"trainfan1" wrote in message
et...
Del Cecchi wrote:

"trainfan1" wrote in message
...

K. Smith wrote:

trainfan1 wrote:


K. Smith wrote:


That's the exact issue runaway your marketing is based on your
"claims" & every single time they're independently tested (so far)
you are found out as fudging. When independently tested a Merc made
the claimed 250HP (+),



On premium fuel, required, on a factory hopped-up motor...


The article makes it clear the Bomb people were there prepping their
motor also, so I'd say it's independent testing, the losers will
always have the dealers making excuses. In this case the Bomb engine
was 13HP below the Merc that's a fair bit of HP.


a Yamaha was slightly under it's claimed 250HP & your engine Co's


was way down on HP & to some users more importantly; torque.



BUT the peak torque comes in at a lower & more usable rpm...


I think that's a fair comment & probably it would have been relevant
if the engine made the claimed HP as the others in the class did, but
when it's only a 239HP engine it sounds like the dealers are trying
to still sell no matter what???

Remember these engines are thousands of dollars dearer than the
competition, not hundreds but thousands!!!! Where is that extra money
going?? certainly we can't see it going into the engines which are
simple old style 2 strokes with a ficht injector system??? No
multiple variable timing cam shafts,multi valves per cyl,super
chargers,world leading & proven GM technology base?? none of that
with these super priced whipper snipper motors.

The clear suspicion needs to be that the "extra" money is being
thrown at the dishonest dealers so they'll flog them & say/do
whatever it takes to make their windfall profits. There's no way the
dealers or bomb will ever admit any of this indeed the rebate,
subsidy, training BS money return schemes are so well hidden not even
dealer staff are aware. The same marketing ploy was used to flog the
Fichts & the dealers of course even in this NG denied it all day
long, till the bankruptcy court uncovered the truth when the dealers
tried to recover the kickbacks. Which was Her Honour found the
dealers had extracted 30% post retail sale kickbacks & that they were
never entitled to them, indeed we were hoping she'd refer them for
resale price maintenance:-) The dealers were flogging known defective
ficht engines for extra money (one even made it clear they'd said
they'd stop selling ficht unless they got bigger rebates etc).

Now these dealer idiots think they can run the exact same scam &
nobody will say anything??


A name change doesn't clear the slate,



It's more than a name change - & you know it... actually you
probably don't...


It's nothing more than a name change, all the claimed "improvements"
are about trying to get enough engines to hold together long enough
that the dealers will sell sell sell for their super markup??.

How does a treated bore stop detonation??

Better & more even heat transfer to water jackets eliminating hot
spots in the chamber.


How do high melting point pistons stop detonation???

Endothermic friendly metallurgy promotes heat transfer from hot piston
centers & to cylinder walls & water jackets. Lowers & evens cylinder
temperatures reducing detonation.


Could you explain what "Endothermic friendly metallurgy" is?

No.

Well, the alloy used in the pistons can absorb and transfer heat more
readily. If they had to, they could even go to ported pistons for even
more transfer.

So this is some alloy significantly different from the aluminum alloys
used for conventional pistons?




How does high temp oil & then even less of it stop detonation??

Low ash high temp oil has a higher flash point, resisting
combustion/dieseling syndrome, reducing detonation.


I thought they used TCW-3. Do they require some unusual oil to be
reliable?

Only if you commit to it and have the engine rigged for it.
Are you saying that this special oil is necessary to achieve reliability
in etec?




How does an impact injector/garden hose nozzle combo provide enough
atomisation to stop detonation???

It doesn't. The combination of chamber shape, heat dissipation,
cylinder, piston, & head materials, as well as coatings, all affect
flame travel, & tendencies toward detonation or not. The injector
system, however you may "want" to characterize it, is at the end of
the whole process. Controlled by a properly programmed ECM, the
injectors should provide an optimum charge, atomized enough for good
combustion, and in sufficient quantity for additional cooling of the
compression/injection stroke, with proper droplet size, all to attain
stoichiometric proportions in the approach to complete combustion.
This is the balancing trick - and hence the other tweaks - the lean
charge must also be enough to complete the cooling process too.

I didn't know gasoline absorbed that much heat when evaporating. Is
this really a significant factor?

In 2 strokes it sure is. The fuel is part of the cooling system.

OK, here is a calculation. Air has a specific heat of 723 J/kg-degree,
and gasoline has a latent heat of vaporization of 300kJ/kg. So at 15 to
1 you get 20kJ or about 30 degrees celsius, less at leaner mixtures.
That about right? Is that really significant in preventing detonation?
Doesn't seem like much help in cooling the motor to lower the temp by 30
degrees.

And saying what the "properly controlled by ECM injectors *should* do
sort of begs the question of what they actually do.

Well, a 14.7:1 A/F Ratio is ideal, but not attainable in practice, as
there is not enough time in direct injection to vaporize the fuel. A 2
stroke will leave behind some exhaust gasses too. The injector must
be able to atomize the fuel into droplets small enough to approach
vapor, but large enough to absorb some of the heat of combustion. What
E-Tec is trying to do is minimize the losses associated with
overlapping strokes in 2 stroke design theory, while using as little
fuel as possible. The chamber design is very critical.

The above is sort of a truism, eh? Droplet size shouldn't matter in heat
absorbtion because it all evaporates as it burns, right? The trick is to
get it to evaporate so it can be burned at the right time.

How does running an engine at power on hugely lean mixtures stop
detonation??

This is the balancing trick - and hence the other tweaks - the lean
charge must also be enough to complete the cooling process too.

it caused the base heat buildup that starts detonation.

How does a beefed up huge extra drag gearcase stop detonation??

Keeps the Sidewinder/Switzer kids from picking this model to run WOT
all day long up on a jack plate...


Better not put one on your bass boat. Those guys love their jack
plates. And they love WOT.

I just made that up.

Oh. I have heard that some of the etec motors were having lower unit
problems, not that that would have anything that I can see to do with
the fuel induction system .


The answer is none do: all those things are a lame (is not an MP3
emulator:-)) attempt to make the engines able to withstand the
inevitable detonation consequences when run lean at power on poorly
atomised low pressure injection with very questionable lubrication.

Thanks for the E-Tec spruik Rob but hey I'm sure you got a lucrative
deal to fit them?? much more dollars than the other brands???

You REALLY don't know me...

but what is it to your advantage to de-spruik something you don't
understand?



Always looking for technical details. The geekier the better.

del


I can see the dilemma and confusion K. Smith is facing, but the engines
do work. The BRP units are an improvement over the OMC offerings,
which did have isolated issues - as there are thousands still in use.


Yes, but there was a significant failure rate among at least the 150/175
Fichts. Is more rugged construction, (presumably) higher pressure
injection, and new combustion chamber/piston shapes sufficient to resolve
them?

I have been curious for some time about why the 150/175 was said to have
many more problems than the big blocks. Do you have a theory? Or even
facts?

del