Ok so after months of taking up garage space at my inlaws Im finally going to drop my LT1 into my car on Thursday (Canada Day) But I have a few questions.

1. wiring up the Fuelpump (LS1 01 tank with everything) do I need a relay to go with? (dumb I know but I don't know the answer)

Ill be taking plenty of pics, have constant access to a PC so hope fully I can get through the whole thing I a weekend. (fingers crossed)

 

How are you doing the LT1 swap with a LS1 tank? I don't think the LS1 tanks came with a return line.

 

I believe I read somewhere on here that they do have a return ... if not they are plastic so I can also fab something.

any ideas on the relay thought?

 

I have a return line on my car.....

 

That could be where I read it

thats on the fuel tank yes?

 

The fuel comes in at the bottom of the AFPR and the return line leaves the APFR on the right hand side through the braided hose back to the gas tank........IIRC

 

which basically there is a return line connection available on the fuel tank assembly yes?

 

interesting, perhaps someone else will chime in, but from what I understand LS1 engines in vettes and camaros have no return line, pressure is regulated by the computer varying the speed of the pump not by venting return to the tank..

Flynlow, you had the conversion done for you correct? I believe they fab that to enable a proper return connection for a thirdgen, makes things easier for the swap..

for my swap I just got a sending unit from a tpi car from hawks and put a walbro 255lph in with it, it was a plug and play affair if I hadn't of done braided lines..

 

Then the following picture doesn't make much sense.......

I'm not 100% sure, I'm going by what Roy told me........

There you can see the return line.....bottom right picture.....

 

Im pretty positive the LS1 gas tank doesn't come with a return line. Take a look in a real LS1 equipped vehicle, there is no return line.

 

I have the fuel tank sitting at my parents and I need to pic it up anyways I will snap some picks of it, worst case is the guy I buy my parts from is about 5 min from where Im swapping so I can alwasy work something out .... but Im pretty sure it being plastic I can adapte a return line to it.

 

The gas is regulated at the gas tank in an LS1 car, so there is no return line

 

Ok so I know I need to adapt a return line

shouldn't be hard to do.

Thanks for the heads up.


Anyone know of the top of there head what the size of the return line is.

5/16 return can anyone confirm that's what I came up with in a search.

 

3/8ths supply 5/16th return..

as an alternative I used russel compression fittings at the tank and braided 6an the whole route, return and supply..

 

Ok thanks,

Im trying to use the hardlines for now.

I will run just ahigh pressure hose for return as there should be to much pressure. but probably run braided from the supply into the lines for the rails.

man this is gonna be fun

 

Well it's begun, engine has be disconnected and it and the tranny are ready to be pulled first thing tomorrow morning.

one question I have the fuel rails I got don't look quite right, and so the question is can I get a shop to pull the lines running into them and get them to install so AN fittings?

 

First question -

How can I get fittings onto those fuel lines to run braided lines without welding?

or am I stuck welding?

my thought where to put one of those nuts that slides up to a flared end and locks the other end to it (description is bad ill try for a pic later)

 

Installed new Poly motor mounts from energy suspesion.

man am I happy I did that.

 

and here is a shot of the fuel tank Im installing (plastic LS1 tank from 2K TA)

Ill figure out how to hook up a return line and then post it up as a tech article.

 

forgot to post pic

 

you can run the russel 5/16 and 3/8 to 6an compression fitting off those hardlines. you will have to cut them with a mini-tubing cutter though then the connections just slip on and screw down tight, very tight.. what you are left with is a nice 6an fitting..

can't remember the part number for the 3/8ths fitting but you can find it at the russel website. The 5/16th fitting is part # 165056 also to be found there.


if you go to performanceplumbing.com they have the 6an adaptors to the LT1 fuel rail there for sale.. that would complete the circuit for you.

 

Perfect that should work nicely ill check it out

thanks

 

here is the link to performance plumbing: LT1 connectors

I can't find the 5/16ths adapter, the 3/8th hardline compression fitting from russel can be found at jegs, performance plumbing should be able to help you though..

 

ok so I plan to flare the four tubes up front the two hardlines and the two lines off the rails, (one is already flared with a tube nut on it)

and I plan to use earls tube nuts and tub sleeves.

Now my question is ... is the pressure still high on the return line? or is it lower >20psi?

also for the LS1 cars does anyone know how they connect the hard plastic lines to the hardlines .... if no one knows ill need to make a trip to my chev dealer and see what they have as far as parts ordering is concerned.

Thanks

 

The 97 vettes had a return line, anything after that didn't. Flyinlow, how come you swapped in an lt1 tank? They're pretty much the same as your stock tank. If you were gonna swap tanks, why not go with an LS1 and eliminate the return line all together?

 

Fuel tank is out, so now the fun part of adapting lines and figuring out the return line .... pics to come shortly.

 

ok so because the 5/16" return line is a B@stard size as I have been told and that finding fittings is all special order (not that bad but eh!) I am sourcing a 3/8" supply line to use as my return line so both lines will be 3/8"

Ill post pics of that when I finish up as with how it will be re-routed - hopefully this weekend coming up.

 

Here is the latest, I am reloacting the fuel lines closer to work better with the LT1, this should cut down on the amount of braided line required and make it alittle cleaner.

 

Also here is a shot of the Hooker 2055 headers, I made some modifications

Checking the colletor it necks down to 1 7/8" ... I found that unacceptable, so I carved off some, and opened it to 2 3/8" now, and it still fits and seals well in the Y-pipe.

 

what method did you use to open up the collectors? They look real good.

 

Sawzel, and then I plan to use a dremel to clean up them up.

Flow wise this is much better, not to sure why they wanted to gor from 3" collectors to 1 7/8" .... oh well not anymore

 

Stopped by my local Chevy Dealer, to find out/order the hard plastic supply line .... under $50 CAN for it so not bad, also after talking with them,I found out that the LS1 tanks DO have return lines, parts numbers and all listed for it, also after looking at the fuel tank there are just too many lines for there NOT to be one.

So long story, I should be getting my supply line next week, and I should have it all hooked up and in the car in 2 weeks.

Hoping to drop engine in this weekend as the fuel line relocation is almost done and my Earls AN fittings should be in this week as well. thanks to www.Summitracing.com

More pics posted this weekend. lots of the fuel tank and it's connections and of course the engine drop in.

 

I used a 4" high speed angle grinder. The die grinder wouldn't touch it (although I was using a stone, not a carbide bit).

I hope your y-pipe seals when you get it all in the car. Mine didn't mount centered on the ball flange. I didn't do the "surgery" until I could do a fit check in the car.

 

I can tell you for a fact that my 2000 Z28 has no return line! Early models may have, I don't know, but mine certainly does not. If you have LS1 fuel rails with no return line then just run a tank without one as well and get rid of more things that aren't needed.

 

the tank is out of an 01 T/A,

if you look at the pic above of the fuel tank you can see 4 to 5 different connections going into the tank 3 into the pump assembly and 2 into the tank it's self.

also GM diagrams showed return lines and listed part numbers and that was for the 5.7L not the 3.8.

Ill see if I can get some better pics in the next day or so and post.

 

You know what, you're right. It does have a return line that is hidden. After taking a look, both the feed and return line are wrapped up together into 1. Good info actually. Thanks.

 

Glad to help ... hopefully my install I should have all the info necessary for a tech article and then it will be easy to know that 82-02 fuel tanks all interchange.

plus with the fill next being a two piece with rubber style hose in the middle it can be easily adapted to a thirdgen. (I hope)

PS

Since you have a 4th gen LS1 would you mind helping me identify the return line ... I have two connections that I think it could be ... 1. goes into the charcoal canister the other back into the pump ... now I assume its the one into the pump but was hoping to confirm that.

I won't be back to my chevy dealer for another week so I can always then.

 

The return line goes back into the pump. It is the farthest of the 3 lines away from the filler neck.

 

PERFECT!!! - this is going to speed things up nicely.

Thanks for the help!

 

GM had my hard plastic line from tank to hardline in, in record time

So this week/weekend I will wire up the fuel tank and put it back in.

Only question .... the LS1 pump has 4 wires coming off it, 2 are ground/power to work the pump, anyone know what the other 2 are for and it I even need them.

Also plan to use a relay and hook to ecm .... I assume the other two wires are not necessary put someone if they could clarify would be nice.

 

ok so Im wiring up the tank, should get some nice pics of it installed this weekend, then mount the rest of the accessories onto the engine, drop in and start on the engine harness.

Oil cooler and PS parts order from summit!!!

Also I installed my headers but had a question about how to tighten the bolts to proper torque specs when I can't get a socket or even a wrench onto some of them????

whats the deal?

 

here's another pic of a '99 plastic tank

 

Could you weigh it? That would be a nice way to cut some weight if it's 5lbs or more lighter.

 

no scale at the juju house o' pain . it is my understanding it is 18 lbs. lighter than a '98 tank . still feels like a heavy lil' bugger to me. the four wires are power and ground for fuel pump , yet another ground and signal for fuel gauge .

 

well I went to drop the motor in yesterday, and the thing doesn't line up properly on the mounts, I am using stock thirdgen clamshells and it seems to be about 1 inch forward of the mount on the K member on the drivers side, and if I twist the motor so both line up it's making the tranny point to the rear passenger wheel.

Can anyone clarify?

I ll see about picks today or tomorrow.

"Aftermarket or special motor mounts are not necessary. The passenger side uses a modified original mount that has the front corner ground down to clear the A/C compressor. The drivers can use either mount. Both must be moved back from their stock location."

I took that quote off TexasLT1's original swap guide is this, a true statement?

 

Engine is IN!!!!

Ill post pics of it in ... damn I am so fing happy tranny xmember is bolted up, next stop gas tank.

Ill post pics ASAP in the next day or so.

ill also show the LT1 vs SBC Gen I clamshell mounts.

Texas and Pasky, thx for the help it was the AC Stud that was in the mount, pulled the stud moved the mount and it was in like a glove.

WOOT damn this is a good day.

 

Looks nice sitting in there.

Well this week should have the 4th gen plastic tank installation completed and the rest of the drive line done, then onto plumbing the gas/oil/power steering/coolant.

should be fun.

 

4th gen plastic tank is in .... NOT A DIRECT BOLT IN!!!

but its pretty damn close, I had to use half inch spacers and 2" bolts instead of the stock 1" and adjust the straps alittle, but other wise it's in .... what I am going to check into for later is actual 4th gen straps.

oh well, Im into plumbing now, gonna have to put a small bit of braided into the back half, because the plastic line is very long because it is supposed to snake around. but I removed the section with the fuel filter because I had a different fitler and different routing. Ill post pics in the next few days of the tank and of the braided lines.