Header & Exhaust Wrap question

R

raymond

Member
Location
Netherlands
Car
FX35 RWD
In stead of ceramic coating the headers i was planning on using the DEI Titanium Exhaust wrap. Looks really cool and easier for me to arrange then ceramic coating.
Now i was alking to a freind of mine who was doubting if it was advisable to do this on my F/I projekt as he thought t might get to hot in the headers when F/I. Now our OEM headers are quite thick and i was thinking in a better velocity for the turbo when heat was contained.

Any ideas on this matter....??
 
even with a n/a engine, it gets hot enough for the headers to develop cracks at certain points despite having wrapped with those header wraps. there's only so much time a header can be safe with DEI's. I WOULD NOT SUGGEST A HEADER WRAP AT ALL FOR YOUR FI ENGINE. and you certainly don't want to take of the header again and again for repairs.
 
with FI & assuming 304ss headers, which is probably the best you could hope for yours to even be really, wrapping is not a good idea at all & wrapping will promote premature cracking... the truth is, even ceramic coating is bad for the 304 stainless steel itself because it too is designed to hold heat in, while this is an advantage for performance it is a disadvantage to longevity of the header... the real "best" way is to run uncoated raw 304 headers & then building heat shields to protect the surrounding items from the heat radiated from them... this will allow the headers to last as long as they can, still not forever, but longer than wrapped or coated... the truth is that 304ss is really not ideal for an FI application & is really just a compromise, it's much better than carbon steel but each & every time the headers reach ~1,200*f or more the 304ss will have carbide precipitation introduced & the stainless properties will deteriorate little by little, these temps are unavoidable with FI when pushed hard...

to REALLY do a set of headers that will not deteriorate under these conditions then a higher grade stainless would be used, think at least 321 ss, but there your talking big $$, even 321ss, while raising the point of carbide precipitation by a few hundred degrees is not the best even, better would be inconel, but there your talking extremely huge $$$ & really not in the realm of reasonable at all for an average FI passenger car at all...

the bottom line, they will last longest if they are left natural ss finish... a race car may benifit a bit from the performance advantage of wrapping but at the same time they are sacrificing longevity... but a race car will not see the kind of mileage that a pass car will too & a race car can factor in the cost of replacing the headers every so often, not something you'd probably want on a street car... leave them raw for best longevity
 
Hey John,

Thank you for the intell. And clear on that....!! Was planning on mounting the OEM heat shields and wrapping them in some heatresistant stuff.
The rest of the system isn't a problem to wrap i gues isn't it. I think even advisable........i freaking hope so otherwise i have a couple of rolles of wrapping in stock :wink:
 
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well truth is that even downpipes can suffer from the same thing, BUT I do plan on wrapping my down pipes anyway, just to try & contain as much of the radiated heat as possible. my thinking there is that 1, the down pipe will not be nearly as susceptible to cracking as headers, mainly because they will usually not have any where near the amount of stresses on them as headers in the first place & 2, a crack in a down pipe is much easier to deal with that a crack in a header... if your down pipe is a nightmare to install & remove then maybe think twice about wrapping & also if you do, I'd recommend ending the wrap before it reaches underneath the car... reason being another draw back of a wrap is that it will hold moisture & promote deterioration that way too, better to not have it where it will be exposed to splashing water on a regular basis, plus, there is little benefit of reducing radiating heat by the time it reaches underneath enough to be in the air flow path... you've got to balance performance vs longevity & on a street car I'd tend to favor longevity over trying to squeeze a little more performance at the cost of sacrificing longevity...
 
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