A pretty good answer to the question and what lead up to it......

Some issue of a magazine published in mid 2005 using a Suzuki:


The questionable "story"...

Ti pipes make more hp (than stainless) and the dyno proves it.....

The test's conclusion surprised:
1. me
2. successful tuners I know
3. engineers I know
4. the pipe manufacturer

First... the conclusion (actually, the last word in it)
Ti really shouldn't make better power unless the pipe wasn't optimal in it's stainless version and the increased heat loss property of titanium corrected, in some amount, the deficiency in the geometry of the stainless steel exhaust.
Titanium conducts heat better than stainless steel and loses more heat energy - and that means lower gas velocity......... and unless the slower gas helped the original, slightly less than optimal stainless steel pipe's resonant factors, Ti would simply be slightly less efficient at gas extraction.



Exhaust systems are designed to control the velocity profile of the
exhaust gases along the length of the system through both geometrical
and thermal means. The material properties that affect exhaust system
performance are related to the material's ability to maintain gas
temperature and velocity (kinetic energy), primarily thermal
conductivity and heat capacity. To maximize gas energy, its thermal
energy transfer to the exhaust system tubing must be minimized by
selecting a material with lower thermal conductivity and lower heat
capacity (think silica or asbestos). Below are some material properties
that I pulled from http://www.azom.com/details.asp?ArticleID=1569 and

Ti ASTM Grade 2 - thermal conductivity: 21.6 W/m*C, heat capacity: 523
CRES 304 (18/8) - thermal conductivity: 16.2 W/m*C, heat capacity: 500

So, with properly-configured tubing geometry, the stainless steel system
should yield higher engine output, better durability and better
afford ability at the expense of a pound or two of system weight because
it maintains more energy in the gases to be used for scavenging and
stuffing the combustion chamber.
If you like, I can let you use our 2005 GSX-R1000 with stock, Akro SS and Akro Ti systems for testing... AABACAB or otherwise Phil
Collins/Genesis yourself to your heart's extent.

(name withheld to protect the qualified......)

> > -------- Original Message --------
> > Subject: Re: Story feedback? My 2nd response -
> > From: Marc Salvisberg <factory2@ix.netcom.com>
> > Date: Sat, September 24, 2005 10:03 am
> > To: xxxx@xxxxxxxxxx.com
> >
> >        (all following written in good humor)
> > 
> >  Hi Xxxx -
> > 
> >  I only 1/2way expected a response like this -
> >  I was imagining perhaps......
> > 
> >  Hi Marc -
> >  I understand what you are saying.
> >  I noticed that he didn't swap the pipes and maps back a second time.
> >  Hmmm... that only would have taken an hour or so to verify, I wish he would have done that to verify the results.
> >  Yes, it was interesting that even the people who made the pipe were somewhat surprised.
> >  Ok - I'll do what I can to get something up there. Try not to take 6 months.
> >  Thanks, Marc - Have a good weekend -
> >  XX
> > 
> >  lol! Maybe in another life! Oh, well!
> > 
> >  If science requires at least an A-B-A-B test to be valid, then this simply isn't valid - regardless of what you think
> >  that I think. Or what I really think. lol!
> >  Reality being the harshest concept for the world, luckily or unluckily, I'm not a journalist and you aren't a tuner.
> >  We both do well in our own corners - I could never do your job, I type way too slowly and run my sentences on an a
> >  maddening fashion accompanied by multiple conditional statements to make as sure as I can, that what I'm writing is
> >  as true as I can make it.
> >  I offered to do a more valid, more scientific test that would be verifiable - to professional standards, for free.
> >  As far as any testing that I had done with "Ti / steel comps", none of them were done to standards that I would publish - that's why "http://www.factorypro.com/tech/indextech.html" doesn't have "Titanium, does it make power?" in the "T" section.
> >  Best regards -
> >  Marc
> >  (btw - what the heck does 6 months and your friend Mxxx Hxxxxxxx have to do with me? I'm the guy who did your "114.7
> >  on pump gas" (120-122 est. on U4), 6 hour wonder, zx6r in two evenings, in between AMA practices! Remember?)
> > 

> >  xxxx@xxxxxxxxxx.com wrote:  MArc:
> >  
> >  If you're gonna complain, at least read the article first. The second test made
> >  more power, despite ambient air temp going up. So much for losing power due to
> >  the cases not being hot enough, 
What does ambient have to do with case temp? - I never even mentioned ambient. Any correction factor takes ambient
into account. I understand that I write long sentences, though. M
> >  and a new map was made for each pipe to address
> >  the richness question. And both pipes were run within 25 minutes of each other.
Never mentioned that, either. Even avoided it specifically. It *was* in the 1st response letter I *didn't* send, though. M
> >  Instead of assuming this test is not valid despite not having done your own
> >  back-to-back test, how about you get back to me when you've actually got
> >  something other than your untested opinion (like some test results) and your
> >  well-known hatred of anything done using a Dynojet dyno?
I did say that it didn't quite jive with my impressions - I did not claim or even insinuate to have done a valid test, valid 
enough to print. That's why I offered to do a valid test for XXX. Even with a dj dyno - I wouldn't have mentioned 
the article if they had done A-B-A-B.
I would have been curious what would be the results sans "tuned to an a/f ratio scheme, though - but, not enough to 
warrant an offer to help.
Hatred is your description of how you think that I think. Since the majority of your experience is with your dynojet 
sponsored team, I can understand your protectiveness of your business partners. If the shoe were on the other foot, I'd 
be a bit more elegant in my prejudices, though.
You have the big XXX gun and the people who know more, simply don't talk to you anymore. M
> >  And no, I'm not gonna
> >  send you a bike and pipes because I can't wait 6 months for the test to be
> >  completed. Hell, my friend Xxxx Xxxxxxxxx gave up and quit road racing by the
> >  time he got his bike back; now he's doing Super Moto and is selling the bike,
> >  after missing the heart of the road racing season!
In psychology, I think that's called "transference" - I have nothing to do with your friend or the 6 months
that he didn't use his bike - There's more to that than a one day pipe test? 6 months? Hmm..... was that a stock engine?
> >  
> >  Best regards,
> >  
> >  Xxxx Xxxxxx
> >  Xxxxxxxxxx Xxxxx
> >  
> >  
> >  Quoting Marc Salvisberg <factory2@ix.netcom.com>:
> >  
> >   Regarding: The Ti pipe made more horsepower and the dyno proved it -
> >  
> >  Whenever we find test results that seem to be unexpected, we generally 
> >  do the tests over or at least internally label the test results 
> >  "suspicious" and don't publish the results. Most all that's on the site, 
> >  www.factorypro.com, has been verified to eliminate flukes as well as 
> >  possible, and knowing that we always measure power under load with an 
> >  EC997 dyno, and not dj inertia style. We use the same dyno that Robert 
> >  Jensen, Vesrah Racing and F-USA uses.
> >  
> >  Since these mild steel / Ti pipe test results seem to surprise people 
> >  (to at least "one eyebrow raised" level) who might be considered 
> >  "experts" in building performance parts and then perhaps the lack of 
> >  what some might call proper test procedures, I'll leave this story as a 
> >  memory left in the "interesting result, might be something to it, but 
> >  maybe not" inconclusive bin of my memory.
> >  
> >  I guess that I could throw something else in - it doesn't necessarily 
> >  jive 100% with my experience with other "steel vs. identical Ti" pipe 
> >  experiences in the past. Sometimes Ti was better, sometimes it 
> >  wasn't..... Interestingly also, was that the usual result from ceramic 
> >  coating an existing exhaust system or wrapping the pipe in thermal wrap 
> >  *usually* also resulted in very little change in power, though, 
> >  sometimes the optimum jetting was different (odd, but true).
> >  
> >  Typical "high accuracy" method of testing, is A-A-B-C, A-B-C and are 
> >  desired, especially if the results are if the results aren't close to 
> >  what was expected.
> >  A = stock exhaust (for a control)
> >  B = mild steel system
> >  C = Titanium system
> >  with equal amount of time between each test to attempt to control heat 
> >  soak of the engine.
> >  The first test of the day (the first A, in our example) should be thrown 
> >  out (just a rule that we eventually came up with).
> >  If we don't see a consistent trend of results between the tests, then we 
> >  start looking for a new factor that we weren't previously monitoring.
> >  
> >  Also - the temp of the fuel does make a difference, so that should be 
> >  controlled - or at least monitored to keep it within a range during the 
> >  runs. I just did a Husaberg 450 that the hot fuel and frame air inlet 
> >  dropped 4 True hp after 4 hours of jetting changes - The next day, when 
> >  the fuel and air inlet was cooler it made 4 hp more True loaded hp.
> >  
> >  The engine case temperature also makes a difference - as much as 3% to 
> >  4% in True HP, depending on whether it's high, low or moderate. For 
> >  instance, a case temp of 140f will suck 2% to 4% heat power away from an 
> >  engine as compared to 180f case temp. 200f+ case temp. will start 
> >  dropping power, too, because the intake tract heats up and heats the 
> >  incoming air, lowering density.
> >  
> >  If the fuel injection is set a bit richer than what the engine wants, 
> >  it'll make less power on subsequent runs. The inverse is true, also.
> >  Using an O2 sensor to arrive at a "desired" a/f ratio as a tuning goal, 
> >  rather than providing the amount of fuel that the engine actually wants, 
> >  usually results in less than optimal power for several different 
> >  reasons. If you give the engine the fuel that it wants, it makes best 
> >  power and it's less sensitive to small temperature changes.
> >  
> >  The warmer the drive roller and the warmer the tire, the better the 
> >  traction on marginal traction surface, like a used knurled drive 
> >  (anything not "sharp" is worn). The higher the rate of transferred power 
> >  (less slippage) = higher hp. Newer design chassis dynes use a licensed 
> >  slotted drive roller concept for about 33% better traction, and hence 
> >  less heat, tire wear and better power transfer.
> >  We use a slotted drive roller instead of a knurled driver roller to 
> >  decrease the knurled drive roller error.
> >  
> >  I know it's difficult to do testing on a journalist's tight schedule, 
> >  from the 04 ZX6rr XXX Project bike experience, but I can donate the time 
> >  and experience.
> >  
> >  Provided with a test bike and the 3 exhaust systems and a week, I'd be 
> >  happy to redo the tests - then we'd be as sure about the power 
> >  differences between the steel and Ti. (At least as we are sure that 
> >  there is only one dimensional difference between the pipes.)
> >  
> >  To make it really sure that it's not an M4 unique design something or 
> >  other, we should probably have another manufacturer's identical mild 
> >  steel and Ti pipes to verify - like Yoshimura? Muzzy?
> >  
> >  Best regards -
> >  
> >  Marc Salvisberg
> >  
> >  
> >  
> >  -- 
> >  Marc Salvisberg
> >  Official Dyne system of Formula USA - Home of TrueHP.com
> >  
> >  Factory Pro Tuning
> >  179 Paul Drive
> >  San Rafael, CA 94903 USA
> >  800 869-0497 USA/CN
> >  415 883-5620
> > > > www.factorypro.com > > www.truehp.com ....................
Some people have their own magazines and can pick and choose what and who 
they want to pump up and who to ignore. 
I don't have a magazine - I just have this lonely ole website that a million people have visited....
Ever wonder what happens behind the scenes in industry that you usually don't ever hear about?