RE: Water Injection

[jacobss@greatoaks.com]

Water injection only has its big gains on supercharged engines - like every
HP idea it comes and goes in favor.  Back in the early 80s some VW turbo
people used water, RAJAY kit comes to mind.  The air cooled people also used
it, probably more than the water pumpers.  The main advantage then and now
was a slight cooling effect on the charge as the water turned into vapor -
you will cool the charge ~20F or so.  And water increased the octane rating
of the fuel - still does.   Water injection has been around since the
beginning the supercharged engine, why cheap way to make more power or help
prevent detonation.  In W.W.II we used it on some aircraft engines.

Lets see why it is not used today much.
Intercoolers can drop the charge much more effectively, if my intercooler
only dropped the charge temps buy 20F I would toss the thing.  The advent of
fuel-injection that is sensor smart for metering fuel.  FI has made the
turboers dreams come true.  In the old days we relied on carbs to do the
trick - no it is PFI (programmable fuel injection)  Why because it can
change the fuel map to meet all sorts of variance in the engines
environmental demands.  It works well with a turbo in keeping the fuel
matched with the air mixture.  The Callaway and other systems got around
this on the K jet cars by adding another FI system to add fuel at boast - to
supplement the K-jetronic system.  Another is weight and reliability - water
weights ~ 8 pounds per gallon, and if you relay on water to make up the
octane and cooling of the boast charge, what happens when you forget to fill
the tank.  Probably an expensive bill, VW bottom ends are strong, but they
don't like an over boasting.

Also as Shawn mentioned water has a wearing effect, and depending on where
you place its injector will determine how much effect it has on the system
as a whole.  If place before the turbo - you intake wheel will get blasted,
and eaten away over time, much faster wear cycle.  If placed after the turbo
before the intercooler - you may get pooling in the intercooler, plus you
have to pump the water at a higher rate to over come the boost pressure.
After the intercooler is a good choice but still must pump it in at a high
pressure than you current boast pressure.  And you can get much the same
effect by spraying water onto the surface of the intercooler thus dropping
the core temp of the charge and not adding the wear factor - or use a more
efficient intercooler.

HTH

Stephen Jacobs

> -----Original Message-----
> From:	skerocdriver@juno.com [SMTP:skerocdriver@juno.com]
> Sent:	Friday, August 21, 1998 2:14 AM
> To:	stv@cyberdude.com
> Cc:	scirocco-L@scirocco.org
> Subject:	Re: Water Injection
> 
> 
> On Fri, 21 Aug 1998 01:24:33 -0700 Stv <stv@cyberdude.com> writes:
> >I have noticed no one is talking about  Water Injection at all.
> >
> >I have always believed that Water Injection is a great thing for cars.
> >
> >Any opinions???
> >
> >Regards.
> 
> 
> Kind of a boring topic is why. :)
> 
> Actually, water is a great way to enhance power. In a stock motor, it
> wont do MUCH to give added power. Also, introducing water into the intake
> system does tend to speed up the wear process. Valves and seats corrode
> faster. Water just wreaks havoc on everything inside the motor.
> 
> Now, if your building a purpose built race motor, whether it be drags or
> whatever, water in addition to a Supercharger or turbo can give good
> gains making the tradeoff, worthy. I tend to watch the import drag racing
> scene (Since its really the hot ticket right now for the import car
> scene) and althought they have really stepped up to the plate with
> amazing turbo systems, I have yet to see one application that uses water
> injection in addition to a turbo and intercooler. I've recently seen an
> advertizement in turbo mag offering a water injection kit. So maybe there
> is hope. 
> I think NOS is a cheaper alternative to buying motor parts too. (As if
> you wont stretch a few valves with that drug..... :)
> 
> 
>               Shawn Meze
> 86' Jetta GLi           82' Scirocco GTi
> The Fastest, Quickest, Cleanest and
> best looking Scirocco in all of San Diego!
> http://www.Geocities.com/MotorCity/Speedway/1308/index.htm
> 
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