stock fuel tank. in tank fuel pump intall

[dale68z]

I have been having several fuel related issues with my car.
1. fuel gauge swings wildly when less than 1/2 tank
2.My fuel pressure drops dramatically when coming out of a corner if I have less than 1/2 tank of fuel
3 Had vapor lock issues at spring mountain and Inde, both are higher elevation tracks.

I ended up baffling a stock tank and adding a Tanks PA4 fuel pump module.

We ran last Saturday, a warm day, at 4100' and the fuel pressure was rock solid all day. I ran 3.5 sessions without any additional fuel with no issues. The half session was our first, new tires and new brake pads needed to be broke in. I used to have to add fuel after 2 sessions.

http://www.tanksinc.com/index.cfm/pa...prod/prd84.htm

My plan was to recess the pump into the tank so the pump fittings would not hit the trunk floor. I ran into issues. The stock tank on a 71 Camaro is 6" deep. The electric pump is like 5 1/4" long. It will work, but I need to recess the pump module into the tank 1" to keep the fitting from hitting the floor. The best I could do is recess the pump 5/8".

So I used a brownie pan to start with. It felt like it was a good thick pan about equal to the thickness of the stock tank.



I decided to set the pump in the center of the tank toward the front which is the deepest part of the tank



I tool some pictures inside the tank of the eec system in the stock tank. The small nipples on the tank look like this.



The large nipple goes all the way to the filler neck



I added baffling to the inside of the tank. The baffles are 13" wide, and go all the way front to rear inside the tank, and top to bottom. It is a big rectangle that I welded inside the tank

yep I cut myself

[dale68z]

pan is cut and welded in, can see the baffling









The end result is the fittings are still to tall. I could re work the fittings. But decided to shim the tank lower with 4- pieces of 1/2" square tubing. The stock straps still worked.



Added a oil pressure switch PS 64. This turns off/ on the pump with oil pressure and also provide a ground for my low oil pressure light. My battery and fuel pump relay is in the trunk, so it also makes it so I only have a ground wire that goes to the rear of the car, rather than a power wire.

http://www.summitracing.com/parts/smp-ps64

I run a carb, but the only thing that matters is the pressure regulator. I am running a low pressure Fuel Lab regulator. If I had fuel injection I could have gotten away with using the stock 5/16 return line

http://fuelab.com/products/performan...ure_regulator/

Initially I was returning the fuel through the stock vapor line on the left side of the car. I could not get my fuel pressure below 13#. I had to replace the 5/16 with 3/8. As soon as I replaced the line my pressure dropped to 3#, and I was able to adjust the pressure to 6 1/4.





The only concern from here is I used a duct to make my baffles in the tank. The metal duct was coated. I did set some fuel, and even carb cleaner on the coating, it did not make it soft. But, I don't know how it will do, long term, submerged in fuel.

[Build-It-Break-it]

I think you might have issues later with the way you welded it in. The Tanks Inc fuel pumps are made to be a basic install without the welding and usually include an internal baffle . I think your tank might end up rusting inside and some of the weld slag at the bottom of the tank that isn't removed will become loose over time along with some of your mig welds. If anything it should of been tig welded in.

[dale68z]

Could be. Rust was a concern for me. I also thought I should coat the interior with airplane fuel tank sealer. The car doesn't sit much. I drive it to work about 30% of the time. The other days I drive the 68. And, I live in Arizona.

I don't have a tig welder. I did contemplate brazing instead of mig.

Only time will tell

I need to pull the tank. in this car it is super easy. The fuel gauge remains on full far to long, so some adjustments to the float are needed. I can then check for debris in the tank. I did rinse the tank multiple times in different stages and beat/ scratched on the welds to loosen crap up.

[dale68z]

I pulled the tank to calibrate the fuel level sensor. All looks good inside the tank. This was a week or so after the install. As for the slag, I had removed the majority of it prior to putting the pump in. I had sprayed the tank with a nozzle cleaner spray to keep the splatter from sticking.

We have ran 2 track days. Last weekend I ran the car till the fuel gauge was a hair above E. Absolutely no fuel pressure weirdness.

I am very happy

[dale68z]

More update.
I saw the fuel pressure drop to 4# for about a second this weekend with about 1/8 tank running Chuckwalla speedway. So, it is not perfect. This was pretty extreme situations, long, fast corners and 2:10 sec lap times

If I were running fuel injection I would need to keep more fuel in the tank.