[lust4speed]

Tom, so if I follow correctly the surge tank consists of one fitting at the top to return excess fuel and possibly some vapor back to the tank. Then there would be a fuel inlet that accepts fuel from the rear - what height on the surge tank would this fitting be placed? Would putting it low allow the surge tank to drain after the engine is shut off? Would it be better to place it maybe an inch lower than the return bung? And finally you would have the outlet at the bottom of the surge tank sending fuel to the mechanical pump.

Would a 3/8" feed to the surge tank and a 1/2" return be suitable to insure very little restriction in the return line? This larger line should prevent excess pressure building up in the surge tank and possibly feeding excess pressure to the mechanical pump. Would a regulator be needed before the surge tank to reduce the high pressure of the EFI pump, or would the free flow of the system take care of this?

Wouldn't it also be important to have the tank totally sealed with no cap to prevent anyone from opening the system? Even with the 1/2" return I would suspect several pounds of pressure being in the tank with the engine running.

[torqhead]

Finally got to the paint shop and pulled the tank. The tank is only about a year or so old as I replaced my previous tank because I got tired of the external sump I had added to the previous one and the looks of it.

A couple of things I found with the 1/2 inch line RobbMc pickup. Although the design is nice, one thing I discovered and why it's easily affected and loses the ability to pick up fuel is that from where the sending unit mounts in the tank to the bottom of the tank is about 6 3/4 inches. The RobbMc pickup is less than 6 inches in length, leaving more than 3/4 of an inch between the bottom of the pickup tube and the bottom of the tank. That's quite a bit of distance (at least my opinion). I don't know if all of their pickups are this short that they sell but it's definitely part of my problem. Another thing I discovered was the problem causing my gauge to read empty when I had a least 1/4 tank still left. I discovered the float set up is bottomed out at about 5 inches from where the sending unit bolts in to the tank. Needless to say the float bottoming out about 1 and 3/4 inch from the bottom is why my needle goes to empty so quick. Going to reach out to RobbMc to see if the short tube was by design, but I think the tube should be as close as 1/4 inch to the bottom of the tank and may look at elbowing it a bit.

Next I'm headed to a radiator shop and have my baffle design installed. I'm convinced it's going to make a significant difference and I'm estimating I'll be able to run my tank easily down to an 1/8 without having the "fall flat on it's face in 2nd gear syndrome".

[torqhead]

Reached out and talked to a gentleman at RobbMc about the issues with my pick up. His perspective is it wasn't too far off as they go for 1/2 inch clearance from the bottom of the tank.

IMHO, I think that's still a little too high as you are pulling from the circumference of the tube since it dead heads straight down. With it 3/4+ inch off the bottom I'm estimating I'm unable to pick up 3-4 gallons at minimum and it's what's definitely increasing the impact of running out of fuel while driving around. I'm going to look at extending it and curling it a bit towards the rear of the tank and effectively will be towards the baffle as well.

I'm also going to bend the swing arm for the float to fix the calibration of level of fuel in the tank as it's not adjusted correctly.

[torqhead]

Alright boys and girls, I've had the baffling system installed in my tank. Was able to find someone here locally that would work on it. I'm pretty happy with it as you can't tell the mod was made, very minor burn on the bottom that will be concealed when I paint it and feel very confident its going to address my issues.

Keep in mind my requirements were:
Make a change to solve the "falling flat on its face in 2nd gear while pulling hard"
No external view of modifications
Run factory tank and maintain the 19+ gallons of gas

I considered a number of the solutions everyone proposed including the $1000 tank that's made by Rick's, although the tank they sell does not look like the factory. In my case I had bought a new tank a couple of years ago to replace my then dry sump modified one when I was running injection. The guy that did the work charged me by the hour for labor, he also extended my RobbMc pickup too by 1/2 inch to solve the manufacturing design in my mind (remember this is a personal opinion and not slamming RobbMc). Total was 5.5 hours labor and cost of $410. I was able to get them to take pics of the process, I'm including here. If anyone is interested I'll be glad to pass on their info to you.

Once the car gets finished being painted I'll be able to drive it as the weather cooperates and provide you feedback, although I'm probably just going to put 5 gallons in it right off the bat and test...

[First Bird]

That's very nice. Thanks for posting the pictures. Now you have me thinking about doing this mod.

[Ollie]

Has anyone considered a 4th gen. Trans Am / Camaro fuel pump module?
This is what I am running in my 79 TA.
To use this Fuel pump module with a carburetor would require some modification, as the fuel injection operating pressure is 60 psi.
I was thinking of looking in to a fuel pump for a TBI as the operation pressure is much lower.
This would also require an adjustable fuel pressure regulator.

[Joel Koontz]

I am not using a 4th gen. Trans Am / Camaro fuel pump module, but I am using a TANKS Inc. module http://www.tanksinc.com/index.cfm/pa...prod/prd84.htm with a high pressure FI style in tank pump and a Quadrajet. I am using a RobbMc return style regulator with a 1/2" supply line and a 1/2" return line.

I have not done any drag strip runs, but it seems to work great on the street.

I am currently running a 255 LPH pump and it is probably all I need on the street. If I wanted to run at the drag strip I would consider installing two in-tank FI pumps as the factory did on the Supercharged Ford Cobra Mustangs(and others)

[niceta]

Nice work on the tank torqhead. I hope it solves your problem. I am just in the process of fabbing my fuel system and the tank is dry (new)at this point. may as well do it right now instead of later. I also have Robbmc 1/2" fuel pickup so may go this route.

Hey Ollie just wondering if you have the dimentions on the 4th gen pump (hole size and hight). Wondering if it will fit in 73 F-body tank. Looks like it has a level transmitter on it as well. Nice. Looks like the tanks inc. module does not. How noisy is the 4th gen pump?. That would be ideal if it dropped right in.

Great thread.

[FatfreeGTO]

Wish I would have seen this one sooner. You can take a tank from an 80's Buick Grand National which is properly baffled and install it in your 68+ It will bolt right in only a minor modification is needed to the filler neck.

[Ollie]

Originally Posted by niceta

Hey Ollie just wondering if you have the dimensions on the 4th gen pump (hole size and hight). Wondering if it will fit in 73 F-body tank. Looks like it has a level transmitter on it as well. Nice. Looks like the tanks inc. module does not. How noisy is the 4th gen pump?. That would be ideal if it dropped right in.
Great thread.

The GN tank will not fit in a TA.

I am installing this setup on a 79 TA, The 73 tank should be the same, so yes the pump will fit in 73 F body.
The dimensions on the 4th gen pump are 3.875 hole. The pump bucket is spring loaded. It is 10 inches tall and will compressed down to 9 when installed.
The fuel level sender is not compatible with 2nd gen fuel gauge. The 2nd gen fuel gauge operates on 0 - 90 ohms, while the 4th gen operates on 40 - 240 ohms. There are two ways to fix this.
There is a 0 - 90 fuel level sender that is available That is a direct replacement. The alternative method is to install the 4 gen pump next to the stock sender. The fuel level sender is easy to remove and replace.
The fuel pressure regulator is also mounted in the fuel pump module and is easy to remove
if you want to mount a vacuum referenced pressure gauge on the fuel rail.
The beauty of this set up is there is a venture (jet) pump in the bucket that helps to keep the bucket full. There for no need for baffles.
Photo 1 Russell adapter needed to connect the GM quick disconnect to AN hose.
Photo 2 Showing the method to install the fuel pump module in the 2nd gen. tank and retain the stock fuel level sender
Photo 3 Fuel pressure regulator.
Photo 4 Fuel pressure regulator removed, It is held in place with the spring clip.
Photo 5 Fuel level sender. It is held in place by the white plastic clip.

http://www.vetteworksonline.com/ls1_conversion_fuel.htm

[Joel Koontz]

This link has a photo of a GN Tank. http://www.ebay.com/itm/84-87-Buick-...-/110741129449

I don't know if it would fit, but it sure would not look anything like a stock tank. The spare tire on a GN stands up vertically on the passenger side of the trunk so the tank does not go from frame rail to frame rail.

[FatfreeGTO]

I never said anything about a TA, I was replying to the OP about his A-body.

Joel you are correct it would not look exactly like the A-body tank. The GN tank is a little bit less wide but also a little bit deeper to allow for baffles/sumping within the tank for fuel injection. The straps line up between the two.

Stock: 39-1/4 x 24-1/2 x 7-3/4 in

GN: 36-1/4 x 24-1/4 x 8-7/8

There are some 68-72 Chevelles that have run this when doing LS engine swaps.

[Dragncar]

I have been using the answer to this for years.
I took my stock tank and silver soldered a 1/2" steel tube from the front, top, middle corner, and it runs to the low spot in the tank right in the middle.

The car runs 11 flat and pulls 1.45 60 foots.
With 5 gallons it will have problems, but with 7 it pulls hard the whole way.
I also silver soldered a drain plug in the low spot too.

[niceta]

Another great idea Dragncar. Sounds pretty easy.
Thanks for the info on the 4th gen pump Olli. Sounds like a bit of messing around though. Where do you get the senders from GM?
Hope we havn't sidetracked your thread Torqhead. Can't wait to see how the baffling turns out, unfortunatly I may not be able to wait that long

[Ollie]

niceta
You are correct about hijacking this thread,
You have a PM

[torqhead]

No worries on high jacking as that's what these forums are about, getting open communication. I wish I had more of these feedback before I ran down the path I did, although I think I'm going to be very please with the result, I'm betting I can get down to 2-3 gallons and still hopefully pull hard!!!

[torqhead]

Originally Posted by torqhead

Reached out and talked to a gentleman at RobbMc about the issues with my pick up. His perspective is it wasn't too far off as they go for 1/2 inch clearance from the bottom of the tank.

IMHO, I think that's still a little too high as you are pulling from the circumference of the tube since it dead heads straight down. With it 3/4+ inch off the bottom I'm estimating I'm unable to pick up 3-4 gallons at minimum and it's what's definitely increasing the impact of running out of fuel while driving around. I'm going to look at extending it and curling it a bit towards the rear of the tank and effectively will be towards the baffle as well.

I'm also going to bend the swing arm for the float to fix the calibration of level of fuel in the tank as it's not adjusted correctly.

I was talking to someone about this tank situation and they asked if I got an actual measurement of fuel that I was unable to pick up, thought I would share it here. The actual amount was just over 4 gallons that I could not pick up out of the tank. Needless to say that definitely was adding insult to injury on the launches without a baffle.

[BruceWilkie]

Originally Posted by Ollie

Has anyone considered a 4th gen. Trans Am / Camaro fuel pump module?
This is what I am running in my 79 TA.
To use this Fuel pump module with a carburetor would require some modification, as the fuel injection operating pressure is 60 psi.
I was thinking of looking in to a fuel pump for a TBI as the operation pressure is much lower.
This would also require an adjustable fuel pressure regulator.

I think you can run the high pressure efi pumps through a bypass regulator, then carb feed from that to a regular holley "dead head" regulator to reduce psi at the carb. Probably bypass regulators that can do this by themselves.

[niceta]

Finished extending my Robb MC 1/2" pickup by about 3". It has brought it down some(actually touches the bottom of the tank now) and extends to where the tank starts to transition /slope up. I had to screw the extension on while inside the hole as it will no longer fit through the hole. This is on a 73 T/A tank that will be street/strip/auto cross.
unfortunatly I wont be able to post results for a couple years lol.

[Joel Koontz]

Originally Posted by BruceWilkie

I think you can run the high pressure efi pumps through a bypass regulator, then carb feed from that to a regular holley "dead head" regulator to reduce psi at the carb. Probably bypass regulators that can do this by themselves.

See post # 27