Starving a 540 Big Block
Race Director
Joined: Nov 2000
Posts: 11,872
Likes: 12
From: Waterloo ontario Canada
Originally Posted by zwede
Norval: You're being very mean to your pumps. If you think about it, what happens if you prevent an electric motor from spinning? It will draw a bunch of current and get real hot. That's what you're doing to your pumps. They want to pump an enormous volume of fuel but the regulator dead heads and only allows them to deliver a fraction of the designed volume except at WOT. So the pumps are being highly stressed (electrically and thermally).
Compare this to a return system. This allows the pumps to pump the full volume even at idle. Any unused fuel is returned to the tank. The pumps draw much less current and also receive much better cooling as they are cooled by the fuel they pump.
Running an electric pump dead-head might work (atleast for a while) but it's not the correct way to do it.
Someone might have noticed there is no return line on the new LS1's but they still have a return except it's inside the tank. They then use higher pressure (58 PSI) to the engine to avoid boiling fuel.
Compare this to a return system. This allows the pumps to pump the full volume even at idle. Any unused fuel is returned to the tank. The pumps draw much less current and also receive much better cooling as they are cooled by the fuel they pump.
Running an electric pump dead-head might work (atleast for a while) but it's not the correct way to do it.
Someone might have noticed there is no return line on the new LS1's but they still have a return except it's inside the tank. They then use higher pressure (58 PSI) to the engine to avoid boiling fuel.
I never knew that it was a problem to run the pumps deadhead. I have been running these same 2 holley high pressure pumps for 14 years, same with the mustang, a pair of high pressure holley pumps but one of these days one of them is going to cause a problem. 
Race Director
Joined: Jan 2000
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From: Corsicana, Tx
2020 C2 of the Year - Modified Winner
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NOW I know who you are!!! New 540 guy!!
I'm sure your helper has told you all about my setup. I'm using the Aeromotive pump with a return line to top of tank from regulator. It's been on there a couple of years now and so far has done great with no heat issues and the big pump has made lots of highway trips without the issues that many guys report with having big race pumps overhat etc. I think the return system really helps.
Of course I've run many Holley and Mallory pumps dead headed over the years too and had good luck...but they are a lot milder pumps on milder engines.
Also got by with feeding my 540 with a Holley mechanical pump out of a 3/8" line for 3 years. I made lots of high speed banzai runs and never felt it nose over, as well as make well over 600 RWHP with it, but I'm sure I was on the edge. I never got a chance to make it really pull while using slicks..it never made it more than about 6" off the line before I chunked rear end parts. I'm sure that if I had put it under a real hard pull through the gears instead of sideways featherfooting, spinning stuff, issues would have surfaced.
Sounds like you have it figured it out. You can use wire braided or go to a diesel supply or hose place and see if you can get a deal on Aeroquip or Stratoflex stuff. Might be a little cheaper..just not as shiny.
JIM
I'm sure your helper has told you all about my setup. I'm using the Aeromotive pump with a return line to top of tank from regulator. It's been on there a couple of years now and so far has done great with no heat issues and the big pump has made lots of highway trips without the issues that many guys report with having big race pumps overhat etc. I think the return system really helps.
Of course I've run many Holley and Mallory pumps dead headed over the years too and had good luck...but they are a lot milder pumps on milder engines.
Also got by with feeding my 540 with a Holley mechanical pump out of a 3/8" line for 3 years. I made lots of high speed banzai runs and never felt it nose over, as well as make well over 600 RWHP with it, but I'm sure I was on the edge. I never got a chance to make it really pull while using slicks..it never made it more than about 6" off the line before I chunked rear end parts. I'm sure that if I had put it under a real hard pull through the gears instead of sideways featherfooting, spinning stuff, issues would have surfaced.
Sounds like you have it figured it out. You can use wire braided or go to a diesel supply or hose place and see if you can get a deal on Aeroquip or Stratoflex stuff. Might be a little cheaper..just not as shiny.
JIM
