If I go with 1200cc injectors, Do I need to have someone tune the PFC or can just changing the injector # to 1200 from 850 do the trick...

 

im wondering the same thing....
im wanting to change out to 1300cc injectors
ive been told i need to use an upgraded fuel pressure regulator like SX's and then others tell me that i dont need to

i know on the PFC you will have to change the injector size as well as the lag time and pulse correction values, but what are the values for those parameters???

where do i get the numbers from for the calculations??

thanks

 

i found the PFC manual...it says for secondaries you only need to change the injector volume value which would be 1300cc and then the lag time correction value

(1300cc lag time)-.77=+0.__ms

is there any way to calculate this knowing that the 1300cc injectors are just the 850s bored out??
it wouldnt be the same number would it (correction value =0.00)??

someone please bestowest your knowledge......

 

Sorry for bringing this back from the dead, but I need to know this info as well. I have 1200 secondaries.

 

The AFRs will change some but not drastically, BUT is it allways better to recheck your AFRS after changing any fuel system components.

 

Sorry for not clarifying, but this is the info I need to know...

 

Since they are enlarged, they will be slower (more lag).
I used a lag of .10 for my 1200s.

 

Ok, that's well and good, but I'm trying to learn how to program and tune my own car, so I'm trying to figure out HOW you get .10 and other calculations for other parameters.

What I need is a list of equations to plug in "x" values to figure out what my settings should be.

 

Either from the company that enlarged your 850s by reading many posts on this and other forums, or just experimenting.

What you want does not exist.
Can you teach someone how to swallow food?

 

Very bad example.... eating/swallowing food is an instinct we are all born with. Tuning a ECU is not. So what is your point?

 

You can't learn to be a F1 driver or a great mechanic. You can learn some of it, but what you are born with is the main deciding factor.

Inherited instinct is the factor, not some formula to give all the answers.
Does that explain it.

 

So you're saying if I don't have "the gift" then there's no hope...

I feel if the determination and means are there, anything is possible.

 

As Chuck said, the company (RC Eng?) boring out the injectors will provide the new lag time. Again as Chuck said, the imprecision in lag time and other conversion factors will likely result in small AFR variations. Best to verify you are still ok.