DIY_EFI Digest       Friday, September 17 1999       Volume 04 : Number 530



In this issue:

	Newbie questions #438-443
	Re: DIY_EFI Digest V4 #529
	RE: O2 and water question

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Date: Fri, 17 Sep 1999 13:41:52 +0200
From: Nic van der Walt <nvdw@xxx.za>
Subject: Newbie questions #438-443

Jo

I'm designing the parts I'll have manufactured for my bike's
EFI manifold and have been wondering about a couple of things.

Is there a standard form factor for injectors that I can base
the design on? Can I for example design for a Bosch injector
and then be able to swap injectors around until I get a type
that works well? Anyone have any dimensioned drawing they are
willing to share?

I take it the dynamic range of an injector is determined by the following
parameters:
Minimum on time.
Maximum flow. ( Depends on maximum pressure and nozzle )
Maximum on time ( Depends on max RPM and duty cycle  <140uS for 14000rpm )

What is a reasonable minimum on time for an injector? The injector
will have to flow around 3.5l/h at WOT. How do I go about actually
buying something? Any brand to look out for? What is a good fuel
pressure to work at?

I intend referencing the the fuel pressure regulator from the surge
tank to ensure the pressure differential across the injector is 
independent of boost pressure. Is it then correct to assume the 
charge delivered for a given pulse width stays constant regardless
of actual boost?

The bike currently has four carbs. I have been considering using the carbs
as is, closing of all the ports and mounting the injector basically opposite
of where the main jet used to be. This makes the mechanical side of things
very 
simple and cheap, but places the injector at a right angle to the air flow. 
Will this affect anything? Should the tip of the injector protrude into the
airflow or not?

Thanks
Nic.

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Date: Fri, 17 Sep 1999 11:59:15 -0400 (EDT)
From: William T Wilson <fluffy@xxx.org>
Subject: Re: DIY_EFI Digest V4 #529

On Fri, 17 Sep 1999, DIY_EFI Digest wrote:

>  I recently read some messages claiming O2 sensors could be damaged by
> water in the exhaust stream.  Is this true?  Would it have to be liquid
> water, or would steam be a problem?  I'm contemplating substantial water

I haven't heard of this.  Water is a combustion byproduct and comes out of
the exhaust in spades.

Just to be safe, it's probably best to keep liquid water away from the O2
sensor, but water vapor is safe.

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Date: Fri, 17 Sep 1999 11:05:28 -0700
From: "Buchholz, Steven" <Steven.Buchholz@xxx.com>
Subject: RE: O2 and water question

>  I recently read some messages claiming O2 sensors could be damaged by
> water in the exhaust stream.  Is this true?  Would it have to 
> be liquid
> water, or would steam be a problem?  I'm contemplating 
> substantial water
> injection to control detonation under boost; this is all 
> going to go out
> the exhaust valve as dry steam.

... given that one of the byproducts of the combustion process is water I
can't see why a bit more vapor from a water injection system would cause any
harm ...

Steve Buchholz
San Jose, CA (USA)

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End of DIY_EFI Digest V4 #530
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