Author Topic: Who Runs A Boost Referenced Fuel Pressure Regulator?  (Read 7482 times)

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Offline Skip Pipes

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Who Runs A Boost Referenced Fuel Pressure Regulator?
« on: March 17, 2012, 02:40:15 PM »
I'd like to get more info on what being run.

This is what I envision as a system to feed my Toyota 2jzgte turbo 3.0L in my F/BFR

2 high capacity 60-micron fuel filter (recommendations?) on inlet side of each pump feed.
2 Bosch 044 pumps, each with its own dedicated -8 inlet feed.
Both pumps will have -8 out merging into an -8 Y manifold to a single -10 out.
Fuel Filter (recommendations) 
-10 to fuel rail, which has 0.800” ID.
Boost referenced fuel pressure regulator at opposite end of fuel rail from inlet, with -8 return to tank.

Thanks
Skip Pipes
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Offline SPARKY

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Re: Who Runs A Boost Referenced Fuel Pressure Regulator?
« Reply #1 on: March 17, 2012, 03:34:38 PM »
I have been told to move the fuel pressure regulator as far away from the fuel rails and as close to the fuel tank as possible---that has changed in the last few years as folks learned more about fuel rail hormonics.

I know a very successful turbo guy that runs a pump from each end of the fuel rail and takes the bypass or fuel return out of the middle of the rail between the ends---all to help mitigate pressure waves nodes.



« Last Edit: March 18, 2012, 10:28:30 AM by SPARKY »
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Offline Rex Schimmer

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Re: Who Runs A Boost Referenced Fuel Pressure Regulator?
« Reply #2 on: March 17, 2012, 03:51:13 PM »
Skip,
Sounds like a pretty good plan. If you happen to have the pump inlet filters below the fuel level I would suggest a ball valve before each filter so that you can change/inspect/cleasn the filters without draining the tank. Make sure the 60 micron inlet filters are at least -10 inlet/outlet and big, pumps don't like to suck. On the outlet side of the fuel pumps use at least a 10 micron filter, again as big as you can fit into the space, do not use the little filters that use a small disc of stainless wire, not big enough. I have had good luck with the Aeromotive fuel filters, I use a 100 micron, stainless screen filter for the pump inlet and their 10 micro fiber filter after the fuel pump. The larger the filter the slower the fluid flows through it and the better it works.

Rex
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Offline Rex Schimmer

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Re: Who Runs A Boost Referenced Fuel Pressure Regulator?
« Reply #3 on: March 17, 2012, 04:04:44 PM »
If fuel like harmonics prove to be a problem, and you can only check that with a high response pressure transducer and appropriate electronics , a gage is to slow, another way you can add some capacitance to the system is to have a tee at the inlet to the pressure regulator (from the fuel rail) and then add several feet of hose, with a plugged end, at the tee, this will attenuate the the pulsations of the fuel system. This is something that most of us really don't consider but I would think that a turbo motor with big injectors, high boost and high fuel pressure could easily have some harmonics challenges which could certainly have an affect on fuel mixture that could be detrimental to performance and engine life.

Rex
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Offline johnneilson

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Re: Who Runs A Boost Referenced Fuel Pressure Regulator?
« Reply #4 on: March 17, 2012, 11:53:41 PM »
Skip,

not knowing what system you are looking into, I question the need for fuel pressure boost gain.
It is my understanding that if EFI and boosted, the ECU should control fuel delivery by monitoring the boost.
Spark lead and fuel changes as boost changes. If the fuel pressure is not constant the ecu will likely not follow mixture.

Like I said, not sure what system you are looking at.

John
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Offline hotrod

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Re: Who Runs A Boost Referenced Fuel Pressure Regulator?
« Reply #5 on: March 18, 2012, 06:23:59 AM »
I run the peterson fluids stainless screen fuel filter on my system with the 45 micron screen.

http://www.petersonfluidsys.com/filter_600.html

They also have the Y manifolds  you probably are looking for:

http://www.petersonfluidsys.com/plumb_yman.html

Larry

Offline RansomT

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Re: Who Runs A Boost Referenced Fuel Pressure Regulator?
« Reply #6 on: March 18, 2012, 10:36:54 AM »
I'd like to get more info on what being run.

This is what I envision as a system to feed my Toyota 2jzgte turbo 3.0L in my F/BFR

2 high capacity 60-micron fuel filter (recommendations?) on inlet side of each pump feed.
2 Bosch 044 pumps, each with its own dedicated -8 inlet feed.
Both pumps will have -8 out merging into an -8 Y manifold to a single -10 out.
Fuel Filter (recommendations)  
-10 to fuel rail, which has 0.800” ID.
Boost referenced fuel pressure regulator at opposite end of fuel rail from inlet, with -8 return to tank.

Thanks
Skip Pipes


I run a boost reference regulator on my Taurus SHO that is forced (T-Trim).  All Mallory pieces.  Starting at the tank, -10 feed line running to a micron filter into a Large Mallory gear rotor pump (pump is a "wee bit" lower than the tank and is within a foot of the tank), the a ten foot section of -10 to the regulator to the engine bay.
The -10 feeds the fuel filter and then almost directly into the Mallory regulator where I branch the feed to the two engine banks with a -6 AN (those are deadheaded but with a balance tube).  The return is a -8 AN back to tank from the regulator.  I reference boost from the intake of course post throttle body. According to my data from the EEC, the crank is seeing about 600 HP.

Only issues I have seen after many years is that where I branched off to feed the to engine banks with a deadhead, it has a tendency to vapor lock after setting 10 minutes or so with a non running warm engine.  Takes about 15 minutes to cool off and start.  And the fact that the SHO is too fast for my safety equipment. :)
« Last Edit: March 18, 2012, 01:24:16 PM by RansomT »

Offline dw230

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Re: Who Runs A Boost Referenced Fuel Pressure Regulator?
« Reply #7 on: March 18, 2012, 12:42:54 PM »
Thank you for a re-post of previous two posts.

DW
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Offline Rex Schimmer

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Re: Who Runs A Boost Referenced Fuel Pressure Regulator?
« Reply #8 on: March 18, 2012, 03:04:24 PM »
This quote from RansomeT's post: "Only issues I have seen after many years is that where I branched off to feed the to engine banks with a deadhead, it has a tendency to vapor lock after setting 10 minutes or so with a non running warm engine.  Takes about 15 minutes to cool off and start.  And the fact that the SHO is too fast for my safety equipment. " is exactly why you should always mount the fuel regulation valve down stream of the fuel rails. The fuel regulation valve maintains the set fuel pressure by bleeding off excess fuel so that the set pressure is maintained and the fuel that is bleed off is returned to the tank. By mounting this "relief valve" down stream of the fuel rails, i.e. between the fuel rails and the fuel tank, the fuel that is bleed off insures a constant flow of the fuel, at the set pressure, thorough the fuel rails. Most of these valves are of a three port design which makes it appear that you should run the fuel line from the pump into the through port and then connect the return port to the tank line. This method fits with the mounting of the regulator before the fuel rails but when you do this you have fuel dead headed at the ends of the fuel rail, and on start up after a long time of non operation you will have entrapped air at the very end of the fuel rails which takes time to be dissolved into the fuel and you will have problems with heat as the fuel that is dead headed at the end of the fuel rails can pick up heat and boil as described by RansomeT. If you uses the fuel pressure regulator at out let of the fuel rails then you need to plug one of the through ports and then only run the return line back to the tank.

Regarding referencing the fuel regulator valve to the boost pressure it can depend upon your ECU, some of the very latest designs do monitor the manifold pressure with a transducer and then regulate fuel pressure based upon this, but to have this type of system you need to have a fuel pump that can vary its speed, output, to control fuel pressure, this is not the system you are describing. The standard electronic injector is a rapidly opening and closing valve that is designed to pass a certain amount of fuel based upon the differential pressure between the fuel pressure and the manifold pressure. The amount of fuel is regulated by the amount of time that the injector is held open and, of course the differential pressure that it is subjected to. Therefore you need to reference the fuel pressure regulator to the intake manifold pressure which will compensate for the intake manifold pressure being more or less than atmospheric pressure. All good regulators will have typically a 1/8 NPT connection in the diaphragm chamber which is the port to connect the manifold pressure to. This line should not be larger than 1/4 inch max. I am not aware of any after market ECUs that will monitor manifold pressure and fuel pressure and then modify the  injector timing pulse to maintain the required fuel flow based upon a varying differential pressure but I am sure it could be and might be done.

Rex
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Offline Skip Pipes

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Re: Who Runs A Boost Referenced Fuel Pressure Regulator?
« Reply #9 on: March 18, 2012, 08:19:33 PM »
Thanks everyone for sharing your experiences and recommendations.
 
The Supra engine is a straight six, so the fuel rail in about 18” long. And, it had a fuel pressure regulator port in the center of the rail. Therefore, I like Sparky’s comment on feeding both ends of the rail.

I also like Rex & Sparky’s suggestion to move the FPR away from the fuel rail. Additionally, this will be a moderate boost, but very high volume injector (2150cc) set up.

Thanks John for the feedback concerning boost referencing, however I feel I need the added safety of a boost referenced FPR.  Anyway, the proof will be in when it runs. If it’s too rich/too much fuel, I’ll pull the vacuum to the FPR.

Hotrod, yes, those will work perfectly. Thank you.

And RansomT, thanks for sharing your real world set up. There are a number of ways to achieve the goal and I appreciate you sharing your experience. Can you rear drive that engine? Have any pics?

Thanks again,
Skip Pipes
Skip's Garage
Builder of the SUNBEAM ALPINE Police Interceptor

Offline RansomT

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Re: Who Runs A Boost Referenced Fuel Pressure Regulator?
« Reply #10 on: March 19, 2012, 09:55:07 AM »
Rex, I agree.   However, just to bring up a point for discussion ....

When I started designing my fuel system, I was dealing with uncharted territory for a forced inducted Taurus SHO running ~20+ psi of boost.  So everything I was doing was an experiment.   I mocked up 2 designs, one of which is what I am using, the other was a pass through system with the regulator downstream of the fuel rails as you noted.  My concern for the pass through system was with fuel rail harmonics and I was limited on the size of the cross over tube; I was afraid of over pressurizing one bank while starving the other.  I went with the deadhead hybrid design with the intention that if it was problematic I would switch to the pass through design.  I learned to deal with the vapor lock situation without much to do and left it that way.

Now the point: There are a lot of OEM designed dead head fuel systems on the road today with the regulator upstream of the fuel rail(s).  Most notable for me is the Hayabusa. This is probably the single biggest reason that I tried my hybrid design first.  With that said, then how do OEMs get around the issue of the air getting trapped causing vapor lock using a deadheaded fuel system?

and as side note:  A year later when I started racing motorcycles, I designed my fuel systems exactly as you stated, got rid of the OEM deadhead stuff, went pass through with the regulator downstream of the fuel rails.

Skip:  Yes you can rear drive that motor using a T-5 and some creative engineering.  I do believe a couple of folks have raced the engine in that configuration at Bonneville.   The 3.0L SHO motor is strong and the heads flow extremely well.  With the exception of pistons, offset ground cams, and stronger valve springs, my motor is stock.  I raced a production SHO a few years back and was turning upwards of 9K.  My supercharged SHO I keep under 8300 RPM.