Bman2000

so at least untill you max out the injectors, the computer will take care of the fuel requirments per whatever the afr is from factory, Or im assuming you can change that as well by adding fuel through out the RPM range, but for NA applications we dont really have to run richer correct? which means that part is fine, but your saying that new cams likly have a different intake opening degree which means your adjusting when the injector shoots fuel based on what the cam sensor says for position? and that to adjust idle quality your adding fuel to basically keep the cylinder filled with the right mixture due to the amount that escapes from the overlap. so idealy your just looking to replace just enough fuel at idle to keep the same amount in there before the cam change...that makes sense. And finally i supose this depends on your cams though and that raising the idle speed, which id imagine youd only have to do under really high overlap and ?lobe sepiration? basically stage 2 cams keep a realitivly normal idle beyond that you have to start changing alot of things right? Hope i kinda got it? Although im assuming i cant go in my tuner and find the cam scaling stuff, but is that a number that would come with the cam? or is that a number you have to do some math to find cuz 348.5 for factory is found how? just curious. Thanks for answering. So if i put a set of stage 2 cams in...and i knew the degree number, could i get away with just adding fuel at idle and have it run perfectly safe and good? im sure the power output wont be maximized, but just keeping options open. Because id like to do blower cams, but it might be a while before i can get the blower on there, and id hate to spend tons of money on a dyno tune with out the blower, or leave the car parked all summer cuz it wont run...i just want to drag!!

H0SS302

for my buddies car his AFR was extremely lean at wot with his motor in n/a form. I had to add .6 to get the AFR to 13. That was just with stage 1 heads and turbo cams.

Bman2000

well the heads and cams though id think that youve now gotten to the max of the 19# injectors right? well i guess that still wouldnt matter down low. Im wondering why that is though, because the MAF combined with the o2 sensor should be able to keep a constant AFR until the injectors have no fuel left to give or the MAF gets pegged? or am i missing somthing that keeps that from happening? is the computer programed to not allow the system to make drastic adjustments when air flow and fuel requirments go way up?

cliffyk

I will be brutally honest here, my first reaction was to completely ignore this unreadable "glob" of text--however as it's a Sunday I decided to tackle it. But please in the future try to make use of the Caps and Enter keys...

Yes, the additional volumetric efficiency (at certain RPMs and loads), I.e. improved air flow, brought about by the HP cams will be reported by the MAF and the PCM will do what it can to make the AFR what it believes is needed.

The OEM tune tends to be a bit rich in open loop mode, more so for the late '02 through '04 models with the 21lb/h (pink) injectors. Unless you wish to run richer than the factory settings there is no need to change anything--the MAF will report the improved air flow and the PCM will do what it can to make the AFR what it believes is needed.

Yes...

Yup...

It will be included with the cam's specs...

If you have the ability to add fuel at idle then you have the ability to make the other tweaks, I don't understand why you would not?

cliffyk

I agree with Bman2000, the 19lb/h injectors were only barely adequate for the stock PI engine (running 90% to 95% DC), thats why Ford put the 21lb/h units in the later models...

H0SS302

he had 24# injectors, it had nothing to do with not having a good supply of fuel, it just needed more of it if that makes sense.

cliffyk

There are at least 50 ways a modern EFI tune can be modified to adjust AFR, ranging from the low and high injector slopes, to the the open loop tables and MAF curve (like so-called "calibrated" MAFs do).

The "problem" is that, as I have observed over the years, very often each tuner has a fixation on one way of adjusting AFR. Sort of like the difference between plumbers and carpenters--a plumber's first reaction to a problem is to grab a Stillson wrench, the carpenter will grab a hammer...

Bman2000

thank you for the response, and sorry that i made it one big blob. Ill work on that. As far as being able to tweek fuel? I have an SCT tuner, i know its capable but without a wide band o2 i dont see how i could effectively adjust much more than a little bit at a time for idle purposes, and for that matter i wouldnt even know where to look to find the cam degree thing?

Do you know if sct has a spot to deal with the cam timing? or is it just under like a pulse timing option? And finally, it sounds like if i do just the cams that it might be needed to get bigger injectors, last thing i want to do it WOT and fry my motor because i thought i had enough fuel...stage 2 cams full bolt ons and19# injectors may not work...lol