| fuel pressure regulator - Click HERE for Original Thread |
| CanuckDave |
| the link doesn't work |
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| CanuckDave |
oh thats this:
http://www.vortechsuperchargers.com...l/fuel_fmu.html
I used one on my Supra when I turbo'd it. If I were to do it again, I'd go another route, the only adjustability is by changing to different ratio disks, and thats really not sufficient to tune a car well.
Not to say it doesn't work, you can put it on a dyno and change disks til you get it running rich, and just leave it that way, but you're going to get crappy milage and you won't even be close to getting your full power potential.
Cartech makes a unit that has far better adjustability
http://www.cartech.net/fmu2020.htm
keep in mind that you shouldn't use an rrfpr if you're going to boost past 9psi, as the fuel pressure required at that point can be getting to an unsafe level. |
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| Blaine B. |
quote:
Originally posted by CanuckDave
the link doesn't work
Forshadowing of the functionality of the product?:dunno: |
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| jayc |
| FMU and AFPR are the same thing. Different names for a rising rate fuel pressure regulator. |
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| CanuckDave |
quote:
Originally posted by jayc
FMU and AFPR are the same thing. Different names for a rising rate fuel pressure regulator.
Thats not true, a vortech FMU is a rising rate FPR which works by increasing fuel pressure by a number of lbs per psi of boost (depending which ratio disk is used), while an AFPR is used to set base fuel pressure. |
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| Blaine B. |
quote:
Originally posted by jayc
FMU and AFPR are the same thing. Different names for a rising rate fuel pressure regulator.
Wrong.
AFPR is adjustble as far as base pressure goes. Up or down from factory spec in psi.They rise at a 1:1 rate with boost.
An FMU rises at different rates. Most common is 4:1. |
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| jayc |
Symantics. They do the same thing. Raise fuel pressure refrencing boost or vacuum. What does the A in AFPR stand for? Aux or Adjustable? Either way a unit like a Vortech is adjustable by changing discs, the BEGI or Cartech unit just uses a needle valve to bleed boost to change the rate of rise.
If Corky Bell refers to HIS Fuel Pressure regulator as either an FMU or FPR then I will to.
quote:
The BEGi rising rate fuel pressure regulators (FPRs), also referred to as fuel management units, are designed specifically to provide additional fuel to EFI engines, whether normally aspirated (N/A) or pressure fed with turbos or superchargers. This is accomplished by using the manifold vacuum/pressure to drive the fuel pressure up as the boost rises, or with the N/A engines, as the vacuum goes toward atmospheric.
We introduced the rising rate fuel pressure regulator to the market over 20 years ago and we’ve been improving on that original design ever since. Why is the BEGi unit the best on the market? Billet manufacture, improved valve design, and fewer parts with the integrated accessory design. Further, we’ve increased the span of adjustment for broader rates of gain. Even the onset of gain is adjustable! No other regulator provides the onset adjustment. We also offer all regulators in a billet aluminum finish.
http://www.bellengineering.net/Pages/products_FPR.html
Jay |
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| jayc |
quote:
Originally posted by Blaine B.
Wrong.
AFPR is adjustble as far as base pressure goes. Up or down from factory spec in psi.They rise at a 1:1 rate with boost.
An FMU rises at different rates. Most common is 4:1.
The function you speak of is not mutually exclusive. I've owned a Vortech unit that was 12:1 (because that's the disc that was installed), onset of gain could not be adjusted. But I can change the disc out to a 8:1 or 6:1 if I wanted. I now own a Bell Engineering unit that is adjustable by using a need valve for rate of rise and the onest of gain is also adjustable via another set screw.
4:1 is common for what? Amount of fuel pressure at any given level of boost is going to depend on a lot of factors. Generally you don't want to go way beyond 100psi of fuel pressure. Injectors become less reliable and efficient, and I'd also worry about putting added stress on fuel line, connectors and fuel rails.
Jay |
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| fatbastard |
| Adjustable fuel pressure regulators are typically a 1:1 rising rate, 1 psi of boost means 1 extra psi of fuel pressure to equal out, ensuring that the boost pressure is NOT working against the fuel pressure. FMU's are rising rate, 1psi of boost can equal 4/5/8/whatever of extra fuel pressure. They aren't the same thing. |
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| Blaine B. |
quote:
Originally posted by jayc
The function you speak of is not mutually exclusive. I've owned a Vortech unit that was 12:1 (because that's the disc that was installed), onset of gain could not be adjusted. But I can change the disc out to a 8:1 or 6:1 if I wanted. I now own a Bell Engineering unit that is adjustable by using a need valve for rate of rise and the onest of gain is also adjustable via another set screw.
4:1 is common for what? Amount of fuel pressure at any given level of boost is going to depend on a lot of factors. Generally you don't want to go way beyond 100psi of fuel pressure. Injectors become less reliable and efficient, and I'd also worry about putting added stress on fuel line, connectors and fuel rails.
Jay
I can see you still don't get the difference, so I will drop it.
4:1 is common for lots of applications if designed by somebody who knows what they are doing when they designed the entire fuel system. FMU's have their place but they are far from optimal. You do know Corky's book is getting a little long in the tooth, the lingo has evolved and become more specific. |
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