cfamilyfix

iTrader: (15)

Want to run my Edelbrock 600 with my Carter 4070 and holley regulator. The Edelbrock requires 5.5lbs of fuel pressure at all times (according to my readings) The carter seems to have a unique feature where it is internally self regulated and can vary it's max pressure between 4 and 8 lbs. will this feature on the pump cause it to run below 5.5lbs?? I really like the carter and have used it on a couple of other applications (weber and Nikki) with no drama. This is my first dealing with this carb so I am trying to eliminate any pitfalls. Engine is a 13b 6 port with stock ports. Thanks for any advice you can provide.

wankel=awesome

regulate it down to 4.5 and youll hit its internal reg all the time. It wasnt designed to be run at its "max" RPM.

Can you believe people say that they dont install regulators on the 4070 and it "works just fine"?

Anymore I see "Works just fine" as code for "Im too dumb to know the difference."

Its internally bypassing, so its peaking GPH. In my experience with both Holley and Edelbrock, you dont need that magic PSI number they recommend. Turn it down to 4.5, and tune it. It will be rock solid and consistent there. And hey, if it isnt, your regulator wont let it fluctuate more than .5 psi.

cfamilyfix

iTrader: (15)

Thanks Wankel...I was hoping someone with your knowledge and experience level on carbs would chime in. Any recommendations on a type of regulator? I want to run a return on this set up. Holley ok?

wankel=awesome

I like this one: 31800.064 - Carburetors Unlimited

I found one at a swap meet 2 years ago that was probably ages old when I found it. I had no idea what it was worth, but I did use it for a short time. It is absolutely silent, (no bypass clicking or vibrations) and it is rock steady consistent. Plus, they can do boost too :P

It is getting hard to find anymore, but many of the "REDLINE" dealers on Ebay can get you one for under 100$ if you pm them the part #31800.064

Edit: That is not a junk regulator. That is an Italian OEM Weber Regulator. The same one found on vintage Ferrari's and many supercars of the 1970's...

Jeff20B

iTrader: (13)

I can mirror what wankel=awesome said. I've found that running an RB Holley at RB's recommended 6psi caused all kinds of stumbles and common carb glitches. When I lowered it to like 5psi, virtually all of them went away and it ran & drove better than an Edelbrock.

As for Edelbrock, 4.5psi worked great.

I've noticed the internal bypass of the Carters causing a surging sound and making a plastic fuel filter (Fram G2 or G3) bulge in time with the surging sound. This was with a dead-head (non return style) Holley fpr. I've since stopped using this particular setup. Makes me want to swap to a Mallory 4309 for the return capability letting the pump run cooler.

Speaking of which, wankel=awesome, that 31800.064 fpr looks kinda like a malpassi that came with a weber I got a few years ago. The malpassi only has a simple in and out. The question I have about the 31800.064 is whether it can handle boost because it looks like it could. Does vacuum reference = boost reference?

Dont get me wrong. I love the 4309. Just curious.

wankel=awesome

Yep, it does boost Lots of blow though euro builds are running it. Its a great piece. Extremely hard to find in the states, but a more reliable regulator there is not.

I like the 4309 too, and since its readily available it gets used a lot in the states. Its still second best, though. In my opinion.

And I believe "MALPASSI" actually built them for weber. Mine had that name on it too iirc.

Heres the one you had, the more common 31800.063
http://www.ebay.com/itm/Weber-Redline-Carburetor-Universal-Fuel-Pressure-Regulator-1-5-to-20-psi/400666831415?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D29903%26meid%3Dca78c169d4b6434699292357042ff72e%26pid%3D100005%26rk%3D4%26rkt%3D6%26sd%3D281081137107&rt=nc

Jeff20B

iTrader: (13)

It looks like the malpassi is a bit more convenient due to already having some 5/16" nipples. No need to also buy and then install a bunch of fittings.

Any plans on running the malpassi on your boosted setup? Appears to cost a little less than a new 4309.

Edit: Yep, that's the one I have.

Can it really handle 1.5 to 20 psi? That's great! Much more convenient than holley and also less likely to leak out of the diaphram.

wankel=awesome

Yep it really does 1.5-20. AND it has a max inlet pressure of over 50 psi. Its kindof perfect.

The diaphragm is one of the heaviest and most rigid I think on the market. Boost should be easy for it.

wankel=awesome

Weber Fuel Pump Regulator With Boost Reference Port (1.5-12lbs)

It reads 1-12 PSI, but it does go up to 20. Mine did anyways.

Also yes, I planned on running it.

cfamilyfix

iTrader: (15)

Wow lots of good info here...