water injection question

[Richard Tanimura]

Brett,

You are correct, it was Corky Bell. That said, after reading and rereading
Corky Bell for years, I think he may be slightly dated - or maybe it is just
my early edition. I think he wrote a great primer on turbos. But I find no
discussion of topics like trim, shaving the wheels, hybrids, etc. I am sure
he knows a ton. E.g. the FAQs on his IC website are fabulous. I guess I just
stopped taking his stuff as scribed in stone.

My 0.02 Euros,

Richard

-----Original Message-----
From: quattro-bounces at audifans.com
[mailto:quattro-bounces at audifans.com]On Behalf Of Brett Dikeman
Sent: den 18 mars 2004 03:29
To: Jim Green; Livolsi, Stephane
Cc: Quattro list
Subject: Re: water injection question


At 3:07 PM -0800 3/17/04, Jim Green wrote:

><Stephane.Livolsi at investorsgroup.com> wrote:
>>  All this talk of water injection has got me thinking
>>  about following
>>  through and finally doing it.

Be prepared to buy a new exhaust with regular frequency; high
temperature steam is extremely corrosive.  Also, you need to use
rather pure water or you can expect a lot of mineral buildup in all
the wrong places, and it's a LOT harder to get off than carbon
deposits and such.  You will get fantastically clean exhaust valves
and combustion chambers though!

Also, you need to make absolutely sure you don't have any drips/leaks
when the engine is shut off, or you will have a very nasty surprise
next time you go to start it up!  Another problem is condensation; if
it's not finely sprayed enough, it'll condense on the walls of the
intake system and pool somewhere.  Freezing is another consideration,
so now you need to add something to the water to keep it from
freezing.

>  > 1 question I have is about the engine management.
>>
>>  water injection helps reduce detonation under high
>>  pressure and let's
>>  you advance the timing. right?

It reduces the intake charge air temperature and can provide some
in-cylinder cooling, depending upon where you inject and so on.

>  >
>>  So, if you install water injection, will the ecu
>>  'understand' that it
>  > can advance the timing and do that autonomically

Charge air temp reduction, yes- in cylinder cooling, no.


>With WI, you
>could probably increase the boost without getting into
>knock, then you wouln't be in the dangerouse situation
>of having your knock sensor control your timing for you.

Proper engine management doesn't use knock sensors to "control"
timing nor boost.  It is only designed to prevent engine damage; a
very important distinction there.

I believe Corky Bell's book states that "a properly designed
turbocharger system does not require water injection".  I got the
distinct impression he considered it a hack.  Could have him confused
with someone else though.

Brett
--
"They that give up essential liberty to obtain temporary
safety deserve neither liberty nor safety." - Ben Franklin
http://www.users.cloud9.net/~brett/
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