Following up on my saga: What could be causing a distinct exhaust drone in a tight band around 3250 rpms on a 2004 Subaru WRX?

At the end of that quest, we concluded that the right hand exhaust manifold heat shield was resonating at a particular rev band. One of the common suggestions is to remove those heat shields: they're made of poor quality metal that will rust / corrode / vibrate / what have you after a certain amount of salty winters.

However, on a turbo motor, it's a bad idea to let heat out: at a minimum, you're reducing the exhaust energy available to the turbo.

So, is it possible to use header tape or other heat insulation to replace these metal heat shields? I.e., can you get as good or better heat insulation without the metal, the vibration, the horribly rusted bolts, etc. by wrapping the manifold (or at least that part)?

1 Answer 1


From past experience, I've found that headerwrap (a company called Thermotec makes some nice stuff) is a lightweight alternative to replace heat shields.. HOWEVER..I've found that the wrap traps moisture. I had used this stuff on a set of headers and within 2 years (this is in the west coast mind you - no salt or snow), i had 2 primaries rust and disintegrate beneath the wrap.

So short answer - no.

  • ooo, that's a convincing argument.
    – Bob Cross
    Commented Jul 6, 2011 at 1:10
  • 1
    I've heard similar things from quite a few people who have tried it, the exhaust just rusts out in no time ( bearing in mind how quickly exhaust manifolds rust anyway )
    – Nick C
    Commented Jul 6, 2011 at 8:49
  • It's fairly common for DSM owners to just toss the exhaust manifold heat shield with no change in performance. However, those seem to be the same people that go through an alternator every year... Heat may damage other nearby components? +1 on the header wrap rust issue... Commented Jul 6, 2011 at 11:38

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