Fuel pump
 

At what point do you really NEED a larger fuel pump. I get the feeling that a big pump is the way to go since I have never read on here that someone shouldn't get one, unlike the injector issue where many people say 24#ers are overkill on a mildly modified engine. Can someone give me some symptoms of too small of a pump....hesitation etc. Thanks

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87 GT, BBK shorty's, offroad H-pipe, ASP pullies, 70mm T.B., Cobra intake, no smog pump, Windsor Jr irons, Comp cams 1.6 rollers, F303 cam, H.D. export W.P., Tri-Ax, FMS subframes, Battle boxes, SSM liftbars, FMS King Cobra clutch, mass-air conversion, 73mm C&L, 24lb injectors, BBK fuel pressure regulator, 3/8" no EGR spacer, and other piddly sh*t.

IMO the stock pump isn't enough for a stock engine. Usually a 110 lph is the best step for a stock engine instead of 88 lph. Once you have heads/cam/intake, you should move upto a 155, 190 or 255 lph pump. After that, well then it gets complicated.

From your sig, I'd say you should get a 190 or 255 for your combo, assuming you have a stock pump in there it will cause your car to feel sluggish, and hesitate slightly, any possibly even have starting problems.

Thanks 86GT. Yeah, I do have the stock pump in there, I am still sitting on the 190 I've had for a few months now. I plan to put it in Thursday. It does hesitate at low RPM, but feels good at WOT now.

A 190 will do you just fine well into mild-moderate S/C.

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'90 LX 5.0; 12K original miles (no sh*&); 3.55 gears; pulleys;Edelbrock Performer Heads; BBK shorties; MSD 6AL box w/ blaster 2 coil; Motorsport E303 cam; Pro-M 75mm MAF; BBK 70mm TB; Eibach spring kit; Southside welded subs; K&N cone filter charger; Hurst shifter; fiberglass turbo hood; A/C-less; rear seat-less; cat-less; 2 chamber Flos; Corbeau racing seats (fronts);
30# injectors; 190 lb fp; FPR; TFS track heat Intake - 12.513 @ 112 mph (Pre-inj/fuelpump/FPR/intake)

Could I replace the stock pump now (engine is still stock...but not for long) without changine the injectors?

Or is it better to do both at the same time? Don't the injectors kick back the extra fuel the pump will be trying to send through? I believe that's bad for the pump if I'm not mistaken.

From my understanding of the fuel system, any fuel not used by the injectors is just passed through the return line into the tank again. Putting on a good adjustable fuel pressure regulator will help fine tune the car whether you upgraded the injectors or not.