Question for you NSXperts...

[Speedmaster]

I have a set of 1997 OEM headers. I no longer have the heat shields. I wonder if that really matters that much (I presume they are there for a reason/trunk and bulkhead heat transfer reduction). But, I also notice that Comptech and other headers do not have shields. Is there a difference the tube wall thickness of an aftermarket header that doesn't necessitate a heat shield or is the theory, "you are going modified, you can handle the heat"?

So, what do you metallurgists think?

 

[Honcho]

I'm just a lawyer, not a metallurgist, but the NSX engine bay is pretty tight, so the shields are there to protect a lot of stuff- bulkheads, oil lines, etc. Heat accelerates the degradation of rubber, so it also helps with the valve cover seals. Finally, the A/C compressor face is right next to one of the primaries, so it helps with that too. Honestly, you would get about the same effect if you just had your 97 headers ceramic coated. I had 97 headers with heat shields in my last NSX and I did notice a difference in engine bay temps compared to the later Pride headers with no shields. Tube thickness shouldn't matter much in the equation.

 

[jwmelvin]

I agree. A separate heat shield, regardless of its thickness, is much more significant for radiative heat transfer than increased tube thickness in a header (which I would expect to have nearly no effect on radiative heat transfer). An insulating coating will reduce surface temperatures and therefor radiative heat transfer but still not nearly as much as a conductively separated heat shield. That said, I have Comptech headers on my car and it doesn’t seem to be much of a problem.

 

[Old Guy]

Aftermarket header vendors probably don't worry too much about heat related failures that occur 3-5 years after the header is installed. They are probably safe in assuming that the owner is unlikely to connect the dots. They also probably fall back on the 'this is a performance part and the seller offers no warranty, express or ....' - I am sure you know the drill.

The car will clearly operate without the heat shields. Its more a case of are you willing to accept the accelerated deterioration in parts exposed to higher temperatures.