Anyone with an iPhone and the Bosch "Light 'Em Up" dyno app???
I'd almost forgotten that it was on my phone, but yesterday on a whim (on a short stretch of road in Mexico) I decided to try it out with my 2006 E55.....just to see what kind of number I could get with no real effort or advance planning.

My setup values were:
Rollout (speed tests) = 0"
Rollout (distance tests) = 12"
Trigger = 0.10G
Car weight = 4050Lbs
Drivetrain loss = 0%
I ended up with a 0-60 of 4.81 seconds (A/C on, no tire warming, no practice launches).....just came to a stop, selected the app and floored it when the "GO" light turned green.
60' Time was 2.37 seconds @ 31.6 MPH
330' time was 5.80 seconds @ 66.7 MPH
I ran out of road, so I only got to 74 MPH before backing out of it....
Now that I can see that some of the assumptions are really off, I will update the car weight and add maybe 19% for driveline losses and try again.
If anyone else happens to have this app, I'd be curious to see your results.....stock, modded or whatever.

-G
Like I said, it's a free app (I don't think you can save the images with the free one though) and I'm sure Bosch has an Android version too.... grab a copy and play with it a little bit. I'd be interested to see the results.
I didn't get any appreciable wheelspin (ESP on, no LSD) on my launch. I would like to find a longer stretch of road to really let it pull hard and see if I can confirm that my IC pump is working correctly??? I imagine that the acceleration curve will fall on it's face as heat-soak sets in.
-G
Last edited by GregMB; Aug 11, 2011 at 01:33 PM.
I've noticed that the app can sometimes give weird values if the phone is shifting around during the test, so you need to hold it firmly against the dash or center console during the tests so the accelerometers are only measuring the car and not phone movement.
I'm sure there are ways to fine tune the rollout values and the triggering g-force to get it to match other "trusted" timeslips or sophisticated data loggers like the V-box.
-G
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What were your setup options?
Rollout....launch Gs, etc?
Did you firmly anchor the phone during the acceleration run? If it shifts around at all you will get bogus acceleration values.
I'm sure it's not as accurate as the $500 V-box unit, but I'm sure it it capable of more accurate results than what you got on your first try...
As far as I know, the Bosch app only uses the accelerometer. I never considered that it might also use GPS but for longer runs it might. I few years ago I bought one of those G-Tech suction cup mounted devices (around $150) and the only thing it used for acceleration and HP estimates was a simple accelerometer. Even back then people said it was relatively accurate for 1/4 mile times (usually within a couple MPH and maybe 0.10 seconds).... The iPhone should be at LEAST as good as that thing was...
Please try again and report back.
-G
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Car Setup:
- TCU "Sneaky Reset" just before runs
- Suspension in Comfort Mode / Raised Setting
- Transmission in Sport Mode
- A/C Off
- ESP On
- Ambient Air Temp 70F
- Rollout (Speed Tests)= 0"
- Rollout (Distance Tests) = 12"
- Trigger = 0.10G
- Weight = 4050
- Drivetrain Loss = 0%
- App Version 1.xx??
Also, I just noticed that this Bosch app is actually built from the Dynolicious software, so the results should be just as valid as what Dynolicious provides in their app.
First run: Full-Throttle launch....massive wheelspin, ECU shut down the power for a couple of seconds in the early part of the run. Could totally feel the "bog" while I waited for the ECU to open the throttle back up.
Look at the blue line (G's)....it completely lays down for the first 1.5 seconds until the ECU finally agrees to open the throttle back up for me...

Second run: Tried to launch at slightly less than 100% throttle to avoid the ECU nanny.... the holeshot was much quicker, but interestingly the calculated HP was much lower (327HP vs. 435HP)
The blue line (G's) on this one hits it's peak value at the 1 second mark (0.76 G's). Much better.

Obviously the HP numbers aren't even close with the vehicle weight too low, and the driveline losses at 0%...but they are interesting as a relative comparison to each other.
The TCU Reset trick is a real monster! The car is WAY harder to launch now than it was last week when the car had been "dumbed down" with all my around-town lazy driving adaptations.
RAW DATA:

That first run extrapolates out to a 1/4 mile run of 14.660 @ 119.3 MPH. Obviously the car has the HP to make a strong run, but with such a lousy launch this is the kind of weird ET/MPH you have to expect.
Fun stuff!

-G
Last edited by GregMB; Aug 19, 2011 at 11:04 AM. Reason: Added raw data...







