Date:         Thu, 20 Dec 2001 22:15:03 -0600
Reply-To:     Marshall <mjruskin@HOME.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Marshall <mjruskin@HOME.COM>
Subject:      Re: Boston Bobs day at the dyno
Content-Type: text/plain; charset="iso-8859-1"

This is an interesting topic - how much headroom does DigiFant/DigiJet have
for performance increase?

According to that Bosch book on fuel injection tuning - not much, especially
at higher RPM's. - plus, you'd have to recalibrate the AFM for the
additional airflow, too. Tricky.

What does have TREMENDOUS headroom, though - is CIS.

I cannot help but think that if one want's more HP from a 1.9 or a 2.1- the
thing to do is to incorporate a CIS system from another vehicle. Maybe even
add dual injectors or dynamic fuel pressure!

Marshall Ruskin
84 Westy, Winnipeg Canada

----- Original Message -----
From: "Chris Stann" <ChrisS@INFORMS.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Thursday, December 20, 2001 10:51 AM
Subject: Re: Boston Bobs day at the dyno


> I am attempting to apply some rational thinking to the lean-mixture
dilemma.
> Tell me what you think.
>
> It appears that the stock FI system was unable to compensate for the
> additional air flow.  It seems that the Air/Fuel system either maxed out
or
> still thinks you are running same amount of air through the engine.
Several
> possibilities come to mind:  1)  The oxygen sensor is bad - not likely  2)
> The fuel injectors are unable to flow more fuel even with higher fuel
> pressures and/or 3) the AFM is either not perceiving the increase in air
> flow above the factory requirements or is unable to relay this information
> to the injectors.
>
> Such issues are nothing new to the tuners, such as Bob.
>
> It seems that bolt-on modifications, such as ratio-rockers, would have
> limited effect if the above issues are not resolved.  I find this a bit
> puzzling since some people did report power increases with just ratio
> rockers.  After all, we've all been told that the FI systems have some
> ability to compensate for air-flow changes.
>
> Chris,
>
> '85 Westy.