Okay so I know the basics of how a fuel pump works. I also know that when boosting the BP, people will usually go with a higher rated fuel pump (Correct me if I'm wrong but the late 80's RX-7 fuel pump can be used as a higher LPH pump). Now my question is, if running a stock BP with anticipation to boost later on, would upgrading the pump do any harm? Is upgrading the fuel pump going to throw off the air/fuel mixture when running a stock setup?
I am just curious as to how that works. I am still running the factory fuel pump, and it's got 155,000 miles on it. I am thinking of replacing this pump soon, but would only want to replace it with one that I can use for my 10-12 PSI boost setup.
quick question on fuel pumps.
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Re: quick question on fuel pumps.
Do you know how a FPR works?
99% of the flow produced by the pump is sent back to the tank (at idle)
Your stock fuel pump will become an issue when it cannot maintain the pressure needed when the extra volume of fuel is being used by the bigger injectors/longer timing.
The stock pump maintains the PSI it needs at all RPMS, but as soon as you get bigger injectors and a more aggressive tune, it may not be able to maintain the PSI with the extra flow, so you need a high flow pump that can maintain the proper pressure.
99% of the flow produced by the pump is sent back to the tank (at idle)
Your stock fuel pump will become an issue when it cannot maintain the pressure needed when the extra volume of fuel is being used by the bigger injectors/longer timing.
The stock pump maintains the PSI it needs at all RPMS, but as soon as you get bigger injectors and a more aggressive tune, it may not be able to maintain the PSI with the extra flow, so you need a high flow pump that can maintain the proper pressure.
Now with Moderator power!
Black '93 BP RS - wrecked, parted, scrapped.
Green GS - Sold.
Black GS - Summer DD/Race car - Fancy KLZE
Red GS - K8-ATX -> MTX-KLDE - Frakencar. Scrapped
White GS - Rusty. Parts. Scrapped
1997 BMW M3 - my summer baby
2002 BMW 325Xi - sold
2003 Forester Xti - EJ20K swapped.
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Black '93 BP RS - wrecked, parted, scrapped.
Green GS - Sold.
Black GS - Summer DD/Race car - Fancy KLZE
Red GS - K8-ATX -> MTX-KLDE - Frakencar. Scrapped
White GS - Rusty. Parts. Scrapped
1997 BMW M3 - my summer baby
2002 BMW 325Xi - sold
2003 Forester Xti - EJ20K swapped.
Feedback
Re: quick question on fuel pumps.
I ran a Walbro 255 LPH on a stock setup for over a year with no problems before
I turbocharged.
You can purchase a nice FPR and get the fuel system out of the way now to make
doing things later easier / less expensive all at once. Do not cheap out on the FPR.
I turbocharged.
You can purchase a nice FPR and get the fuel system out of the way now to make
doing things later easier / less expensive all at once. Do not cheap out on the FPR.

1994 MX-3 RS
Worklog: viewtopic.php?f=46&t=62251
B6 goodies for sale:
viewtopic.php?f=2&t=66333
2nd BP engine: http://www.clubprotege.com/forum/showthread.php?t=46695
Re: quick question on fuel pumps.
Check out my post, might help. viewtopic.php?f=1&t=76200 The HP is good for aspirated and turbo'd.
2004 Subaru WRX Silver, stage 2, minty interior.
2002 Subaru WRX Blue, SOLD (best E test numbers I've ever seen)
94 MX-6. Sold
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96 GS 5 speed, KLZE, Sold
95 GS Minty Shape Sold
92 GS Sold
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7477th member.
I know you believe that you understand what you think I said but I'm sure you realize that what you heard is not what I meant.
2002 Subaru WRX Blue, SOLD (best E test numbers I've ever seen)
94 MX-6. Sold
92 GS KLZE 5 Speed
96 GS 5 speed, KLZE, Sold
95 GS Minty Shape Sold
92 GS Sold
92 GS Parts Car scrapped.
Feedback viewtopic.php?f=37&t=66348" onclick="window.open(this.href);return false;
7477th member.
I know you believe that you understand what you think I said but I'm sure you realize that what you heard is not what I meant.
- Ryan
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Re: quick question on fuel pumps.
QFTMi|<E wrote: You can purchase a nice FPR and get the fuel system out of the way now to make
doing things later easier / less expensive all at once. Do not cheap out on the FPR.
Don't want to lean out, or blow a line.
Now with Moderator power!
Black '93 BP RS - wrecked, parted, scrapped.
Green GS - Sold.
Black GS - Summer DD/Race car - Fancy KLZE
Red GS - K8-ATX -> MTX-KLDE - Frakencar. Scrapped
White GS - Rusty. Parts. Scrapped
1997 BMW M3 - my summer baby
2002 BMW 325Xi - sold
2003 Forester Xti - EJ20K swapped.
Feedback
Black '93 BP RS - wrecked, parted, scrapped.
Green GS - Sold.
Black GS - Summer DD/Race car - Fancy KLZE
Red GS - K8-ATX -> MTX-KLDE - Frakencar. Scrapped
White GS - Rusty. Parts. Scrapped
1997 BMW M3 - my summer baby
2002 BMW 325Xi - sold
2003 Forester Xti - EJ20K swapped.
Feedback
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- Regular Member
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Re: quick question on fuel pumps.
okay awesome information!!! That's what I figured!!! Thanks!