Automotive Forums .com - the leading automotive community online! Automotive Forums .com - the leading automotive community online!
Automotive Forums .com - the leading automotive community online! 
-
Latest | 0 Rplys
Go Back   Automotive Forums .com Car Chat > Engineering/Technical
Engineering/Technical Ask technical questions about cars. Do you know how a car engine works?
Reply Show Printable Version Show Printable Version | Email this Page Email this Page | Subscription Subscribe to this Thread
 
Thread Tools Search this Thread
Old 09-13-2007, 07:57 AM   #1
MetalHeadZaid
AF Enthusiast
 
MetalHeadZaid's Avatar
 
Join Date: Apr 2006
Location: Auckland
Posts: 854
Thanks: 0
Thanked 0 Times in 0 Posts
FPR/pump questions.

a friend of mine is swaping a VR4 vg63 into his old hatch mirage, and wants to run a walbro 255 fuel pump. he tells me the pump will be getting 13.4 volts, and is confused about how high his fuel pressure will be. i told him that the FPR should sort out any issues with high fuel pressure because that is it's job

basically i'm wondering if he'll need an aftermarket adjustable FPR like a sard for this. he's gonna run a T04E so he'll be needing plenty of fuel.

under what circumstances does somebody need an aftermarket FPR? when the engine needs more fuel OR when the pump is giving more fuel???
__________________

S13
Silvia Q's - R.I.P.
R32 GTST Type M Sedan - Sold
R32 GTST Type M Coupe - Sold
S14 Silvia K's - daily
R32 GTS4 - BETTER BE READY!!!
MetalHeadZaid is offline   Reply With Quote
Old 09-13-2007, 08:12 AM   #2
Greenblurr93
Kind of a Big Deal
 
Greenblurr93's Avatar
 
Join Date: Jun 2004
Location: Mesa, Arizona
Posts: 3,898
Thanks: 12
Thanked 34 Times in 24 Posts
Send a message via AIM to Greenblurr93 Send a message via MSN to Greenblurr93
Re: FPR/pump questions.

when you get a highter pressure or highter flowing fuel pump an adjustable FPR is HIGHLY recommended
__________________
Greenblurr93 is offline   Reply With Quote
Old 09-13-2007, 06:19 PM   #3
UncleBob
AF -Advisor
 
Join Date: Feb 2006
Location: Seattle, Washington
Posts: 1,482
Thanks: 0
Thanked 0 Times in 0 Posts
Re: FPR/pump questions.

its purely a question of flow of the FPR. If the fuel pump has too much flow for the return line on the FPR, then the pressure will climb

if the feed line to the FPR is too restrictive, then the fuel pump will be limited by that, which will make it work harder for no added benefit

The question I'd be asking is, does it *need* more flow? a 255 is a popular pump for forced induction. If that is why he's installing it, he needs a boost-happy FPR anyway, but you'd want a higher flow FPR IMO
__________________
life begins at 10psi of boost

Three turbo'd motorcycles and counting.
UncleBob is offline   Reply With Quote
Old 09-13-2007, 07:36 PM   #4
Black Lotus
AF Regular
 
Black Lotus's Avatar
 
Join Date: Oct 2004
Location: Anywhere, Washington
Posts: 398
Thanks: 0
Thanked 36 Times in 33 Posts
Re: FPR/pump questions.

I put a Walbro 255 pump on my turbo car and had no problems with the GM FPR. The return line was 5/16 dia., I think. My only objection with the pump was that it was a bit noisy when cold. The upper pressure limit for the pump was about 105 PSI (the blocked line test). I only ran it at about 80 PSI, with a rising rate regulator, so there was plenty of flow volume.
As an aside, my OEM pump would run about 45 PSI at atmospheric, and about 55 PSI at 10 lbs boost. Since the pump wasn't capable of going over 60 PSI (the blocked line test again), a higher pressure pump was necessary.
Black Lotus is offline   Reply With Quote
Old 09-13-2007, 11:13 PM   #5
UncleBob
AF -Advisor
 
Join Date: Feb 2006
Location: Seattle, Washington
Posts: 1,482
Thanks: 0
Thanked 0 Times in 0 Posts
Re: FPR/pump questions.

just because a pump is capable of acheiving a dead head psi, doesn't mean it'll flow anything at that psi. Gotta be careful on that
__________________
life begins at 10psi of boost

Three turbo'd motorcycles and counting.
UncleBob is offline   Reply With Quote
 
Reply

POST REPLY TO THIS THREAD


Bookmarks
Go Back   Automotive Forums .com Car Chat > Engineering/Technical

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 02:08 AM.

Community Participation Guidelines | How to use your User Control Panel

Powered by: vBulletin | Copyright Jelsoft Enterprises Ltd.
 
 
no new posts