[urq] Interesting question about manifolds?

[Buchholz, Steven]

... definitely agree on the EH stuff ... although I'm not sure how much it costs to get the manifold Extrude Honed.  The upside is that EH would give you a clean surface for the coating to attach to.  

Opinions vary to be sure, but if the goal is to keep heat in the exhaust gasses and minimize underhood heating (my goals) all you should really need is to coat the inside of the part.  If you coat the inside and outside then all energy that gets through the interior coating would end up in the casting and could cause warping and cracking.  

I *still* have a brand new 2-piece EM in my garage ... at one time my plan was to have the parts cryo-treated first ... have the manifold surfaces replanarized if needed ... perhaps EH ... and then ceramic coated inside and out.

I don't have BTDT on the risk of possible damage that the ceramic coating getting burned off the inside of the manifold might pose to the turbo, but I figure there are already some small bits in the exhaust from time to time as is ... carbon deposits and such ... so I doubt there's much risk of turbo damage from the coating flaking off.  Now, some nut or washer sucked into the intake tract somehow can cause some real damage!

Steve B
San José, CA (USA)
> 
> I think I'd go the extrude hone way before coating the inside of
> anything for the intake tract.
> 
> On Dec 12, 2006, at 4:33 PM, quattrodude at comcast.net wrote:
> 
> > Since it looks like I will be ceramic coating either the manifold I
> > have, or another I can find in good shape...(patience is an 83 Semi
> > stock URQ)
> > Should one also coat the INSIDE? as well as the outside? does it
> > make sense? would it flake off? if not done right and damage the
> > turbo? and I guess I would consider doing the down pipes and waste
> > gate too?
> > look nice as well? thoughts comments?