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Torgus

Colonel
Nov 6, 2016
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ACF 6466 E92 + METH
just a thought wasn't there a issue with the PR top hat, where people were emptying one side of the tank, as it wouldn't move fuel over from the driver to the passenger side.


Yes, from my understanding while you are cruising it is not going to move fuel over to the passenger side of the tank. This is because it only moves fuel over when the PR FPR is actually bleeding fuel off. So at Idle or cruising it will not be bleeding off fuel. Once you 'step on it' it then starts sucking fuel over to the passenger side tank again as the FPR is doing it's job keeping a steady 72psi. At least this is my limited understanding. I am hoping my fuel gauge in the passenger tank will tell me when it is getting low...I also wonder if I can just set 1 pump with my BMP4 to always be 'bleeding off' fuel. Like set it so it is always making 76psi and the FPR is set at 72PSI for instance. I am not sure if BMP4 can do this, but if any fuel pump controller can this is likely the one. I have yet to play with their software. Given how little I drive the car I don't think I am too worried about wearing out the pump.

I kept the PR driver's side top hat for a couple of reasons:

1) It removes the inherent restriction in the fuel filter which they claim is good for 15% more fuel
2) It comes with a vacuum set FPR. I need a FPR for my injectors to inject 'correctly' as 30 psi of boost needs to be accounted for, for instance.
3) Easy to hook up to my new larger fuel line


IF any of it becomes a problem I will set the FPR in the driver's side hat to bypass mode and then install a FPR in the engine bay and run a return back to the passenger side bucket. At that point I would probably do a number of things differently in the fuel system...honestly at this point I would probably do things slightly differently but I have all the parts so I am going to install them and see what I end up with.

People make 700+ whp with much less fueling modifications. Many don't even run a return and dead head it. My hope is this set up works for my needs. If not, time to dump in more money.
 
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Torgus

Colonel
Nov 6, 2016
2,225
1,768
0
Boston
Ride
ACF 6466 E92 + METH
Someone could make a 'Shit N54 owners say' video VERY easily.

"Once you tune one, it's faster than an m3 in a straight line"
"You can run 10s on the stock turbos"
"Timing corrections are normal"
"It's just wastegate rattle, they all do this"
"My twin turbos make 850 whp"
 

RuskiRacer

Captain
Jul 17, 2019
1,110
675
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2009 e93 335i

Yes, from my understanding while you are cruising it is not going to move fuel over to the passenger side of the tank. This is because it only moves fuel over when the PR FPR is actually bleeding fuel off. So at Idle or cruising it will not be bleeding off fuel. Once you 'step on it' it then starts sucking fuel over to the passenger side tank again as the FPR is doing it's job keeping a steady 72psi. At least this is my limited understanding. I am hoping my fuel gauge in the passenger tank will tell me when it is getting low...I also wonder if I can just set 1 pump with my BMP4 to always be 'bleeding off' fuel. Like set it so it is always making 76psi and the FPR is set at 72PSI for instance. I am not sure if BMP4 can do this, but if any fuel pump controller can this is likely the one. I have yet to play with their software. Given how little I drive the car I don't think I am too worried about wearing out the pump.

I kept the PR driver's side top hat for a couple of reasons:

1) It removes the inherent restriction in the fuel filter which they claim is good for 15% more fuel
2) It comes with a vacuum set FPR. I need a FPR for my injectors to inject 'correctly' as 30 psi of boost needs to be accounted for, for instance.
3) Easy to hook up to my new larger fuel line


IF any of it becomes a problem I will set the FPR in the driver's side hat to bypass mode and then install a FPR in the engine bay and run a return back to the passenger side bucket. At that point I would probably do a number of things differently in the fuel system...honestly at this point I would probably do things slightly differently but I have all the parts so I am going to install them and see what I end up with.

People make 700+ whp with much less fueling modifications. Many don't even run a return and dead head it. My hope is this set up works for my needs. If not, time to dump in more money.
Highly doubt you'll have any issues. I'm running the stock regulator at 23 psi full e85 on my 6875 and the fuel pressure stays pretty consistent
 
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STE92

Corporal
Mar 3, 2017
199
66
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E92

Yes, from my understanding while you are cruising it is not going to move fuel over to the passenger side of the tank. This is because it only moves fuel over when the PR FPR is actually bleeding fuel off. So at Idle or cruising it will not be bleeding off fuel. Once you 'step on it' it then starts sucking fuel over to the passenger side tank again as the FPR is doing it's job keeping a steady 72psi. At least this is my limited understanding. I am hoping my fuel gauge in the passenger tank will tell me when it is getting low...I also wonder if I can just set 1 pump with my BMP4 to always be 'bleeding off' fuel. Like set it so it is always making 76psi and the FPR is set at 72PSI for instance. I am not sure if BMP4 can do this, but if any fuel pump controller can this is likely the one. I have yet to play with their software. Given how little I drive the car I don't think I am too worried about wearing out the pump.

I kept the PR driver's side top hat for a couple of reasons:

1) It removes the inherent restriction in the fuel filter which they claim is good for 15% more fuel
2) It comes with a vacuum set FPR. I need a FPR for my injectors to inject 'correctly' as 30 psi of boost needs to be accounted for, for instance.
3) Easy to hook up to my new larger fuel line


IF any of it becomes a problem I will set the FPR in the driver's side hat to bypass mode and then install a FPR in the engine bay and run a return back to the passenger side bucket. At that point I would probably do a number of things differently in the fuel system...honestly at this point I would probably do things slightly differently but I have all the parts so I am going to install them and see what I end up with.

People make 700+ whp with much less fueling modifications. Many don't even run a return and dead heaT

This is incorrect, the top fpr hat always circulates fuel back to the passenger side by designed of the fpr and the venturi it has to. As long as the pump is on, it will move fuel over.
 

Torgus

Colonel
Nov 6, 2016
2,225
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0
Boston
Ride
ACF 6466 E92 + METH
This is incorrect, the top fpr hat always circulates fuel back to the passenger side by designed of the fpr and the venturi it has to. As long as the pump is on, it will move fuel over.
Per PR product description:
"The factory venturi in the bucket consumes .2gpm that’s why there is an increase when it is ditched with a bucketless system. There is a 2nd venturi that you can’t ditch located on the fuel filter side. It pumps fuel from the driver’s side up over the driveshaft hump and to the passenger side so you can use your full tank of gas. This venturi happens to also consume .2gpm but since it can’t be removed we have to get the gas over somehow we decided to take the waste off the built in adjustable regulator and use it to drive the venturi."


I spoke with @nyt about this in detail and he explained PR got rid of the venturi which transfers fuel from driver to passenger side this creates the issue of moving fuel over the drive shaft hump at idle and cruise. Once you go WOT, the DME requests full fuel flow, 100% duty cycle. The pumps will kick on max and bleed off any of the excess fuel to keep the pressure there at 72psi. The regulator returns that fuel to passenger side bucket. My 'plan' is to run the BPM4 at high duty cycle with no vac hooked up to the FPR and set it that way. Then rehook up the vac to account for the boost I am running to allow the injectors to do their job. Hopefully this will make it always bleed off some fuel and move fuel from one side to the other. At least this is my initial plan.

The product is discontinued and wiped from PR website. The lack of venturi is why they stopped selling the part I have been told. I was told they are redesigning it to fix this issue but I doubt that will ever happen because the part was expensive and I bet very low volume for them. I'm pretty sure I bought their last one as it was removed from the website right after. It is a little annoying they don't disclose this 'issue'. The FPR is also not at the best spot(just like the stock FPR) as you could have pressure drops at the end of the system. This is inherent in any dead head fuel system set up.

Again, worse comes to worse I run an external FPR after the lp injectors and a return to the bucket and then just modify my stock driver's side hat. This would be a bit of a pain as it means I spend even more money on my LP fuel side, have to modify and add in components, etc.
 

STE92

Corporal
Mar 3, 2017
199
66
0
Ride
E92
Per PR product description:
"there is a 2nd venturi that you can’t ditch located on the fuel filter side. It pumps fuel from the driver’s side up over the driveshaft hump and to the passenger side so you can use your full tank of gas. This venturi happens to also consume .2gpm but since it can’t be removed we have to get the gas over somehow we decided to take the waste off the built in adjustable regulator and use it to drive the venturi."


I spoke with @nyt about this in detail and he explained PR get rid of the venturi which transfers fuel from driver to passenger side this creates the issue of moving fuel over the drive shaft hump at idle and cruise. Once you go WOT, the DME requests full fuel flow, 100% duty cycle. The pumps will kick on max and bleed off any of the excess fuel to keep the pressure there at 72psi. The regulator returns that fuel to passenger side bucket. My 'plan' is to run the BPM4 at high duty cycle with no vac hooked up to the FPR and set it that way. Then rehook up the vac to account for the boost I am running to allow the injectors to do their job. Hopefully this will make it always bleed off some fuel and move fuel from one side to the other. At least this is my initial plan.

The product is discontinued and wiped from PR website. The lack of venturi is why they stopped selling the part. I was told they are redesigning it to fix this issue but I doubt that will ever happen because the part was expensive and I bet very low volume for them. I'm pretty sure I bought their last one as it was removed from the website right after. It is a little annoying they don't disclose this 'issue'. The FPR is also not at the best spot(just like the stock FPR) as you could have pressure drops at the end of the system. This is inherent in any dead head fuel set up.

Again, worse comes to worse I run an external FPR after the lp injectors and a return to the bucket and then just modify my stock driver's side hat.
It does not get rid of the venturi used to pick up the fuel from the bottom on the driver side , per installation instructions from PR you keep that set up.... you have to. All it does it re routes to the internal tank return and not in the fee were kt causes a restriction. Now its a weak point as is plastic and and side of pressure it breaks
 

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Torgus

Colonel
Nov 6, 2016
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Boston
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ACF 6466 E92 + METH
It does not get rid of the venturi used to pick up the fuel from the bottom on the driver side , per installation instructions from PR you keep that set up.... you have to. All it does it re routes to the internal tank return and not in the fee were kt causes a restriction. Now its a weak point as is plastic and and side of pressure it breaks

Sounds like I should have RTFM.

Well, if it is not an issue great. I wonder why they discontinued it then from the website if it works as advertised...

Some more reading on the subject: https://www.spoolstreet.com/threads...sion-raceworks-in-tank-regulator-filter.7631/