hey everyone i have a ? about my fpr

[TalonESIT]

hey everyone,

i do A LOT of reading on this site and never post and you guys seem to answer my questions. thanks a lot for that. but i've never been able to get my fuel pressure reg. ? answered:

i am running a 420a with hahn turbo, fmic, injectors, 255fp, yeah you know the routine...
the engine just got out of the machine shop(h-beam rods, je pistons...) i have an obx FPR and i dont know too much on how to tune it what is the proper psi reading i should have on the gauge cause i dont know if im running too rich or too lean. stock fuel rail with like 245cc injectors. i currently have it reading about 52psi... i called hahn and they said that their regulator runs at like 80psi... that seems a little high to me

im only running at 5-6 psi or boost on the turbo cause i wanna wait until i break in the new engine...

just like a said im not new to the forum i just dont post, but can someone please help me out... the motor that was just in the shop was brand new from rpm motors. it was a stock block 420a motor everyone said that the hahn stage 1 kit would run fine on a stock block and i had all the parts to install with it (fuel pump, fpr...) well my engine crankwalked on me...HAHA isn't that sad so i had to get a whole new crank as well as the pistons and everything... my uncle and i are trying to trouble shoot the problem because there were metal shavings all in the oil pan and...man it was a wreck... i know everything else was setup alight on my car that why im wondering what my fpr should be set at...

i was so sure our engines could never crankwalk ... ill explain in detail to who ever wants to know... but can someone help me out please

 

[TalonESIT]

sorry if this is in the wrong section this is my first post...haha

 

[TalonESIT]

anyone please help out?!

 

[DSM-ZERO]

what exactly is your Q???

 

[TalonESIT]

how many psi's should my obx fpr at least be set at for idle so that that im not running too lean

 

[Sean485]

You need a rising rate fpr and I dont think the obx is, at idle the fuel pressure should be the same as when you were NT assuming your on stock injectors since when your idleing/cruising your flowing about the same amount of air as when you were NT. When you get under boost though you need to raise fuel pressure at a certain exponential rate (depends on injector size, boost pressure, etc) to force more fuel through the injectors since you are forcing more air into the engine without the ecu knowing about it.

 

[TalonESIT]

the obx Fpr claims to be an adjustable one unlike the b&m one though... doesn't that mean that it will allow the fuel pressure to rise? or better yet what is a good rising fpr?

 

[siueclipse]

Vortech SFMU

 

[XMasta19]

the s-fmu is awesome, if you're lookin to spend that much money, then go for it. it does pretty much everything you want. you could also go with a regular not as expensive fmu, if you're looking to keep your stock fpr in place for the base idle pressure. the s-fmu takes its place instead and does its job plus more

 

[TalonESIT]

im lookin at the vortech fmu and most come with the 12:1 calibration disc already... i know that i can just change the disc but isn't 12:1 a lot for my car since im only boosting 5-6psi right now with only like 245cc injectors?

 

[unpainted]

Check this link out if you havent already.

http://www.2gnt.com/www/corbin/choosefpr.html

I found it over on 2gnt.com. Corbin has a few other pertinent write-ups that you may find useful. I had to do some figuring for a custom project I am working on myself. Also, a great book to buy is "Four-Stroke Performance Tuning" by A. Graham Bell. That should get you well on your way.