Technical fuel pressure regulator install question

https://nz.gsparkplug.com/1x-malp**...V6PF-UsQigCoBLwjq-WTZ25rN_2aKhkxoCzQYQAvD_BwE

for a turbo situation - pressurised - I guess there are plenty of different types out there, - I am learning every day……..

 

They have a few different models - the byp*** ones obviously have a return line - I believe it is out the bottom.

 

Yes - the issue is that the fuel pressure needs to increase in about a 1:1 ratio with boost - depending on if you're blow through or **** through. That is why I've encouraged the OP to talk to a fuel-system provider and spec out the whole system. You can ruin an engine really quick (especially under boost) if you don't have your fuel system completely sorted out.

 

A byp*** regulator and a return byp*** are two different animals. A byp*** regulator will take the incoming pressure, hold it, and return excess to the tank.
Putting a regulator on the return line, I’d think the seat in the carburetor would have to hold the incoming pressure, then the regulator allows it to flow to the tank.
I know it works in EFI just fine, but a WAG would be an injector can hold 50 times the pressure of a needle and seat can.

 

I will call you if I ever need to build a dam……...
( I am already sorted on the placement of my regulator, see post 14, - so won’t require any help there )…..…

and here I was thinking that the bi-p*** regulator would allow any excess fuel to return, so therefore the pressure from a say 7 lb pump, would actually never hit 7 lb, as the regulator is always open and the pressure between the pump and regulator is always at 3 lb - or whatever you set it at.
So the seat/needle valve/thingy in the carburettor never sees more than 3 lb and thus the required result is obtained.

 

Clem, you stay out of the bundy now. Rum is the drink of scoundrels and pirates, after all.

 

Mike is correct.
If you had a 15 psi fuel pump and a 7 psi byp*** regulator, the pressure between the pump and regulator will never go above 7 psi [it will open and dump into the return line]
This also ,is exactly how a relief valve in an oil pump works on an engine.

Deadhead regulators will have the same fuel line pressure as the pump is capable of, but they only allow the preset psi past it [most carb fuel pumps are at a pressure lower than the vapor pressure and boiling point in the engine bay]

This ^^^ is why we used 2 regulators [actually 1 regulator and 1 relief valve] and an EFI pump on a race car. We needed enough fuel line pressure to prevent fuel boiling in the engine bay [and enough volume in the return flow to cool it] but this pressure is was above the carb " pressure" [hence the 2nd regulator]

Remember pressure is pressure and volume is volume [pressure is controlled but volume is generally "demand" as a simple explanation]

The higher the HP lb/hr demands =the higher volume is needed BUT with faster acceleration , the higher the pressure.
With the pump mounted at the rear ,it must be able to overcome the weight of the fuel ahead of it. [1G = 14.7psi]

Early G***ers overcame this with a Moon tank in the Grille

 

Kerry explains it above much better than I can “thumb out”

 

Another thing we've not talked about is that dead-head regulators don't deliver as smooth of a fuel-flow as byp*** regulators. Due to the fact that they've stopped all flow and must open it back up again, there tends to be more pressure spikes and volume variations hitting the carbs. Just think about how you put your thumb over the end of a hose, then let it off . . . crude example.

With a byp*** regulator it will be byp***ing most of the time, so the fuel pressure on the regulated side will tend to be smoother and more consistent.

It is also good to have an inline fuel-cooler on the return line of the byp*** system - to take some of the heat back out of the fuel as it cycles.

Looks like we lost the original OP . . . hope he/she learned enough to be more dangerous! LOL

 

His 4.6 Modular 4 valve engine is off topic here. [but his car isn't]
That shouldn't stop members here contributing information that could benefit others