ed1max
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| posted on 12/3/11 at 12:00 PM |
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Heat wrap
Any advice on the pro's and cons of heat wrapping the exhaust.
I have a 1600 Xflow which runs hot in the summer.
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rusty nuts
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| posted on 12/3/11 at 12:13 PM |
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Wrapped mine due to running problems when stuck in traffic, think the fuel was vaporising? Haven't had any problems since. Also might be a good
idea to fit a heatshield over the alternator , had one fry on me . Have you any bonnet vents? , makes a huge difference to underbonnet temperature if
the heat can escape
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ed1max
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| posted on 12/3/11 at 12:20 PM |
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quote:
Originally posted by rusty nuts
Wrapped mine due to running problems when stuck in traffic, think the fuel was vaporising? Haven't had any problems since. Also might be a good
idea to fit a heatshield over the alternator , had one fry on me . Have you any bonnet vents? , makes a huge difference to underbonnet temperature if
the heat can escape
Thanks for the quick advice
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ed1max
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| posted on 12/3/11 at 12:22 PM |
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quote:
Originally posted by rusty nuts
Wrapped mine due to running problems when stuck in traffic, think the fuel was vaporising? Haven't had any problems since. Also might be a good
idea to fit a heatshield over the alternator , had one fry on me . Have you any bonnet vents? , makes a huge difference to underbonnet temperature if
the heat can escape
Is there much difference in quality as it comes in a wide price range.
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DH2
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| posted on 12/3/11 at 12:29 PM |
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Bear in mind that when you wrap the manifold, that heat has to go somewhere. So the rest of the exhaust will be hotter, and also more heat will be
retained in the head. Also, you need to be very careful with the wrapping to ensure there are no gaps, as these create very hot spots - this applies
not only during initial fitting, but also during the life of the wrapping as it dries out, goes crusty and falls off.
DH2
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rusty nuts
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| posted on 12/3/11 at 12:36 PM |
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quote:
Originally posted by ed1max
Is there much difference in quality as it comes in a wide price range.
Can't tell really, my first manifold was covered in some that I picked up at a show , the new one was wrapped in some I got off ebay . As long
as you wrap it fairly tight and get some extra stainless ties it seems to be OK . As I pointed out some extra venting helps to keep the underbonnet
temperatures down
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austin man
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| posted on 12/3/11 at 01:16 PM |
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One of the probems with the Seven is getting rid of the heat, when driving this isnt too bad as much is forced down the tunnel, not good in summer
though as it warms the thigh. Flarinf the side panes out an inche or so allows hot air to escape down the side of the car. On a 2 litre zetec we noted
a 10 degree drop in running temperature
Life is like a bowl of fruit, funny how all the weird looking ones are left alone
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Strontium Dog
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| posted on 12/3/11 at 01:43 PM |
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quote:
Originally posted by DH2
Bear in mind that when you wrap the manifold, that heat has to go somewhere. So the rest of the exhaust will be hotter, and also more heat will be
retained in the head. Also, you need to be very careful with the wrapping to ensure there are no gaps, as these create very hot spots - this applies
not only during initial fitting, but also during the life of the wrapping as it dries out, goes crusty and falls off.
DH2
Why will more heat be retained in the head? Wrapping the exhaust manifold pushes the heat further down the pipe which tends to increases gas speed
which is good for breathing. I am not sure how the head could hold more heat though!
As said above, get some vents in somewhere if you don't have them to let hot air out and reduce temps in the bay. It will also allow more air to
get through the rad and thus it to will work more efficiently! Without effective vents you can end up with a positive pressure behind the rad which
acts against the air trying to pass through it.
Painting the wrap with HTP is a good idea as well. It makes it last longer and keeps the water out on wet days which helps preserve the manifold
too!
[Edited on 12/3/11 by Strontium Dog]
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DH2
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| posted on 12/3/11 at 06:39 PM |
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quote:
Originally posted by Strontium Dog
Why will more heat be retained in the head? Wrapping the exhaust manifold pushes the heat further down the pipe which tends to increases gas speed
which is good for breathing. I am not sure how the head could hold more heat though!
Because there will be more retained heat in the manifold (it'll be wrapped in a nice blanket) which will be conducted into the head.
Additionally, it causes a theoretical performance loss, and speeds up exhaust valve seat wear.
DH2
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40inches
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| posted on 12/3/11 at 08:47 PM |
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quote:
Originally posted by DH2
quote:
Originally posted by Strontium Dog
Why will more heat be retained in the head? Wrapping the exhaust manifold pushes the heat further down the pipe which tends to increases gas speed
which is good for breathing. I am not sure how the head could hold more heat though!
Because there will be more retained heat in the manifold (it'll be wrapped in a nice blanket) which will be conducted into the head.
Additionally, it causes a theoretical performance loss, and speeds up exhaust valve seat wear.
DH2
Are you sure? I thought that preventing heat escaping from the header actually created a higher gas speed, and drew heat from the head, surely
increasing gas flow speed, lowers the head temp?
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Strontium Dog
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| posted on 12/3/11 at 09:06 PM |
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As 40inches said, wrapping the pipe will increase gas speeds and this will cause greater cylinder scavenging resulting in the potential for more power
not less I have not noticed any higher head temps but would need to test specifically for that to know for sure. I doubt it though!
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DH2
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| posted on 13/3/11 at 09:36 AM |
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OK, well if you want do some further research, I believe Peter Burgess and Vizard have both published info on dyno tests in this area...
DH2
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