North American Turbocoupe Organization



Fuel pressure adjustment spec
TurboBoost88 Offline
Member
#1
What is idea fuel pressure at idle with vacuum line on. Stock motor, turbo , etc... put a kirban on and I set it at 39. Just wanted an opinion on it . Thanks in advance
88 TurboCoupe,Midnight Metallic Blue on Blue cloth, 140 m.p.h. speedo, 96,000 miles, 5spd. Gills valve, many new parts waiting to be installed..88 TC, Silver, 5spd, My first car, wish I still had that one! Built for customers: 67 Ford Fairlane,69 Mach I,70 Mach I Clone,95 Ranger 2.3/5.0 EFI Conversion,99 Cobra Procharger SC-1 Install/Tune,Factory Five Racing Mark III Cobra #4114,1955 Black on Black Thunderbird for local Ford Dealer owner's wife.
Reply

Pete D Offline
Administrator
#2
39 is good on a stock motor.
Pete Dunham


Reply

88Boostedbird Offline
Junior Member
#3
Thanks for posting this, as I am about to place a Kirban on my '88TC with big turbo and aftermarket fuel rail. It will come in handy when I get the car up and running.
Lost in translation..........
'88 TurboCoupe, Automatic, stone-stock (as I just got it) for now. Trying to get it back running and roadworthy before mods begin.
Reply

Jeff K Offline
Administrator
#4
With the vac line ON the FPR, 39 is too high on a stock or nearly stock engine, and may be too high even on a somewhat modified engine. Stock pressure is 39 psi with the vac line OFF the FPR. Assuming you have around 20 in Hg vacuum at idle, which corresponds to roughly a 10 psi drop over atmospheric pressure, the fuel pressure should be around 29 to 30 psi. Removing the vac line, the pressure will pop back up to 39-40 psi. the most important thing is for the pressure to increase 1:1 with boost. At 15 psi, pressure should be 54 psi if the base pressure is 39 psi with vac line off.

Unless you are shooting for 450+ Hp, an aftermarket fuel rail is a waste of money. The stock rail can support 500 Hp.
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
Reply

88Boostedbird Offline
Junior Member
#5
A friend is making me the rail, so who am I to say NO!
I am also of the mindset that a larger inside diameter fuel rail will help at elevated fuel requirements/higher rpm as it will act as both a fluid damping device AND a reservoir so I don't run the risk of fuel starvation.
Lost in translation..........
'88 TurboCoupe, Automatic, stone-stock (as I just got it) for now. Trying to get it back running and roadworthy before mods begin.
Reply

TurboBoost88 Offline
Member
#6
Thanks for the reply
88 TurboCoupe,Midnight Metallic Blue on Blue cloth, 140 m.p.h. speedo, 96,000 miles, 5spd. Gills valve, many new parts waiting to be installed..88 TC, Silver, 5spd, My first car, wish I still had that one! Built for customers: 67 Ford Fairlane,69 Mach I,70 Mach I Clone,95 Ranger 2.3/5.0 EFI Conversion,99 Cobra Procharger SC-1 Install/Tune,Factory Five Racing Mark III Cobra #4114,1955 Black on Black Thunderbird for local Ford Dealer owner's wife.
Reply

Jeff K Offline
Administrator
#7
Larger diameter rail will not help with damping at all, as gasoline is not compressible.
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
Reply

88Boostedbird Offline
Junior Member
#8
I guess damping was a poor choice of wording, and I am aware that liquid in not compressible (well, it is but at 3000psi it only compresses .001% of its volume). I was referring to the effect that each injector firing has on the volume of the fluid. Even under pressure, when an injector fires, there is a momentary release/drop of pressure, and when it closes, a momentary spike in pressure. Magnify that by the firing of all 4 injectors and you have a 'harmonic' of sorts rippling through the rail. With a higher volume, this effect is lessened (not that it really matters with our small of a delivery amount). I am just using the rail increased volume to prevent starvation at elevated delivery levels and at higher rpm of the engine.

(Fluid and Thermal dynamics are a portion, albeit a very small portion, of my job fields required base knowledge)
Lost in translation..........
'88 TurboCoupe, Automatic, stone-stock (as I just got it) for now. Trying to get it back running and roadworthy before mods begin.
Reply





Users browsing this thread:
1 Guest(s)



Theme © iAndrew 2018 - Software MyBB