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Heat wrap
ed1max - 12/3/11 at 12:00 PM

Any advice on the pro's and cons of heat wrapping the exhaust.
I have a 1600 Xflow which runs hot in the summer.

rusty nuts - 12/3/11 at 12:13 PM

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

ed1max - 12/3/11 at 12:20 PM

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

ed1max - 12/3/11 at 12:22 PM

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.

DH2 - 12/3/11 at 12:29 PM

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

rusty nuts - 12/3/11 at 12:36 PM

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

austin man - 12/3/11 at 01:16 PM

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

Strontium Dog - 12/3/11 at 01:43 PM

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]

DH2 - 12/3/11 at 06:39 PM

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

40inches - 12/3/11 at 08:47 PM

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?

Strontium Dog - 12/3/11 at 09:06 PM

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!

DH2 - 13/3/11 at 09:36 AM

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