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hi all quick question again :P

my rangie has a sports exhaust with the 4 branch manifolds and the underbonnet temps seem very high and as im planning on going round europe towing a caravan so would like to lower this :blink:

so my question is ........ is it worth getting some exhaust wrap ??

will it lower my underbonnet temps enough to justify doing?

and how much would i need??

thanks all

rob

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hi all quick question again :P

my rangie has a sports exhaust with the 4 branch manifolds and the underbonnet temps seem very high and as im planning on going round europe towing a caravan so would like to lower this :blink:

so my question is ........ is it worth getting some exhaust wrap ??

will it lower my underbonnet temps enough to justify doing?

and how much would i need??

thanks all

rob

I looked in to this a while ago, The use of exhaust wrap will lower you under bonnet temp, I know a few drag racers who use it on their motors as they have found it to improve the torque lower in the rev range. An adult wil be along shortly to explain why!

I decided against it because I use mine in the sticky stuff most of the time and I have heard reports the wrap dosn't cope well with muddy conditions and tends to get a bit soggy and act as a carp trap.

But if it's a road barge then I would give it a go.

Brookers

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yep defo road barge lol

any idea how to work out length needed??

rob

Hi , it will make a huge difference to the temp, my off road Hilux has it and it stays really cool under the bonnet[rad is in the back so this makes a difference as well]

i reckon you will need at least a couple of rolls to do your headers.

cheers woody

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A tip i once heard was to have the roll in a bucket of water as your applying it as this allows you to get it nice and tight aswell as not getting dust anywhere.

I've never tried it so it could well be utter ****e but i'm sure someone may be able to give you an idea....

Will.

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Hello Rob,

I pulled this from my essay on exhaust systems as per the RV8 in SD1's.

Heat! Exhaust gas is hot, and it would be good to keep it hot throughout the exhaust system. Hot gas is less dense than cold gas, so the colder the gas the heavier it gets and therefore takes more effort to remove it from the system. Larger pipes give the hot gas an opportunity to slow down and give the gas more time to cool en-route to the tailpipe.

We don't want our engine to be pushing a heavy mass of exhaust gas out of the tailpipe and it is not just that an extremely large exhaust pipe will cause a slow exhaust flow, which will in turn give the gas plenty of time to cool off en route. Overlarge piping will also allow our exhaust pulses to achieve a higher level of entropy (Sorry! Entropy is the way energy spreads out in a process), which will take all of the hard gained header tuning and throw it out the window, as pulses will not have the same tendency to line up as they would in a smaller pipe.

If keeping the interior of the exhaust system as hot as possible is an advantage, then coating the entire exhaust system with thermal insulation material, such as header wrap or a ceramic thermal barrier reduces the cooling effect significantly. Cost may be prohibitive but a bonus side effect would be a cooler engine bay and down-pipe area

Lots more about pipes, heat, noise and materials in the PDF available from here:

http://www.vintagemodelairplane.com/pages/.../Exhaust01.html

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  • 4 years later...

Good morning

These questions are for maxtherotti. (Not exclusive. Feel free to advise and inform)

How did the wrap work for you? Did you experience a cooler running Rangey?

Did the engine suffer any damage near the exhaust ports?

I am considering wrapping my exhaust as well, seeing that my temperature is very high.

I have fitted one measly electric fan which has to run constantly to keep the temperature

constant. Although the temperature is constant, it is still way past 3/4 of the way on the dial.

Background information : The previous owner fitted aftermarket headers.

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I fit some heatwrap a few years ago on my 4 branch manifolds, I wet it in a bucket of water and as mentioned it makes fitting a lot easier, buy some stainless ties as well and it will look neat. As for mud it's not too bad, it drys up and falls off but after two years it started to disintegrate.

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This is mine, wont be doing the mud stuff if I could prevent it. Wet them before fitting, it is not difficult but it puts sone strain on the hands....lol

I used 1inch wide and 50 feet per side but I was very tight on my windings as you can see....good luck.

post-78608-0-25333300-1378114303_thumb.jpg

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Had it on the 109, hated it, ditched it along with the headers which were also a pain. Zero noticeable difference in power etc.

It collects mud & water and attacks you with glass when working on the engine.

Ramon - surely cooler gas takes up much less space so is preferable to having a large volume to try and shift? Just playing devil's avocado... :ph34r:

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Ramon - surely cooler gas takes up much less space so is preferable to having a large volume to try and shift? Just playing devil's avocado... :ph34r:

Yes, but it is more dense. You're still pushing the same amount of stuff out the exhaust. Just thinking from a logical perspective - hotter stuff would have to move faster which could potentially create more back pressure.

However - I doubt there's enough heat dissipated from the gas through the walls of the exhaust to make a difference to the 0-60 time of an LR.

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Yes, but it is more dense. You're still pushing the same amount of stuff out the exhaust. Just thinking from a logical perspective - hotter stuff would have to move faster which could potentially create more back pressure.

Indeed - but maybe faster moving gas is more efficient than slow-moving stuff? I've never heard anyone cite the weight of the gas as a major factor in exhaust design before.

However - I doubt there's enough heat dissipated from the gas through the walls of the exhaust to make a difference to the 0-60 time of an LR.

That's the crunch - in reality on a 2t 4x4 it makes bvgger all difference.

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Indeed - but maybe faster moving gas is more efficient than slow-moving stuff? I've never heard anyone cite the weight of the gas as a major factor in exhaust design before.

That's the crunch - in reality on a 2t 4x4 it makes bvgger all difference.

You've piqued my interest. After hastily revising my very rusty fluid dynamics using wikipedia:

It revolves around Reynolds Number - the value of which is proportional to velocity of the gas and proportional to the density of it. As the density decreases (increase in temperature) the velocity increase (which is hard to predict) balances this effect.

Result - difficult to say precisely without experimentation, however the maths suggests a very small or zero effect whatsoever.

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Wrapping a exhaust only makes a notable difference to the performance when coupled with the correct material and tuned primary and secondary lengths....i.e. on a bogo standard aftermarket system it will make no difference.

Ceramic coating however is fantastic

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I wrapped the headers on a Chev Rat motor I fitted in a 110 CSW many years ago.Whilst it cut the underbonnet temp down - which was horrific with 8.2lts of not very efficient engine gobbling unleaded at a heady rate.... It also caused the headers to corrode at an alarming rate,holding in moisture after the engine was shut down. Alloy heat shields would be a better deal,something similar to the laminate versions on a P38 v8 RR would be a much better deal.

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I would recommend ceramic coating anytime, I went for the wrap because of the look and under bonnet temp for my duel battery system that still needs to find its place under the bonnet, performance or my 0-60 times are completely irrelevant.

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