Dave88z

Just thought I would share some interesting info I learned today. I am a BMW tech and during a training class we were discussing return/non return style fuel systems. A huge factor in using a non return style system was fuel temperature.
BMW states that the non return style dropped fuel temp 70*!
On most of the cars the regulator/filter assy is located approx under the drivers seat area and the fuel is returned to the tank from there. I guess the constant circulation of fuel under engine covers in a hot engine compartment really heats the fuel.
Not sure where they put regulators on factory f-body's and vette's, my third gen's is under the hood. I am running the victor jr manifold w/rails and I am seriously thinking about relocating the regulator somewhere else. Any pro's/con's
anyone can think of. I have heard people say to mount the regulator as close to the rail as possible but I don't know why?

TrakDay

iTrader: (7)

That is certainly something I never thought of, but I would think regardless of where you locate the regulator it is still holding the same pressure in the same lines and not moving the fuel through the lines any faster or slower given the location. So I would think that regardless of where you locate the FPR you will still heat the fuel up just as much. Thats just my guess and I am no technician so i could most certainly be wrong!

Dave88z

It will make a difference because as the fuel keeps circulating from the tank, thru the rails and back, it is heating up. It never gets a chance to cool off. By putting the regulator close to the tank the circulating fuel never reaches the hot,under hood area. Only fuel that is needed runs thru the rails and is quickly used.
I wonder if the difference in temp has any effect on H.P., I have seen fuel cooling cans for race cars before.

SPEEDYws6

iTrader: (9)

LS1's have intank regulators.

Dave88z

F-body's and vettes do? So they are both returnless systems then?

slow

iTrader: (7)

They are quasi return systems, they have a loop in the back, and a single line that T's off the loop to feed the rails. (97-98 vettes have a front mounted regulator)

Fuel temperature, or more importantly, the EVAP emissions caused by high fuel temperature are why returnless fuel systems became popular recently. 99+


Ryan

ESR

iTrader: (7)

It wont hurt you too bad. Just think of all us turbo guys underhood temps.......

Dave88z

Yeah, its always worked in the past. I was just wondering if there would be any measureable gain by putting my regulator in a different location closer to the tank.

CATDIESEL

Only if you run a "returnless" fuel system , you will haveto put the regulator near the tank and run one line to the fuel rails. It is the fact that the fuel that goes to the engine does not go back to the tank on a "returnless" that keeps it cooler.

lt170chevelle

iTrader: (2)

Not to disagree but how is a returnless style fuel sytem that pushes fuel to the motor slowly not going to heat the fuel up more compared to a return style at the rail that is constanly circulating cool fuel from the tank? sorry but i just dont get it.

MikeMs01TA

iTrader: (2)

What I don't get is how you found a thread from 2006

Lonnies Performance

iTrader: (16)

High underhood temps increase the temp of the fuel in the tank significantly when a return system is used, but an underhood regulator gives the best pressure control.

You can't have everything.

I prefer to take the stable pressure control & properly size the pump (or run a controller) to prevent excess circulation & high temps.

MeentSS02

iTrader: (11)

Exactly...granted this thread is old as ****, but I moved my regulator from the tank up to the engine bay, and the pressure control is much, MUCH better than it was. Returnless may decrease evaporative emissions, but the pressure control sucks *****.

lt170chevelle

iTrader: (2)

Oh so its more of a pressure fluctuation im guessing having a returnless style?

LOL yeah i was trying to dig up some dirt on locations of the fpr port.

I have a truck manifold that i smoothed out(the ugly top) and relocated my map and fpr port. I believe the map port is good right at the very back of the intake up top , but am having a driveability issue and dont know if its a weak fuel pump or if my location of my fpr vac port coming off one of the intake port runners is ok ,or would i need to move it so its getting the vac source from the plenum.

jimmyblue

iTrader: (11)

You could wrap the rails and the close-in plumbing,
and see a lot less rise. You could also put some sort
of heat exchanger on the return line if you have a
relatively cool air space, just pick something that
can take an off-road event without breach.

t/a98

iTrader: (6)

dont forget that fuel is the only thing your in tank fuel pumps have to keep them cool, so the hotter the fuel the less hours your pump will be able to live, especially people with high performing pumps like most of us..