Fuel Pressure
Thread Starter
Racer
Joined: Mar 1999
Posts: 258
Likes: 13
From: New Mexico
Fuel Pressure
I need suggestions on what I should set my fuel pressure too.
I have a 1990 L98, highly modified six speed C4.
Mods:
Motor is a 383, with AFR 195 (Eliminator) Heads, 10 to 1 compression ratio, Modified HSR manifold (fits under the hood), BBK 52mm Throttle-Body, LT4 Hotcam, Full length headers, no CATS, true dual exhaust, FAST XFI 2.0 with Dan White Adaptor harness (BTW: Dan is a great guy to deal with), and 32lb Bosch-3 fuel injectors with a new C4 stock fuel pump.
Currently I am set to 44 psi. Any ideas, Thanks.....
I have a 1990 L98, highly modified six speed C4.
Mods:
Motor is a 383, with AFR 195 (Eliminator) Heads, 10 to 1 compression ratio, Modified HSR manifold (fits under the hood), BBK 52mm Throttle-Body, LT4 Hotcam, Full length headers, no CATS, true dual exhaust, FAST XFI 2.0 with Dan White Adaptor harness (BTW: Dan is a great guy to deal with), and 32lb Bosch-3 fuel injectors with a new C4 stock fuel pump.
Currently I am set to 44 psi. Any ideas, Thanks.....
Safety Car
Joined: Nov 2009
Posts: 3,970
Likes: 340
From: Adelaide South Australia
Most injector manufacturers use 43.5 psi as the standard to rate their flow,
Some people will recommend using higher pressure but keep in mind as fuel pressure goes up, fuel flow (in gallons per hour) drops,
Also look up the duty cycle of injectors, its never a good idea to bump up the pressure too high and work the injector too much.
Some people will recommend using higher pressure but keep in mind as fuel pressure goes up, fuel flow (in gallons per hour) drops,
Also look up the duty cycle of injectors, its never a good idea to bump up the pressure too high and work the injector too much.
Thread Starter
Racer
Joined: Mar 1999
Posts: 258
Likes: 13
From: New Mexico
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
....need to check AFR at WOT and adjust accordingly....should be around 900mv on O2 sensor.
Safety Car
Joined: Aug 2009
Posts: 3,745
Likes: 275
From: Melbourne, Victoria, Australia
48-52 psi works well on a TPI engine, if you need to get emission checked do not install an adjustable fuel pressure regulator (install washers to increse the spring tension so it is not obvious.
The car will run rich at idle with 48/50 psi fuel pressure however you get more mid range and top end go with more fuel pressure.
My bosch 111 injectors have no problem with up to 75 psi fuel pressure, that is variable in relation to boost.
I am running a blower and have a vortec FMU that pretty much restricts the fuel return to the tank, to raise fuel pressure and force more fuel thru the injectors at around 5 psi per psi boost.
That works great with more standard fuel pressure at idle and way more at higher rpm so it never leans out in my application.
The car will run rich at idle with 48/50 psi fuel pressure however you get more mid range and top end go with more fuel pressure.
My bosch 111 injectors have no problem with up to 75 psi fuel pressure, that is variable in relation to boost.
I am running a blower and have a vortec FMU that pretty much restricts the fuel return to the tank, to raise fuel pressure and force more fuel thru the injectors at around 5 psi per psi boost.
That works great with more standard fuel pressure at idle and way more at higher rpm so it never leans out in my application.
Drifting
Joined: May 2013
Posts: 1,736
Likes: 31
From: Reno Nevada
48-52 psi works well on a TPI engine, if you need to get emission checked do not install an adjustable fuel pressure regulator (install washers to increse the spring tension so it is not obvious.
The car will run rich at idle with 48/50 psi fuel pressure however you get more mid range and top end go with more fuel pressure.
My bosch 111 injectors have no problem with up to 75 psi fuel pressure, that is variable in relation to boost.
I am running a blower and have a vortec FMU that pretty much restricts the fuel return to the tank, to raise fuel pressure and force more fuel thru the injectors at around 5 psi per psi boost.
That works great with more standard fuel pressure at idle and way more at higher rpm so it never leans out in my application.
The car will run rich at idle with 48/50 psi fuel pressure however you get more mid range and top end go with more fuel pressure.
My bosch 111 injectors have no problem with up to 75 psi fuel pressure, that is variable in relation to boost.
I am running a blower and have a vortec FMU that pretty much restricts the fuel return to the tank, to raise fuel pressure and force more fuel thru the injectors at around 5 psi per psi boost.
That works great with more standard fuel pressure at idle and way more at higher rpm so it never leans out in my application.
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