racinskittle

I've been hearing that you need a FPR if you were to upgrade injectors and pump.

Is this true?

danl

You need a bigger FPR when your stock one gets over run by a big pump when the clickers aren't opening very much at idle (injectors). A stock FPR is good with a 190lph walbro pump, but usually causes a little bit of overrun with a 255hp.

racinskittle

Alright thanks a lot. I appreciate the response. I will have 450's and a 255lb and just heard that a new FPR is necessary.

So i just purchased one and then started having the withdrawls "did I really need this, maybe the stock will work fine"

Thanks.

T-sohctec

I did not need a FPR and you shouldn't either. I'm running 450's & a walboro pump. that's it. Stock FP.

DA-MAX

how many psi over stock does the Walbro 255 raise FP?

scttydb411

stock pump and stock fpr...and i'm still running on the rich end...10.5-11.0 a/f ratio.

racinskittle

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by scttydb411 &raquo;</TD></TR><TR><TD CLASS="quote">stock pump and stock fpr...and i'm still running on the rich end...10.5-11.0 a/f ratio.</TD></TR></TABLE>

what's ur boost at. I was gonna boost up to 10 psi. I'm installing a Walbro though so that's why I was wondering.

scttydb411

running 9psi right now, but i want to get it on a dyno to see what hp i'm making before going to 10 or 11. i've still got stock bottom end d-series.

T-sohctec

are you guys running stock injectors?

scttydb411

450cc dsm injectors. i was going to install the walbro 255 fuel pump, but after wideband tuning i don't see the need. i'm still running on the rich end even at 9psi.

fsp31

My stock FPR is working fine with the Walbro 255 lph high pressure, and dsm 450's.

drastik

so many setups - so many options.
whatever works for you and makes you feel safe pinning it I guess.

psileepR

stock fuel pump, stock fpr, dsm 440's and 8psi boost daily no probs

boosted hybrid

I have personally seen and used the stock FPR work on 500whp set-ups. If you keep your fuel pressure at stock and run large injectors there isnt a need for an aftermarket unit.

BTW, the fuel pressure doesnt increase with an aftermarket fuel pump such as the Walboro. The purpose of the stock fuel pressure regulator is to regulate the fuel pressure to its intended pressure. If you understand how a FPR works, you'll understand that its virtually impossible to raise the fuel pressure by only having a higher flowing fuel pump.

danl

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by boosted hybrid &raquo;</TD></TR><TR><TD CLASS="quote">If you understand how a FPR works, you'll understand that its virtually impossible to raise the fuel pressure by only having a higher flowing fuel pump.</TD></TR></TABLE>

Its EXTREMLY easy to raise the base fuel pressure on a stock DSM with a walbro 255 HP. It is just as easy to do it on a honda. WHen you outflow the return orifice in teh regulator, it can not drop the pressure to the desired level and theirfore pressure backs up in the fuel rail.