ECU tuning: was; The whole 1.8T puny injector debacle

[amalventano1@comcast.net (Allyn)]

holy crap, i was messed up again!
i thought the rising rate ones compensated 1:1
now that i think about it, i suppose 'rising rate' should have clued me into what it actually does
:)
sorry bout that
(Al` smacks himself in the forehead)

----- Original Message -----
From: "Dan Bubb" <jdbubb@ix.netcom.com>
To: "Allyn" <amalventano1@comcast.net>; "Joe Doty" <rocco2nr@hotmail.com>
Cc: <scirocco-l@scirocco.org>
Sent: Sunday, June 16, 2002 7:04 AM
Subject: Re: ECU tuning: was; The whole 1.8T puny injector debacle


> A normal FPR maintains a constant fuel pressure above manifold pressure i.e.
> the  if you have a 4bar FPR then if manifold pressure is 1 bar absolute then
> the fuel pressure is 4 bar. If the manifold pressure is 2 bar absolute (15
> psi boost) then the fuel pressure is 5 bar.
> A rising rate FPR increases the fuel pressure faster than an increase in
> manifold pressure. So, a 2:1 rising rate would give 6 bar at 15 psi boost in
> the above example.
> If you've actually programmed an ECU then you would know that programming
> for a regular FPR is relatively straight forward. Programming for a rising
> rate throws another curve into the equation that makes it more difficult to
> intuitively see what the map needs to look like.
> Rising rate FPR's allow more power from smaller injectors. OEM's may use
> them since with a smaller injector they will have better fueling control at
> idle and low load conditions for cleaner emissions, longer CAT life, less
> expensive injectors......
>
>
> ----- Original Message -----
> From: Allyn <amalventano1@comcast.net>
> To: Joe Doty <rocco2nr@hotmail.com>
> Cc: <scirocco-l@scirocco.org>
> Sent: Saturday, June 15, 2002 10:36 PM
> Subject: Re: ECU tuning: was; The whole 1.8T puny injector debacle
>
>
> > eagle talon tsi as well as alot of audi models come with rising rate fpr's
> (where do you think us
> > cheapasses get em from?). yes, some factory turbo cars come with rising
> rate fpr's (i doubt they are
> > taking any kind of 'cheap route' there..
> > i misspoke there on taking map out of the equation, it doesnt do that, but
> it does let you get more
> > boost ran on lower flow injectors. a rising rate fpr compensates for
> change in manifold pressure,
> > thus keeping a constant d/p across the injectors in all conditions
> (normally the d/p drops as boost
> > rises, effectively lowering the flow rate of your injectors). this
> compensation makes tuning easier
> > as it turns one of the variables into a constant. it also makes the range
> of the fuel map smaller in
> > the end (doesnt have to go way up to compensate for increassed manifold
> pressure).
> > Al
> >
> > ----- Original Message -----
> > From: "Joe Doty" <rocco2nr@hotmail.com>
> > To: <amalventano1@comcast.net>
> > Cc: <scirocco-l@scirocco.org>
> > Sent: Saturday, June 15, 2002 9:23 PM
> > Subject: Re: ECU tuning: was; The whole 1.8T puny injector debacle
> >
> >
> > > I would disagree with you there.  A rising rate FPR a cheap way to get
> more
> > > fuel without touching the fuel injectors or fuel maps.  Most kits that
> use
> > > rising rate FPRs max out at 8-9 psi.  It's an enrichment device.
> > >
> > > I believe the best way would be an adjustable FPR.  If you are able to
> > > adjust the mappings via a chip or standalone management, tuning it
> properly
> > > there would be the best idea.
> > >
> > > >yea, rising rate fpr is a good move on turbo cars. it takes manifold
> > > >pressure changes out of the
> > > >equation
> > >
> > > Most fuel maps ARE based on manifold pressure changes.  It's probably
> better
> > > to tune the car there rather than futzing with the fuel pressure.
> > >
> > > Joe
> > >
> > >
> > >
> > >
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