Technical Fuel Pressure Regulators and Issues and Options

I have these poppet valves that open at whatever you want, they return back to the inlet of the fuel pump. lots of people on here use them, I have them made by Enderle Fuel Injection, they're made from brass, a couple inches long. Shoot me a PM if you are interested, this is a new computer and I don't have any pics of one but will get some.. They hook up to -6 AN

 

One of the old ways was to run a 1/4" line back to the tank, and essentially "regulate" the return by using a Holley jet. Sizes of say 50-65 might do it for ya. And yes, it simply dumps back into the tank. The jet goes in the hard line at the tank end of things. You're a man of talent, I think you can imagine this working. Where to return from, well possibly from one of the outlets of a multiple-outlet regulator. Use 1 side to a distribution block off to the 2 (or 3) carbs, the other as the restricted return. The nice thing is that it doesn't bother volume at high-zoot operation. Yes, some trial and error is in order but isn't that often the "juice"? A little technical revue of F.I. systems and returns would be helpful in setting something up.

As for any of my regulated experiences I can only refer to my racer. I ran one of the Holley "blue" regulators that was something like 5-9 PSI settings (memory fog) right at the carb on a 1050 Dominator. I had a gauge out of an opposite inlet of the carb for settings and also monitored main input pressure in the car with an isolator style gauge. At WFO in the eyes at 7600 RPM I held 12 PSI main line pressure, at idle I had 16. I set the carb at 6. I ran 2 Holley blue pumps fed by -8 hard lines and both feeding into a 'Y' block to a single -10 to the front, -8 to the regulator, -6 stainless lines to each bowl. It wasn't 1/2 bad looking and provided more than enough fuel to feed that hungry bitch. I didn't use a return, simple bracket racer get up.

 

When you need 3-5 psi. Why would install a higher psi pump and regulate it down to 3-5 psi? When all you need is a 3-5 psi pump.
OJ addressed this earlier. Post #28


Sent from my iPhone using The H.A.M.B. mobile app

 

One reason might be that if the smaller pump won't supply the volume needed.

 

That’s not it. You would need to then choose a pump for the correct tube size. I’m addressing engines that are of medium performance that a lot of hot rodders use.


Sent from my iPhone using The H.A.M.B. mobile app

 

Please let me know where to get such a pump for a sbc, most standard ones are 7-8 psi and most new ones are 9-10psi out of the box.
The new part of this thread was started at post 32 referring to holley 94 carbs which require 3psi max.

 

Click to expand, there is a diagram in there somewhere.

For what it is worth, I plumbed my return line back into inlet line before the fuel pump, haven’t used it much but seems to be working.

 

Good point. I understand that sometimes there is no choice and you have to use a regulator. Carter makes a SBC pump with a max output of 5 psi. The 94 carbs are a situation where you probably need a regulator.
This may not apply to this thread. But quite often, a pump that has significant psi is installed and then regulated down. My point is, if you can find a pump that is within the necessary specifications. Just do that and avoid a regulator.


Sent from my iPhone using The H.A.M.B. mobile app

 

Oh. Four answers, six different ways to set it up.

 

Here's a picture of my poppet. I set them for whatever pressure you want and provide shims so you can change the settings. The easiest way to plumb them is to put a tee in the line above the pump, install the poppet and run from the poppet back to the inlet of the pump. Done. You can also put them up near the carb so the fuel returns near the end of the fuel circuit to get the most protection against vapor lock.
They are normally used on all mechanical fuel injection systems, at much higher pressures. I spoke with Jim at Enderle and he makes these for me with much lower spring pressures (the pressure they pop 'off' at), I generally set them at 3psi, the poppet opens to let fuel run thru it back to the pump, if pressure falls the spring closes to restore pressure and send the fuel to the carb.
Here it is in the For Sale section with better pics of how its plumbed: https://www.jalopyjournal.com/forum/threads/3psi-adjustable-regulator.982809/

 

Some time ago I was kicking this idea around with a buddy who is a full time mechanic, SAE cert and all that, and he questioned if that would work. He thought that the pump would stall with equal pressure on each side. But I told him, so what? Then the carbs will consume more fuel, the pump outlet pressure will recede and the pump will no longer be stalled and will start pumping again. He thought about it and shook his head, just couldn't see it. I haven't tried it, but your post clarifies what I was thinking should work just fine. But like I said, so far things are working fine with no return line, I see no need to complicate things unnecessarily.

 

Returning fuel to the inlet of the pump has been used for ages, the dragsters, funnycars, altereds with mechanical fuel injection etc have been doing it since the 50's. If you look at a dragsters' fuel cell sitting way forward there is the just the supply line coming from it to the pump, generally there are 3 or 4 return lines, the 'Main ByPass' the 'High Speed ByPass' and fuel shutoff that have return lines, rather than running a bunch of #8 hoses back to the front they take them to a 'log' thats plumbed into the pump inlet. To shut the engine off you literally run the pump output back into the pump inlet. Thats what that little lever does on the brake handle.

 

I think I’ve seen sbc fuel pumps with a return right on the mech pump, I could be wrong in my remembering though

 

Alchemy there is a thread on the Hamb on a return line to relieve pressure on the Strombergs after shutting off the key to prevent gas running into the engine. I can't find it. I am considering a return line on the fuel filter Wix 33040 or 33041. Just not sure where I am going to put the filter, before or after the regulator. I would like to see some options on how people actually did theirs. Not just their assumptions.

 

I remember that thread. Stromberg themselves wrote their answer to the problem. I just need to know where the optimal places to make connections are. If the job can be done with a short loop from the outward side of the regulator to the inward side of the pump, then great. If you are better running it all the way back and dumping into the tank, then so be it, that's what I'll do. I hope to be running lines for a new car in the next year, and it's engine is a big investment. Hate to wash the cylinders down with too much fuel.

 

https://www.jalopyjournal.com/forum/threads/new-stromberg-big-97-issues.1015931/#post-11481591
Found it. Sounds like in his opinion you can run it to the tank or before the pump depending on your application.

 

That would be Wex65, 'The Gentlemans Coupe'?

 

And that surprises you? We came up with at least 10 different techniques to wash the dust off of a barn find!

 

IMO, for that application the orifice should be located at the end of a fuel log that supplies the carbs.

 

I looked for a thread already well thought out and subscribed too to hash these situations around and come up with options and I am glad I did...No need to start new ones and whats even better is things discussed have been applied and tried and it gives some meat to the bone as in does it work...

I have done two things and I'm taking a chance but as Blues said and I agree the Dial Regulator is on the surface fitting to the engine bay and adjustable...Quick question...when did this style of regulator become available...

I have ordered a die cast version of the same with brass fittings...again mine I just peaked at looks to be actually Die Cast BUT with plastic fittings and the Reg itself is a Mr. Gasket Labelled Product that has lasted I suspect 9 years...

When I install the replacement I will verify I get 1 to 1.5 psi and go with it if it seems stable. I may also try to elbow the gauge to monitor from the cabin when driving...Trust Me 9-10psi will be easy to spot...

What I will also do is disassemble the old regulator and check what going on in there...Anybody taken one apart? Maybe it only needs a couple of Gasoline resistant O-Rings...and it will be good for another 5 more years...

Anyways I will report back and I enjoy tossing around relevant discussion...

 

Try again......


Some bi-pass regulators stipulate option B only, which places the regulator after the carb, something one may not expect.
Standard regulator = deadhead regulator or blocking regulator.

 

Very interesting thread. Lots of good information. The thread on the fuel seepage issue on the new Strombergs was enlightening. All solutions so far seem to address return lines, fuel pressure, and float levels. Would merely shutting off an electric fuel pump 30 seconds or so prior to shutting the engine off bleed off enough pressure to eliminate seepage? Going to try this next time I have my car out. ( I notice a strong gas smell for a while after shutting the engine off. Everything else seems OK. )

 

Me too as much as we covet fuel the Ole 94's I have seemed to generally have a raw vapor and some wetness with the carbs after a stop and it takes a while for the garage to air out...I hope less pressure relieves it but I have never had a fuel free air.

My pump is mechanical and the concept of flow and restriction due to fuel use and regulation is interesting...

Could you post a link to that thread Mike...Thanks...

 

There are many fixes for leaky float valves and at least half of them work.
The one I like is the Viton or Neoprene tip needle. Never had one leak since 1953.

Another system that works very well is shown in the pic. It is a FLOATLESS setup with Stromberg 48's.
Requires NO REGULATOR. Fuel goes in the old jet plug holes and overflows out the original opened up inlet.
I have run 4 carbs set up like this on a flathead. They made the same power as Hilborn injectors.
Some well known winners that ran them were the Bean Bandits, Jazzy Nelson and Tom Beatty.
This mod can be done to many different carbs.

 

Stogy,
The link to the 97 seepage issue is www.jalopyjournal.com/forum/threads/new-stromberg-big-97-issues.1015931/#post-11481591. Hope this works for you. I am running 94s as well. My challenge is sealing the throttle bores on the end carbs. I am running on the middle 2 (6X2 setup) until I can get the end carbs sealed.

 

Someday I will spread out the fuel dispursment...and what a thrill that must be...

I have to probably replace the bases and they repop or offer rebuilt lowers and I'm sure I need a Shiload of other pieces to complete those and then its its install and experience...Good luck with them and give us follow up when you can...

 

I think it is a better idea to limit the pressure output of the fuel pump rather than regulate it down afterwards, as has already been suggested.
To do this, select a rebuildable pump and replace the main spring that pushes against the diaphragm with a lighter one. You can use trial and error, or measure the spring rate of the original and the output fuel pressure and do some math to determine what spring rate new spring you need.

You can rebuild a mechanical pump, and wind new springs from spring wire, right?

 

After a comment on another thread, (about spring tension determining the pressure), I have been wondering all day if this was possible, and whether anyone has actually done this.
Thanks for your timely post. - And awaiting further replies.