Fuel Line Sizing - Return vs Feed



Fuel Line Sizing - Return vs Feed

Postby phantomjock » April 18th, 2010, 8:04 pm

Greetings - 1st post. Do some other forums and THANKS Grumpy for this great resource!

I just don't quite get the feed at -8AN and a return of -10AN. Now, some of the fuel has to get spent in the CARB - and left overs might be less than the initial input.
So, is the rationale - that the regulator - has MUCH less push after the Carb - and therefore needs a larger diameter fuel line -- just to keep from choking the flow through the system? Or is there some other reason not so obvious.

Otherwise the simplistic answer might be -10AN IN and -8AN out.
Can you help with some "splain-in here?

And would it be the same on a seperate fuel line for NOS -8AN in and -10AN out for the fuel?

TIA
Cheers Jim
Returned - Baghdad, Iraq
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Re: Fuel Line Sizing - Return vs Feed

Postby grumpyvette » April 19th, 2010, 8:34 am

Image

ok, first heres the diagram I,m assuming your referring too?
it is a good clear, no frills diagram, of fuel line routing

viewtopic.php?f=55&t=635

heres (above) a thread that helps explain the FUEL PRESSURE REGULATOR function, the basic idea here is that any restriction to flow in the return line tends to reduce the FUEL PRESSURE REGULATOR, correct function,but your correct that the carb does use some fuel and that at least in theory the AN8 feed could be fully supported bye a similar AN8 return line, but the size of the fuel pump and flow volume, and pressure going thru the lines will effect the results.


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IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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GOOD FUEL FILTER INFO OFF THE INTERNET

Postby grumpyvette » December 18th, 2011, 9:46 am

IM RE-POSTING THIS, I DIDN,T WRITE IT BUT AGREE WITH IT...


I know theres some guys on the site that have the glass and chrome inline filters on their cars. I used to have one on my 72 Nova. One day a friend of mine told me that someone he knew had his 68 Camaro go up in flames because the filter hit something metal under the hood, the glass broke and the gas sprayed all over the hot exhaust. I took mine off that day and never used one like it since. That was probably back in 1988.
One of my friends from my old job has a mint 78 Camaro. The car is pristine. Small block. Detailed to death under the hood. One day I noticed he had one of those glass filters. I told him the story about the other Camaro. He said if he had time he would look for another type of filter. So I get a call from him the other day. Hes on the side of the road. Empty gas tank. I drive up there with 5 gallons of gas to get him home. You can guess what the problem was. That filter broke. Gas washed the whole engine compartment. There was a trail of gas down the road. The guy was a nervous wreck. He was very lucky. I think the fact that he has stock manifolds instead of headers might have helped but Im not sure. Everything that was painted with regular paint looks like crap. It was all over the firewall, the frame, the booster. All that work ruined for a $15 filter. You guys out there better take a good look at the setup under your hoods and make sure that NOTHING hard can come in contact with the filter. Hitting one pothole can do it if theres enough slack in the fuel line ! Hate to see a nice car turn into a pile of black rubble over a cheap fix.
"


BTW alcohol in fuel tends to cause aluminum to oxidize over time

http://video.foxbusiness.com/v/2000862202001/
Image

http://www.youtube.com/watch?feature=pl ... uIoAa5RRBs
Image
for the few guys that might not know ,hes referring to these KNOWN FIRE HAZARDS I've seen several leak, break and cause fires , they are restrictive and un-safe to use
, if you insist on mounting a fuel filter next to the carb, these filters in this link below work and are not a fire hazard
http://www.robbmcperformance.com/products/filters.html
Image
Image
http://www.jegs.com/i/Professional-Prod ... 6/10002/-1

Image
HOSE LIKE THIS WAS NEVER DESIGNED TO BE FUEL LINE IT HARDENS WITH HEAT OVER TIME,BECOMES BRITTLE AND CRACKS, ITS ALSO EASILY MELTED, ITS ALSO A FIRE HAZARD
Image
BTW THESE ARE STILL PATHETIC AS A FUEL FILTER BUT ARE FAR SAFER THAN THOSE GLASS SCREW TOGETHER DISASTERS, the ALUMINUM FILTERS ABOVE ARE BETTER AND SAFER

THIS THREAD REMINDS ME!
I was just talking with a neighbor who used that reinforced clear plastic fuel line on his car back in the 1980s, it was on a mustang, he owned at the time, he used one of the clear plastic fuel filters and a couple small hose clamps ... well he says he remembers just about everyone used those back then, but he was sitting at a traffic light one day and started smelling strong fuel,odors, and smoke started coming out from under the dash and thru the air conditioning ducts, he pulled over to open the hood and found gas spraying in a fine mist from a crack in the hose that had turned yellow and hardened with heat and age in the engine compartment, the smoke was from the fuel mist hitting the hot engine,the crack was where the clamp was on the filter, he had no idea why the engine failed to catch fire. but he replaced the hose and filter , and when he got home he called a friend that he knew was using a similar set-up, the friend said he had already replaced his fuel line after having a small fire when he moved the cars air cleaner and busted the hose!
Image

HERES SOMETHING FAR SUPERIOR
Image
http://www.aemelectronics.com/?q=produc ... uel-filter


KEY FEATURES
Machined from 6061-T6 aluminum and hard anodized black
Flows up to 12.32 gpm @ 45 PSI and 2.63 gpm @ 6 PSI with -10 port fittings
Filters as low as 7 microns
Viton o-rings and gaskets ensure outstanding performance when using gasoline, alcohol or gasoline/alcohol blended fuels
End caps are machined with -10 AN female fittings with o-ring receiver groove
End caps have pressure intensifiers for greater sealing of end gaskets
2” OD x 10” length for easy mounting
Commonly available replacement filter cartridges
Laser etched with AEM logo, flow and filter replacement information

The AEM High Flow -10 AN Inline Fuel Filter is CNC machined from 6061-T6 Aluminum and Hard Anodized Black. AEM’s engineers designed this filter with the racer in mind and with the intention of maximizing flow, filtration and ease of installation. The end caps are machined with -10AN female fittings with o-ring receiver groove that allow the filter to flow up to an astonishing 12.32 gpm @ 45 PSI and 2.63 gpm @ 6 PSI. All sealing o-rings and gaskets are made of Viton for outstanding performance when using gasoline, alcohol or gasoline/alcohol blended fuels. The commonly available replacement filter cartridges filter as low as 7 microns. The standard 2” OD allows for easy mounting virtually anywhere in the vehicle.


BTW I WONDER IF VERY MANY GUYS BOTHER TO READ INSTRUCTIONS
http://www.jegs.com/i/JEGS-Performance- ... 2/10002/-1
heres a fuel filter I see some guy installed on his 750 holley carb equipped car and he wonders why he runs out of fuel in third gear,think about it, hes got a fuel filter rated at 130 gallons per hour , certainly adequate...until you realize hes using a manual fuel pump that produces maybe 9psi and the filter flow rates rated at 75 psi, , more than 8.3 times the pressure, so hes likely getting 1/6-1/8th the flow at 9 psi

read thru these

viewtopic.php?f=55&t=211&p=7776&hilit=fuel+filters#p7776

viewtopic.php?f=55&t=635

http://aeromotiveinc.com/wp-content/upl ... ter-NN.pdf

viewtopic.php?f=55&t=109

viewtopic.php?f=55&t=1939

viewtopic.php?f=55&t=10664

viewtopic.php?f=55&t=4381
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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EFI Fuel Pumps and Fuel system design

Postby Strictly Attitude » August 7th, 2014, 4:16 pm

I am familiar with the Bosch 044 and also see the walboro brought up in a lot of discussions also. I will be replacing the whole fuel system. How do feel about tandum pumps run off the ecu so on kicks on under heavy throttle conditions
"IF YOU CAN SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR SUSPENSION NEEDS MORE WORK!!"

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Re: EFI Fuel Pumps and Fuel system design

Postby grumpyvette » August 7th, 2014, 4:27 pm

Strictly Attitude wrote:I am familiar with the Bosch 044 and also see the walboro brought up in a lot of discussions also. I will be replacing the whole fuel system. How do feel about tandem pumps run off the ecu so on kicks on under heavy throttle conditions


the use of dual or tandem fuel pumps is, in most cases, needlessly complicated and poses little or no advantage over a correctly installed single fuel pump, fuel cell, and lines of the correct size.
electric pumps can handle 1800 hp on gas engine mechanical engine driven pumps well past 4500hp, when matched to the correct size lines and fuel cell.
theres zero question that youll need to upgrade from OEM size fuel lines and to aftermarket fuel pump sizes as power increases but fuel pumps with AN#10 ports that flow significantly more volume ARE readily available


HERES A FAIRLY NEW ,AND VERY INTERESTING ADDITION TO THE POTENTIAL FUEL SYSTEM DESIGN, as IT INCREASES THE FUEL PUMPS ABILITY TO ACCESS FUEL

http://www.motoiq.com/MagazineArticles/ ... rvoir.aspx
BUT READ THIS
viewtopic.php?f=55&t=6105

AN fittings mounted to a sump welded to the lower surface of any fuel tank or fuel cell have certainly worked well for decades but as technology has advanced the in tank fuel pumps have certainly improved measurably to the point they have now shown some advantages, obviously not having and potential leaking fittings or a sump extending below the fuel cell floor can be an advantage as the fact that in the tank electric fuel pumps tend to be cooled by sloshing fuel.
something like this would certainly add performance up to about 600 N/A hp, keep in mind its AN #6 fittings and pump output will restrict power near 600hp,
there are obviously other options with larger fittings and fuel pumps with a fuel cell. So a bit of research, on PUMP FLOW RATES,FITTINGS, LINE SIZES AND FUEL CELLS is well warranted if your thinking of exceeding 600hp

http://aeromotiveinc.com/phantom-fuel-system/

https://www.youtube.com/watch?v=Ge0ny7I0lBk
[/b]
Image
Image
http://www.weldonracing.com/products/Pr ... Pumps.html
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http://www.racerpartswholesale.com/cate ... FuelCells2


READ THRU THESE LINKS AND SUB LINKS
viewtopic.php?f=55&t=1939

viewtopic.php?f=55&t=1200

viewtopic.php?f=55&t=211

viewtopic.php?f=55&t=733&p=1030#p1030

viewtopic.php?f=55&t=1030&p=1912#p1912

http://www.atlinc.com/racing.html

viewtopic.php?f=55&t=7787

viewtopic.php?f=87&t=2141&p=25201#p25201

viewtopic.php?f=55&t=4111&p=10917&hilit=ethanol#p10917

viewtopic.php?f=55&t=613&p=817&hilit=ethanol#p817
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: EFI Fuel Pumps and Fuel system design

Postby Strictly Attitude » August 7th, 2014, 4:50 pm

Sweet information so far I plan front to back -8 AN fuel line Teflon/PTFE seems to be the rage. -8 AN on the return also good to have some room for upgrades down the road. I am aiming a 20 gallon cell not sure if I am going to go pump in the cell or external which is more cost effective?

I know the pump in the cell is better as far as cooling of the pump is concerned but would also involve baffling and probably a much more expensive design needed.

I also have thought about an aluminum sump cell with external fuel pump. Have heard horror stories about fuel cell foam breaking down and causing mayhem.

I am really trying to keep it in my head that I will be using the car as a mainly street car. I want it to be able to take turns with out starvation but I also know it won't be taking turns like that often and it would see hard launches more than hard turns as I am still on the mechanical aspects of the car.
"IF YOU CAN SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR SUSPENSION NEEDS MORE WORK!!"

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Re: EFI Fuel Pumps and Fuel system design

Postby grumpyvette » August 7th, 2014, 5:26 pm

if you can weld aluminum you can build a decent fuel cell with internal baffling should you choose to start fabricating , and a few sheets of perforated aluminum sheet can go a long way toward fuel slosh baffle construction
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: EFI Fuel Pumps and Fuel system design

Postby philly » August 7th, 2014, 5:31 pm

yea man the cell foam alot of people dont realize is in fact a service item, it needs to be replace periodically, moreso with the additive of ethanol in our fuels now... grumpy had a great thread here (that for the life of my searching i cant seem to find now) that detailed the different materials of fuel line and what they are capable of carrying as far as resistance to ethanol goes. if you are starting completely fresh from scratch i would recommend not fighting the tide and just going e85 from the start, probably pick up more power anyway. that is of course if you have plenty of e85 stations native to your area.

i actually just purchased all new fuel system for 280zx as it has become necessary to put that car back into service,

i got a bosch 044 pump
http://www.bosch.com.au/car_parts/en/do ... lpumps.pdf
http://www.summitracing.com/parts/bch-61944

new rubber 3/8 feed and return lines

a regulator from FAST
http://www.fuelairspark.com/fas/30-70-p ... feedshtml/

an inline fuel filter from redhorse and all the associated fittings to make it come together
http://www.redhorseperformance.com/

i still need to make the fuel rail for my holley 83 lb injectors
https://www.holley.com/products/fuel_sy ... ts/522-831

and then ill be ready to fire it up and start tuning.
Last edited by philly on August 7th, 2014, 6:01 pm, edited 1 time in total.
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Re: EFI Fuel Pumps and Fuel system design

Postby 87vette81big » August 7th, 2014, 5:53 pm

I like External Fuel pumps best myself.
If there are problems it can be serviced in a parking lot or on the side of the road.
Unless your using Pure Race Gas or Pure 100 LL Aviation gasoline, water asorbtion into E10 & E85 & Methanol is a constant issue. Corrosion.
Even break down Anodized AN Fittings.
Just 304 Stainless Steel or better won't corrode ever.
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Re: EFI Fuel Pumps and Fuel system design

Postby 87vette81big » August 7th, 2014, 6:04 pm

The newer Holley 4-bbl carbs are no longer Zinc Diachromeated Plated.
The Classic Gold & Green tint finish.
I have seen severe corrosion issues recent on the New Gen of Holley Carbs ran on E10 Gas.
Carb bodies crumbled apart when touched.
Cracked too.
The Silver ball milled tumbled shine finish.
Holley 4160 750 cfm on 366 & 427 Tall deck BBC in local firetrucks.
I had to replace the carbs with new again. Just 2 year old 2012 Holleys.
Came in for poor idle problems....found out why.

Good reason to use Q-jets, old Carters AFB & my 65 GTO Tripower & Bo Laws.
All Gold Zinc Diachromated finished.
Resist E10 gas.

Think EPA Banned the Zinc Diachromate.
Hazmat waste according to them.
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Re: EFI Fuel Pumps and Fuel system design

Postby 87vette81big » August 7th, 2014, 6:09 pm

Those MARINE USE WATER SEPERATORS GRUMPY SHOWED US ALL IN THE PAST I NOW CONSIDER A MUST HAVE ON E10 Piss Water.
Can use 2 or more in Parallel for high fuel flow needs.
Have to get one for my '63 GP & '71 GTO 455 Project yet soon.
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Re: EFI Fuel Pumps and Fuel system design

Postby philly » August 7th, 2014, 6:10 pm

need to drop a fuel additive in the tank to keep the corrosion down... lots of companies make em nowadays.

and theres plenty of dichromate holleys

http://www.summitracing.com/parts/hly-0-9776/overview/
http://www.summitracing.com/parts/hly-0-4777c/overview/
http://www.summitracing.com/parts/hly-0-8007/overview/
http://www.summitracing.com/parts/hly-0-4779c/overview/

those just the first four i found scrolling thru summit
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Re: EFI Fuel Pumps and Fuel system design

Postby 87vette81big » August 7th, 2014, 6:15 pm

Have to keep a close eye Phil.
20 years I found only 2 guys that would replate my Tripower carbs.
EPA Was trying to Ban the process then.
Fning Luberals....
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Re: EFI Fuel Pumps and Fuel system design

Postby philly » August 7th, 2014, 6:17 pm

two of these set up in parallel could handle alot of horsepower if you wanna go that route...

http://www.wixfilters.com/Speciality/Fu ... ators.aspx
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Re: EFI Fuel Pumps and Fuel system design

Postby Strictly Attitude » August 7th, 2014, 6:21 pm

Not allot of e85 around here but there are pitstop gas stations ethanol free 91 octane .30 more expensive a gallon but you get that back in fuel economy.
"IF YOU CAN SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR SUSPENSION NEEDS MORE WORK!!"

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Re: EFI Fuel Pumps and Fuel system design

Postby philly » August 7th, 2014, 7:16 pm

Strictly Attitude wrote:Not allot of e85 around here but there are pitstop gas stations ethanol free 91 octane .30 more expensive a gallon but you get that back in fuel economy.


thats a good deal, we have 93 in florida, for whatever those 2 octane points are worth.
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