23lbs and 21lbs, how much of a difference does that make?

Searching revealed that the stock fuel pressure/lbs is 49/23 for a 97' 4.0l, I've acquired some xf2e-c4b which from I've searched is 49/21, how much of a difference is that 2lbs actually going to make? I don't want guesses or "you won't hardly feel it" I would greatly appreciate actual answers and facts about this, will my motor lag, run rough, Use more/less gas to compensate, lower/higher mpg, Or will the PCM fix it and adjust it perfectly?

Demonoid369 said:

Searching revealed that the stock fuel pressure/lbs is 49/23 for a 97' 4.0l, I've acquired some xf2e-c4b which from I've searched is 49/21, how much of a difference is that 2lbs actually going to make? I don't want guesses or "you won't hardly feel it" I would greatly appreciate actual answers and facts about this, will my motor lag, run rough, Use more/less gas to compensate, lower/higher mpg, Or will the PCM fix it and adjust it perfectly?

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Especially on a Renix, the ECU has a limited range it can compensate for on injectors. You shouldn't need anything other than the stock flow rate unless you have done other modifications such as boring, stroking, true headers, etc. Just adding more gas normally will only help you in those situations or at wide open throttle. It can negatively impact your mileage.

An upgraded design injector (multiple holes and better pattern) can help power and efficiency for the same flow rate. Go too big and you are hurting.

I live at high altitude and run a stroked Renix with headers, 2.5" exhaust and performance cam. I went up to a 21lb injector set and it was too much. It ran too rich and flunked emissions. You would think that the ECU should be able to compensate that much, but it didn't. I built a MAP adjuster and dialed back the mixture and all if fine.

The best way to tell in your circumstance is to install the injectors, run some BG44K through them to make sure they are clean and flowing well, then take it to a mechanic and have them do a tailpipe sniff and tell you what your air fuel ratios are doing.

Ya I a 2.5 exhaust and a k&n cold air intake right now, I do have a throttle body that's been bored to 60mm and have a newer air intake(curvy not log style) I have a 97' Cherokee which is why I got them and with the mods I have and the mods I will do(throttle body, newer intake) am I actually going to notice these injectors? Or are all these mods going to actually hurt these injectors? Most of all I'd like to here from talyn since he's the one that's recommends these on almost all of injector threads here,

The mods you have don't necessitate larger injectors.

Personally I think the whole injector swap is over rated. The injector is firing into the back of a closed hot intake valve, so it already atomizes pretty well. The PCM maintains a 14.7:1 AFR in closed loop, which is most of the time. And when in WOT it already runs rich even with mods, so larger injectors are a bad idea. If the stock injectors are old and clogged, only then I would replace them.

well thats what i'm trying to figure out, these arent lager injectors, they actually flow less than the stock injectors but... you have recommended these a lot on a bunch of other threads so i'm trying to find out if all the mods i do and have done already will make up or hurt the injectors i have gotten(xf2e-c4b)

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Ditto

Delete lol sorry, tapatalk was being retarded

Come on talyn! Lol need some answers since your the one who recommended these fuel injectors, they flow 2lbs less than stock fuel injectors but have 4 holes. I have a k&n air intake and 2.5 exhaust. These aren't bigger injectors, so are these going to hurt performance do nothing and stay the same or improve performance. Ya can't really just throw out injectors recommendations without at least telling us lol

Bad idea using those injectors if you run E10 and even worse if you're ever forced to run E15. For reference 14.7 is stoich for straight gas, E10 is 14.12 and E15 is 13.79

What can happen with e10? Is that what normal gas comes with?

According to wiki Oregon is one of the 10 lucky states with mandatory E10.

http://en.m.wikipedia.org/wiki/E10_fuel

The combination of E10 and an injector with less flow will cause lean mixture when in open loop. Possibly you could get lean misfires, higher NOX, or possibly burning a valve if its severely lean. The EPA is pushing for E15 which is required to carry a warning to be used in 2001 or newer cars. this should give you an idea how close we are to the limit running E10 with properly sized injectors.

Well talyn should never had recommended these lol oh well, lesson learned lol

The stock fuel map is set to run rich in open loop, even with mods. I don't believe these injectors will be a problem. The CPM tried to maintain a 14.7:1 afr, which is leaner than stoich for E10, E15. You can throw in a larger than stock injector and it will try to do the same thing.

Demonoid369 said:

Well talyn should never had recommended these lol oh well, lesson learned lol

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How about you get a wideband, data logger, several sets of injectors, a piggy back, do the testing, and come with your own recommendations. Or how about I drag all that crap out of my XJ, fly out to where ever in BFE you are, install the injectors, my gear, and do the testing for you. Would that suit you? :rattle:

But you haven't shown any data for the xfe2-c4b, all you've wrote on many many threads is that they run 21 lbs on 49 pressure. I've managed to get them and you haven't told me if they will actually work and do good or not. You keep saying larger injectors and I'm trying to figure out why you keep saying that when these injectors flow less than a stock injector?!?!? What I'm trying to say I'd if your going to but out recommendations, please go to some depth about them and how they will react to a stock to mildly modified jeep engine instead of just saying "hey these could work"