Sidestick

iTrader: (1)

Which map do you all use for leaning or richening the fuel, the PIM or INJ map? Does manipulating the values on one affect the other?

What I really need is a tutorial on this piece of electronic wizardry, from explaining the basic terms all the way up to high performance tuning. With so many of you PFC users out there, I'm sure someone can take some time out to at least explain the basics of fuel & ignition adjustments.

I know I'm not the only one that needs this info as I've seen others asking similar questions without satisfactory answers.

Thanks.

mmaragos

I have used both, increasing the % on the PIM volt and correction INJ map.

The PIM volt affects the basic injection map. The correction INJ map also affects the basic injection map.

The basic injection map is set up to achieve ideal stoichiometry 14.57:1 (AFR). You don't have access to this map through the commander (the Datalogit software does give you access - although you really don't need access to this map...maybe with a single turbo?).

The INJ correction map allows you to increase or decrease the amount of fuel on a cell by cell basis (RPM vs. pressure). The unmodded maps that come with the PFC are supposed to be tuned to provide at least safe AFRs (high 10s to mid 11s) for an FD3 with some mods.

The PIM volt modifier allows you to increase or decrease the amount of fuel on the basic injection map based either on the pressure sensor voltage (boost) or at specific RPM.

Ideally, you want to have at least a wideband O2 before you start playing with these maps. Once you have a wideband, you can monitor your AFR and modify the INJ correction maps to improve your AFR. Without a wideband, you will be blindly guessing and will likely blow up your engine.

The PIM has worked for me when I am on the street and notice a rich or lean condition at a certain RPM, kind of just rough tuning by taking out or putting fuel in at certain RPMs.

The correction INJ map is really the place where you do the fine tuning.

I have the Datalogit and suggest that you get it. I really can't see doing effective tuning without datalogging. Additionally, with the Datalogit (and with the Commander), you can "map trace" so you know what cells are being used at specific points in time (boost & RPM). This allows you to go back and change the fuel and/or timing in the proper cells without having to guess which were being used.

For boost less than 18 psi (you shouldn't boost more than 14 psi with the stock turbos) AFR should be in the range of 11.4 to 11.7. For boost over 18 psi (single turbo, ported, race gas, etc.) AFR no leaner than 11.1 to 11.3.

Timing is more difficult. For a stock port @ 14 psi, no greater than 20-23° advance with no less than 5° split (unless you feel your system can control the timing accurately enough for less split). For a street port the amount of advance is reduced (the more porting, the greater the reduction). My advice would be to not play with the timing, until you are comfortable with the AFRs and you can get the car on a dyno with someone that has tuned a rotary before.

One last thing...

READ THE PFC MANUAL!

Use the above information at your own risk.

Sidestick

iTrader: (1)

Thanks a hell of a lot man! That's the best response I've seen so far for us PFC Dummies. I have read the manual, & I do see what they're saying about changing this or that, they just don't explain fully what this or that is in basic terms.

Sidestick

iTrader: (1)

Ok, now that the ball is rolling I have two more basic questions. I've been looking at peoples maps on skotx's database site & noticed the press. column on the left goes all the way up to 19.4 (is thst psi? my manual isn't close by now). Anyway suppose you're boosting only to some value below that, what do you do with the cells above that value?

Next, what the hell do all the nos. in each cell mean? Eg., Is 112 additional fuel over stock/base map, or is it leaner? How do you tell? What about those in the ignition tables? Do those represent actual ign advance in degrees or what?

Thank you all.

2black7s

I have the same questions as SideStick.
Chuck, Kyle, if your out there- help!
What is the link to skotx's database?
I am getting in late on the datalogit deal, so I am gathering as much info as I can until I can get my
unit.

Bryan
93 touring
90 GTU

Sidestick

iTrader: (1)

http://www.exorzero.com/skotx/powerfc/

You know, with all the supposed PFC users on this forum who are always talking about adding fuel here, leaning fuel there, retarding here, advancing there, you'd think there'd be some answers by now about what I think are really basic questions. Is everyone just lazy?

Lost Time

Your first question: Yes, the 19.4 is psi.

Your second question: All the cells should be correctly numbered in the event that you happend to wander into one that you don't normally use. Let's say it's real cold out and you spike to an unusual 16psi. If you didn't adjust the upper cells...... you get the idea.

Third question: The higher the number, the richer. Conversely, the lower the number, the leaner.

Fourth and final question: If the number is positive, it is advance. Negative numbers are retard.

And yes, we are lazy.