I was sitting in Calculus mulling over life when this came up. I can't remember some specifics.
The map sensor that comes with the gmpp kit can read what amount of boost?
What can the reflashed ecu account for if given the proper sensor.
Say for example, I wanted to run a 2.6" pulley with the 'stock' reflash. Could I tune the fuel consumption with an adjustable FPR and a wideband? I know many of you will say HPTune it, but I'm mostly curious.
If the supercharger were to be ported, the boost level would drop, but the amount of air going into the engine would increase, could the reflashed ecu account for this and keep the same air/fuel ratios? Or would it run it lean because of the lack of manifold pressure?
Now that I'm on the topic of fuel...
Stoich is 14.7. When in boost, why are very rich air/fuel ratios desirable? I understand that running rich is safer than running lean, but why to the extent of 12:1 and numbers like that? What would be wrong with tuning for a 14:1 so it's still rich, but not robbing as much power?
I'm not sure about the details of some of your questions; but as far as 12:1 on boost...richer = cooler. And as you said its safer. Suppose you run an arbitrary 6psi daily...perfectly tuned to 12:1 AFR, acceptable EGT's and a good ignition tune. Something happens in your system and you get a boost spike...you have a good margin of safety, so the engine doesnt detonate. Now imagine the same case tuned at 14:1...
The GMPP MAP sensor is 2 bar, 1 bar is up to atmospheric pressure (14.7psi, 0 on a boost guage), so 2 bar is up to 14.7psi of boost (positive pressure).
The ecu is based on MAP vs. RPM when at WOT, so it won't account for extra cfm of air. You could tune it with an afpr, but then it would be pulling fuel through the rest of the operating conditions to compensate.
You could try to tune for 14:1 AFR, but I would guess you would see enough KR to blow the engine long before acheiving a good tune.
15.3 @ 89.97mph, 14's on the way?
IIRC the GM MAp sensor on the Ecotec kit is a 2.5BAR sensor. Stupid...yes but this is GM we're talking about.
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14.7:1 yields the best emissions, best power is a different story, which is why richer a/f's yield more power. 14.7:1 is the air to fuel mixture that yields the most complete burn, while richer ratio's make higher emissions, but more power.
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Ian Brydon wrote:The GMPP MAP sensor is 2 bar, 1 bar is up to atmospheric pressure (14.7psi, 0 on a boost guage), so 2 bar is up to 14.7psi of boost (positive pressure).
Team Vision Racing (aka hypsy) wrote:IIRC the GM MAp sensor on the Ecotec kit is a 2.5BAR sensor. Stupid...yes but this is GM we're talking about.
hypsy is right the TMAP is 2.5 bar , not 2 bar
the 2.4 s/c map is 2 bar
