Can anyone recommend a good high flow one? I am seeing 32-38 psi at the test port, and the fuel pressure safety switch for the nitrous system keeps cutting out. How hard is it to replace?
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1995 Firebird Formula
(A4 3.23)Ram Air w/ K&N, TransGo Shift Kit w/3 washers
,SLP~Shorty headers, LoudMouth, Air Foil, LineLocks. Catco Cat. Hypertech 160. TB Bypass. MSD~8.5mm. Walbro 255lph. FT MAF ends. LT4KM. BMR~Adj LCA's, Rear sway, Panhard rod. HAL QA1 rear shocks. Random Tech adj TQ arm. Nitto NT555R's. Covered in Zaino. 13.466@103.85 N/A. [1.948 60' 
13.410 @ 102.66 11/20/05] -
CHeclk the pump by watching the gauge while giving it WOT. The pressure should not drop at all. IF it does, time for a new pump. Changing it is not horrible. I would recommend cutting the access hole in the floor of the trunk. YOu can find directions if you search google. You have to install the new pump in the "module" which is a plastic "bucket" that containd the pump itself. You will need a good epoxy that will withstand the gasoline to put it back together.
Check these guys out. They have real good prices on the walbro pump specifically designed for our cars.
http://www.autoperformanceengineering.com/96 WS6 Formula: Ram Air, 383 Stroker, Ported LT4 Heads and Manifold, 1.6 Crane Rollers, 58MM T.B., AS&M Headers, Borla Exhaust, Meziere Elec. H2O Pump, Canton Deep Sump Oil Pan, 100 HP OF TNT N2O!! , T56 Conversion w/ Pro 5.0 shifter, SPEC Stage 3 Clutch, Hotchkiss Subframe Conn., Lakewood Adj. Panhard Bar, Spohn Adj. LCA's, BMR Adj. T.A., Custom 12 bolt w/ 3:73's, Moser Axles, Eaton Posi, Moser Girdle
11.6 @ 123mph (1.6 60' - getting there
)
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The NX guage is bouncing at 34-36 psi under light/mid throttle, nitrous not engaged. My future plans are for a procharger, with the nitrous to hold me over untill then. I want to step up to a 125 shot eventually, if I can find out where to get the jets. Should I go to 255, or is the 190 good enough?1995 Firebird Formula
(A4 3.23)Ram Air w/ K&N, TransGo Shift Kit w/3 washers ,SLP~Shorty headers, LoudMouth, Air Foil, LineLocks. Catco Cat. Hypertech 160. TB Bypass. MSD~8.5mm. Walbro 255lph. FT MAF ends. LT4KM. BMR~Adj LCA's, Rear sway, Panhard rod. HAL QA1 rear shocks. Random Tech adj TQ arm. Nitto NT555R's. Covered in Zaino. 13.466@103.85 N/A. [1.948 60' 13.410 @ 102.66 11/20/05]Comment
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34-36 sounds low. YOu should be at about 41 or so. GO with the 255 as long as your in there.
This is the part # you need. Walbro F20000169.96 WS6 Formula: Ram Air, 383 Stroker, Ported LT4 Heads and Manifold, 1.6 Crane Rollers, 58MM T.B., AS&M Headers, Borla Exhaust, Meziere Elec. H2O Pump, Canton Deep Sump Oil Pan, 100 HP OF TNT N2O!! , T56 Conversion w/ Pro 5.0 shifter, SPEC Stage 3 Clutch, Hotchkiss Subframe Conn., Lakewood Adj. Panhard Bar, Spohn Adj. LCA's, BMR Adj. T.A., Custom 12 bolt w/ 3:73's, Moser Axles, Eaton Posi, Moser Girdle
11.6 @ 123mph (1.6 60' - getting there )
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The stock pump, if its healthy, should support your mods and a 50-shot. Do the correct fuel pressure check.
Start the engine and pull the vacuum compensation line off the fuel pressure regulator. Pressure spec is 43.5psi, but the factory manual says anything from 41-47psi without the vacuum line is acceptable.
Reattach the vacuum line, and fuel pressure should drop proportional to intake manifold vacuum. For a stock cam, you could see idle values as much as 8psi below what you measured with no vacuum line attached.
When you drive, fuel pressure will vary with throttle position. At part throttle, its going to dance around from 36-40psi. At WOT, it should return to the "no vacuum" value, and stay within 2psi of the "no vacuum" pressure all the way through max rpm/max power.
If the pump can't keep up, it needs to be replaced. A lot of people seem to go with the Walbro 255, which is available alone, or in a variety of install packages from any number of suppliers. Check the Racetronix stuff. Seems to be well thought out packages, but their install instructions appear to be non-existant, based on numerous posts on a number of different boards.Fred
381ci all-forged stroker - 10.8:1 - CNC LT4 heads/intake - CC solid roller - MoTeC engine management - 8 LS1 coils - 58mm TB - 78# injectors - 300-shot dry nitrous - TH400 - Gear Vendor O/D - Strange 12-bolt - 4.11's - AS&M headers - duals - Corbeau seat - AutoMeter gauges - roll bar - Spohn suspension - QA1 shocks - a few other odds 'n ends. 800HP/800lb-ft at the flywheel, on a 300-shot. 11.5 @ 117MPH straight motorComment
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That racetronix kit looks just like what I need. The NX chart says 34-47psi Free Flowing Pressure, and it is cutting out below 34psi at WOT. Thanks1995 Firebird Formula
(A4 3.23)Ram Air w/ K&N, TransGo Shift Kit w/3 washers ,SLP~Shorty headers, LoudMouth, Air Foil, LineLocks. Catco Cat. Hypertech 160. TB Bypass. MSD~8.5mm. Walbro 255lph. FT MAF ends. LT4KM. BMR~Adj LCA's, Rear sway, Panhard rod. HAL QA1 rear shocks. Random Tech adj TQ arm. Nitto NT555R's. Covered in Zaino. 13.466@103.85 N/A. [1.948 60' 13.410 @ 102.66 11/20/05]Comment
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