LS1 with no return line-Dead head pressure?
LS1 with no return line-Dead head pressure? I was just reading this months carcraft. They have a spread on LS1 engines.
I am getting ready to put one in my 69 Camaro.
They have a single feed, and no return.
So, does that mean you go ahead and run the EFI pump straight to the rail with no return or regulator?
I am getting ready to put one in my 69 Camaro.
They have a single feed, and no return.
So, does that mean you go ahead and run the EFI pump straight to the rail with no return or regulator?
I believe the f-body LS1 has a built in regulator in the tank. Part of the pump mounting stuff....
The 97 and 98 vette had a return line. The v6 f-body also had a return line. When I swapped an LS1 in to my v6 f-body, I kept the return line, and used a 97 vette fuel rail which supports the return-type system.
The 97 and 98 vette had a return line. The v6 f-body also had a return line. When I swapped an LS1 in to my v6 f-body, I kept the return line, and used a 97 vette fuel rail which supports the return-type system.
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There is a regulator. There is no return line because it cuts down on hydrocarbons, such as fuel vapor that is created by cycling fuel through a return system. Charcoal canisters and canister purge systems are the way manufacturers used to deal with that problem.
That is interesting because the article in Car Craft talks about the LS1 being a "dead head" pump system.
I have access to a 98 Vette Fuel rail. If I swap that for my non-return, I then wonder if I can run the LT1 fuel pump in the caprice/impala gas tank and hook it all up, more or less as if it was in the LT1?????
I have access to a 98 Vette Fuel rail. If I swap that for my non-return, I then wonder if I can run the LT1 fuel pump in the caprice/impala gas tank and hook it all up, more or less as if it was in the LT1?????
That's basically what one of the local guys did with an LS1 swap he did into his '92 RS. Wasn't an LT1, but was on the old style pump.
I'm still running the v6 pump for the moment...
(although it's 30% overdriven via a kb boost-a-pump from my nitrous v6 days)
If the rail doesn't come with the fpr, you'll need to round up one of those too.
I'm still running the v6 pump for the moment...
(although it's 30% overdriven via a kb boost-a-pump from my nitrous v6 days)
If the rail doesn't come with the fpr, you'll need to round up one of those too.
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There is a return line in the LS1 fuel system. It is T'd in back real close to the tank. The pressure regulator is in the fuel tank. If there wasn't a return the system would need some sort of pressure regulated pump controller which it doesn't have.
There IS a return just not from the fuel rail.
There IS a return just not from the fuel rail.
Originally Posted by XLR8NSS
There is a return line in the LS1 fuel system. It is T'd in back real close to the tank. The pressure regulator is in the fuel tank. If there wasn't a return the system would need some sort of pressure regulated pump controller which it doesn't have.
There IS a return just not from the fuel rail.
There IS a return just not from the fuel rail.
I guess I am a bit old school, because all the EFI systems I have ever dealt with had a regulator controlled by engine vacuum that would dictate pressure. Even my 69 Vette 454 has a regulated return system with a vacuum control on the Pro-Flo EFI.
I can't understand how it can regulate without a control. I assume otherwise it keeps a constant regulated pressure regardless of engine vacuum??????
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it keeps 58 psi static, the fueling is controled through the computer and the map sensor
extremely stupid imho, as it won't read boost and makes it when you add a blower, the injectors get smaller under boost (not good)
Ryan
extremely stupid imho, as it won't read boost and makes it when you add a blower, the injectors get smaller under boost (not good)
Ryan
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Verdad Gallardo Okay..I am learning something here. 
So, when they say "dead head", they mean that pump is just pushing hard against a maxed out regulator all the time (58 psi), which I think is about the max regular pressure a pump designed for let's say a 1996 LT1 would push.
Why is a 96 lT1 signficant????? I just bought a smashed 1996 5.7 liter LT1 cop car running for parts when I was going to do a LT1 in the 69 Camaro. It looks like I can at least yank the tank and lines for my project, then sell off the rest. These leaves me with a Killer plastic tank with OEM plumbing. If I put a new LT1 pumpi the tank and hook all that through the 1998 Vette fuel rail...in theory at least, I should be okay.
My other option would be to run JUST the feed line and throw a gauge on there when I am first testing it. It is possible with NO regulator that will run no less or no more than 55 or 58 psi all the time. Or, I could put the regulator with return) right at the gas tank and avoid the extra hose running up the chassis. I could also add that at the fuel filter area where I would have cool quick connect lines, etc.
Now you guys got me thinking!
So, when they say "dead head", they mean that pump is just pushing hard against a maxed out regulator all the time (58 psi), which I think is about the max regular pressure a pump designed for let's say a 1996 LT1 would push.
Why is a 96 lT1 signficant????? I just bought a smashed 1996 5.7 liter LT1 cop car running for parts when I was going to do a LT1 in the 69 Camaro. It looks like I can at least yank the tank and lines for my project, then sell off the rest. These leaves me with a Killer plastic tank with OEM plumbing. If I put a new LT1 pumpi the tank and hook all that through the 1998 Vette fuel rail...in theory at least, I should be okay.
My other option would be to run JUST the feed line and throw a gauge on there when I am first testing it. It is possible with NO regulator that will run no less or no more than 55 or 58 psi all the time. Or, I could put the regulator with return) right at the gas tank and avoid the extra hose running up the chassis. I could also add that at the fuel filter area where I would have cool quick connect lines, etc.
Now you guys got me thinking!
Adkoonerstrator
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Originally Posted by 69MyWay
I can't understand how it can regulate without a control. I assume otherwise it keeps a constant regulated pressure regardless of engine vacuum??????
If you can, put the regulator up at the fuel rail and run the return back to the tank. That will help keep fuel pressure steadier if you'll be running a high hp setup. With the regulator back in the tank pressure in the LS1 system tends to start to drop at WOT in higher hp apps.
Yep, you can just run the corresponding vette fpr, just don't hook up the vaccum line to it. Then the stock ifr table will be right. Or if you want to hook up the vacuum line, get ahold of a corresponding ifr table (it will have flatter values).
