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My injectors and fuel pump regulator are coming monday and what i want to know is how to set the regulator up for the correct psi.

550cc injectors, after installation, how do i set the proper fuel pressure?
 

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Waiting on mine from DM to come in, should be here next week.

There should be an adjustment nut on it, which is secured with a locking nut. Loosen the locking nut and turn the adjustment nut with a wrench. Hook up the gauge to it and watch it as you turn the nut, set it to 43 psi and you're done.
 

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They're referring to what most people see the best AFRs at with the Lex/550 combo not a stock tune.
 

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BHG
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Same for Map sensor?

Waiting on mine from DM to come in, should be here next week.

There should be an adjustment nut on it, which is secured with a locking nut. Loosen the locking nut and turn the adjustment nut with a wrench. Hook up the gauge to it and watch it as you turn the nut, set it to 43 psi and you're done.
Is this for the lex/550cc combo only? What if your going MAPECU and eliminating the MAF for a MAP?
 

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The injectors are usually rated @ 43-45 psi so I'd run around there. Then adjust as needed.. Thats why you bought an adjustable one right? lol
 

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running would be ideal, though there probably wont be hardly any difference with the injectors pulling fuel out the rail at idle vs them not.
 

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Im sorry to awaken an old thread, but why do people suggest Running the Fuel Pressure regulator without the vaccum line hooked up to it? what purpose does that serve?
 

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You would run rich all the time outside of boost
your tune is tuned for a variable fuel pressure between 0 kpa and 100 kpa,
when you get into boost fuel flow would actually decrease as boost increases and if by chance you run 43 psi of boost then the injectors would open but no fuel would come out

And many other reasons

Basically its a bad idea
 

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S
You would run rich all the time outside of boost
your tune is tuned for a variable fuel pressure between 0 kpa and 100 kpa,
when you get into boost fuel flow would actually decrease as boost increases and if by chance you run 43 psi of boost then the injectors would open but no fuel would come out

And many other reasons

Basically its a bad idea
. So your saying leave the vacuum line off? I’m guessing I should just plug it, right?
 

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Bmettie hade described a BAD situation, you just didn't understand.
NO, don't leave it off.

As boost comes up, fuel pressure has to come up by the same amount.
Flow through the injector depends on 3 things:
Injector size
Injector on time
Effective fuel pressure, that is the pressure at the injector, VS. pressure in the intake.

If both pressures are the same, nothing moves, NO fuel.
Even at low boost you need more pressure than you need at idle, or no boost.
If you have 30 psi fuel pressure at idle, or no boost.
With the vacuum line disconnected (not really a 'vacuum' line, but a 'boost reference' line), and under heavy throttle, and just for argument, say 20 psi boost, the effective fuel pressure is only 10 psi, or way less than the engine needs.
 

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Bmettie hade described a BAD situation, you just didn't understand.
NO, don't leave it off.

As boost comes up, fuel pressure has to come up by the same amount.
Flow through the injector depends on 3 things:
Injector size
Injector on time
Effective fuel pressure, that is the pressure at the injector, VS. pressure in the intake.

If both pressures are the same, nothing moves, NO fuel.
Even at low boost you need more pressure than you need at idle, or no boost.
If you have 30 psi fuel pressure at idle, or no boost.
With the vacuum line disconnected (not really a 'vacuum' line, but a 'boost reference' line), and under heavy throttle, and just for argument, say 20 psi boost, the effective fuel pressure is only 10 psi, or way less than the engine needs.
 

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Thanks. I’m trying to install a Summit FPR (SUM-220056). I think I have to run a -6 line from the fuel filter to the FPR, plug one of the outlet ports, and run a -6 to the back of the stock fuel rail. Is that right?
 

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No.
Put the regulator at the end of the chain, after the injectors, at the outlet of the fuel rail.
Maintains pressure at the injectors, out let goes back to the tank.
That way, all fuel bypassing the regulator keeps the fuel rail cool, and carries the heat, and any bubbles back to the tank.

Summit regulator ???
Hope you know all their 'house' brand stuff is chinese crap.......
I wouldn't use that shit on a lawnmower.
Same goes for Jeg's and Speedway.

Buy only name brand stuff.
 

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No.
Put the regulator at the end of the chain, after the injectors, at the outlet of the fuel rail.
Maintains pressure at the injectors, out let goes back to the tank.
That way, all fuel bypassing the regulator keeps the fuel rail cool, and carries the heat, and any bubbles back to the tank.

Summit regulator ???
Hope you know all their 'house' brand stuff is chinese crap.......
I wouldn't use that shit on a lawnmower.
Same goes for Jeg's and Speedway.

Buy only name brand stuff.
I realized that too late. Going forward Drift Motion will be my go to. So you’re saying connect the fuel line closest to the firewall. Right? I have an AEM wideband, Turbo Smart manual boost Controller, a Walbro 255, 550 injectors, and an A’PEXi neo AFC. Hoping to get 360 @ the wheels. :)
 

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Yes, and be careful with the NEO, as it has way too many parameter adjustments, and it's easy to get lost, or adjust the wrong one.
I've always used the 2 previous models, as they only have fuel, high & low throttle settings, and ramp.
Always write down your settings, and never let buddies fuck with them.
 

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Yes, and be careful with the NEO, as it has way too many parameter adjustments, and it's easy to get lost, or adjust the wrong one.
I've always used the 2 previous models, as they only have fuel, high & low throttle settings, and ramp.
Always write down your settings, and never let buddies fuck with them.
OUTSTANDING. Thanks.
 
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