O.E. 5.7 Vortec CPI intake with 16197427 PCM ?

[1project2many]

The injectors will operate fine in batch mode.
The upgrade injectors replace the poppets with tiny injectors at the end of the fuel lines.
MAF is optional.
Injector corrections might be tough to work out but I'll bet you could get something figured out.

[pmkls1]

I was kind of hoping for that kind of reply. The salvage yards are full of complete intakes because the trucks that end up there usually have a blown motor or bad tranny so most of the time people just yank the heads off and leave the rest behind. I also see a lot of trucks where the engine is gone but the intake is sitting somewhere in the truck. I have also seen complete assemblies on ebay for $100-200 if I can't find anything better at the local yards. I've seen plenty of used ones around that have had the upgrade installed so I hope that I can come across one just to avoid the typical problems with the poppets and plastic lines. Either way, I think that going with this setup should at least ease tuning and eliminate any problems that I possibly had with the TBI setup. I'll save the performance mpfi setup for the next engine due to be built after I build one for the S10. Stock vortec is plenty for the ole firebird seing as it makes nearly 100hp over the original L03.

[dave w]

The injectors will operate fine in batch mode.
The upgrade injectors replace the poppets with tiny injectors at the end of the fuel lines.
MAF is optional.
Injector corrections might be tough to work out but I'll bet you could get something figured out.

I agree the SCPI conversion to MFI is an excellent idea when considering using a '7427 PCM. http://www.amazon.com/Delphi-FJ10566.../dp/B000TYLIFS

I agree, the challenge is getting the injector voltage offset figured out! Maybe the injector voltage offsets from the "Black Box" PCM would be a good place to start looking? I'm thinking maybe because it's a conversion designed to work with OEM computer.

dave w

[pmkls1]

Yeah, I was going to study the "black box" calibrations thoroughly to get an idea of where to start with injector latency and VE. I know there is a difference there with the way I will be firing the injectors and I plan on sticking with speed density and avoiding a MAF sensor. But, the stock calibrations should still give me a good starting point.

[pmkls1]

I knew that amazon had the upgrades cheaper than anyone. Depending on what I end up getting and how much it costs I may go ahead and spring for the upgrade. I did just now notice that multi fuel capability is stated in the notes. I'm thinking that I may like going stock more than I imagined, or at least I hope.

[EagleMark]

Not much to Vortec voltage corrections?

4 to 17 volt...

0.799805
0.850098
0.916992
0.958008
0.970215
0.980957
0.992188
1.000000
1.000000
1.000000
1.006348
1.015625
1.025879
1.035156

[1project2many]

Stock L31 intake enhances low rpm power like L98, but without the large choke at 4500 rpm. It's going to feel far stronger than the TBI system.

[dave w]

I've been thinking the injector voltage offset of the black box PCM is for sequential firing injectors, so batch fire would have different impedance (resistors in parallel)? I'm wondering what the impedance of four SCPI to MFI conversion injectors would measure in parallel? Four injectors in parallel would have a very low impedance, maybe very close to the impedance of one TBI injector?

dave w

[dave w]

I measured the impedance of one stock L31 vortec injector = 13.2 ohms. Four stock L31 vortec L31 injectors in parallel = 3.3 ohms. One factory TBI injector will typically measure 4.4 ohms. I would think a 1.1 ohm 10 watt resistor in series with four stock L31 injectors in parallel would allow the '7427 PCM to operate in TBI mode. I would think using the four stock L31 vortec injectors in parallel only would require the '7427 sense resistor modification if wanting to use the '7427 in MPFI mode.

dave w