Fuel Pump Upgrade
Dec 26, 2003, 04:17 AM
#16
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Originally posted by shiv@vishnu
Typically, the term "rising rate regulator" describes a regulator that doesn't follow a 1:1 manifold to fuel rail pressure rise. That is, it will increase fuel pressure by say, 6psi, for each additional 1 psi of boost pressure. These regulators, sadly, are used often in applications where injectors are undersized such as in poorly designed aftermarket turbo kits. The factory regulator, like most factory regulators, simply maintains a constant pressure differential between fuel rail and manifold pressure (1:1).
Just my 2c,
shiv
Typically, the term "rising rate regulator" describes a regulator that doesn't follow a 1:1 manifold to fuel rail pressure rise. That is, it will increase fuel pressure by say, 6psi, for each additional 1 psi of boost pressure. These regulators, sadly, are used often in applications where injectors are undersized such as in poorly designed aftermarket turbo kits. The factory regulator, like most factory regulators, simply maintains a constant pressure differential between fuel rail and manifold pressure (1:1).
Just my 2c,
shiv
Chris
Dec 26, 2003, 10:01 AM
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Originally posted by Chris in HB
So based on this, Shiv, should I purchase an adjustable FPR? I had already considered the upgraded fuel pump and possibly larger injectors. Thanks for your assistance.
Chris
So based on this, Shiv, should I purchase an adjustable FPR? I had already considered the upgraded fuel pump and possibly larger injectors. Thanks for your assistance.
Chris
Dec 26, 2003, 10:55 AM
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Unless you have a fuel pressure gauge, you won't know if you are having fuel pressure problems at idle. On dsms the 255 flows too much and the stock fpr can't flow enough fuel away from the rail to lower the pressure. The problem is also in the small diameter and restrictive fuel return line. I was just curios if the evo's fpr and return line were better equiped to handle the increased load at idle.
Dec 26, 2003, 11:18 AM
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Originally posted by shiv@vishnu
Why would you want an adjustable FPR? Unless, of course, you wanted to do fuel tuning yourself on the dyno by adjusting the screw that preloads the FPR diaphram.
Why would you want an adjustable FPR? Unless, of course, you wanted to do fuel tuning yourself on the dyno by adjusting the screw that preloads the FPR diaphram.
Dec 26, 2003, 11:21 AM
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Originally posted by Chris in HB
I am asking this because in a previous post you made it sound as if the stock FPR wasn't up to the task. I am trying to make my car more reliable as well as more powerful - what do I need to do to upgrade the fuel system to support ~400whp max?
I am asking this because in a previous post you made it sound as if the stock FPR wasn't up to the task. I am trying to make my car more reliable as well as more powerful - what do I need to do to upgrade the fuel system to support ~400whp max?
Shiv
Dec 28, 2003, 04:27 PM
#24
Originally posted by ShapeGSX
So you get 42 to 45psi of fuel pressure in the fuel rail with the FPR boost line disconnected from the FPR? And 33psi at idle with the FPR boost line connected?
So you get 42 to 45psi of fuel pressure in the fuel rail with the FPR boost line disconnected from the FPR? And 33psi at idle with the FPR boost line connected?
Is this a question or a probe for a response to which you already have an answer? I respect your knowledge of the 4G63 and I am getting ready to install the Walbro 255 pump for a Stage1+ car per recommendations on this forum. It seemed as though it would be a no brainer until the FPR overun issue surfaced.
What has your experience been, what is your recommendation, and why?
Thanks,
Dec 28, 2003, 05:05 PM
#25
Originally posted by jfh
Josh,
Is this a question or a probe for a response to which you already have an answer? I respect your knowledge of the 4G63 and I am getting ready to install the Walbro 255 pump for a Stage1+ car per recommendations on this forum. It seemed as though it would be a no brainer until the FPR overun issue surfaced.
What has your experience been, what is your recommendation, and why?
Thanks,
Josh,
Is this a question or a probe for a response to which you already have an answer? I respect your knowledge of the 4G63 and I am getting ready to install the Walbro 255 pump for a Stage1+ car per recommendations on this forum. It seemed as though it would be a no brainer until the FPR overun issue surfaced.
What has your experience been, what is your recommendation, and why?
Thanks,
Dec 28, 2003, 05:47 PM
#26
Originally posted by jfh
Josh,
Is this a question or a probe for a response to which you already have an answer?
Josh,
Is this a question or a probe for a response to which you already have an answer?
On my DSM, the Walbro 255 overran the stock fuel pressure regulator, and I got fuel pressure creep in low load/low IDC situations. I had to install an aftermarket FPR.
I was just wondering if the measurement had been done. Some people only want to know if it is adequate. Some people want to know why.
If the measurements are the same as stock after the fuel pump upgrade, then the FPR is fine.
Dec 28, 2003, 05:50 PM
#27
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That is a very good point and I told a friend with a 1g DSM to do the 190 pump because the 255 from what I understand will over run it. I think Shiv said that it will be fine for the evo.
Originally posted by ShapeGSX
It was a question. The same question I ask anyone who has installed a larger fuel pump.
On my DSM, the Walbro 255 overran the stock fuel pressure regulator, and I got fuel pressure creep in low load/low IDC situations. I had to install an aftermarket FPR.
I was just wondering if the measurement had been done. Some people only want to know if it is adequate. Some people want to know why.
If the measurements are the same as stock after the fuel pump upgrade, then the FPR is fine.
It was a question. The same question I ask anyone who has installed a larger fuel pump.
On my DSM, the Walbro 255 overran the stock fuel pressure regulator, and I got fuel pressure creep in low load/low IDC situations. I had to install an aftermarket FPR.
I was just wondering if the measurement had been done. Some people only want to know if it is adequate. Some people want to know why.
If the measurements are the same as stock after the fuel pump upgrade, then the FPR is fine.
Dec 28, 2003, 05:57 PM
#28
Originally posted by ShapeGSX
I was just wondering if the measurement had been done. Some people only want to know if it is adequate. Some people want to know why.
If the measurements are the same as stock after the fuel pump upgrade, then the FPR is fine.
I was just wondering if the measurement had been done. Some people only want to know if it is adequate. Some people want to know why.
If the measurements are the same as stock after the fuel pump upgrade, then the FPR is fine.
Dec 28, 2003, 09:57 PM
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I had a fuel pressure gauge hooked up to my EVO a while back and noticed no such abberant fuel pressure irregularities after the pump upgrade. Same with the WRX. I suspect this is because modern cars have multi-speed pump systems that drive the pump slowly (lower voltage) at idle/low load and ramp them up to full spin (12v) only when needed under higher loads. I don't know if the DSMs had this. If they didn't, this could have been the cause of the "backing up" they saw with fuel pump upgrades.
My 2c,
shiv
My 2c,
shiv
Dec 29, 2003, 05:34 AM
#30
Thanks for reminding me about that, Shiv. I read that in the Evo tech manual a while back, but I wasn't sure if it would be enough. The Evo Tech manual doesn't specify the resistance that is used to lower the supply voltage. It is a pretty cool feature, though, since it means heating up the fuel less when there isn't any need for it.