Miatapower List Archive

This read-only message was archived from a public mail list.
Mail From: Ron Van Vliet <(email redacted)>

Further to my post earlier this week regarding 100% duty cycle on my 440cc
injectors at 14 PSI on a 1.6 FM2:

Bought a fuel pressure gauge and tee'd in to supply line.

40 PSI at fuel prime. In spec.
35 PSI at idle. In spec.
Goes to 55 PSI under boost, fluttering about 2 PSI, eventually dropping off
to 48PSI at 7000RPM and 14 PSI.

Datalog of two runs while measuring fuel pressure showed max injector duty
cycle of 92%. Nothing but the ambient temps changed from runs where I
datalogged 100% duty cycle, so that's a bit puzzling.

How do the high-boost high-RPM fuel pressures compare to other's experience?

Ron Van Vliet

This read-only message was archived from a public mail list.
Mail From: "Ray" <(email redacted)>

Pressure should hold constant at 55 psi throughout the rpm range at 14psi
boost. If the filter has been replaced recently then I'd start looking at
the pump and/or the in-tank (pickup) filter.


----- Original Message -----
From: "Ron Van Vliet" <(email redacted)>
To: "Miata Power List" <(email redacted)>
Sent: Saturday, August 24, 2002 2:43 PM
Subject: Fuel Pressure Under Boost


> Further to my post earlier this week regarding 100% duty cycle on my 440cc
> injectors at 14 PSI on a 1.6 FM2:
>
> Bought a fuel pressure gauge and tee'd in to supply line.
>
> 40 PSI at fuel prime. In spec.
> 35 PSI at idle. In spec.
> Goes to 55 PSI under boost, fluttering about 2 PSI, eventually dropping
off
> to 48PSI at 7000RPM and 14 PSI.
>
> Datalog of two runs while measuring fuel pressure showed max injector duty
> cycle of 92%. Nothing but the ambient temps changed from runs where I
> datalogged 100% duty cycle, so that's a bit puzzling.
>
> How do the high-boost high-RPM fuel pressures compare to other's
experience?
>
> Ron Van Vliet
>
>
>
>

This read-only message was archived from a public mail list.
Mail From: Ron Van Vliet <(email redacted)>

Thanks Ray, I'll swap in a fresh filter Monday, re-test and post my results.

Ron

----- Original Message -----
From: "Ray" <(email redacted)>
To: "Miata Power List" <(email redacted)>
Sent: August 24, 2002 4:12 PM
Subject: Re: Fuel Pressure Under Boost


> Pressure should hold constant at 55 psi throughout the rpm range at 14psi
> boost. If the filter has been replaced recently then I'd start looking at
> the pump and/or the in-tank (pickup) filter.
>
>
> ----- Original Message -----
> From: "Ron Van Vliet" <(email redacted)>
> To: "Miata Power List" <(email redacted)>
> Sent: Saturday, August 24, 2002 2:43 PM
> Subject: Fuel Pressure Under Boost
>
>
> > Further to my post earlier this week regarding 100% duty cycle on my
440cc
> > injectors at 14 PSI on a 1.6 FM2:
> >
> > Bought a fuel pressure gauge and tee'd in to supply line.
> >
> > 40 PSI at fuel prime. In spec.
> > 35 PSI at idle. In spec.
> > Goes to 55 PSI under boost, fluttering about 2 PSI, eventually dropping
> off
> > to 48PSI at 7000RPM and 14 PSI.
> >
> > Datalog of two runs while measuring fuel pressure showed max injector
duty
> > cycle of 92%. Nothing but the ambient temps changed from runs where I
> > datalogged 100% duty cycle, so that's a bit puzzling.
> >
> > How do the high-boost high-RPM fuel pressures compare to other's
> experience?
> >
> > Ron Van Vliet
> >
> >
> >
> >
>
>

This read-only message was archived from a public mail list.
Mail From: "Ray" <(email redacted)>

If that 94% now produces a too-rich mixture (it might if you're autotuning
with a narrowband sensor) the current pump might do OK for a while.


----- Original Message -----
From: "Ron Van Vliet" <(email redacted)>
To: "Ray" <(email redacted)>; "Miata Power List" <(email redacted)>
Sent: Monday, August 26, 2002 7:44 PM
Subject: Re: Fuel Pressure Under Boost


> Well, I swapped in a new fuel filter this evening and sure enough,
although
> the old one had less than 5000 miles on it, saw an immediate improvement
in
> fuel pressure at high RPM's under maximum boost. 58 PSI max, dropping to
55
> PSI only at the rev limit. However, the datalogs I generated still show a
> max INJ% of 94. Any ideas? Still time for a new pump?
>
> Ron
>
> ----- Original Message -----
> From: "Ray" <(email redacted)>
> To: "Miata Power List" <(email redacted)>
> Sent: August 24, 2002 4:12 PM
> Subject: Re: Fuel Pressure Under Boost
>
>
> > Pressure should hold constant at 55 psi throughout the rpm range at
14psi
> > boost. If the filter has been replaced recently then I'd start looking
at
> > the pump and/or the in-tank (pickup) filter.
> >
> >
> > ----- Original Message -----
> > From: "Ron Van Vliet" <(email redacted)>
> > To: "Miata Power List" <(email redacted)>
> > Sent: Saturday, August 24, 2002 2:43 PM
> > Subject: Fuel Pressure Under Boost
> >
> >
> > > Further to my post earlier this week regarding 100% duty cycle on my
> 440cc
> > > injectors at 14 PSI on a 1.6 FM2:
> > >
> > > Bought a fuel pressure gauge and tee'd in to supply line.
> > >
> > > 40 PSI at fuel prime. In spec.
> > > 35 PSI at idle. In spec.
> > > Goes to 55 PSI under boost, fluttering about 2 PSI, eventually
dropping
> > off
> > > to 48PSI at 7000RPM and 14 PSI.
> > >
> > > Datalog of two runs while measuring fuel pressure showed max injector
> duty
> > > cycle of 92%. Nothing but the ambient temps changed from runs where I
> > > datalogged 100% duty cycle, so that's a bit puzzling.
> > >
> > > How do the high-boost high-RPM fuel pressures compare to other's
> > experience?
> > >
> > > Ron Van Vliet
> > >
> > >
> > >
> > >
> >
> >
>
>

This read-only message was archived from a public mail list.
Mail From: Ron Van Vliet <(email redacted)>

Well, I swapped in a new fuel filter this evening and sure enough, although
the old one had less than 5000 miles on it, saw an immediate improvement in
fuel pressure at high RPM's under maximum boost. 58 PSI max, dropping to 55
PSI only at the rev limit. However, the datalogs I generated still show a
max INJ% of 94. Any ideas? Still time for a new pump?

Ron

----- Original Message -----
From: "Ray" <(email redacted)>
To: "Miata Power List" <(email redacted)>
Sent: August 24, 2002 4:12 PM
Subject: Re: Fuel Pressure Under Boost


> Pressure should hold constant at 55 psi throughout the rpm range at 14psi
> boost. If the filter has been replaced recently then I'd start looking at
> the pump and/or the in-tank (pickup) filter.
>
>
> ----- Original Message -----
> From: "Ron Van Vliet" <(email redacted)>
> To: "Miata Power List" <(email redacted)>
> Sent: Saturday, August 24, 2002 2:43 PM
> Subject: Fuel Pressure Under Boost
>
>
> > Further to my post earlier this week regarding 100% duty cycle on my
440cc
> > injectors at 14 PSI on a 1.6 FM2:
> >
> > Bought a fuel pressure gauge and tee'd in to supply line.
> >
> > 40 PSI at fuel prime. In spec.
> > 35 PSI at idle. In spec.
> > Goes to 55 PSI under boost, fluttering about 2 PSI, eventually dropping
> off
> > to 48PSI at 7000RPM and 14 PSI.
> >
> > Datalog of two runs while measuring fuel pressure showed max injector
duty
> > cycle of 92%. Nothing but the ambient temps changed from runs where I
> > datalogged 100% duty cycle, so that's a bit puzzling.
> >
> > How do the high-boost high-RPM fuel pressures compare to other's
> experience?
> >
> > Ron Van Vliet
> >
> >
> >
> >
>
>