Big Block MPFI Pressure regulator setups

[1BadAction]

Intake swap is beginning to take shape and I'm trying to decide what way to go with my fueling. Pump is relatively new, application was a 97 Vortec 454 Suburban so it should have no issue running at MPFI pressures. Keep in mind this has a specialized single fuel rail with a built in pressure damper that houses all injectors at the center of the intake so I'm somewhat limited in what I can do. I've narrowed it down to a few options.

1. Corvette filter/regulator mounted in stock filter location. 58psi. Excellent option, clean, cheap, factory stock reliable and keeps the fuel nice and cool... but they are not vacuum referenced. Since the 7427 doesn't have VAC vs Fuel pressure tables like the LS PCM, this might create some tuning headaches.

2. Aeromotive mounted on the frame rail just behind the point where the braided line jumps from the frame to the engine. Adjustable (will likely run 58psi) clean, possibly more stable pressure, cooler fuel, vacuum referenced so pressure is constant and will have no tuning issue. Cons: 50% more expensive than the vette filter/regulator and not sure how a long vacuum line from the manifold to the regulator will effect the fuel pressure.

3. Aeromotive mounted on intake/firewall before the rail. More traditional. No question in its function. Cons: same as on the frame, more fittings required, somewhat unsightly, AND these setups introduce a ton of heat into the fuel system. At the end of the day this is a tow rig not an all out race vehicle.

Any other ideas? Comments? I'm leaning toward the aeromotive mounted on the frame... but I can probably be swayed.

[brian617]

The 96-00 BBC Chevys with MPFI used a singe fuel rail??

[1BadAction]

Its a marine intake. 100% different from a vortec truck intake.

[brian617]

Got any pictures of yours sans the upper plenum?

[1project2many]

I had some similar questions helping a friend put an LS engine into an S10. In his case we found a fuel rail and came up with a way to change the upper part of the regulator. As I remember there is no access to the Vette regulator in the filter combination assy.

What did Merc originally do for regulator? This seems to suggest they used an external part.

Does the damper look anything like a regulator? I've has some success taking regulators apart and putting them back together using special clamps. Hard to see but this regulator has one of these clamps holding the halves together.


I have built special fittings to install these regulators in places where they were not originally found. Here's one on a smallblock marine intake:


The steel sleeve fitting was made on a drill press. The regulator, a stock part from a Cavalier 2.2, can be rotated to any position.

[1BadAction]

[Hog]

The 96-00 BBC Chevys with MPFI used a singe fuel rail??

Yup, all the 1996-2000 L29's and L21's had a single fuel rail, right up the middle of the valley. The marine intake is similar in function, different fitment. On the SBC Merc marine intakes, they run at 58psi, but have 2 fuel rails while the Merc BBC marine intakes use a single rail. peace Hog

[Hog]

Same fuel rail as used on the Ramjet 502(502-502hp), Ramjet ZL1(454-510hp) peace Hog

[1BadAction]

Same fuel rail as used on the Ramjet 502(502-502hp), Ramjet ZL1(454-510hp) peace Hog

Same as the hp500 Merc racing intake. I think the next bbc truck I build is going to be a 2dr Tahoe setup with 4l80e/AWD and an AFR headed 540 sprayed Merc racing blue. :eek:

[Nasty-Z]

A few years ago when I ran that intake setup I used the 13107 Aeromotive regulator , it is an LT1 rail mount unit , but I used a fitting from Aeromotive to convert the inlet to -6an . Mounted it on the firewall with braided stainless line to and from , fully adjustable and easy to get to , as you know that intake takes a good chunk of real estate. One of the reasons I used the Aeromotive is I already had it set up with the TBI I was running , it was one of the only reliable regulators that would allow high (60-70 psi) injector pressure and provide a vacuum reference. I simply re used it with the intake swap. The other options you listed are fine also , just what worked for me. TOM