Fuel line size upgrade - worth it?
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From: Lakeland, FL
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St. Jude Donor '03, '06, '17
Fuel line size upgrade - worth it?
After checking my A/F ratio, I noticed that I'm running on the rich side and that fuel starvation is not an issue with my 3/8 factory fuel lines.
So I wonder, would it make sense to still upgrade the fuel line size to #8 braided line? Would there be any benefits considering that I'm already getting enough fuel?
So I wonder, would it make sense to still upgrade the fuel line size to #8 braided line? Would there be any benefits considering that I'm already getting enough fuel?
Burning Brakes
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From: Des Allemands LA
Oliver,
I noticed in the other post you considering shooting the juice to your motor. To me it's cheap insurance to do the upgrade. It may be overkill, however I'd rather have a little too much always than not quite enough just once.
ltlevil
I noticed in the other post you considering shooting the juice to your motor. To me it's cheap insurance to do the upgrade. It may be overkill, however I'd rather have a little too much always than not quite enough just once.
ltlevil
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From: Lakeland, FL
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St. Jude Donor '03, '06, '17
Originally Posted by ltlevil
Oliver,
I noticed in the other post you considering shooting the juice to your motor. To me it's cheap insurance to do the upgrade. It may be overkill, however I'd rather have a little too much always than not quite enough just once.
ltlevil
I noticed in the other post you considering shooting the juice to your motor. To me it's cheap insurance to do the upgrade. It may be overkill, however I'd rather have a little too much always than not quite enough just once.
ltlevil
My question is just regarding my current setup and if there's any benefit going with a larger fuel line considering that my engine seems to get enough (or more than enough) fuel right now..
Last edited by GrandSportC3; Oct 19, 2005 at 02:12 PM.
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From: Foxfield CO 1970 Convertible
Another consideration:
The instructions for my pump specified the -8 line size. This is because many external pumps are cooled by the gas itself, so a large line size both feeds the engine and cools the pump.
The instructions for my pump specified the -8 line size. This is because many external pumps are cooled by the gas itself, so a large line size both feeds the engine and cools the pump.
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From: Lakeland, FL
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St. Jude Donor '03, '06, '17
Originally Posted by Z-man
Another consideration:
The instructions for my pump specified the -8 line size. This is because many external pumps are cooled by the gas itself, so a large line size both feeds the engine and cools the pump.
The instructions for my pump specified the -8 line size. This is because many external pumps are cooled by the gas itself, so a large line size both feeds the engine and cools the pump.
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Melting Slicks
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From: Orrtanna Pa.
I had fuel starvation with the Q-Jet,but once I switched to the 3310 it was cured.Blew the trans shifting at 6500 rpms.All with the stock fuel line and a mechanical Edelbrock 110gph pump.I'd spend the cash elsewhere for something that would make a difference. 
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From: Lakeland, FL
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St. Jude Donor '03, '06, '17
Originally Posted by The Money Pit
I had fuel starvation with the Q-Jet,but once I switched to the 3310 it was cured.Blew the trans shifting at 6500 rpms.All with the stock fuel line and a mechanical Edelbrock 110gph pump.I'd spend the cash elsewhere for something that would make a difference.
Racer
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From: Salem MA
Originally Posted by ram82fire
I run four two barrel side draft webers fed by #6 braid and have never had a fuel delivery problem . I monitor fuel delivery pressure onboard while driving with a digital readout .
Geo
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I really think you're on the ragged edge with a 3/8" line especially if you're not feeding 60 psi or something into it. I ran a 3/8" and a mechanical pump on my 540 for a long time and seemed to get by OK.....but I know I was on the edge. When I changed combo and added a couple hundred HP at high rpm, I changed fuel system.
I've always been concerned with your MPH. 600+ HP with 2800#'s ought to MPH much higher even in FL temps. I would spend $$ to upgrade system..it will be well spent and will allow any thing you want later.
One of the advantages of multiple carbs is the extra needles and seats that flow more fuel. That was one of the reasons that having 8x1 bbls etc hung around so long...the nitro guys with early Hemis etc needed the increased needle/seat area to get enough fuel in the motor..it wans't just the increased airflow. They were better off with lots of small carbs and 8 needles instead of one big one with one or two needles. Just interesting trivia.....
JIM
I've always been concerned with your MPH. 600+ HP with 2800#'s ought to MPH much higher even in FL temps. I would spend $$ to upgrade system..it will be well spent and will allow any thing you want later.
One of the advantages of multiple carbs is the extra needles and seats that flow more fuel. That was one of the reasons that having 8x1 bbls etc hung around so long...the nitro guys with early Hemis etc needed the increased needle/seat area to get enough fuel in the motor..it wans't just the increased airflow. They were better off with lots of small carbs and 8 needles instead of one big one with one or two needles. Just interesting trivia.....
JIM
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From: Lakeland, FL
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St. Jude Donor '03, '06, '17
Originally Posted by 427Hotrod
I really think you're on the ragged edge with a 3/8" line especially if you're not feeding 60 psi or something into it. I ran a 3/8" and a mechanical pump on my 540 for a long time and seemed to get by OK.....but I know I was on the edge. When I changed combo and added a couple hundred HP at high rpm, I changed fuel system.
I've always been concerned with your MPH. 600+ HP with 2800#'s ought to MPH much higher even in FL temps. I would spend $$ to upgrade system..it will be well spent and will allow any thing you want later.
One of the advantages of multiple carbs is the extra needles and seats that flow more fuel. That was one of the reasons that having 8x1 bbls etc hung around so long...the nitro guys with early Hemis etc needed the increased needle/seat area to get enough fuel in the motor..it wans't just the increased airflow. They were better off with lots of small carbs and 8 needles instead of one big one with one or two needles. Just interesting trivia.....
JIM
I've always been concerned with your MPH. 600+ HP with 2800#'s ought to MPH much higher even in FL temps. I would spend $$ to upgrade system..it will be well spent and will allow any thing you want later.
One of the advantages of multiple carbs is the extra needles and seats that flow more fuel. That was one of the reasons that having 8x1 bbls etc hung around so long...the nitro guys with early Hemis etc needed the increased needle/seat area to get enough fuel in the motor..it wans't just the increased airflow. They were better off with lots of small carbs and 8 needles instead of one big one with one or two needles. Just interesting trivia.....
JIM
The car is not 2800#.. it's 2850 (empty) and I usually use 5 gallons of fuel in the tank (+30 lbs) and my 215 lbs + 10 lbs in clothing + helmet = approx. 3100 lbs race weight with me, fuel and gear in it..
I also never tuned the car.. I never changed the jetting on my carb etc. I only set the lash once and that's about it.. I did change the jetting for my last track visit and lost ET because I went in the wrong direction. (jetted richer but should've jetted leaner)..
For now, I have no intention on upgrading my current engine except with NOS which will be fed with a separate fuel system.
I will, at one point, go with a Big Block in the car and that will be the time that I'll upgrade the fuel system for sure..
Last edited by GrandSportC3; Oct 20, 2005 at 08:35 AM.
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From: In Dreams There Is Truth Ohio
Oliver, Oliver, Oliver... 
Whazzamattawizyouanyway? All GM high H.P. big blocks had 3/8" lines, fuel starvation was never an issue, and no issue with yours, so why even consider the added expense?
Whazzamattawizyouanyway? All GM high H.P. big blocks had 3/8" lines, fuel starvation was never an issue, and no issue with yours, so why even consider the added expense?
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From: Foxfield CO 1970 Convertible
Got my new Super Chevy mag last night when I got home. There's an article about fuel pumps, carbs, and lines that might be of interest to you. It's says that their studies show that there are often problems with carb bowls emptying after about 200 ft, the engine starving somewhat, then the pump catching up towards the last part of the strip. Talks about the different pumps, sizes, etc., and has some calculation examples for determining fuel delivery required based on HP and engine type.
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From: Lakeland, FL
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St. Jude Donor '03, '06, '17
Originally Posted by Z-man
Got my new Super Chevy mag last night when I got home. There's an article about fuel pumps, carbs, and lines that might be of interest to you. It's says that their studies show that there are often problems with carb bowls emptying after about 200 ft, the engine starving somewhat, then the pump catching up towards the last part of the strip. Talks about the different pumps, sizes, etc., and has some calculation examples for determining fuel delivery required based on HP and engine type.
http://media.putfile.com/airfuel
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From: Foxfield CO 1970 Convertible
Originally Posted by GrandSportC3
I know for a fact that this isn't happening because I have the reading of my air/fuel gauge throughout the pass and it never leaned out.. Therefore I know that there was no fuel starvation at all..
http://media.putfile.com/airfuel
http://media.putfile.com/airfuel
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From: eville in
Originally Posted by GrandSportC3
I know for a fact that this isn't happening because I have the reading of my air/fuel gauge throughout the pass and it never leaned out.. Therefore I know that there was no fuel starvation at all..
http://media.putfile.com/airfuel
http://media.putfile.com/airfuel
