Bigger Pump or bigger lines ?
Thread Starter
Safety Car
Joined: Nov 2009
Posts: 3,973
Likes: 341
From: Adelaide South Australia
Bigger Pump or bigger lines ?
Aeromotive 340 v Walbro 255 or bigger lines ?
I ran at the Hillclimb on the weekend, it was a different one that I usually run, its twice as long (1400 metres). this is the first time that the single plane intake has run without the intake vacuum leaks after having the intake machined.
It looks like it needs more fuel, the knock sensor was activating at anything over 3/4 throttle, the engine was leaning out (engine light on, code 43). tried varying loads of fuel up to a full tank, also advanced and retarded timing (between 2 and 8 degrees) with no difference.
Im currently running a Walbro 255, with 30lb Bosch 3 injectors, and -6 lines from the fuel filter to the regulator. The reg is at 50 psi.
Does anyone have any experience upgrading the fuel system, i.e. do the hard lines from the tank to the fuel filter become a restriction, or will they flow enough to feed -6 lines at the engine end,
does anyone know how much flow or hp the steel lines can support ?
will upgrading to a Aeromotive 340 lph be enough to overcome the problem ?
I ran at the Hillclimb on the weekend, it was a different one that I usually run, its twice as long (1400 metres). this is the first time that the single plane intake has run without the intake vacuum leaks after having the intake machined.
It looks like it needs more fuel, the knock sensor was activating at anything over 3/4 throttle, the engine was leaning out (engine light on, code 43). tried varying loads of fuel up to a full tank, also advanced and retarded timing (between 2 and 8 degrees) with no difference.
Im currently running a Walbro 255, with 30lb Bosch 3 injectors, and -6 lines from the fuel filter to the regulator. The reg is at 50 psi.
Does anyone have any experience upgrading the fuel system, i.e. do the hard lines from the tank to the fuel filter become a restriction, or will they flow enough to feed -6 lines at the engine end,
does anyone know how much flow or hp the steel lines can support ?
will upgrading to a Aeromotive 340 lph be enough to overcome the problem ?
Safety Car
Joined: Sep 2001
Posts: 4,157
Likes: 554
From: Glenbeulah Wi
What was your fuel pressure during the run? How do you know you were leaning out? I am running about 550 HP with my stock lines and a Walbro 450 LPH pump and E85.
If you add a fuel pressure gauge at the connection of the fuel pump to the rear hose on the car by the fuel tank and a gauge at the fuel rail you will see what the differential pressure difference is and that will tell you how restrictive your fuel lines are. At a set pressure of 50 PSI (engine off key) on the regulator is allowing the pumps full flow at that set pressure to pass through the regulator and return to the tank.
If you add a fuel pressure gauge at the connection of the fuel pump to the rear hose on the car by the fuel tank and a gauge at the fuel rail you will see what the differential pressure difference is and that will tell you how restrictive your fuel lines are. At a set pressure of 50 PSI (engine off key) on the regulator is allowing the pumps full flow at that set pressure to pass through the regulator and return to the tank.
Thread Starter
Safety Car
Joined: Nov 2009
Posts: 3,973
Likes: 341
From: Adelaide South Australia
What was your fuel pressure during the run? How do you know you were leaning out? I am running about 550 HP with my stock lines and a Walbro 450 LPH pump and E85.
If you add a fuel pressure gauge at the connection of the fuel pump to the rear hose on the car by the fuel tank and a gauge at the fuel rail you will see what the differential pressure difference is and that will tell you how restrictive your fuel lines are. At a set pressure of 50 PSI (engine off key) on the regulator is allowing the pumps full flow at that set pressure to pass through the regulator and return to the tank.
If you add a fuel pressure gauge at the connection of the fuel pump to the rear hose on the car by the fuel tank and a gauge at the fuel rail you will see what the differential pressure difference is and that will tell you how restrictive your fuel lines are. At a set pressure of 50 PSI (engine off key) on the regulator is allowing the pumps full flow at that set pressure to pass through the regulator and return to the tank.
I guess my situation is different using it for hillclimb, you are going up a steep hill and turning left and right at the same time, I guess that will always be a test for a c4 fuel system !
Im pretty sure its a lean out, its very throttle sensitive, squeeze past 3/4 throttle and the knock sensor will activate and the check engine light with code 43 will come on, ease of the pedal slightly and it will pick up revs again. In the burnout it will hit 6200 rpm at about 1/2 throttle with no engine light or knock sensor activation.
maybe another option is to put it on a wheel dyno and load it up ?
