8AN, 1/2 inch fuel line
 

Has anyone else gone larger on the fuel line?

I'm switching to an 8AN fuel system for my Roush 427R-095 in anticipation for new side pipes from Buckshot Racefab. I already changed to larger carb, 2 inch primary headers, more surface area on air filter and high volume 100 micron Aeromotive fuel filter. I'm going nuts waiting to have all together and testing. :) I think the line with all the other changes will add some nice gains.

My Superformance fuel tank is beautiful stainless work, but had a 3/8 inch pick up line. I replaced with 1/2 inch pick up to 8AN through the rest to fuel pump. I'm putting on a higher volume mechanical Carter fuel pump too.

This article is an interesting read.
http://www.fordmuscle.com/archives/2...Line/index.php

Good info on the first page, but to get page 2 & 3, you must buy a subscription. :(

The 2nd and 3rd page lays out the install of fuel line for their demonstration car along with pictures. They use the fuel sending unit mount location on top the fuel tank to weld on 8AN fitting and 1/2 inch fuel line pick up. The sending unit was slightly relocated. They install the fuel filter and dual feed 8AN lines to the carb. Pretty much they just show you they made everything bigger.

Greg,

I run a similar engine, RDI 427W (444 rwhp). I have an isolated system fuel pressure gauge in the cockpit and haven't seen any indication of fuel pressure falloff or starvation on the dyno, track or strip.

Mechanical pump, ProSystems 780cfm Holley HP, Vic Jr manifold and heads.

This combination runs to 155mph (checked via GPS), 11.8 / 120mph quarters and will hold 6k rpm w/o faltering.

I have also looked into 1/2" line but associates that know way more than I do don't think it's necessary.

Now that you have changed it was it difficult? Anything in particular that compelled you to make the change?

Jim
SPF 1855 in Grand Rapids, MI

Hey Jim, If you need help with any projects over the winter, give me a call! :3DSMILE:
Brad


Greg,
In the article, on the right side by the pictures, it sais;
"Eventhough our project '67 Mustang is making over 500 horsepower at the wheels, it is running out of fuel due to the factory 5/16" fuel line (left.) We're upgrading to 1/2" (right), which will provide a nearly 150% increase in area. A rule of thumb; 5/16" (-5AN) will support up to 300 horsepower, 3/8" (-6AN) will cover up to 500 HP, and 1/2" (-8AN) is good to 700HP."

Those HP numbers are at the wheels right,... so the "3/8" (-6AN) will cover up to 500 hp", is at the wheels, and should be good well up over 600 HP at the motor,... right?

For my Superformance 2040 as delivered with Roush 427R-095 everything was fine. I had the Roush supplied 750 CFM Double pumper on there, Superformance headers, side pipes, 1 inch tall oval air filter. Back then I took it to a load bearing Dyno at Dyno-Comp, www.dyno-comp.com , for a base line run. It came out corrected a touch over 400 rear wheel HP. I guess the number would be a little bit higher on a Dynojet. I then put on the different headers, 1000ish CFM carb from Pro-Systems, taller air filter and I eliminated the Superformance fuel filter noting improvement with each change. The car is faster from original to today. With the changes I had some fuel starvation issues in 4th gear full throttle around 140 mph at a track day for a club. Even though air fuel was fine at lower speed, less load, it still seemed to run out of fuel up top in 4th full throttle. Scary. I've been to the drag strip a few times. Trap speed would depend on density altitude, but corrected to sea level it's over 130 mph.

Once I put on the soon to arrive 3 inch internal side pipes with a performance type collector I'm thinking it will have potential to move more volume, potential for dangerous condition if I left the fuel components and lines as they were. There was a 90 degree cast elbow going into the fuel pump which looked dangerously restrictive. I might have been able to replace that one elbow and call it good, but I want to be safe knowing the fuel system is good for 700 HP and I'm never going to hit that. The hardest part about the job was deciding if I wanted to have the 1/2 inch line welded into the tank or use an 8AN part through a 3/4 inch hole. There was a bit of a research and learning curve, but the rest is pretty simple once you climb under there and blow a few hundred bucks on parts.

After I set this all up I'll force myself to pay the $ for a test with air fuel on the same Dyno that I started with. I'll post again after it's all done.

I'm leaning toward adding a little 50HP wet shot nitrous system some day for kicks. The larger line and new fuel pump will give me peace of mind if I pencil it out.

This is probably one of those things were you could ask lot's of people the same question and have many answers. I'm sort of leaning toward the views of the performance minded. I'd rather be safe with a system that's a bit overkill.

On the other side of the coin I guess if people want to run a 16,000 dollar engine with a 3/8 inch paper element fuel filter and cast 90 degree 6AN bends that's cool. It probably works fine for most people.

Here's a good read.
http://www.centuryperformance.com/fuel1.asp

Be careful when your welding on your gas tank. I forgot to empty the gas out, so when I struck my arc, I was immediately engulfed in flames. I ran out of the garage, while everyone akwardly stared at my charred, nude, body.:JEKYLHYDE

Ronnie

Hmmm, I'm sorry to hear that.

I took my tank off the car, emptied, cleaned twice and filled completely with water to drill the one hole I needed. I attached the new fuel pick up line by mechanical means without welding.

I cut the tank and put in an atl 6x10 plate with a hard 1/2 line return and pickup from an ATL check valved fuel box to prevent starvation. I have 8 an with an aeromotive pump to and from the regulator.

It took a while to iron out all the details, but I can send pics if you want them.

Hey Ramey,

I'm interested in the pictures....and more details! I want to install an Aeromotive pump and bypass regulator in my Superformance but I'm stalled on the fuel tank connections. Sounds like you have already solved my problem!

Rodger

Sorry no pics.

I've sealed mine up however if you were to remove the carpet in your trunk(Velcro attached), then the screws on your trunk bottom access area you could see the tank. From there remove the screws on the round plate. That's your fuel level sending unit. You can look inside the tank once that's removed. Inside you'll see a 3/8 inch line with a bend at the bottom. At the fuel pick up location it has a bevel cut facing upward. That line is within a little boxed in area to keep fuel around at low level around corners and such.

I put in the 1/2 fuel pick up line right next to the old one with the same design while being careful to have good bends that don't restrict flow. So far it works good with as little as 1/8 of a tank. The fuel tank is baffled in addition to the little slosh box area at the pick up location. I used the overflow inlet from the gas fill location down for a fuel tank vent and capped off the original fuel line pick up with a vacuum line cap and safety wire.

From the tank I used 8AN line with all 8AN high quality parts to the carb. I changed the self regulating fuel pump with another self regulating fuel pump of higher volume and slightly higher pressure and put in a 7000 rpm rev limit.

All of this is in anticipation for my new side pipes which should be on this next weekend before a club drag race day. My goal is to be able to have a non-aggressive start from low RPM and produce high 10 second passes around 130 mph consistently. I don't want to beat up on the car to make it go. I just want it to go.

I've been running -6 from the tank to the carb on a BB with over 600HP at the crank with no problems on fuel starvation. If you were getting starvation at the track in 4th at 130 MPH+ you may have been starving from fuel slosh in the tank.

Thanks Greg.

I remember seeing a cutaway of an SPF fuel tank at Dynamic when I ordered the car (due around March 1). I'll look at it closer the next time I'm there.

How did you seal the new 1/2" line where it goes thru the tank?

If I do something similar to what you did, I might use the original 3/8" line for the regulator bypass return.

I like your last two sentences...you should add it to your signature!

Rodger

I first attached the line using 8AN parts and an elbow. It was slightly too high. I found some 1/2 inch stainless tubing at Ace Hardware of all places and lined up a qualified welder to put the line in. After thinking about it I thought, man this would stink if I went through all the trouble and it didn't work properly. I built a test pick up line out of 1/2 inch aluminum and set it in position with JB weld putty. Sounds cheesy, but it works perfect and is rock solid. I coated it with a similar material that's on the tank. It looks pretty good.

My fuel issue seems to be gone. I tried a pass with my G-tech Competition to 141 mph and it was still pulling like a mother. It was a chilly morning with a low enough DA to get me in trouble. :eek: It propelled the car to 130 mph in about 10.6 seconds with 12 inch rollout. The 1/4 mile was an 10.9 @ 132 mph.

I ran a similar time with the old 3/8 fuel line and DA slightly lower (better condition for speed). The car shut off at the top of 4th gear around 142 mph when I let off the throttle.

I recieved my Buckshot Racefab pipes. They're fricken awesome looking. I can't wait to put them on the car, but I must have some time to work on it. Soon I'll take some pics and such.