Do I need more Injector/Fuel pump

[ExDude]

 

[Notpretty]

Lots of feedback that...has me unsure what to do.

I crawl at 1200-1500 rpm 90% of the time but in snow or mud I will push the motor as far as I can...6000 +. Yes the cam limit of 5200 is a compromise between torque and a true high rpm motor...which mine is mostly not. But I have gearing in the transfer case (atlas 4.3:1) and diffs (5.13:1) and granny gear trans (6.69:1). Total crawl ratio over 150:1. This is where most of my torque comes from. So I sacrafice some motor low end with this cam but not all. Gain some high end but do not forget that most of the time I'm at 1200 rpm. It is truly a dual purpose motor. Trust me...when I dump the throttle it will be no less than as if doing a quarter mile....and snow slips allowing even higher rpm. I'll rev limit the motor for safety.

So based on fly wheel HP...my HP at ground given the drivetrain...trans/tranny/tcase and 40 inch tires would be extremely hard to predict...I'm still...I think...sitting at the 300 to 325 HP area. Simple question. Should I fear leaning out with 19# injectors if I set the rev limit at 6k?

Great info guys. Thanks. Very confusing though.

 

[Notpretty]

To further explain why 19's would be better that 24's or 30's is that you would not be maxing them out (overworking them) in your application. As said before, unless you have a dedicated race car that is constantly getting rev'd north of 5,500 rpm (with your kind of motor) it's not a problem. Considering the average 302 (in a mustang) with HCI makes max power around 5,000 rpm but gets rev'd to 6,000-6,500+ is one of the reasons for the %80 injector rules as that the demand is really more than just what the peak HP the motor is putting out at peak. Absolutely, richer (for safety) is better than lean, but you won't be maxing out 19's in your app as RangerSVT reminded, because your rpm will be limited to 5,000. From the other extreme of washout (which honestly I have no experience of) is injectors being stuck open due to over working. Like running your motor at redline all the time vs 4,500. But that will not happen in your case because you won't be stressing the 19's that much.

I come from a mustang background so I often confuse the 302 engine needs between low/midrange power for truck/crawling and 6,500+ rpm track/racer needs. My Bad.

Okay...I hear you, but do you think the mod's I've made to the motor...Heads/Cam/Headers/Roller rockers... are enough to push the 19# injectors. In your above example you are talking "typical Mustang" and I want to know if you are taking into account my mods and how they affect my set up and thus needs for fuel pump/injectors. Also...is the stock fuel pump enough? General question about how EFI works...When the motor reads lean which is done I assume based on O2 sensor feedback what does it do to increase fuel? Does the computer hold the injectors open longer? Does it increase fuel pressure and if so how...how does it get more fuel into the motor? Again...no expert here. Trying to learn.

 

[RangerSVT]

Fuel pressure (ie delivery to the motor/injectors) is automatic VIA vacuum. With a lot of vacuum (ie no load on the motor like in idle condition) there is plenty of vacuum, so when the fpr sees this vacuum it opens releasing fuel pressure. When there is a load such as full throttle, there is little to no vacuum, so the fpr closes allowing more fuel pressure to build...injector pulse is controlled via readings from the maf and tps, basically, how much throttle is being applied and how much air is entering the motor...

SVT

 

[Notpretty]

Completely lost. Fpr gps...? I litterally have no idea what you said.

Edit

Wait...fuel pressure regulator. So the O2 sensor which reads the results of combustion has nothing to do with fuel delivery? Still don't know what gps is.

 

[FIND]

I think that was a typo, he meant to type TPS, throttle position sensor. FPR means fuel pressure regulator.

edit:

O2 sensors do also have something to do with fuel delivery. The fuel maps are basically tables that are based on throttle position and RPM. MAF readings and O2 sensor readings basically just shift things around a little bit.

 

[ExDude]

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[RangerSVT]

Sorry, it is tps, not gps (damn auto-correction)...

SVT