has anyone ever tested one of these?

ive got the p4389 carter universal pump that most of use have, installed like kenetsu's writeup, on the frame rail. i'm using all straight fittings and 5/16" or 8mm fuel lines, 2 stock fuel filters, one in the stock spot and one under the hood by the carb.

for the PP mazd gives a spec of 1.5L every 30 seconds, or 3L/min = 180L/hour = 47GPH @4.3 psi at the carb. my test bottle is marked every 100ml.

first test was with the holley regulator turned up to its maximum of 4.1psi, the pump volume is about 1000ML/30 sec or 2l/min or 31.7GPH.

next test is without the regulator, pressure rises to 4.3psi, volume goes up to 1200ml/30 sec or 2.4L/min or 144L/hour or 38GPH.

battery voltage was 12.31 voltage at the pump is about 11.3

so i have more questions than answers...

since i'm getting about 80% of what mazda wants, this is still good enough for about 200flywheel HP (260 x.8).

but the pump is rated @72 gph. is the voltage too low? are the stock lines/filters etc too small? is this my 5000RPM hesitation?

i do notice the IMSA car has like 3 of these pumps in it, maybe this is why?

 

I have the 4070 and it appears to flow as advertised. One thing I
noticed is that its very sensitive to the voltage. It requires a minimum
of 12v. Mine was kind of loud at first but then I added a relay and
a direct feed from the battery positive and it queited down a lot.

I think 11v is too low in your case.

 

I somewhat know what you meant by that. I actually noticed it too but didnt really pay attention. light blue RX-3= holley blue midnite blue RX-3 = carter 7spi

it seems the carter draws more juice than the holley

 

yeah i was thinking about finding out what voltage is like with the engine running, and see what it flows with that voltage.

can't do both!

 

The 72 gph Carter comes with 3/8" fittings. Maybe your stock 5/16" / 8mm lines are a little small at the lowish psi of your carb. Maybe swap in some 3/8" and try again?

The carters use what they call dry fittings where you're not supposed to use any teflon tape or thread seal compound typically used is household plumbing. Well what I found is carter fittings are basically NPT 3/8" or 1/2" (it's one or the other) so if you had to, you could grab a couple of 3/8" barbs from your local hardware store and they should thread into the carter ok. Maybe use some type of thread sealer for extra piece of mind?

As for wire size, use 10 gauge. I need to rewire my REPU with it because the PO used something a little smaller than 14 guage and I've got the 110 gph carter under there. It makes the ignition wires warm. They used to get hot before I added a relay for my ignition. Gotta add a another for the fuel pump.

 

i don't recall where my fittings came from, but i think they ARE 3/8" with the 5/16 hose over it, cause they dont have 5/16 fittings in the stores here, i could be wrong though.

and the PSI i'm recording is @the carb, with NO regulator. so the carb isn't in the picture, just to clarify

i'm using the stock wires, so that could totally be an issue, although it just goes thru a fuse and the IGN switch.

 

Ah, it sounds like the fittings are correct. Now you need some bigger fuel line.

Yeah, upgrade the wires when you can.

 

imma have to double check the fittings, out of sight out of mind, but the spec is 72GPH free flow, and a max of 6 psi with 1/4" fittings

 

heres an update in my RX-3. the battery is in the trunk so it was a quick change. I used a 10gauge wire (for amps) into a 30amp fuse to the carter 4594 pump. I used the stock fuel pump wire to trigger a 30-amp relay. no more problem with flactuating voltage even with lights, hazard, fan etc were on. so thanks Jeff for the idea.

 

Good to hear wacky, I got a few 30a relays dying to be used!

 

You're welcome. Gald I could help.