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I recently had a 3" dump fitted and the original heat shield over the turbo and dump was removed.

Should I get some exhaust wrap on the dump?

How effective is exhaust wrap in reducing under bonnet temps?

www.flyn.com.au is selling 6m of fibreglass exhaust wrap for $48. Anybody using this stuff? Is this stuff any good?

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Im looking into doing the same thing this coming week fo rmy new dump pipe. An estimate from an exhasut shop was that i would need approx 10m to do a 3" dump pipe. This would allow the dump/front pipe to be covered past the bottom of the firewall.

Add to this the expense of the clips to secure in place, and the coating to protect from the elements and i have decided to get the dump pipe ceramic coated. At approx $80 it is neater and perhaps better value, i cant say which works better as i have never used the exhaust wrap.

I have had my exhaust manifold and exhasut housing done by Competition Coatings and i have been happy with their work.

10mtrs was for dump and front pipe, as the front pipe normaly had a heat shield that goes all the way down to the cat.

My thinking is they are shielded for a reason so want to do the same to be sure that nothing on the firewall/floorpan is damaged by the hot exhaust. (My old R31 used to cook the floorpan as i had the exhuast tucked up nicely to ensure good ground clearance.

With the exhaust housing of the turbine after a 30min drive you can hold your hand about 1" from the housing for about 15sec before things start to get hot, so would seem to be working. I wish i could have tested it with a thermocouple before/after but didnt want to have to take the turbo off after having instaled it as the coating takes about 4-5 days.

I'd definately recommend wrapping the dump. I'm having mine ceramic coated, then wrapped. The ceramic coating alone is enough to allow you to touch the dump/or exhaust manifold without burning yourself.

The secondary advantage to keeping the heat trapped in the exhaust gasses is that they help spool the turbo quicker:D

I imagine that it not only allows the turbo to spool quicker but it MAY also reduce back pressure as the gas has a faster velocity hence it gets out of there quicker allowing the motor to breathe a little better in the higher rev's?!?! Maybe... :)

Depends what material you use. I have heard of a number of stainless manifold cracking, but usually due to the poor choice in stainless type (there are many type with different compositions). My manifold is made from steam pipe, it has a much greater thermal mass, and therefore isn't prone to cracking like the thin-walled stainless.

I had a 3" dump of mild steel and the engine bay got bloody hot, so hot that I got paranoid so I wrapped it, which made a huge difference to underbonnet temps.

Have now fitted a stainless ceramic coated dump, and I dont think it is quite as cool as the heat wrapped mild steel, so I will be heat wrapping it aswell.

Having higher velocity in the exhaust, apart from spooling up the turbo quicker, can aid in cylinder scavenging. Also increased velocity decreases pressure, and back pressure is not your friend either:)

Bottom line, if it makes the car go faster/harder, its all good. People have been coating and wrapping manifolds/dumps/turbines for a long time for good reason.

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