway driving, I experienced the dreaded cough n splutter....

I read, with interest, the forum section on heat-soak, and there's a heap of good stuff, but I do have a question;

I have a full roll of header wrap left over - can I wrap the fuel rail and injector bodies with it, or am I wasting my time? Surely the accumulated heat transfer that builds up under the hood, would simply 'soak' through the wrap....?

Anyway, I am certain there are many in the forum with higher expertise with heat and it's transfer that can answer this for me.

Cheers,

Rich
Click to expand...

I tried exhaust wrap but it fell apart whenever I was wheeling, I eventually tried Ceramic coating with Jet-Hot and it works great. Comes in a cool color while keeping my engine bay a lot cooler.

https://www.jet-hot.com/offroad
 
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