IFR: Idle and part throttle

[GuitsBoy]

Hi all -

I have found that most people will have you multiply the entire IFR table by .9x in order to get your LTFTs back into the slightly negatives. My problem is that I already am in the negatives at idle, like -15 or so. However the rest of the FTCs have LTFTs up around +10. Which side of the table should I not touch, so that I can keep my idle from bottoming out at -25? I would guess that Idle = closed throttle = high VAC = low KPA. Does this mean that Idle should be adjusted at the right hand side of the IFR table? I guess this would make sense since thats where the injectors are declared to flow more (higher vacuum is sucking more fuel through).

Thanks for any input,
-T

[jimmyblue]

Is your MAF stock? Most people with trims that jacked,
get there by either having a ported MAF / ends / GMAF
or by headers' thermal effects messing up the tune.
The IFR table "properly" only represents fuel flow,
fuel pressure aspects. There is also an injector offset
that you can use -if- you think it's a fuel delivery, rather
than an air delivery calculation error term. This being
more appropriately hit by the VE tables (for idle-only
problems or off-idle problems especially) or the MAF
table (if the MAF is non-stock).

Try and lay out the car's mods and mixture effects in
your mind and figure out the most straightforward
cal correction strategy. If there've been a lot of 'em
done, you might even want to take a step back for
purposes of clearing up confusion (like for example,
put a stock MAF onto a car just so you know the
MAF table is right, get the rest tuned up, then go back
to your chosen MAF knowing that -only- the MAF
table needs retouched, etc.).

Food for thought.

[GuitsBoy]

Thats probably the best idea. I do currently have a ported MAF, but I did my initial tune with my stock MAF (I have both, so I can switch back and fourth). I only got my tune semi-correct before I figured I'd switch over to the ported MAF. I figured no sense in fine tuning it twice. Obviously theres LOTS of sense in fine tuning it twice. Ill go home today and switch back to my stock MAF and get it dialed in that way... Once Im satsfied there, Ill switch back to the ported MAF and adjust the MAF freq tables accordingly.