Exhaust Wrap

[Warren S Smith]

Does anyone use Exhaust Wrap? This is a product supplied by Demon Tweeks to reduce under bonnet temperatures. Is the product good? Does it have any unwanted side effects?

 

Thanks,

[greg]

I was thinking the same thing yesterday, as my engine temp was hovering arrounf 100 in Trafic, and the transmission tunnel was getting warm. This is a great excuse not to ware shorts ("Oh the the tunnel will burn my legs"), but I was also wondering if the exhaust was not contributing to the heat, and whether wrap would help (and at what cost to performance !).

 

Greg, Q 880 RAE (Green/Ali XF)

[Chelspeed]

It shouldn't have any detrimental effect on performance.

 

It will have a beneficial effect on a tin top as a reduced underbonnet temperature will reduce the temperature of the air being fed to the engine. I wouldn't think this would have any benefit on a Se7en if you're air filter is tucked out thro the bonnet.

 

It's alleged to improve performance by keeping the exhaust gas temperature higher which is alleged to increase power but I find this unlikely and if it is real it will be negligible.

 

Plus points are that if your alternator or starter motor are close to the exhaust (the alternator is on a Vx and the starter is on a K) then the life of these components is better if they're not cooked by the radiant heat from the exhaust.

 

Concerns are that it can look very tatty fairly quickly unless installed very carefully which usually means taking the headers off the car. It was alleged that there have been fires on fibreglass kit cars with exhaust wrap under the bonnet because the unwrapped bit of exhaust thro the bulkhead or wing was much hotter than before because all the heat was kept in the wrapped bit (crap explanation but I know what I meant to say...). Not a concern on a Caterham of course. I have seen rally cars with leaky rocker cover gaskets leak oil into the exhaust wrap which then holds all the oil on the manifold and also makes a lovely wick!! We were running the finish control and the exhaust manifold was burning nicely after every stage!! Again not a problem if your cars reasonably well maintained.

 

All sounds negative but I ran exhaust wrap to keep my alternator and dry sump tank cool, I never had any problems and would fit it again. Can't recall the tunnel being any cooler though.

[Mike Biddle]

My car is a left drive VX so the headers are very close to my feet, and high footwell temperatures are a major problem here where ambient temperatures can go to 50C. I have used exhaust wrap, and there was a big improvement, but it only lasted one season.

I have now gone to internal and external ceramic coating of the headers which does the same job, looks much better and lasts a lot longer. I also had the rest of the system ceramic coated in a yellow colour to set of the BRG of the car. Looks great, and no more polishing!!!!!

[Richie]

I used exhaust wrap on my racing Caterham last season but had it taken off by Ratrace who are supporting me this season. Their reasoning was that it was added weight, it had a negligable effect on performance, it made it difficult to get to any engine parts in the exhaust area, it looked messy, and a light weight cloth heat sheild does a better job of protecting the alternator and other electrics.

 

As you can see I wouldn't recommend it.

 

Richie

[Mr Locust]

This product is good if you are using a non crossflow engine i.e. exhaust under carbs (like the Triumph fitted to my car). It vastly reduces fuel vapourisation etc. due to heat convection.

 

But beware - if you have a carbon steel tubular manifold, it absorbs moisture and holds it next to the tube causing premature corrosion of the steel and the need for a new manifold - ouch!

[I.Mupferit]

If all you are looking to do is protect the alternator or starter motor, I found a much cheaper/easier and effective solution was to use a heat resistant soldering mat. Only £5 or so from your local diy store and is a good localised heat shield which works very well.

Brent

[Noel Mclaughlin]

I have used exhaust wrap with great success on my x flow Caterham. In Australia we often have HOT temps in summer and the passengers feet really cook !!! It helps a lot in this regard, don't know about a performance increase though in spite of the theory about higher exhaust velocity due to thermal effect of retained heat. The ringing sound from the pipes is reduced though.