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Just ordered my Rebello 3.0, now what


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I strongly question the accuracy of a 0-60 time based on a consumer grade GPS app, but I'll give it a try. If anyone knows of one that correlates accelerometer and gps data in the calculations, let me know. It's currently snowing like crazy anyway... Again, more delays in Antioch. Hopefully engine is here by Friday at least (was previously Monday as of last Wednesday).

Kurby, we should try the same app and see what we get for results ;) I'm very curious; perhaps as curious as I am to see what these bored carbs look like. If anyone has suggestions for some velocity stacks and filters... Or what to use to replace the factory airfilter rubber gasket o-ring thing.

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Distance sensitivity aside, how frequently does your phone sample for a position? If it does it every 1/10th of a second and there is up to 3 yards in error for each measurement, how does it accurately know when you're even doing 60 MPH? I'm assuming these apps, (AND legit GPS speedometers, like the Autohut gauges) average speed based on average points over a set time. So while it's timing abilities may be accurate, I somewhat doubt that the time a car reaches an extrapolated velocity over an estimated distance is going to be much better than you can do with a stop watch.

Watching some user videos of "aDyno" in action, shows a 0-60 time starting to calculate over a second after the car left the line and not giving a final result until several seconds after the speed was reached. There is some sort of algorithm at work, taking averages and making stuff up. Maybe that math works well in the end, but these same apps are doing theoretical dynos based on your cars mass and how quickly it pull from one RPM to the next in a certain gear, and of all times, a 0-60 is tricky to measure. A 1/4 mile app may be more accurate given a longer distance, with less acceleration.

If the app considers accelerometer data, than it should know when you drop the clutch, when you shift, and when you're at speed based on acceleration alone. That would be an app I would use, but do phone accelerometers even work for that range of force? Do they all have the same standards, calibration and methods of detecting movement? Also, a lot of these will pair to an OBDII dongle and grab speed data from there in which case I imagine the GPS data isn't even used.

I'll try it out, but if it says 5 seconds, and really I'm 5.5 or 4.5, that's an absolutely huge difference. I might buy an actual recording device for this, just to play with anyway.

Maybe I'm mistaken.

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Dave Rebello likes compression. I had to talk him down from 11:1 and remind him I live at 4500ft and regularly drive through a 7000ft pass and down to sea level.

Same here. He's building mine at 11.5:1 and I live at 6200 ft. After being hesitant he promised that it would be fine. Hope so....

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