Upsized The Crossfire Fuel Injectors With Good Results

Discussion in 'Engine: Repairs and Modifications & generally corv' started by Crossfire Mike, Sep 1, 2021.

  1. Crossfire Mike

    Crossfire Mike Active Member

    I went from the stock size of I believe one at 65 lbs per hr and the other at 68 lbs per hr to 80 lbs per hr for both. I did not change my fuel pressure and left it at 16psi. As I understand it every two PSI increase flows about 1 lb per hr more so I was pushing a bit more fuel than the stock flow rates with my PSI setting. The main reason for doing so was it was going lean in the upper RPM @WOT. The car reacted very well and according to my A/f ratio gauge has good/normal A/F's at idle and part throttle and swings 12.0-12.8 @WOT. I did upgrade to a heated 3 wire O2 sensor which helps I believe. I can feel the difference pulls much harder at WOT and feels better everywhere else actually. The old injectors were basically new as I replaced them not too long ago and run a 85 TPI pump. I'd say if your chasing a fueling issue rather than messing around with fuel pressure too much and cranking it up, up size the injectors and run a closer to stock fuel pressure this seems like it would be easier on the fuel pressure regulator and gives more upside fueling potential.
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  2. B&R Racing

    B&R Racing reliable source of info

    Larger injectors do work better than bumping up Fuel pressure.
    If you can tune the Crossfire ECM Should have even better results.
    Crossfire Mike likes this.
  3. B&R Racing

    B&R Racing reliable source of info

    The tailpipes looking at the the amount of soot and carbon.
    Pump gas when dialed in no catalytic converters used you will see a light brown grey coating.
    Wipe it with your finger it should be dry not much residue comes off.
    Catalytic converters used it's often Ghost clean the tailpipes when the EFI and ignition dialed in.
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  4. B&R Racing

    B&R Racing reliable source of info

    Spark plugs when checked dialed in they are often bone White clean on pump gas 93 octane.
    Sometimes a tinge of Yellow on porcelain.

    Pump gas 87 often burns dirty.
    See lots of black carbon in the tailpipes but spark plugs stay clean as 93 octane checks dialed in.
    Crossfire Mike likes this.
  5. Grumpy

    Grumpy The Grumpy Grease Monkey mechanical engineer. Staff Member

    yes your correct, bumping up the injector size almost always results in a more effective change than boosting the fuel pressure on the crossfire vettes,
    Im rather surprised that Ive yet to see larger flow rate throttle bodies advertised for the cross fire vettes, yeah, we all know they are available, but Id have expected a (KIT) upgrade and some vendor bragging about a 30hp boost available.
    I know Ive installed quite a few crane Cam #114132 with my 1.6 ration RR's , that boosts effective specs too, .469/.484 lift 210/216 Duration.
    and that always results in a very noticeable boost in seat of the pants acceleration results
    matched to a renegade intake and throw the trash OEM heads in the trash,
    replace them with the 180cc AFR HEADS
    and you get VERY impressive results
    especially if you install hooker full length headers and a full three inch exhaust with an X pipe and low restriction mufflers.
    BTW adding a baffled 7 quart, road race style oil pan is a very effective way to increase durability
    Last edited: Sep 2, 2021
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