In-tank fuel pump help.

[derotoreut]

Going to be doing my first frame-off with LS swap on a '71 swb. I'm having a chassis built by Scott's Hot Rod, who is providing the fuel cell with Walbro in-tank pump. They are also doing all the plumbing (brake lines & fuel lines) on the chassis. They are providing fuel lines with feed and return lines. From what I understand, there are LS configurations with either a return or return-less system. My friend told me to have them install a return-less style pump, so I wouldn't have to mess with return lines. Is this something I should be pushing for? Scott's says they only provide their systems with the Walbro in-tank pump, but if I wanted to send them a pump, they would install it. Since they are plumbing this up, maybe it doesn't matter. I'm probably looking at installing an LS2 or LS3 with 4L60e trans. Any help is appreciated.

[BR3W CITY]

The LS2/3 would be returnless, as are pretty much all of the LS motors past late 2003. HOWEVER I still prefer keeping a return system because aftermarket rails/regs/fueling systems just make more sense to me keeping the return.

[scottybaccus]

The return less system is a myth. The return was simply moved to the tank with the pressure regulator.
The Vette system put both inside the fuel filter, outside the tank, but away from the engine. A short return line runs from the filter to the pump. The filter is supposed to be a 100k mile item, and you get a new regulator when it's replace.
The third option puts the regulator on the fuel rail, and has a full length return back to the tank.

Each has benefits and drawbacks. If you use option 1, all service requires dropping the tank. Option 2 uses a disposable pressure regulator? This just seems odd to me, and an opportunity for introduction of a quality issue. The 3rd option circulates fuel past the fuel rails and sends excess back to the tank, through twice the plumbing.
Pick your poison...

[BR3W CITY]

Thats just muddying the water.

The 'vette setup is a bypass, but its commonly known as returnless. An actual non return system would be a dead-head, which wouldn't fly with EFI. Its gonna confuse the crap out of people to call it anything else. For all intensive purpose, there is return, and returnless.

The fun starts with the new LT1's. DI fuel systems will be trouble for people.

[derotoreut]

Still trying to understand this. The LS thing is new to me, so I have a lot to learn. Since the chassis will be plumbed with supply and return lines, it sounds like it will have full length supply and return lines. Is this OK? This is how Scott's Hot Rod configured this on their Goodguys C10 Give Away Truck. According to them, this is how they do it on all of their chassis. I just want to make sure I shouldn't be requesting something else, that I am unaware of.

[BR3W CITY]

I'm sure if you just ask them "hey were you guys doing it for the return style, or returnless style?" they'll tell you what they are configuring it for.

Changing between the rails isn't hard. You might also wanna find out what injectors your harness is being wired for (the genIII truck injectors and car injectors use different injector wiring).

[ls1nova71]

You need to get your engine first, and see what fuel rail it has on it. As BR3W said, most engines newer than 2003 are going to be returnless. Unless you are wanting to put aftermarket fuel rails on it, you are most likely going to want to run a Corvette fuel filter/regulator. Here is what it looks like, you can get them at most any auto parts store, but I wouldn't get a cheap off brand one as they have been known to have issues right out of the box. A Wix or AC Delco is the way to go. http://www.summitracing.com/parts/wi...zZMaAgTe8P8HAQ. The way it's plumbed is, feed line from your fuel pump in the tank, to the Vette filter/regulator, a return from the filter back to the fuel tank, and a third line coming out of the filter (filter has 3 fittings) to the engine. I think this is going to be your best bet, but until you actually have an engine you won't know for sure.

[Andy4639]

Well my opinion does account for much but any way they do it should be fine. If your paying them for it they will be taking care of it.Mine is a 2003 and I have the return system.

[derotoreut]

Thanks guys. According to Scott's they set it up for a return style system. It will be completely plumbed by them, so I guess that's what I'll have to work with. I also have another "fish to fry", which is the transmission. I'll probably post this on a different thread, but In short I planned to go auto trans. Scott's recommended going with a 4L60e, so they're planning to set up the chassis accordingly. I need to determine if I made the right decision before they get to far along with the chassis fab.

[BR3W CITY]

If you go 4l80e the only difference in terms of chassis would be how far back the trans xmember is.

[solidaxel]

Originally Posted by derotoreut

Thanks guys. According to Scott's they set it up for a return style system. It will be completely plumbed by them, so I guess that's what I'll have to work with. I also have another "fish to fry", which is the transmission. I'll probably post this on a different thread, but In short I planned to go auto trans. Scott's recommended going with a 4L60e, so they're planning to set up the chassis accordingly. I need to determine if I made the right decision before they get to far along with the chassis fab.

Ask Jeff to install two tabs for the trans 1. for the 4l60 and 2. for the 4l80
The engine will be in the same location.
Have your drive shaft built locally when you decide.

[derotoreut]

Originally Posted by solidaxel

Ask Jeff to install two tabs for the trans 1. for the 4l60 and 2. for the 4l80
The engine will be in the same location.
Have your drive shaft built locally when you decide.

Who is Jeff? Is he someone that you know that works for Scott's? That's a good idea if they can do it. This way it would give me some flexibility on my choices. I planned on worrying about the driveshaft later on in the build anyway. Since the rear axle will be 9" I figured that I would require something special.

[solidaxel]

Who do you talk to when you deal with Scotts, Jeff or Justin

[derotoreut]

Originally Posted by solidaxel

Who do you talk to when you deal with Scotts, Jeff or Justin

I've only talked to Justin. I dealt with him in the past on other things too. Some times I get the feeling he's just pushing to get the sale, or keep things moving. Don't get me wrong… I think I'll be satisfied with my decision for the chassis, especially since I would've made all of these mods any way. It's just that I might want to slow things down a bit if I need to. I need to be sure of my choices. Since I haven't selected an engine/trans combo, I want to make sure its going to be right for me. I figured the chassis would be the first place to start. I guess I never thought about having to make a quick decision on my transmission. Again the LS thing is new to me, so I'm not that well versed in it. My build is going to be pretty comprehensive (and expensive), so I want to do things right. Once of them is selecting the right transmission.

[BR3W CITY]

Devils advocate; people who's projects sit around any commercial shop will pay more, or at least not be 1st priority. Any project is real estate in a shop, so "slowing down" means "wasting space and time" to most for-profit shops. If building it isn't actively making them money, they want it out the door.

[derotoreut]

Originally Posted by solidaxel

Ask Jeff to install two tabs for the trans 1. for the 4l60 and 2. for the 4l80
The engine will be in the same location.
Have your drive shaft built locally when you decide.

Thanks for the idea. I talked to Justin at Scott's and they agreed to provide a trans crossmember that would be set up for both 4l60 and 4l80. He said they've never done it before, but would be willing to do it for me. That takes the pressure off for a while until I decide which way to go. Thanks.

[derotoreut]

Originally Posted by BR3W CITY

Devils advocate; people who's projects sit around any commercial shop will pay more, or at least not be 1st priority. Any project is real estate in a shop, so "slowing down" means "wasting space and time" to most for-profit shops. If building it isn't actively making them money, they want it out the door.

Not talking about slowing them down. I'm saying maybe I need to slow down a bit and be sure about my own build ideas. Maybe I jumped the gun on deciding to have the chassis built with a fuel return system and trans mount that will accept a 4l60 vs 4l80, without really considering my options. They're moving full speed ahead with the chassis and I can't wait to get it. No slow down on their part.