Vacuum source for vette FPR
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Vacuum source for vette FPR Does anyone know where to tap into for a vacuum sourve for the FPR that comes on the '97 vette fuel rail? I have heard that it comes from in front of the TB. Is that true? It seems like it would be using the wrong type of vacuum. Shouldn't it use manifold vacuum? Thanks for the help.
The 97 vette FPR doesn't use vacuum. It uses barometric or atmospheric pressure as a reference and has a sensing line that senses pressure outside of the engine compartment to get a better reading.
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Originally Posted by 70 LS1
The 97 vette FPR doesn't use vacuum. It uses barometric or atmospheric pressure as a reference and has a sensing line that senses pressure outside of the engine compartment to get a better reading.
Joined: Nov 2001
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From: Anderson, Indiana
You don't even have to put a hose on it at all. It will work just fine left open.
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91 Z28 LS2 408CI, LS9 Supercharger, LPE GT7 cam, Yank3000, 3450 raceweight.
Latest numbers: 9.71 ET, 141.42 MPH, 1.40 60' , 610 RWHP Mustang Dyno
www.speartech.com
91 Z28 LS2 408CI, LS9 Supercharger, LPE GT7 cam, Yank3000, 3450 raceweight.
Latest numbers: 9.71 ET, 141.42 MPH, 1.40 60' , 610 RWHP Mustang Dyno
www.speartech.com
Don't think of it as a vacuum reference. The LS1 is different in that it runs a constant fuel pressure regardless of engine load. Because of that it needs a constant reference for its FPR. Post 98 vettes don't even use this type of regulator.
The vacuum sensing regulators need to vary fuel pressure with engine load, i.e. vacuum.
The vacuum sensing regulators need to vary fuel pressure with engine load, i.e. vacuum.
the ls1 is a stupid system 58 psi static.
the normal "vacuum referenced" type is nice, as you get a constant differential between the intake, and the rails, great for tuning.
the 58 static of the ls1 is alrightunless you go forced induction, and then your injectors get smaller as you get into boost (NOT GOOD)
Ryan
the normal "vacuum referenced" type is nice, as you get a constant differential between the intake, and the rails, great for tuning.
the 58 static of the ls1 is alrightunless you go forced induction, and then your injectors get smaller as you get into boost (NOT GOOD)
Ryan
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So basically, that open port just gives it a constant vacuum to provide a constant fuel pressure. I guess that makes sense. Come to think of it, I don't recall seeing a vacuum port on the '98 and later vette regulator/filter assemblies.
Like I said before, that seems odd, but it makes sense. I guess I'll just leave it open. Just out of curiousity, what would happen if it was hooked to manifold vacuum? How would it affect the fuel pressure, if at all?
Like I said before, that seems odd, but it makes sense. I guess I'll just leave it open. Just out of curiousity, what would happen if it was hooked to manifold vacuum? How would it affect the fuel pressure, if at all?
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To answer your question the OEM location for this connection is a hole in the rubber bellows just in front of the TB and behind the MAF conenction. This is how mine is set-up (I just poked a hole, inserted the tube with a dab of silicone) and it now mimic's the OEM set-up (less the silicone!).
Joined: Nov 2001
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From: Anderson, Indiana
Originally Posted by bad86z28
So basically, that open port just gives it a constant vacuum to provide a constant fuel pressure. I guess that makes sense. Come to think of it, I don't recall seeing a vacuum port on the '98 and later vette regulator/filter assemblies.
Like I said before, that seems odd, but it makes sense. I guess I'll just leave it open. Just out of curiousity, what would happen if it was hooked to manifold vacuum? How would it affect the fuel pressure, if at all?
Like I said before, that seems odd, but it makes sense. I guess I'll just leave it open. Just out of curiousity, what would happen if it was hooked to manifold vacuum? How would it affect the fuel pressure, if at all?
__________________
91 Z28 LS2 408CI, LS9 Supercharger, LPE GT7 cam, Yank3000, 3450 raceweight.
Latest numbers: 9.71 ET, 141.42 MPH, 1.40 60' , 610 RWHP Mustang Dyno
www.speartech.com
91 Z28 LS2 408CI, LS9 Supercharger, LPE GT7 cam, Yank3000, 3450 raceweight.
Latest numbers: 9.71 ET, 141.42 MPH, 1.40 60' , 610 RWHP Mustang Dyno
www.speartech.com
sorry to drag this up... on a LT1 car, with LS1 engine vette ealry rails.. is the reg rail mounted? could I hook it up to a vacuum source, plug stock fuel lines into it and go?
Joined: Nov 2001
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From: Anderson, Indiana
Yeah, or just hook it all up and skip hooking up a vacuum line and be even better.
The 97-98 Vette fuel pressure regulator is rail mounted but not vacuum referenced.
The 97-98 Vette fuel pressure regulator is rail mounted but not vacuum referenced.
__________________
91 Z28 LS2 408CI, LS9 Supercharger, LPE GT7 cam, Yank3000, 3450 raceweight.
Latest numbers: 9.71 ET, 141.42 MPH, 1.40 60' , 610 RWHP Mustang Dyno
www.speartech.com
91 Z28 LS2 408CI, LS9 Supercharger, LPE GT7 cam, Yank3000, 3450 raceweight.
Latest numbers: 9.71 ET, 141.42 MPH, 1.40 60' , 610 RWHP Mustang Dyno
www.speartech.com
Joined: Nov 2001
Posts: 1,707
Likes: 33
From: Anderson, Indiana
No I don't. In fact I really don't even look for them anymore. We use the Corvette filter/regulator for most of the swap stuff anymore. You could use that and just plug the LT1 feed and return into the filter; and then just fab 1 line from the filter to the LS1 fuel rail.
__________________
91 Z28 LS2 408CI, LS9 Supercharger, LPE GT7 cam, Yank3000, 3450 raceweight.
Latest numbers: 9.71 ET, 141.42 MPH, 1.40 60' , 610 RWHP Mustang Dyno
www.speartech.com
91 Z28 LS2 408CI, LS9 Supercharger, LPE GT7 cam, Yank3000, 3450 raceweight.
Latest numbers: 9.71 ET, 141.42 MPH, 1.40 60' , 610 RWHP Mustang Dyno
www.speartech.com
Last edited by Speartech; Nov 17, 2004 at 11:28 AM.
