External Fuel Pump with stock FPR

[TSiRocker]

hi,

I am running stock 450cc injectors and stock FPR.

What will be the problem if I upgrade my internal fuel pump to a high flow external fuel pump?

Will my car run rich when idle?
What will happen to the stock FPR?

 

[TSiRocker]

Im just curious, is this such a hard to answer question for all DSM experts?

I hope not.

 

[TURFNNSURF]

Your car will run PIG rich with the stock FPR. You will have idle issues and the stock FPR will be overrun. External fuel pumps are normally found on cars making more than 450whp, since you are on stock 450 injectors and FPR, IMHO an external fuel pump is overkill. You'll do just fine with a walbro 190lph to replace your stock fuel pump in the tank. Then you won't overrun the stock FPR and you can raise the boost to about 15 to 17psi and the new fuel pump will be able to keep up with demand.

 

[TSiRocker]

Ah, thanks for the reply TURFNNSURF.

That explains why my exhaust tips is full of blackish carbon and I smell strong unburned fuel when idling.

Can I resolve this matter with the little help from S-AFC II by tuning the fuel down for idling and low rpm cruising?

 

[TURFNNSURF]

Not really, the best fix is to get an adjustable FPR like the Aeromotive or SX FPR. Maybe a little fuel can be tuned out with an SAFC but the problem is that no matter what, when the injector opens to squirt fuel, it will squirt more than required because the fuel pressure from the pump is so high. Thus your rich condition and the blak soot like stuff on the exhaust tip and bumper.

 

[TSiRocker]

Thanks. Will take your advise to install an AFPR.
I will see what my budget can hold.