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RE: Re: "Cryogenic Freezing"

I have looked into Extrude Honing, but as you have found it is quite
expensive.  I've heard others who are interested in extracting the maximum
power report that it does really help (It is also possible to have the
turbo's turbine EH treated as well).  My goal is to eliminate sources of
future problems, so I am looking at the cryo-treatment as a way to keep my
EM from warping in the future ... backed up with a thermal coating to keep
the temperatures down, both inside the EM and the engine compartment.  

What I would recommend that you do is to compare the cost of a standard port
of the EM to the cost of the Extrude Hone.  I'll bet comparing these might
show a little less cost difference.  The thing I like about EH is that it
gets to places that are impractical ... if not impossible ... to access
using conventional porting.  In theory it does what you want to do ... wear
down material at places where the flow is being restricted, but the only
question I have is, does the abrasive material flow in the same manner as
exhaust gasses would?  BTW, my father told me that the US air force uses the
EH technique ... 

On the smooth surface vs. optimum flow question ... I know that smooth
surfaces on intake manifolds can actually end up reducing the maximum flow
... but there an attempt is made to keep the flow smooth is made.  I don't
know that this is practiced so much in the exhaust, where you're talking
about pushing out the seething exhaust gasses.  In any event you're talking
about coating the EM, which would smooth it as well.  

You say that you were contemplating having the RS2 EM cryo-treated ...
unless this thing has a tendency to warp or crack I don't really think
there's anything to be gained by doing that.  As I mentioned in my earlier
post ... it does not seem to be commonly done ...

I am by no means an expert on this stuff ... so the best thing for you to do
is to try to find someone who has BTDT for info based on experience.  

Good luck!
Steve Buchholz
San Jose, CA (USA)

> -----Original Message-----
> This is now going beyond the 'theoretical" - I've got a new 
> engine on order
> & just picked up an RS/2 manifold which I'm also thinking of 
> having cryo
> treated as well as "microcoated" for thermal heat control.
> In the course of making those calls, the subject of having the exhaust
> manifold "extrude" honed as also come up.  Have you looked 
> into that at all?
> It's, by comparison to the cryo & micro-coating, relatively 
> expensive.  I've
> had one opinion the effect hey, you don't or may not want 
> things too smooth
> on the exhaust side it can / may / will (??) adversely affect 
> exhaust pulses
> that drive the turbo??
> Would you know or have any ideas about this?
> Michael Pederson
> Two 93 S4's -
> Colorado
> -----Original Message-----
> From: Buchholz, Steven [mailto:Steven.Buchholz@kla-tencor.com]
> Sent: Monday, September 13, 1999 12:40 PM
> To: 'mpederson@bigfoot.com'; 'qlist'
> Subject: RE: Re: "Cryogenic Freezing"
> > improvement for all of the above evils that plague mankind.
> > Second, any ideas re: the sophistication required of the
> > service provider.
> > Is there for example a "recipe" book for how to cure?
> >  Does it vary from material to material?  I.e. do you have 
> to do your
> > aluminum head separate from your pistons?  How long does 
> the tempering
> > process generally take?  Is it one freeze thaw cycle or a dozen?
> > And finally, where or how is one going to see the proof of
> > the pudding?
> ... given that small internal stresses are a commonly found 
> to be the seed
> that causes a failure ... the statement that cryogenic 
> treatment is a cure
> for all evils might not be too far off ... :-)
> I'm pretty sure that the chambers run automatically, so it 
> might not matter
> too much which vendor you choose.  You might want to ask for 
> references and
> more info about the equipment they use.  There is a lot of 
> info available on
> the web.  I did a bit of a search about a year ago and found 
> a guy not too
> far away from where I live that had a fairly small chamber.  
> I am going to
> have my exhaust manifold treated soon ... it is pretty cheap 
> insurance.  The
> guy I've talked to is pretty up front ... he's told me that 
> he's never heard
> of anyone having an exhaust manifold treated before ... but 
> he's more than
> willing to treat mine if I'm convinced I want to try it ... :)
> If you want to have something like an engine treated you have 
> to have it
> completely disassembled.  This is partly due to size 
> limitations of the
> chambers, but also that you want to keep the assemblies as 
> small as possible
> to minimize thermal gradients (which can cause stress).
> The "proof of the pudding" is going to be difficult, as in 
> normal service
> your part would have lasted a long time ... and you're not 
> likely to notice
> that the EM _didn't_ warp ... :-)
> My recommendation to you is to do a bit of your own research 
> and decide for
> yourself if it is worth the expense ...
> Steve Buchholz
> San Jose, CA (USA)