[chiphead]

Need to install a deadhead regulator after my Robb MC mechanical fuel pump. Occasionally it's lifting the floats and running rich. Where are you guys mounting fuel pressure regulators so it doesn't look like a cobble job?

[SRGN]

If you're running a 4150 flange Holley carb, this bracket is a nice piece.

https://ebay.us/m/IZUa64

There's chinese clones available on Amazon for around 30 bucks as well.

[78w72]

With a Qjet that has the normal center inlet, I just put my regulator a few inches away from the carb to clear the air cleaner. Its small and light enough that it works perfect with no bracket using -8 braided line, but could be spliced into factory steel lines too. Ive read that ideally you want the regulator as close to the carb as possible.

What pump & carb do you have? The 550 pump is supposed to be ~6psi, i have the older 1100 pump thats adjustable down to 7psi and it doesnt have any flooding issues on a later cliff built 78 Q-jet.. he actually suggested removing the regulator for better flow if its not absolutely needed. I only added one becaues for race use I turn up the pump to 10+psi then keep the regulator at ~7.

[chiphead]

I'm running the RobbMC 550 with 6AN line back to fuel tank. 4150 QF 750 double pumper that I've been razor tuning for about 2 years now. It runs like fuel injection on a good day, usually defies the double pumper reputation as a slobber machine.

I'm seeing that the fuel level in the bowls will rise and fall in a way that hasn't happened with the cheap shelf pumps. I start the engine, the fuel is in the center of the bowls. After the engine reaches curb idle and warms up, the fuel level drops to the bottom of the sight glass. Both bowls do the same thing at the same time, and I've been through the bowls 3 times, so I don't think its the carb itself. With the new pump, it tends to cruise rich for no reason, then clear up for no reason on the interstate at random. I thought it was the tune until I saw the fuel level behavior.

I put a Holley 803 deadhead regulator and a gauge on it as a test. If I crank the regulator to full pressure, the fuel pressure gauge bounces between 6-7 at idle. If it back it off to 5.5, it's rock steady. So I assume the pump pulses are bumping the float needles open. The plan is to regulate it to 5 PSI and confirm the cruise mixtures don't wander off.

[OCMDGTO]

Chip, aren't you supposed to have 6.5psi for that QF? Maybe you need a bypass regulator w return line. When I ran deadhead regulators it held pressure steady and it was a cheap Holley one

[78w72]

Originally Posted by OCMDGTO

Chip, aren't you supposed to have 6.5psi for that QF? Maybe you need a bypass regulator w return line. When I ran deadhead regulators it held pressure steady and it was a cheap Holley one

Im not 100% sure on this, but I recall Robbmc saying to not use a full return regulator with mech pumps, or that it will severely reduce the psi or flow ratings of the pump. What they recommend for a "return" is their vapor return fitting for the pump that is similar to the factory vapor return, it will help with creep or vapor lock etc but doesnt actually do a full return of unused fuel like a normal return set up. Might be worth asking them about that?

I have a gauge on mine too, it has to be a dry gauge under the hood, wet filled gauges are known to read wacky when heated. Ive ran deadhead with & without a regulator on 2 pumps, first was the edelbrock high flow & now the robbmc 100, both are completely steady on the gauge and at ~7 they dont over power the seat or float on a Q-jet, surprised the holley is having problems at the ~6psi the 550 is supposed to be. Hope you get it sorted out.

[NeighborsComplaint]

I'd bend a hard line from pump to carb and just hang it in the hardline with fittings.. Hide below the PS pump or up high under the alternator.

[chiphead]

The online reviews said the regulator brackets hit the electric choke on holley carbs.

So I fabricated my own bracket. It mounts to the rear bolt of the thermostat housing. I used the same type of special bolt that holds the alternator straps on the front side of the t-stat housing.

[Skippy597]

Originally Posted by chiphead

The online reviews said the regulator brackets hit the electric choke on holley carbs.

So I fabricated my own bracket. It mounts to the rear bolt of the thermostat housing. I used the same type of special bolt that holds the alternator straps on the front side of the t-stat housing.

That is a nice slick setup! I'll running dual quads and have killed my self for hours and hours of how to route the fuel lines until I sat down and drew it out. Hopefully it comes out how I want.