Mechanical Fuel Pump for Drag Race

[skinny z]

Here ya go
Carter with the higher pressure spring, late 90's -10 in - 8 out. This is an earlier one -8 in. We could eventually get them with big enough ports so we didn't have to weld the fittings on. There was no tricks inside, and no need for a regulator. Last car I was involved with was 666hp unleaded 9.5:1. We were making more earlier with Unocal Nascar fuel and no comp limit.

20220830_064709.jpg


Edit, still got a couple, when we switched to unleaded the pumps got unreliable, Goss gave me some replacement valves to try but I never got around to it.

Fuel Pumps.JPG

This is the one I have,
20200228_124710.jpg

If that the mechanical fuel pump that ate the cam lobe on your camshaft?

The mangled cam was mine. The pump used was Edelbrock's 110 GPH version. Standard tip pushrod but the lightweight design.

[RCJ]

Only because someone mentioned dry sumps. I had an ultra lite dry sump suction line that was sucking shut and loosing oilpressure.
.

[Callmewaylon]

In your pictures all that rubber fuel hose and the regulator itself positioned near the HoT exhaust headers IS a FIRE waiting to happen..
Wonder you got thru safety tech inspection at the track with all that rubber hose..
NHRA says max 12" TOTAL combined rubber hose length on the whole car fuel system.
That is a disaster waiting to happen.
Correct the fuel line route ing and loose 80% of that rubber hose.

Stated ealier that I only have about 4-5" of rubber max going from the factory hard line to the fuel pump. The rest is braided AN. If you have any pics of a better setup it would be helpful. I need something to go off of.

[steve cowan]

In your pictures all that rubber fuel hose and the regulator itself positioned near the HoT exhaust headers IS a FIRE waiting to happen..
Wonder you got thru safety tech inspection at the track with all that rubber hose..
NHRA says max 12" TOTAL combined rubber hose length on the whole car fuel system.
That is a disaster waiting to happen.
Correct the fuel line route ing and loose 80% of that rubber hose.

Stated ealier that I only have about 4-5" of rubber max going from the factory hard line to the fuel pump. The rest is braided AN. If you have any pics of a better setup it would be helpful. I need something to go off of.

20220831_152112.jpg

20220831_152105.jpg

20220831_152100.jpg

20220831_151850.jpg

I have run this set-up for several years now, no hot fuel issues ever.
I run -10 from tank outlet to a aeromotive filter and ball valve to shut fuel off when removing/cleaning filter.holley 200 gph mechanical fuel pump. -8 from pump to fuel log to a holley bypass return regulator after the carb and -8 return to tank.
I would not hesitate to go -8 to pump then -6 to bypass regulator then -8 return to tank.
I believe some guys use a bigger return line than feed line but in a application like mine I don't know if it is necessary.

[Tom68]

20220831_152112.jpg20220831_152105.jpg20220831_152100.jpg20220831_151850.jpg
I have run this set-up for several years now, no hot fuel issues ever.
I run -10 from tank outlet to a aeromotive filter and ball valve to shut fuel off when removing/cleaning filter.holley 200 gph mechanical fuel pump. -8 from pump to fuel log to a holley bypass return regulator after the carb and -8 return to tank.
I would not hesitate to go -8 to pump then -6 to bypass regulator then -8 return to tank.
I believe some guys use a bigger return line than feed line but in a application like mine I don't know if it is necessary.

That sintered bronze breather would be working pretty hard, still if it's working, all good.

[steve cowan]

20220831_152112.jpg20220831_152105.jpg20220831_152100.jpg20220831_151850.jpg
I have run this set-up for several years now, no hot fuel issues ever.
I run -10 from tank outlet to a aeromotive filter and ball valve to shut fuel off when removing/cleaning filter.holley 200 gph mechanical fuel pump. -8 from pump to fuel log to a holley bypass return regulator after the carb and -8 return to tank.
I would not hesitate to go -8 to pump then -6 to bypass regulator then -8 return to tank.
I believe some guys use a bigger return line than feed line but in a application like mine I don't know if it is necessary.

That sintered bronze breather would be working pretty hard, still if it's working, all good.

We run that pump on the dyno earlier this year,the boys hooked it up without regulator thinking it would only pump 6psi.
Fired up engine and it had 15psi and before I realised what was going on it blew diaphragm, and fuel coming out of the bronze breather.
I rebuild pump and it works a good as can be.
Still using the same composite pushrod since day one,hardly any wear at all

[skinny z]

Still using the same composite pushrod since day one,hardly any wear at all

I wonder how it would fare if there thousands of street miles on it?
That's one of things about drag racing, limited run time compared to a street/strip deal.
Then again, I put TENS of thousands of miles on my heap in all manner of driving.

[F-BIRD'88]

Once you have re-plumbed your fuel system from tank to pump and pump to carb. you can re-purpose your (non bypass holley regulator to function as a diverter bypass valve . It now "regulates" the amount of flow and pressure of the return line back to the tank.
You plumb it in reverse and put it AFTER THE CARB FEED LINE.
adjust it so the working pressure at idle is say 4.5 psi.
It will bypass return the amount of fuel to maintain 4.5" psi line pressure.. at idle and while driving.
When at WOT high fuel demand and line pressure drops below 4.5 psi it closes the valve and stops divertering flow. (return)
All the fuel flow then goes to the carb.


The internal ball orrifice is 7/32" (.220") so any diameter return line of 3/8" OD tube is fine.

Plenty of regulated bypass return.. No flow loss restriction of a inline regulator.

I recommend you replace the factory fuel line from tank to pump.. (Re-route it AWAY FROM THE HEADERS AND TRANS. 3/8" OD steel or aluminum hard line is fine.
Use a proper tube bender tool to make nice bends to fit it..

Then you could use the old factory fuel line as your return line (or run another 3/8" hard line back to the tank.

Again adding the Carter P4070 "pusher pump" at the back is a great addition.
(Optionally you can control this Carter electric pusher pump to automaticly turn on and off by wireing in a Hobs pressure switch to turn it on and off automaticly based on fuel line pressure.) It will now only turn on during WOT high fuel flow demand.. You won't hear it much @WOT.
Unlike just about every aftermarket fuel pump these good old Carter vane fuel pumps were designed to run full time 100% duty cycle , 24/7. Dead head no problem.
Hard to beat at $57 US.
A manual power switch alliows you to run it while racing.
The Hobs pressure switch makes it run automaticly only as needed during normal street driving duty.

[steve cowan]

Still using the same composite pushrod since day one,hardly any wear at all

I wonder how it would fare if there thousands of street miles on it?
That's one of things about drag racing, limited run time compared to a street/strip deal.
Then again, I put TENS of thousands of miles on my heap in all manner of driving.

Up until this year I drove my red car alot,I have used the composite pushrod and composite dizzy gear on plenty of combinations from cast core SFT to billet roller cams with great success, I am not a fan of bronze.

[70GS455]

Here is a video of fuel pressure during a dyno pull. This is a RobbMc 550 pump feeding a Qjet and made 586 hp/603 ft lb. Pressure started off at 8.5 and never dropped below 6 psi

https://youtu.be/nw-_zqkjL6Y

[Callmewaylon]

Update on the fuel system.

Eliminated the regulator and installed my Holley 3310 vac secondary carb and went to the track.

No more lay down at all that i can notice. AFR 12.5 until half track then 13.5 back half of track. Went up 3 jet sizes in the rear with the same results. Did run 2 tenths better than previous runs 12.50 @ 109.

That was a couple weeks ago. Just got an electric fuel pressure gauge installed. 6psi pretty steady. At full throttle it goes down to 4psi. Would that be enough to cause the leaning out going down the track or should I jet up some more? Maybe jet extensions on the rear?

[F-BIRD'88]

No the 4 psi is fine.. Yes to jet extensions.
Carb may need minor air bleeds tweek.
The 3310 has problems opening the secondaries 100% @ WOT. Add brass sev vac pick up tube in the Vac sec pick up passage to the venturiii. Better vac signal to the vac diaphram.
What is the pri and sec main jetting now?

[Callmewaylon]

No the 4 psi is fine.. Yes to jet extensions.
Carb may need minor air bleeds tweek.
The 3310 has problems opening the secondaries 100% @ WOT. Add brass sev vac pick up tube in the Vac sec pick up passage to the venturiii. Better vac signal to the vac diaphram.
What is the pri and sec main jetting now?

Primary and main jetting was 71/71. I upped the secondaries to 74 with similar results, but only tried one run as it was the end of the day. Not sure what you mean about adding a pickup tube to the vac secondary. I know there's a little check ball in there that I thought about leaving out, but instructions said to keep. I am using the lightest white spring. I have the adjustable kit and verified the secondaries opening with compressed air. Doesn't mean they couldn't open better with the mod your are suggesting if I can figure it out. Also, how do you modify the air bleeds when they aren't replaceable? Drill them out with indexed drill bits?

[F-BIRD'88]

Stock 3310 jetting is 72 pri 80 sec.
Start there.
Ya to mod the air bleeds requires drilling out and pulling those pressed in orrifices and drill and tap for screw in type air bleed jets..
The vac tube mod requires drilling that vac passage and pressing in a small brass tube that extends slightly into the venturi.
The good OEM like 3310 (-1) version had this The later aftermarket 3310-2 → (5) Does not..

The sec jet extensions are a must do.
Be sure that these extensions do not hit the float.
There is a notched float for this.

The now cooler denser Fall season air will improve performance. And will want richer jetting like the stock jetting. 72 pri. 80 sec (no sec powervalve)

[F-BIRD'88]

Next summer when the Hot Hot weather returns you are going to want that Carter lil electric pusher pump added. For drag racing on hot days.