Today I ordered a New Carter 172...

AND A Mallory Comp 140 with 2 port regulator AND a couple different inline filters AND a Carter 7 psi electric AND a Holley Red to add to my collection of pumps and regulators and filters and AN Fittings (and sparkplugs). I will just return what I don't use. I don't have time to figure it out and AND Then order parts. Just need to look at some options then just do it.

Does anyone out there use a Mechanical Backed by an electric just when racing. What pumps are you using ?

I know the Carter pulls through the Mallory 250 just fine on the street with no drop in pressure cruising at 75 to 80 mph.

Tom, do you have an in-car mounted fuel pressure monitor? How big is it?
I was thinking of adding oil & tranny temp, and fuel pressure, but fuel pressure is up in the air since I may be able to grab an AF meter for $245.

matt

I have 2 gauges mounted on an A-pillar pod - vacuum and fuel pressure. Mounted flush in the dash is oil pressure, voltage, water temp and trans temp. A wide band AF would be a nice treat too but not just yet.

I've got a the Carter strip manual 120 gph,with a Mallory 140 pusher,no return line, with the Mallory 2 port regulator. Its fine on the street,but I go a little lean at the track trying to pull thru the Mallory,I just gotta remember to turn it on graemlins/clonk.gif

Bob,

I am assumming you have the Mallory run to the regulator first then to the carter and on to the carb. What pressure do you send to the Carter pump. I was thinking 4 or 5 so as not to push too hard on the diaphragm.

I'm running the Mallory to the mechanical,then to the regulator and carb...I have 8 psi with just the electric turned on...the Carter is supposed to be set at 8 psi itself from the factory,but I was getting much higher readings. I might be blowing thru the Carter?? it seems to work fine as long as I turn the electric on...I have a autogage fuel pressure guage,but its mounted on the pass. side inner fender. It used to be on the cowl til I got the new hood.

Tom,
Great topic!
I'm following this topic very closely...
This is EXACTLY an issue I've got to work out next week when the '70 finally comes home.
Got a Mallory 140, the Carter 172 and 1/2" fuel line ready to install on a sumped factory tank.

Here's what I think,

Since the Carter regulates itself wouldn't it be safer to run maybe 4 or 5 psi to the carter. The problem mechanicals can have is overcoming the forward acceleration. with 14 psi from a 140 pushing forward, the Carter shouldn't have to work anywhere as hard pulling the long column of fuel from the tank as it would without the 140.

Shouldn't be any need to show the carter anymore than 6 with it sitting behind the regulator at 14.

I have used the 172 for 3 solid seasons and stillhave not proved there isn't something else wrong in the system like a clog in the 12" BG filter tucked up into the frame rail. will get to that hopefully tomorrow. maybe a metal frag from sumping the tank escaped the cleaning and is sitting just right to be a restriction.

Bill,

We'll keep you posted. ;)

Before I removed the fuel pressure guage from the cowl,and before I installed the Mallory,my fuel pressure was dipping down to 3-4 psi at the end,,,with the Mallory set at 9psi it would stay between 5-6 at the end. Still it made no improvements in e.t. as I thought it would :confused: I do not have a sump,and pulling thru the stock set up. I have come to the conclusion that I am pretty much maxed out for my heads,cam,current combo. I've got my bionic rat on the engine stand,still in the planning stages ;)

you could take apart the pump and see if the diaphram was damaged by something.