Ok, it seems that the 2 tuners available for the Grand Prix have different ways of editing the IFR vs. kPa tables.
HPT uses g/s vs manifold vac in kPa
DHP uses mSec/g vs manifold kPa
This caused me a lil confusion at first, and would like to share my findings w/ everyone.
1. Injectors are rated in lb/hr @ 43psi fuel pressure by most mfg's.
2. Stock injectors are rated at 36lb/hr @ 52psi fuel pressure (as spec'd by GM)
3. The conversion from lb/hr to g/s is 1 pound/hour = 0.1259978 gram/second
4. MAP kPa is kinda backwards. 0 = lots of vaccum, 100 = 0 vac (atmospheric pressure). The MAP sensor in the GTP is a 2 bar (200 kPa or 29psi) sensor. This is odd, in that the IFR table only goes from 0kPa to 100kPa. I would ASSume that once you get above 100kPa, it maintains the last known value.
5. If you take the rating of an injector, convert it to g/s, multiply by .001, take the inverse of that number, you will get your inj flow rate as recorded in the editor.
Lucas 009 injectors. Rated at 42.5 lb/hr @ 43psi.
At 52 psi, they become 46.47lb/hr.
Converted that is 5.85g/s.
Converted again it becomes .00585 g/ms.
The inverse of that (mSec/g) is 170.65.
If you were to use the rated flow of the injectors it would look like this.
42.5 pound/hour = 5.3549056 gram/second
5.35 x .001 = .00535 gram/mSec
1/.00535 = 186.92 mSec/gram
And stockers would look like this:
36 pound/hour = 4.53592 gram/second
4.54 x .001 = .00454 gram/mSec
1/.00454 = 220.26 mSec/gram
Now, I am not exactly sure how to tune the inj flow rate table w/ this information, but I would assume you would find your base MAP reading (for instance, in Jenays car, at 19in hg vac, her map reads right around 35-36kPa) and stick that number in there. To add fuel using that table, you would increase the g/s or decrease the mSec/g number. This would indicate to the PCM
that you have changed injectors, to a smaller one, therefore holding them open slightly longer and adding fuel.
Anyone else have theories or hard facts on how the inj flow rate table works?