McKay Racing

I have a question about the fuel pump/fuel rail problem with the swap. I have read the question and answer post about this problem. I understand that the stock fuel pump has a return line and the new ls1 fuel rail only has one port. The post suggests modifying the fuel rail to make another port, or getting fuel rails from a Corvette that way you would have the return line.
My question is why can't I replace the fuel pump in the tank with one from a 4th Gen car therefore not needing a return line?
Going to have to replace the fuel pump anyway, right?
Is this approach not valid due to the 4th gen fuel pump not fitting in the 3rd gen tank?\
Just trying to make sense of the whole thing.
Thanks in advance guys!

LS1 IROCZ

here is a pic of mine. its a fbody link so you have to copy and paste on your browser. http://www.fbody.com/members/LS1IROCZ1/045newfuelrails1.jpg


I use the factory fuel supply line run up to the engine, Y off to each side of the new fuel rails, connect the returns of the fuel rails together in a Tee, then that line runs to a pressure regulator. The other side of the regulator is capped off, and the return line from the regulator is hooked to the return line to the tank.

I have my evap line from the fuel tank hooked up to the evap sol. on the engine.

there are lots of pics and explanations on my web site

wm_sorg

You do not need to replace the fuel pump. If the car had a tuned port setup the factory pump will provide the fuel pressure required to feed the LS1.

You can use the 4th gen fuel pump, however, you will be adding unnecessary complexity to your setup. For one thing the PCM needs to be wired to the fuel pump so it can regulate fuel pressure.

LS1 IROC, those fuel lines look great. How are your new mods doing?

89 Iroc Z

You can buy the regulator with the return line that I have a link to in my post. Or the way I am going to do it is use the corvette fuel rail with the return line for cleaner install look and to keep the fuel colder in the rail to get better atomization.

89 Iroc Z

LS1 IROCZ, Why did you replace the stock rail? For looks? I don't see how a factory fuel rail won't be adequate for any hp level under 550 hp. The TPI rails support up to 9 sec 1/4 mile times. Don't the LS1 rails flow the same? Or is it the fuel pressure regulator holding you back?

McKay Racing

I appreciate the help guys. I think I will end up going with the modified fuel rails. I found a place that sells them to fit the LS1, and has a return line fitting.

Soon, I will have this thing in my car. Patience is not my best quality.

wm_sorg

Please post your source and part nums. I may consider this at a later point in time.

McKay Racing

The web site is www.hotrodlane.cc
Click on the "online catalog" button at the top. The fuel rails are on page 63 of the catalog.
I did not see a part number though.
Alot of good stuff on the site for ls1/lt1 swaps.

wm_sorg

Thank you.

LS1 IROCZ

I purchased my fuel rails from Speed Inc. They have 2 different sets, just the rails and complete rails with fittings. I just bought the plain rails. (Much cheaper) and got the fittings locally.

When my car was being dyno tuned, it maxed out at 380 Hp around 6100 rpm. It was very lean. They increased the injectors by 30 % and it had absolutely no effect on the hp and was still lean.
With my set up, I should be over 400 Hp and be able to rev to 6800 rpm.
Sometime in the next couple of weeks I should be able to finish up the dyno tuning.
As for the reason my set up wouldn't support more........ It is possible it was the placement of the regulator. I had mine before the stock rails and only one supply line to the rail and no return line on the rails. (The return line was on the regulator.) I believe the TPI setups have the return line on the rails .... along with the press. regulator. I should look at my old one in the basement.....

The new set up has the regulator after the rails, and both rails getting the same pressure and quantity of fuel.

89 Iroc Z

I would never buy their rails. It's a complete waste of money. All you need to do is get a 97 or 98 Vette rail from a junkyard or ebay. Then buy the fittings that www.hotrodlane.cc sells on page 63 that convert the stock corvette fuel rail fittings to AN lines. Or just braze on AN fittings. Street and Performance sells some way overpriced stock GM parts that you can get cheaper even at a GM dealer.

89 Iroc Z

LS1 it may be the stock fuel pressure regulator. I really don’t think the rail is what was limiting power. The Z06 has 405 hp on the same returnless rail. And there are F-body guys running 450+ hp on the stock rail.

McKay Racing

Cool, I appreciate the advice. I will look into the 97-98 Corvette fuel rails. I believe they are around $273 from the dealer, but I will check some local junk yards, and ebay.

LS1 IROCZ

All I can Say is : The dyno showed the numbers.

McKay Racing

FYI:

I found a new set of 97 Vette Fuel rails rom gmpartsdirect.com (part #12556705) for $136.49!!! Of course the shipping is a bit much, but it still puts the rails at $100 less than what the dealer wanted.

Hopefully someone else in the same situation will see this and not go to the dealer.

wm_sorg

Thanks for keeping us updated. Please post pics. My LS1 roared to life yesterday. Still will need about 3 more weeks before its maiden voyage.