We are currently running on the new domain and server: www.Speed-Talk.com

IMPORTANT: Update your bookmarks to https://www.speed-talk.com/forum/
(Right-click the URL and select "Bookmark this link")

Fuel pump questions (big block street car)

General engine tech -- Drag Racing to Circle Track

Moderator: Team

GRTfast
Guru
Guru
Posts: 4508
Joined: Wed Jul 05, 2017 8:26 am
Location:

Fuel pump questions (big block street car)

Post by GRTfast » Tue Jun 30, 2020 2:50 pm

I have a Holley Blue pump on my big block. My system is configured with a bypass regulator and return line after the carb feeds.

It's been on the car for a few years, maybe 10000 miles. How long do these pumps typically last? I have a spare, but don't want to put it in unless I need to.

Also, this pump is pretty loud.

Is there anything as or more reliable that is quieter?

I used to have a mechanical pump dead headed to the carb, and I was boiling the fuel. I am wondering if I go back to a mechanical pump, and add a restrictor in the return line if that would be sufficient to prevent the fuel from boiling?


Any thoughts/info/suggestions are appreciated.
Take the risk of thinking for yourself, much more happiness, truth, beauty, and wisdom will come to you that way. -Hitchens

F-BIRD'88
Guru
Guru
Posts: 7548
Joined: Tue Mar 27, 2007 6:56 pm
Location: Ontario, Canada

Re: Fuel pump questions (big block street car)

Post by F-BIRD'88 » Tue Jun 30, 2020 3:06 pm

I never had much luck with the blue holley pumps..

Big six valve rotatable body mechanical pump.
The feed line has to be routed AWAY from the exhaust . and headers.
Keep it cool.. Adding a Carter P4070 pump at the back pressurizes the feed line avoiding vapourlock...
Get the correct Seals-It Fuel pump mount heat isolation gasket kit for the mech pump.. If the electric pump is rubber mounted it is a lot quieter... The Carter P 4070 pusher pump only needs to be turned on if when racing or very hot "hotsoak" condition.

Get or make the Holley carb base heat shield to keep the heat away from the carb bowls.

GRTfast
Guru
Guru
Posts: 4508
Joined: Wed Jul 05, 2017 8:26 am
Location:

Re: Fuel pump questions (big block street car)

Post by GRTfast » Tue Jun 30, 2020 3:43 pm

F-BIRD'88 wrote:
Tue Jun 30, 2020 3:06 pm
I never had much luck with the blue holley pumps..

Big six valve rotatable body mechanical pump.
The feed line has to be routed AWAY from the exhaust . and headers.
Keep it cool.. Adding a Carter P4070 pump at the back pressurizes the feed line avoiding vapourlock...
Get the correct Seals-It Fuel pump mount heat isolation gasket kit for the mech pump.. If the electric pump is rubber mounted it is a lot quieter... The Carter P 4070 pusher pump only needs to be turned on if when racing or very hot "hotsoak" condition.

Get or make the Holley carb base heat shield to keep the heat away from the carb bowls.
Fuel lines are away from the exhaust, carb is on a 1 inch phenolic spacer. I have zero boiling issues now, the fuel line and bowls stay cold. I actually get condensation on the bowls in the florida summer. Pump is rubber mounted but it is still loud. My fuel tank is mounted up pretty high in my car, so there is a decent amount of pressure in the line down low at the front of the car. Never had any issues with starvation when I was running the mechanical pump or currently with the electric setup. To be clear I'm not trying to solve an operational problem, just trying to optimize function and reliability.

I guess my questions really boil down to:

1. Is there a better electric pump that I can replace the Holley blue with (quieter, as or more reliable)?

2. Will my old mechanical pump work with a restricted return line? If so, any thoughts on the restriction size? It seems it just needs to be enough to keep the fuel moving. Maybe somewhere between 1/32 and 1/16 inches?
Take the risk of thinking for yourself, much more happiness, truth, beauty, and wisdom will come to you that way. -Hitchens

steve cowan
HotPass
HotPass
Posts: 1094
Joined: Wed Jul 27, 2011 5:22 am
Location: brisbane AUSTRALIA

Re: Fuel pump questions (big block street car)

Post by steve cowan » Tue Jun 30, 2020 4:08 pm

For the last several years on my 11 sec streetcar I run a -10 from tank through a aeromotive filter to a 200gph Holley mechanical fuel pump,Holley bypass regulator after the carb with a -8 return to fuel tank no restriction.
No hot fuel issues ever,gets pretty warm here in summer 40deg Celsius, lots of street driving.
I run a composite pushrod as well with no issues.
steve c

BobbyB
HotPass
HotPass
Posts: 273
Joined: Mon Apr 15, 2013 1:35 pm
Location:

Re: Fuel pump questions (big block street car)

Post by BobbyB » Tue Jun 30, 2020 4:11 pm

To verify that your mechanical will work with a restriction & return to tank, mount a fuel pressure gauge where you can see it and see if it will hold pressure at WOT.
Fbirds suggestion of a carter4070 to be used only as needed along with a mechanical pump might be the best answer.
I really like the carter pumps...but just had one start to fail after 6 months and a few thousand miles. They are sending me a new one, and did not want the failed pump back, making me wonder if they expect failures.
I am currently using a holley blue, rubber mounted, super noisy. If I had it to do over again I would probably try an Aeromotive or Mallory instead of the Holley.
I don't think there is any doubt that electric fuel pumps for carbed engines leave a lot of people stranded. Fbird's idea should be super reliable in that either pump should be able get you home should the other pump fail.
FYI I have used .030 to .065 restrictions in the return line and both worked for me.

novafornow
HotPass
HotPass
Posts: 88
Joined: Mon Feb 04, 2019 2:23 pm
Location: california

Re: Fuel pump questions (big block street car)

Post by novafornow » Tue Jun 30, 2020 4:26 pm

There is a screen in the inlet that gets forgotten about. If you have a pre- filter, take it out. Otherwise clean it periodically. I have had pretty good luck with the Holley pumps on lower hp cars

GRTfast
Guru
Guru
Posts: 4508
Joined: Wed Jul 05, 2017 8:26 am
Location:

Re: Fuel pump questions (big block street car)

Post by GRTfast » Tue Jun 30, 2020 4:46 pm

steve cowan wrote:
Tue Jun 30, 2020 4:08 pm
For the last several years on my 11 sec streetcar I run a -10 from tank through a aeromotive filter to a 200gph Holley mechanical fuel pump,Holley bypass regulator after the carb with a -8 return to fuel tank no restriction.
No hot fuel issues ever,gets pretty warm here in summer 40deg Celsius, lots of street driving.
I run a composite pushrod as well with no issues.
I've always read that those holley bypass regulators don't work well with the mechanical pumps. Interesting. If they do, I can just put my mechanical pump back on and be done.
Take the risk of thinking for yourself, much more happiness, truth, beauty, and wisdom will come to you that way. -Hitchens

GRTfast
Guru
Guru
Posts: 4508
Joined: Wed Jul 05, 2017 8:26 am
Location:

Re: Fuel pump questions (big block street car)

Post by GRTfast » Tue Jun 30, 2020 4:47 pm

BobbyB wrote:
Tue Jun 30, 2020 4:11 pm
To verify that your mechanical will work with a restriction & return to tank, mount a fuel pressure gauge where you can see it and see if it will hold pressure at WOT.
Fbirds suggestion of a carter4070 to be used only as needed along with a mechanical pump might be the best answer.
I really like the carter pumps...but just had one start to fail after 6 months and a few thousand miles. They are sending me a new one, and did not want the failed pump back, making me wonder if they expect failures.
I am currently using a holley blue, rubber mounted, super noisy. If I had it to do over again I would probably try an Aeromotive or Mallory instead of the Holley.
I don't think there is any doubt that electric fuel pumps for carbed engines leave a lot of people stranded. Fbird's idea should be super reliable in that either pump should be able get you home should the other pump fail.
FYI I have used .030 to .065 restrictions in the return line and both worked for me.
Thanks for the info.
Take the risk of thinking for yourself, much more happiness, truth, beauty, and wisdom will come to you that way. -Hitchens

steve cowan
HotPass
HotPass
Posts: 1094
Joined: Wed Jul 27, 2011 5:22 am
Location: brisbane AUSTRALIA

Re: Fuel pump questions (big block street car)

Post by steve cowan » Tue Jun 30, 2020 6:17 pm

GRTfast wrote:
Tue Jun 30, 2020 4:46 pm
steve cowan wrote:
Tue Jun 30, 2020 4:08 pm
For the last several years on my 11 sec streetcar I run a -10 from tank through a aeromotive filter to a 200gph Holley mechanical fuel pump,Holley bypass regulator after the carb with a -8 return to fuel tank no restriction.
No hot fuel issues ever,gets pretty warm here in summer 40deg Celsius, lots of street driving.
I run a composite pushrod as well with no issues.
I've always read that those holley bypass regulators don't work well with the mechanical pumps. Interesting. If they do, I can just put my mechanical pump back on and be done.
Honestly no issues,I run a autometer fuel gauge in the car with the dampner,there is no fuel pressure pulsing and fuel pressure increases slightly as rpm comes up.i am talking 500hp engine with lots of quarter mile passes(100s).
steve c

Kevin Johnson
HotPass
HotPass
Posts: 8836
Joined: Tue Nov 22, 2005 5:41 am
Location:

Re: Fuel pump questions (big block street car)

Post by Kevin Johnson » Tue Jun 30, 2020 10:50 pm

Critical item for your toolbox in the car. It allows for calibrated blows [taps] to recalcitrant electric fuel pumps. You may need a custom length handle.


https://www.amazon.com/Springfield-Leat ... B00CLS52TI

Geoff2
Guru
Guru
Posts: 1285
Joined: Mon Nov 09, 2015 4:36 pm
Location: Australia

Re: Fuel pump questions (big block street car)

Post by Geoff2 » Wed Jul 01, 2020 5:34 am

The Carter electric pumps are more reliable, probably the most reliable of the elec pumps for external use [ not in-tank ] for carbs. They have fuel circulating through the elec motor section to cool the pump & lube the brgs. There is NO internal seal a la Holley to fail. The Holley on my mate's car used to stop occasionally for no reason; he would need to get a hammer out of the glove box, get under the car & give the pump a 'tap' to get it working again; bit of a nuisance when dressed in your Sunday best clothes....

These are the only external carb type pumps that I am aware of that have fuel circulating through the motor & eliminating a seal that would eventually fail. One bloke had one on his car for 19 yrs,daily driver. He replaced it. Not because it failed, but he reckoned it had earned it's retirement!!
The 4600 series are rated at 100 gph. Assuming 90 gph at the carb, with a very generous 50% safety margin, it could supply fuel for about 700hp.

tenxal
Expert
Expert
Posts: 684
Joined: Sun Nov 17, 2013 8:48 pm
Location:

Re: Fuel pump questions (big block street car)

Post by tenxal » Wed Jul 01, 2020 8:28 am

A really good fuel pump for you would be this one. You can bypass the fuel at the pump right back to the tank so the fuel pump runs cooler. It's not super quiet but if you mount it with some rubber vibration mounts it would be reasonable for a street car.

https://www.holley.com/products/fuel_sy ... /30-175QFT

For a regulator, this Quick Fuel is a Holley-style but is a much, much better unit for durability.

https://www.holley.com/products/fuel_sy ... /30-803QFT

rp930
Member
Member
Posts: 135
Joined: Tue Dec 10, 2013 11:47 pm
Location:

Re: Fuel pump questions (big block street car)

Post by rp930 » Wed Jul 01, 2020 9:39 am

“I used to have a mechanical pump dead headed to the carb, and I was boiling the fuel. I am wondering if I go back to a mechanical pump, and add a restrictor in the return line if that would be sufficient to prevent the fuel from boiling?“

I would go this route. Very reliable and quiet.

GRTfast
Guru
Guru
Posts: 4508
Joined: Wed Jul 05, 2017 8:26 am
Location:

Re: Fuel pump questions (big block street car)

Post by GRTfast » Wed Jul 01, 2020 9:49 am

rp930 wrote:
Wed Jul 01, 2020 9:39 am
“I used to have a mechanical pump dead headed to the carb, and I was boiling the fuel. I am wondering if I go back to a mechanical pump, and add a restrictor in the return line if that would be sufficient to prevent the fuel from boiling?“

I would go this route. Very reliable and quiet.
I could always leave my electric pump in place with some plugs in it. It is on the frame right there by where the mechanical pump mounts to the engine. Same lines work for both. If the mechanical pump fails, I can just swap the lines over to the electric pump and connect the wires. would take 5 minutes. I guess I would also need to swap the regulator back in place of the restrictor T after the fuel log. Still pretty easy.
Take the risk of thinking for yourself, much more happiness, truth, beauty, and wisdom will come to you that way. -Hitchens

GRTfast
Guru
Guru
Posts: 4508
Joined: Wed Jul 05, 2017 8:26 am
Location:

Re: Fuel pump questions (big block street car)

Post by GRTfast » Wed Jul 01, 2020 2:16 pm

Going to do the following:

1. new mechanical pump with the "sealed-it" heat barrier gasket system and composite pushrod.
2. 0.032 restricter in the T after the fuel log, with a return line and a fuel pressure gauge.
3. keep my electric pump in place with plugs in the fitting holes and wires disconnected and covered.
4. In my car, I will keep my pressure regulator and tools needed to swap the lines over to the electric pump and swap the restricted T with the regulator.

That should be a quiet and reliable setup, with a contingency plan in case the mechanical pump fails.
Take the risk of thinking for yourself, much more happiness, truth, beauty, and wisdom will come to you that way. -Hitchens

Post Reply