what size fuel pump?

The AntiRice

New Member
Apr 19, 2007
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if i install a 255lph fuel pump on an almost stock setup to accomidate for later upgrades will it hurt anything? i also wanted to do a fuel pressure regulator and was wondering what i all need to install one. should i uprgrade to fuel rails to make things easier? basically just looking for info on upgrading the entire fuel system but dont wanna screw myself by going too big.
 
255 lph pump will work fine.
No need to upgrade fuel rails.
No need for the AFPR, adjustments made to the fuel pressure get eventually "canceled" by the EEC adaptive strategy in the long run and the short term fuel trim function as it "learns".
 
As long as your fuel pressure regulator works correctly there is no need to get an adjustable one with a stock engine. You should have no problem running a larger fuel pump since you will just return the extra fuel back to the tank. No need to upgrade to different fuel rails unless you are planning on pushing out some seriously sick horsepower.
 
255 lph pump will work fine.
No need to upgrade fuel rails.
No need for the AFPR, adjustments made to the fuel pressure get eventually "canceled" by the EEC adaptive strategy in the long run and the short term fuel trim function as it "learns".

the EEC only uses adaptive strategy in closed loop.... which is warm idle and cruise/part throttle accel.the adaptive strategy can only compensate 12%. so a HUGE change in FP could cause the engine to run richer/leaner enough to where the EEC cant correct it.

also at WOT, you use open loop, no adaptive strategy there. so if you increase FP, at WOT you WILL be dumping more fuel into the engine that you would be with stock pressure at WOT only. you could also run into richer conditions upon a cold start seeing how te EEC runs in open loop until the ACT and ECT are up and before it goes into CL


so an adjustable FPR will give you some ability to adjust fuel at WOT where the EEC doesnt use adaptive strategy.
 
the EEC only uses adaptive strategy in closed loop.... which is warm idle and cruise/part throttle accel.the adaptive strategy can only compensate 12%. so a HUGE change in FP could cause the engine to run richer/leaner enough to where the EEC cant correct it.

also at WOT, you use open loop, no adaptive strategy there. so if you increase FP, at WOT you WILL be dumping more fuel into the engine that you would be with stock pressure at WOT only. you could also run into richer conditions upon a cold start seeing how te EEC runs in open loop until the ACT and ECT are up and before it goes into CL


so an adjustable FPR will give you some ability to adjust fuel at WOT where the EEC doesnt use adaptive strategy.

The adaptive strategy correction IS used in open loop, it IS NOT updated in open loop. The corrections done, or learned through the adaptive strategy do apply to open loop mode as well. The system does not use a single, unmodified by adaptive strategy, A/F or Spark advance tables....... open loop tables are modified, tweaked-in, based on the adaptive "offset corrections" (to give it a name) learned and stored in the KAM hence, any alterations made through an AFPR will eventually be canceled in the long run..... - OR - as explained in the GUFB strategy.

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