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Exhaust Header Insulation


geoffbeaumont
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I'm in the process of fitting a nice stainless exhaust and tubular headers to the rangie. The headers are uninsulated (which is obviously fine, as the truck they came off had no problems), but I'm wondering if it's worth heat wrapping them? Do you get more or less underbonnet heat with tubular headers compared to standard cast manifolds?

I guess if I do heat wrap them it would be a good idea to paint the wrap, particularly as this truck does occassionally venture into the mud?

It would be a pain to wrap them, as I think it'll have to be done in the engine bay - getting the headers out of the other truck was, to put it mildly, a little tight, so I think wrapping them beforehand will mean they either won't go in or the wrapping will be ripped off in the process.

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I fitted a stainless system with tubular headers to a Rangy last year Geoff. The exhaust wrap was very itchy and easily damaged. I also had to move the engine forward in order to get the rear bolts in. Took me all day in the end - just to replace an exhaust system. :angry:

Les. :)

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Think these headers are mild steel, although the rest of the system is stainless, so I don't fancy encouraging the tin worms.

Geoff wrap them, trust me, but not past the 4 into 1 on each side.

I did the NAS about 3 years ago, mild steel headers all the way down (wrong see above) the reduction in underbonnet temperatures was incredible. The tape was held on with the supplied stainless wire, did it off the engine before assembly, never a problem. Don't worry about mud, it smells a bit when wet but tends to hold the tape together. :lol::D

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Geoff wrap them, trust me, but not past the 4 into 1 on each side.

I did the NAS about 3 years ago, mild steel headers all the way down (wrong see above) the reduction in underbonnet temperatures was incredible. The tape was held on with the supplied stainless wire, did it off the engine before assembly, never a problem. Don't worry about mud, it smells a bit when wet but tends to hold the tape together. :lol::D

Why not past the four into one? :unsure:

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Why not past the four into one? :unsure:

If you are off-roading it tends to get damaged, I took it pretty well down to bottom of chassis height it was damaged but didn't all fall off. If just road use take it down further. There was also a problem with the lack of clearance in the Nas and a through-flow exhaust, first off-road sortie put a dent in righthand side header at chassis level.

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Two lots of ten peneth to add.

I fitted my headers plain and ran it for a year.

Off road my brakes go soft due to underbody heat I wrapped a coke can around my brake pipes - OK.

Next I added heat tape to he headers, take them off, add wrap and put back on. Not to difficult just watch out with the stainless wire it springs around and cuts you really well :o

Now the engine ran really rich. The tape keeps the heat in so the gasses flow faster therefore the mixture is really out.

Fixed that.

Did it solve the brake problem off road? not really, so I may add somes holes in the bonnet or add some protection to the brake pipes.

It did reduce the problem a bit due to the reduced heat.

Don't know if this was helpful?

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WARNING - pointless post follows

just be glad your headers dont get this hot?

I suspect that the headers in the picture have little or no airflowing over them - and that a Landrover would do just the same. My old S2a with V8 used to get the passenger side manifold glowing dull red on a dark night - that was the only one you could see through the hole on the bulkhead. :)

Chris

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Two lots of ten peneth to add.

I fitted my headers plain and ran it for a year.

Off road my brakes go soft due to underbody heat I wrapped a coke can around my brake pipes - OK.

Next I added heat tape to he headers, take them off, add wrap and put back on. Not to difficult just watch out with the stainless wire it springs around and cuts you really well :o

Now the engine ran really rich. The tape keeps the heat in so the gasses flow faster therefore the mixture is really out.

Fixed that.

Did it solve the brake problem off road? not really, so I may add somes holes in the bonnet or add some protection to the brake pipes.

It did reduce the problem a bit due to the reduced heat.

Don't know if this was helpful?

I was always tought that you cannot compress a liquid. If your brakes are becoming unreliable due to the excess heat then you probably have a problem with the brake fluid containing water and that water boiling. Replace the fluid for new stuff from a sealed container. If the brake lines are getting so hot that good fluid is boiling then they are too close to the manifold and should be moved.

I stole this from a US website, sorry for the Farenheit scale:

DOT 4 glycol based fluid has a higher boiling point (446F) than DOT 3 (401F), and both fluids will exhibit a reduced boiling point as water content increases. DOT 5 in its pure state offers a higher boiling point (500F) however if water got into the system, and a big globule found its way into a caliper, the water would start to boil at 212F causing a vapor lock condition [possible brake failure -ed.]. By contrast, DOT 3 fluid with 3% water content would still exhibit a boiling point of 300F. Silicone fluids also exhibit a 3 times greater propensity to dissolve air and other gasses which can lead to a "spongy pedal" and reduced braking at high altitudes.

Chris

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well i doubt a landy would get quite as hot as a Cosworth DFV even with no airflow. was worth the post though just cause i think its a cool pic.

Can you offer a reason why? I was going (quite by guesswork and assumption) on the fact that any petrol engine, when correctly set-up, burns it's fuel in roughly the same fuel/air ratio as any other petrol engine. It stands to reason that therefor that the gas comes out of the exhaust ports at about the same temperature - give or take. Or do I misunderstand? I guess that a turbo might upset my maths guess...

No question that is a cool pic though. :)

Chris

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I was always tought that you cannot compress a liquid. If your brakes are becoming unreliable due to the excess heat then you probably have a problem with the brake fluid containing water and that water boiling. Replace the fluid for new stuff from a sealed container. If the brake lines are getting so hot that good fluid is boiling then they are too close to the manifold and should be moved.

I stole this from a US website, sorry for the Farenheit scale:

Chris

Thanks Chris,

most likley is water then, it doesn't feel spongy like air so I guess it's due a chage of fluid. <_<

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Well, as it's not clear cut one way or the other, and I've never had overheating problems with the truck (not sure how much difference the tubular headers will make - we'll see), I'm going with the cheaper and easier option and not wrapping them :)

Thanks all!

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