$750 L98

Well I've done my research on the matter, and now I just want to clarify a few points before I dig into it. No one wants to rip apart a car twice.

First off I robbed a gas tank from the corpse of a 2001 Trans Am (with internal regulator and short fuel return line). This will be going in a 1989 TPI (now LQ9) Formula 350.

Using my stock 3rd gen lines, with rubber FI hose connections from the new pump to the old lines, modifications will be:

1.LS1 to 3rd gen lines:
Remove plastic lines from LS1 tank, cannot be adapted to stock 3rd gen lines. Will be using FI hose and clamps to keep it simple.

2. Ls1 Evap:
Keep intact, operation will be defaulted to "vent" to prevent tank over pressure and will still be routed through the charcoal canister - preventing gas smell.

3. Stock LS1 Sender:
will not work, part number #25319676 (1997 Grand Prix 3.8L non-supercharged) will work as a direct replacement for the LS1 sender and measures 0-90ohm. Or stock LS1 sender resistor can be replaced with a 0-100ohm spun wire resistor from fry's/radio shack/etc.

4. Filler neck:
Considering I have the stock LS1 neck, that can be used if the neck is shortened a bit. For those without the LS1 filler neck, 1.25" rubber hose adapted to the stock (3rd gen) filler neck top should suffice.

5. LS1 in tank regulator:
For those with a regulator on the fuel rails the LS1 in tank regulator needs to be removed (removed in my case). For those without a regulator on the fuel rails, the in tank should be used.

6. LS1 tank fit:
LS1 tank is a direct swap and is the same basic dimensions as the stock 3rd gen tank, stock 3rd gen tank strap locations can be re-used.

7. Last, removal and Installation:
Some have removed the tank without touching the rear end, I am not worried about damage to the stock tank and will attempt this first. My over axle portion of the exhaust can be totally removed. With my mufflers removed I can see the tank in it's entirety - it LOOKS like I can drop it straight down, or angle it if necessary.

Some say the entire rear end needs to be out of the way (removed from the car). I have to replace the rear end soon, and would prefer not to do it twice, but replacing the tank cannot wait. Is it necessary to remove the rear end without exhaust in the way?

I appreciate the input and advice, this car is my daily driver, and the tank has developed a leak. How fortuitous that a LS1 tank was handy. If anyone is interested, as I go along with this mod I can compile my results/findings. It seems I will be utilizing nearly every modification that has been talked about in this section, so it may prove useful to combine them into a start-to-finish tutorial?

Let me know if my assumptions are right this far. Thanks guys!



GAS TANK DONE:

Materials used:
2002 LS1 fuel tank
5/16 to 5/16 compression fitting
5/16 "quick disconnect" fuel repair kit - Dorman, Advance auto help isle
LS1 fuel filter
LS1 filler neck
LS1 plastic tank to hard line hoses
Stock tank straps
Stock chassis hard lines
Early style Corvette fuel rail, with built in regulator

How to:

1) Removing the gas tank is covered elsewhere, so I won't regurgitate that (though I did use a hacksaw to remove the stock filler neck for easy removal). For my specific swap I had the corvette fuel rails, in which case my regulator built into the LS1 fuel tank had to be removed. Remove the fuel pump bucket from the tank, and remove the silver colored clip from the regulator (small round black cylinder). The fuel pump bucket can go back into the tank, next is wiring. The LS1 tank harness roughly matched the TPI fuel harness, I matched them up and removed spliced the blk/wht wire into the black ground wire. The tank is ready to bolt in.

2) After strapping the gas tank into the car, the last bit is adapting the LS1 fuel lines to the TPI stock hard line. To accomplish this in the cleanest simplest way possible (USING CORVETTE RAILS):

3) LS1 fuel filter, this will snap directly onto the fuel tank flex line, and the screw in fitting connects the the stock hard line:



4) For the return line, you must remove a small portion of the stock hard line with a tubing cutter, do this behind the little "bump" around the line that the rubber hose was connected to. Then use the compression fitting to graft the 5/16 repair kit to the stock line after cutting a small section of it off, I used about 3-4" of one end.

5) Snap the LS1 return line onto your newly created "quick Disconnect" on your stock hard line.

6) I personally did not want the EVAP routed to the engine bay so I removed the stock TPI evap hardline, and put a filter on the LS1 EVAP line from the tank.

7) Make sure everything is connected and back on the car, panhard bar, heat shields, fuel lines snug, filter tight, harness plugged in and snag free, etc.

8) Prime the fuel pump, check for leaks, if no leaks are seen, fire it up!

Fuel gauge:
For my swap I have converted my stock gauge from 0-90 to 40-250 allowing me to retain all of the stock LS1 tank hardware, while still retaining my stock fuel gauge.

IROC-You

Dropping the rear end is actually very easy, you dont need to take the whole thing out of the car, just drop it to have more room to work.

I think that if you dropped the rear you will actually be able to complete the job faster. IE you will spend less total time dropping the rear than you would trying to get the tank in there without it dropped.

Pocket

iTrader: (24)

The hardest part of pulling the 3rd gen tank is getting the tank angled just right to slide the filler neck out of its access hole

If you dont care about the tank then saw-zall the filler neck off at the top of the tank and it will fall out without a fuss

Lowering the rear is to get more room to swing the tank around. It is not directly in the way of it

If you do lower the rear, just swing it out of the way. Unhook the driveshaft, upper shock mounts and brake line. E-brakes should move enough, but if they bind disconnect them. Let it swing down while still attached to the control arms

$750 L98

sounds good, I'll let yall know what technique I use and what it required. thanks again!

five7kid

iTrader: (14)

Instead of FI hose & clamps, I used Russell disconnect to AN adapters. You could splice the 3rd gen lines from there with compression unions.

james_adams2006

Any update on this swap yet? I have researched this subject as well and everything you've mentioned seems to be all the standard stuff I have seen to do to swap to a LS1 tank and keep a functioning gauge as well. I don't have any experience with this swap but am highly interested in this as I have plans for summer to add a HSR setup with Holley's new HP ecu in my '82 and the ole' carb tank just won't cut it. I have a 84' parts car that was swapped to TPI and I could use the tank out of it, but the greater tank capacity (16.8 gallon vs. my lil 14 gal.) and the fuel sump surrounding the pump to which improves tank scavenging all sound to be pluses for me. Since I'm swapping tank I plan to route new lines with a mix of hard line and steel braided where needed and use the quick connect to -AN adapters that Aeroquip (and also someone said Russell does as well) sells to connect to the tank and -AN fittings everywhere else to connect between hard lines and braided.

I only had one question about the swap though. You said that the evap canister can be kept to prevent fuel vapor smell and that it will be vented to atmosphere? I've seen others say that this is what to do and a filter added to the vent, so all that has to be removed from the cansiter is the purge valve connected to the evap canister?

Keep us posted and I appreciate any feedback I get as well.

$750 L98

I am actually in the middle of this swap right now, the in tank LS1 regulator, does it have to be removed or can it be left alone. Also how is it removed? Just gut it and put the tank back together?

Pocket

iTrader: (24)

The regulator needs to come out if you're not using the LS1 58psi fuel system or have another regulator mounted elsewhere

$750 L98

Perfect timing! Thanks, Wiring up the fuel pump as we speak, got the tank out without dropping the rear or the exhaust thank god. After yanking the panhard bar set up it slipped right out between the mufflers. I did take a hacksaw to the metal filler neck though.

ShMaCk2004

careful with that sawzall...sparks = BOOM!

five7kid

iTrader: (14)

I chose to keep the in-tank LS1 regulator. I used a 3rd gen filter and rigged up the return such:






Some guys use a separate regulator (has to be a return style), I don't see the advantage of that. Some use the Vette filter which provides the fuel pressure regulating function, but you have to use the Saginaw fittings with it.

ericjon262

Exactly what I was thinking.

$750 L98

I used a hacksaw, didn't want sparks either. As for the return system, I use the 1997 corvette fuel rails with the built in regulator, so I removed the intank regulator and popped the sender back in. I then adapted the 5/16 return line to a "quick disconnect" fuel line repair kit, and bought a LS1 fuel filter with the 3/8 disconnect fitting for the feed line. So both the LS1 return and feed lines plug up to my stock likes like they were factory.

Only thing is, I haven't maneuvered the tank into position yet, I am in a apt garage with little room, and the gas tank has a bit of gas left in it. Going to try and get a spare set of hands to help me wiggle it in tomorrow, it seems like the tank wants to go in driver's side first (with the rubber filler tube). Then I'll have to push the passenger side in, unfortunately it's an akward shaped thing and I can't wiggle both side into place at once LOL

ShMaCk2004

Its VERY easy to put in with 2 people...I mean VERY EASY

Pocket

iTrader: (24)

With the early vette rails you need a feed and return so most of your 3rd gen lines can remain

When using the in tank regulator install a T like five7kid posted

The LS1 tank should slip right up in there with the filler neck removed

Firebat

iTrader: (7)

From reading post #1, it seems like you got most of it. I would add these 2 steps though:
1. Since you are just using hose clamps and FI rubber hose, I suggest putting a little bit of a double flare or maybe even just a single flare on the metal thirdgen lines. The quick disconnect repair thing seems like a good alternative though.
2. There is a white/gray valve/vent that hooks up to the thirdgen tank. May want to hook that up and buy a new one. I can't remember where you hook it up at though, probably the line that vents to the atmosphere.

$750 L98

Updated with a small tutorial/example of what I did, I know it's probably useless since no one uses old vette rails - but maybe it will help anyway.

The only NON-ls1 part used was the compression fitting as an adapter to my stock 5/16 hardline. Everything else is purely LS1 tank/lines. Looks stock, I love it this way.

let me know if I need to correct anything or clear things up.

$750 L98

Well found a mistake I need to correct tomorrow. I originally cut the blk/wht wire off the LS1 connector thinking it to be unnecessary. It turns out that this is the ground for the fuel level sender. So currently my gauge does not work.

I will splice the blk/wht wire into the black ground wire on the LS1 harness tomorrow. I also need to fix the GIANT "access" hole ARD carved in my trunk tomorrow. The amateur welds have busted causing it to rattle when the car is running.

I also found out that ARD had not installed a sock on my walbro 255, which i'm sure lead to the poor condition it's in and all the trash it sucked up. Guess i'll be doing injectors soon. Other than that my LS1 tank swap went well and I have no leaks, it also runs MUCH better with a good/non-trashed pump in there!

Pocket

iTrader: (24)

3rd gen splice the sender ground with the fuel pump ground. You can do this or simply ground it to the chassis

Welding up the access hole requires dropping the tank. Not what youd like to hear, but its unsafe to do it otherwise

Since the tank must come down, just replace the pump and put a sock on the new one. Your fuel filter will catch any junk before it gets to the injectors

$750 L98

My solution went a bit differently, Since I already had the half-a**ed access door I fixed it and did it right. That also allowed me to fix the harness correctly without dropping the tank. I ended up using a stock pump or a walbro some one put in the LS1 tank, with the sock attached, I think it may be a walbro It's fairly audible and seemed to make the car run 10X better when I fired it up, I have a feeling the walbro pump in my old 3rd gen tank was on it's way out.

3.1EyeCandy

iTrader: (3)

I know they took the sock off mine...any idea where to find a new bucket w/sock without paying for a pump?? I think I've replaced everything they did except for the tranny - and that has me very worried.

$750 L98

If the trans was done anything like mine was, don't count on it lasting too long. I had to replace the flex plate, torque converter, trans pump, etc. it was all shredded up. Apparently they forced a 4L80E flexplate and spacer to work with a 4L60E causing the plate to bow around the converter and shudder when driving. The movement and slack from the incorrect plate and bolt holes they carved out caused it to destroy the pump splines and converter internals.

Anyhow the "new" pump works much better than the old beat up sockless walbro. The customized gauge seems to work as well, so we will see how everything turns out. I am quickly learning there is nothing I cannot do on my own car, It won't see another shop unless I have no other choice.

Pocket

iTrader: (24)

Ive got a brand new LS1 sending unit. I salvaged the pump for my swap so its just the sender. Be glad you arent using the pump itself because it lasted a whole month before losing pressure

Hows $60 shipped?

camarozz383

iTrader: (2)

any more info and pics, did it work good, I'm going with a 5.3 carbed and I have a LS1 fuel tank complete, this is a good write up! Do I need to do the same for a carbed set up? any more info would be awesome! thanks