Currently running a Holley Red Electric fuel pump that runs at 7psi. Holley says a fuel pressure regulator is not required with this pump. However, my Edelbrock AVS2 states no more than 6.5psi. Am I safe without one or should I install a regulator?
Fuel Pressure Regulator Required?
- Thread starter Mcfarlrm
- Start date
-
I would. You will have plenty of fuel with that pump but 4.5# would be plenty of pressure. No reason to run it on the jagged edge.
I run 4 with my afb over that it floods
Carter AFB/AVS carbs are designed to run up to 10 psi of fuel pressure. If you PM me your email address, I will email you the original Carter spec sheet for adjusting float level for the operating fuel pressure.
While there were some minor changes to the AFB/AVS design when Edel started making these carbs, there were no changes in the fuel delivery system. An Edel air horn with floats in place, placed next to a Carter airhorn will show a mirror image. So Edel carbs will operate with exactly the same fuel pressure as Carters.
The 5.5 psi quoted by Edel gives the datum jetting of the carb because fuel pressure affects fuel level, which affects rich/lean.
While there were some minor changes to the AFB/AVS design when Edel started making these carbs, there were no changes in the fuel delivery system. An Edel air horn with floats in place, placed next to a Carter airhorn will show a mirror image. So Edel carbs will operate with exactly the same fuel pressure as Carters.
The 5.5 psi quoted by Edel gives the datum jetting of the carb because fuel pressure affects fuel level, which affects rich/lean.
Nope, this is from the Edelbrock website and frequently asked questions.
How much fuel pressure should a Edelbrock 1406 have?
At IDLE, there should not be any more than 6.0 psi; if the vehicle has an adjustable fuel-pressure regulator, set it to 5.5 psi. With most fuel pumps the minimum fuel pressure is encountered at high rpm and WOT. Fuel pressure should not drop below 2.0 psi
And it also says on page 9 of the Edel book that there should be a minimum of 4-5 psi at WOT.
I do not know how many times it needs to said but the quoted fuel pressure is for the datum jetting point. If you choose to run 8psi, the float adjustment needs to be changed from 7/16" to about 9/16" to maintain the same fuel level in the fuel bowl for the datum jetting.
Some Holley carbs & clones have externally adjustable float settings, set via a window or removable plug. Exactly the same concept & if this is not understood, then you are not understanding carb basics 101.
I do not know how many times it needs to said but the quoted fuel pressure is for the datum jetting point. If you choose to run 8psi, the float adjustment needs to be changed from 7/16" to about 9/16" to maintain the same fuel level in the fuel bowl for the datum jetting.
Some Holley carbs & clones have externally adjustable float settings, set via a window or removable plug. Exactly the same concept & if this is not understood, then you are not understanding carb basics 101.
So I imagine that once I get the regulator installed, I will have to make some tuning adjustments to the carb correct? We did a bunch of adjustments without the regulator but with the reduced fuel pressure I want to make sure it is operating correctly.
Tried sending you a PM but it says that your inbox is full.
Yeah, inbox is full. Tried to delete 15 messages, no luck. What am I doing wrong?
The reduced fuel pressure will lower the fuel level in the bowl slightly. If it is just a slight amount, you will probably not have to alter anything.
The reduced fuel pressure will lower the fuel level in the bowl slightly. If it is just a slight amount, you will probably not have to alter anything.
For me it's not up for debate. I don't give a five pound CRAP what the spec sheets say. My experience and the experience of everyone I know who has run or does run Carter style carburetors, including Edelbrock, has had trouble with much over 5 PSI. That's just how it is. If it was my setup, I'd run a regulator and a return line.
The carb has been running with 7psi for about a month now with no issue whatsoever. In fact, it has been running better than ever before but don't want to push it if it may cause an issue down the road. I am installing the regulator over the weekend set at 5 or 5.5psi.
Then carry on sir.
Although Carter and edelbrock are similar designs, Edelbrock recommends 5.5# with no more than 6.
French demon
Well-Known Member
To help cold starts, I would like to install an electric fuel pump.
My Demon is totally stock with its 198ci and 1bbl Carter BBS carb.
The FSM tells that the stock pressure for this carb is between 3.5 and 5 psi.
If I install a fuel pump like this one (2.5 - 4 psi) :
Or like this one (3 - 5 psi) :
do I also need to install a pressure regulator?
Thanks
My Demon is totally stock with its 198ci and 1bbl Carter BBS carb.
The FSM tells that the stock pressure for this carb is between 3.5 and 5 psi.
If I install a fuel pump like this one (2.5 - 4 psi) :
Or like this one (3 - 5 psi) :
do I also need to install a pressure regulator?
Thanks
Last edited:
It probably doesn't need a regulator but it would be a good idea to check the pressure regardless. That is a piston typ pump. THey are a suction type pump so you mount it up front. It also won't work properly with a mechanical pump. Are you thinking about using it as a replacement for your mechanical pump? Or, you wanting to use it as a primer pump for hard starts? If so it's not for that.
French demon
Well-Known Member
Hi
I think to use it as a replacement for my mech pump, yes.
So, a regulator would be a security to check a correct pressure? Not really needed, but recommended?
I think to use it as a replacement for my mech pump, yes.
So, a regulator would be a security to check a correct pressure? Not really needed, but recommended?
French demon
Well-Known Member
Thanks Bewy
I will try the cheap EP-500 pump shown above because it's already ordered. I also ordered a PSI gauge to check the delivered pressure
If this pump is inefficient, I will order the Carter #4070. It's offered for a fair price at Rockauto (half price compared to Summit Racing)
for the tip
François
I will try the cheap EP-500 pump shown above because it's already ordered. I also ordered a PSI gauge to check the delivered pressure
If this pump is inefficient, I will order the Carter #4070. It's offered for a fair price at Rockauto (half price compared to Summit Racing)
for the tipFrançois
-
