Exhaust wrap: recommended?

[Cider Andy]

I know from a couple of profiles that some people have fitted exhaust wrap around the manifolds and 'Y'-piece. One supplier claims it can reduce engine bay temperture by up to 70%.

What are your views?

Presumably the exhaust system will retain a lot more heat. Will this shorten the life of the cats (or even lambda sensors)? And does it increase the risk of burning the tub underneath the car?

[HughesieII]

Cats...What cats

[chassis 33]

Not a great fan, the heat has to be dissipated somewhere. Roughly 1/3 of the power produced by the combustion process goes as heat down the exhaust (another 1/3rd is dumped into the coolant and the last third moves the flywheel). While all outside the wrap is nice and cool, inside can get very warm and lead to cracked manifolds cos they metal expands too much.

Do you have a particular issue with under bonnet temperatures, or is it no worse than any other Chimaera?

I guess at the end of the day you pay your money and take your choice.

Regards
Iain

[griffter]

I've wrapped my manifolds but only as far as the front of the block - I just wanted to keep the heat away from the spark plug leads, and didn't want to risk the exhaust under the floor getting too hot. Some people claim wrapping the manifolds leads to moisture trapping and corrosion, but I've not had that problem (yet).

[GarryM]

JamieT posted a week or so ago that exhaust wrap on his has resulted in a rusty, holed manifold. His advice was don't do it!

[tvr keith]

I wrapped the manifolds om the Cobra (RV8 engine) that I built. Both of the manifolds fractured within 3000 miles from new. I didn't wrap the replacements and had no further problems. I may have just been unlucky or had a dodgy pair of manifolds, but the supplier of the manifolds (Pilgrim Cars) did not recommend that I wrap the replacements.

[Boosted LS1]

I once wrapped some turbo housings. I was amazed how they rusted off in great big flakes!

Boosted.

[RichardD]

chassis 33 said:

... cracked manifolds cos they metal expands too much...

Iain, what would be different with ceramic coating? I believe a PH'er with the "monster" Griff has had this done and TVR Power will be doing it as standard on the RV8 supercharger conversion (whenever it appears)....

[Cider Andy]

It's not looking favourable is it?

chassis 33 said:

Do you have a particular issue with under bonnet temperatures, or is it no worse than any other Chimaera?

I don't know if it's any worse than other Chimaeras; it probably isn't. I'm trying to diagnose a misfire and the diagnosis involved swapping the AFM but it was way too hot to touch. Whilst I'm not suffering from an overheating problem (in traffic the coolant temp. gauge is regularly reaching 95°C) I got to thinking that such an amount of heat in the engine bay cannot be doing any of the electrical components any good.

[chassis 33]

Re Ceramic coatings, I don't know to be honest, I've never used them. Another PH'er is Quinny who has them on his Griff 500. Im sure he'll be along shortly, one moment...QUINNY

The best way to manage heat is to get an air flow through an isolated double skin heat shield. Sadly it's not very practical in most automotive applications. I would of thought a heat shield above the manifold would be a better option to shielding the AFM...or wrapping the AFM in insuation?

Regards
Iain

[Wildfire]

www.pistonheads.com/gassing/topic.asp?t=266463&f=9&h=0

[markh]

chassis 33 said:

Re Ceramic coatings, I don't know to be honest, I've never used them. Another PH'er is Quinny who has them on his Griff 500. Im sure he'll be along shortly, one moment...QUINNY The best way to manage heat is to get an air flow through an isolated double skin heat shield. Sadly it's not very practical in most automotive applications. I would of thought a heat shield above the manifold would be a better option to shielding the AFM...or wrapping the AFM in insuation? Regards Iain

Have had ceramic coated manifolds on my Chimaera for 9 months now, and the change is dramatic, even on hot days in Italy the temp is cut back. I can even touch them within 5 mins of switching the engine off.

Mark