Changing from return style to dead head system
Changing from return style to dead head system Last winter I changed from using the corvette fuel filter/regulator to a return style system using a Walbro 450lph bump and a Holley 12-846 bypass regulator and am how running E85 with a NX wet kit. At LS Fest after running ax during the day an then the drag at night I had fuel pump issues. I first checked the filter and it was clean so i went to pull the pump and the fuel was so hot it was very uncomfortable reaching in the tank to remove the pump. After getting the pump removed and swapping the pump i used a temp gun and the fuel temp was still 130*F.
I just set my system up as a dead head system with the regulator under the passenger seat. The 12-846 has in/out on both ends of the regulator but doesn't function that way, I can only get 14 psi at the fuel rail.
Can i use a T fitting off one end of the regulator or should i just buy a dead head regulator?
I just set my system up as a dead head system with the regulator under the passenger seat. The 12-846 has in/out on both ends of the regulator but doesn't function that way, I can only get 14 psi at the fuel rail.
Can i use a T fitting off one end of the regulator or should i just buy a dead head regulator?
TECH Senior Member
Joined: Jun 2016
Posts: 22,300
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From: Central Cal.
The in/out fittings on the end of the Corvette regulator are In/ RETURN, not in/out. The single fitting on the OTHER end of the regulator is the OUT fitting. You had no idea how it works. Is the power wire to the pump big enough? If not things will get hot in a hurry. There is no such thing as a true dead head system. ALL are return systems one way or another. Hook the regulator up CORRECTLY, AND make sure your power wire to the pump is large enough. Then do some homework on how to CORRECTLY design a fuel system.... find out from those who KNOW.
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Last winter I changed from using the corvette fuel filter/regulator to a return style system using a Walbro 450lph bump and a Holley 12-846 bypass regulator and am how running E85 with a NX wet kit. At LS Fest after running ax during the day an then the drag at night I had fuel pump issues. I first checked the filter and it was clean so i went to pull the pump and the fuel was so hot it was very uncomfortable reaching in the tank to remove the pump. After getting the pump removed and swapping the pump i used a temp gun and the fuel temp was still 130*F.
I just set my system up as a dead head system with the regulator under the passenger seat. The 12-846 has in/out on both ends of the regulator but doesn't function that way, I can only get 14 psi at the fuel rail.
Can i use a T fitting off one end of the regulator or should i just buy a dead head regulator?
I just set my system up as a dead head system with the regulator under the passenger seat. The 12-846 has in/out on both ends of the regulator but doesn't function that way, I can only get 14 psi at the fuel rail.
Can i use a T fitting off one end of the regulator or should i just buy a dead head regulator?
https://www.google.com/search?q=Holl...hrome&ie=UTF-8
The 450 draws a lot of amps if you are requesting 58 lbs of fuel pressure (LS1) - looks like 16 amps at 13.5 volts.
https://walbrofuelpumps.com/walbro-f...-fuel-pump-e85
To get 13.5 volts to the pump most run high strand count 10 guage wire to the pump (depends upon how long the wire is to the pump). Stock wiring systems in older cars don't support high amps and is why the stock wiring to the pump is replaced with high quality high strand count 10 guage wire (with a relay).
If there is a bulkhead connector on your tank module to the pump and it hasn't been upgraded it will be a restriction. Most older bulkhead connectors on the module don't support more than 14 amps. The bulkhead connector on a 98 Fbody for example doesn't support more than 14 amps. So running a pump that requires more than 14 amps might possibly overheat the connector and the pump (similar to a brownout) and cause failure in one or the other or both.
For example, doesn't apply to you, but their upgraded wiring kit and bulkhead connector for the 99-2002 F body can support up to thirty amps. The upgraded bulkhead connector replaced the stock bulkhead connector bottleneck from 14 amp to 30 amps.
Visit the Racetronix site for a good explanation of their wiring kits built to overcome the restrictions of the stock wiring system to the pump, and the draw of larger than stock fuel pumps. From time to time they respond in this forum by posting warnings about this issue and how it can limit the lifetime of a fuel pump or cause failure.
BTW - I'm not making a sales pitch for Racetronix, but instead am pointing out that their site has a lot of useful information as described above.
The in/out fittings on the end of the Corvette regulator are In/ RETURN, not in/out. The single fitting on the OTHER end of the regulator is the OUT fitting. You had no idea how it works. Is the power wire to the pump big enough? If not things will get hot in a hurry. There is no such thing as a true dead head system. ALL are return systems one way or another. Hook the regulator up CORRECTLY, AND make sure your power wire to the pump is large enough. Then do some homework on how to CORRECTLY design a fuel system.... find out from those who KNOW.
TECH Senior Member
Joined: Jun 2016
Posts: 22,300
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From: Central Cal.
With the Corvette regulator, there should be NO fuel returning from the engine compartment, warm or otherwise. Fuel is pumped from the tank, to the Vette regulator no more than a few feet from the pump, to either the front of the car or back to the tank. Only one fuel line to the front, contents to be consumed in its entirety. No heat issues that way.
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I ran the corvette filter/ regulator with a walbro 255 correctly from may 2009 to approx. jan 2017 no problems. Have ran a walbro 450 with the vette filter/regulator for a year and did have to update some wiring.{definitely not the way it should have been} I have been running the 450 with a correctly designed return style system -8 line through the bulk head through the Holley filter to fuel rails to regulator, return -6 line from regulator through composition sensor to the tank since jan 2018. Maybe Im wrong but I feel like the problem is that the fuel was being circulated through a very cramped engine bay adsorbing heat and caring it back to the tank and just kept absorbing more heat through the day. Iv ran ls fest grand champion class every year except the first and had many more runs through the day than this year. This seems to have happened after going to a return style.
The one small terminal in the bulkhead connector in link below can't handle the amps for a 450 (one is pos, one is neg, and other two are for the fuel guage sender).
https://www.racetronix.biz/product.asp?ic=bca-4w
Or a bulkhead connector with terminals the size of these? One of the two larger terminals in this bulkhead can handle 28 amps.
https://www.racetronix.biz/product.asp?ic=rcs-027
When you were running the Corvette filter/regulator with the 450 did you have a fuel pressure guage? I've yet to read on this forum where the Corvette filter/regulator is able to maintain 60 psi or less lbs. Most report that psi is over 70. For example, I just installed the C5 filter in my fbody with an Rxp 341 (340 lph). The 340 overpowers the Corvette filter at over 70 psi at idle.
Last edited by dlandsvZ28; Sep 24, 2018 at 06:58 AM.
Have you ruled out the possibility that it is your pump that is overheating, thereby heating the gasoline in the the tank? Seems more logical since the pump failed. Did you hard wire the 450 pump in the fuel module or run the current thru a bulkhead connector with small terminals like this?
The one small terminal in the bulkhead connector in link below can't handle the amps for a 450 (one is pos, one is neg, and other two are for the fuel guage sender).
https://www.racetronix.biz/product.asp?ic=bca-4w
Or a bulkhead connector with terminals the size of these? One of the two larger terminals in this bulkhead can handle 28 amps.
https://www.racetronix.biz/product.asp?ic=rcs-027
When you were running the Corvette filter/regulator with the 450 did you have a fuel pressure guage? I've yet to read on this forum where the Corvette filter/regulator is able to maintain 60 psi or less lbs. Most report that psi is over 70. For example, I just installed the C5 filter in my fbody with an Rxp 341 (340 lph). The 340 overpowers the Corvette filter at over 70 psi at idle.
The one small terminal in the bulkhead connector in link below can't handle the amps for a 450 (one is pos, one is neg, and other two are for the fuel guage sender).
https://www.racetronix.biz/product.asp?ic=bca-4w
Or a bulkhead connector with terminals the size of these? One of the two larger terminals in this bulkhead can handle 28 amps.
https://www.racetronix.biz/product.asp?ic=rcs-027
When you were running the Corvette filter/regulator with the 450 did you have a fuel pressure guage? I've yet to read on this forum where the Corvette filter/regulator is able to maintain 60 psi or less lbs. Most report that psi is over 70. For example, I just installed the C5 filter in my fbody with an Rxp 341 (340 lph). The 340 overpowers the Corvette filter at over 70 psi at idle.
I didnt have a gauge on it when i was running the vette filter/regulator. I did have problems with pressure being to high causing the car to be rich.
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This is a direct quote from Racetronix
"Facts:
Delphi changed the bulkhead connector in their modules from a 150-series to a 280-series type b/c if chronic failures. The 150-series terminals are rated at 14-amps max. at room temp This rating goes down with temp and age. The 280-series terminals are rated at 28-amps. 340LPH pumps typically draw 12-14 amps @ 58PSI @ 13.5V which places this wiring/terminals right at their upper current limits.
When using a Walbro 255LPH pump a pressure rise will occur with the factory regulator configuration. This is b/c the regulator and return flow path is too small/restrictive to handle the pump's flow. Typical pressure at part throttle/idle will be 60-63 PSI vs. the factory set 58PSI. The pressure may drop once the pump/fuel warms up and the vehicle voltage drops. This pressure rise is not as pronounced without a hotwire kit b/c the voltage drop in the factory harness will reduce pump flow/performance.
Running a 340LPH pump with the factory return system may cause premature pump failure b/c of excessive head pressures created. In-house testing here has proven this and that is why we have not offered a F99 340LPH solution yet. Once we are able to offer a complete system which eliminates this restriction we will."
Note that their reply relates to a 340 LPH. You were using a 450 lph pump with significantly more volume (110 lph).
Might be that the damage occurred with the C5 filter/reg and it finally just happened to fail during race day.
"Facts:
Delphi changed the bulkhead connector in their modules from a 150-series to a 280-series type b/c if chronic failures. The 150-series terminals are rated at 14-amps max. at room temp This rating goes down with temp and age. The 280-series terminals are rated at 28-amps. 340LPH pumps typically draw 12-14 amps @ 58PSI @ 13.5V which places this wiring/terminals right at their upper current limits.
When using a Walbro 255LPH pump a pressure rise will occur with the factory regulator configuration. This is b/c the regulator and return flow path is too small/restrictive to handle the pump's flow. Typical pressure at part throttle/idle will be 60-63 PSI vs. the factory set 58PSI. The pressure may drop once the pump/fuel warms up and the vehicle voltage drops. This pressure rise is not as pronounced without a hotwire kit b/c the voltage drop in the factory harness will reduce pump flow/performance.
Running a 340LPH pump with the factory return system may cause premature pump failure b/c of excessive head pressures created. In-house testing here has proven this and that is why we have not offered a F99 340LPH solution yet. Once we are able to offer a complete system which eliminates this restriction we will."
Note that their reply relates to a 340 LPH. You were using a 450 lph pump with significantly more volume (110 lph).
Might be that the damage occurred with the C5 filter/reg and it finally just happened to fail during race day.
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From: Turnin' Wrenches Infractions: 005
All fuel systems are "return style". That IS the way they regulate pressure. If they didn't return, the pressure would be erratic, and whatever max pressure the pump could make.
This is a direct quote from Racetronix
"Facts:
Delphi changed the bulkhead connector in their modules from a 150-series to a 280-series type b/c if chronic failures. The 150-series terminals are rated at 14-amps max. at room temp This rating goes down with temp and age. The 280-series terminals are rated at 28-amps. 340LPH pumps typically draw 12-14 amps @ 58PSI @ 13.5V which places this wiring/terminals right at their upper current limits.
When using a Walbro 255LPH pump a pressure rise will occur with the factory regulator configuration. This is b/c the regulator and return flow path is too small/restrictive to handle the pump's flow. Typical pressure at part throttle/idle will be 60-63 PSI vs. the factory set 58PSI. The pressure may drop once the pump/fuel warms up and the vehicle voltage drops. This pressure rise is not as pronounced without a hotwire kit b/c the voltage drop in the factory harness will reduce pump flow/performance.
Running a 340LPH pump with the factory return system may cause premature pump failure b/c of excessive head pressures created. In-house testing here has proven this and that is why we have not offered a F99 340LPH solution yet. Once we are able to offer a complete system which eliminates this restriction we will."
Note that their reply relates to a 340 LPH. You were using a 450 lph pump with significantly more volume (110 lph).
Might be that the damage occurred with the C5 filter/reg and it finally just happened to fail during race day.
"Facts:
Delphi changed the bulkhead connector in their modules from a 150-series to a 280-series type b/c if chronic failures. The 150-series terminals are rated at 14-amps max. at room temp This rating goes down with temp and age. The 280-series terminals are rated at 28-amps. 340LPH pumps typically draw 12-14 amps @ 58PSI @ 13.5V which places this wiring/terminals right at their upper current limits.
When using a Walbro 255LPH pump a pressure rise will occur with the factory regulator configuration. This is b/c the regulator and return flow path is too small/restrictive to handle the pump's flow. Typical pressure at part throttle/idle will be 60-63 PSI vs. the factory set 58PSI. The pressure may drop once the pump/fuel warms up and the vehicle voltage drops. This pressure rise is not as pronounced without a hotwire kit b/c the voltage drop in the factory harness will reduce pump flow/performance.
Running a 340LPH pump with the factory return system may cause premature pump failure b/c of excessive head pressures created. In-house testing here has proven this and that is why we have not offered a F99 340LPH solution yet. Once we are able to offer a complete system which eliminates this restriction we will."
Note that their reply relates to a 340 LPH. You were using a 450 lph pump with significantly more volume (110 lph).
Might be that the damage occurred with the C5 filter/reg and it finally just happened to fail during race day.
Thanks, i understand that. My goal was to move the regulator out of the engine bay so i wasn't absorbing heat and carrying it back to the tank. I was able to move my return style regulator and run a single line to the motor. I know this is not the recommended way to run the system. If i determine that the pluming or wiring is causing the pump to overheat i will restore it to a correct return style . Thank You .
9 Second Club
Joined: Nov 2003
Posts: 13,616
Likes: 185
From: Norn Iron
Last winter I changed from using the corvette fuel filter/regulator to a return style system using a Walbro 450lph bump and a Holley 12-846 bypass regulator and am how running E85 with a NX wet kit. At LS Fest after running ax during the day an then the drag at night I had fuel pump issues. I first checked the filter and it was clean so i went to pull the pump and the fuel was so hot it was very uncomfortable reaching in the tank to remove the pump. After getting the pump removed and swapping the pump i used a temp gun and the fuel temp was still 130*F.
I just set my system up as a dead head system with the regulator under the passenger seat. The 12-846 has in/out on both ends of the regulator but doesn't function that way, I can only get 14 psi at the fuel rail.
Can i use a T fitting off one end of the regulator or should i just buy a dead head regulator?
I just set my system up as a dead head system with the regulator under the passenger seat. The 12-846 has in/out on both ends of the regulator but doesn't function that way, I can only get 14 psi at the fuel rail.
Can i use a T fitting off one end of the regulator or should i just buy a dead head regulator?
If you are having fuel heating issues, then add a cooler on the return line.
And a temp gun pointed at a liquid is unlikely to get any useful reading. If you're using a suitable ecu, logging fuel temperature is easy, just chuck a temp sensor somewhere suitable.
You could also PWM pump speed so it's doing less work at lower loads.
But if you are building a system where the reg is not local to the rails, definitely monitor fuel pressure at the rails.
9 Second Club
Joined: Nov 2003
Posts: 13,616
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From: Norn Iron
Pump current and wiring is another important matter as others have stated.
Current clamps are dirt cheap these days and readily available for both AC and DC. My 450's pull around 15A each at idle pressure, 45psi or so. So ensure all wiring and connectors are rated well above that given it is a continuous load. And this will rise with pressure, so factor in around 20A 100% duty rating.
In otherwords...build wiring for 30A or so.
Current clamps are dirt cheap these days and readily available for both AC and DC. My 450's pull around 15A each at idle pressure, 45psi or so. So ensure all wiring and connectors are rated well above that given it is a continuous load. And this will rise with pressure, so factor in around 20A 100% duty rating.
In otherwords...build wiring for 30A or so.