I have always wondered how the horsepower and torque gauges (on the SRT tab) get their information from or are they just estimated numbers? Did Dodge program the car to display a certain amount of power at a certain RPMs and accelerator pedal positions or does it measure other parameters.
just a guess, but I would imagine a "power curve" is programmed into the ECU via a lookup table - then it's just a matter of matching the RPM with the transmission gear or speed to determine the HP. if this is true, then any power adders/mods would immediately make this method inaccurate.
on the other hand: how hard would it be to determine the actual output (the same way a dyno does) since our cars already know their own parameters? the only difference from a dyno is that the vehicle is actually in motion vs similated motion...
anyway, it's all just speculation on my part - please do not take any of this as fact
as a side note: I have an app on my iPhone that can display HP/Torque figures via a device that connects to the OBD2 port. like the readouts on the newer models, I have no idea how accurate it actually is, especially since my vehicle has been moded from factory specs.
It's actually a computer algorithm that takes the theoretical SAE certified HP and applies all of the various input parameters it can measure (KR, A/F ratio, MAP data, RPM, etc) and then calculates the data it displays.
It can not, and does not, measure actual HP in any real way.
It is impossible to do that without strapping an actual dynamometer to the wheels.
That makes a lot of sense now. Yeah figured it would just be an estimated number because the car itself does not measure horsepower. I agree with that.
mine too has gone over stock HP (6-8 PSI Boosted) using the aforementioned iPhone app. I think, like Ddaddy said, the ECU is just using the inputs it has available to it, using the preprogrammed algorithm to calculate HP/Torque. mods should/would not necessarily affect the calculation sufficiently. I guess it really depends on how complex the algorithm and how many of the inputs are actually variables vs fixed functions/numbers (eg: timing, stoichiometric values)
I wish there was sure and solid information on what the car measures and the inputs to that algorithm. I'm just very curious. Probably throttle position, maybe A/F mixture, what else though, who knows?
Here is the deal....my challenger does 3.3 0-60, 11.6, and is basicly stock. I have a tune, Hemifier and a cold air sensor hack. My focus has been traction...example... stock mich 20 inch wheels, 2. 60 ft, mt 20 inch at 16 lbs...1.85 solid brick wall and 12.3 seconds. MT drag Radials on 17 inch wheels at 17 lb.....1.51 60 ft....and 11.6 seconds. I also have the shaker intake shielded from heat and the top of the shaker air box sealed off to the hood...and the hellcat tube to the light. Mt gauges....u connect maxes out at 502 hp....but the same gauge on the dash 580 plus when I stomp on it. There are torque sensors on the car...which are limited from the factory. So yes, the car is a relative dyno to itself. I cant help but wonder if, as launch is the biggest factor armatures like us can expect, you don't gain more with coldest air, best suspension setup...and the tune limiting torque inhibition vs going bonkers for more hp. What I did was go scientific...wasted energy spinning wheels has to be recaptured. Have someone take quality videos that can be gone through frame by frame for spin, and wheel hop. I also found out simple things matter. Clean your tires....the gravel from the return road trip sticks to the tires...CLEAN IT OFF...BALL BEARINGS IS NOT A GOOD SURFACE. I could go on and on......but I think there is a lot to be gained focusing on the first 60 feet. Also remember....you are not faster than a computer or the speed of light, you cannot out shift the 8a.!