Gymkata

I have been playing around recently with both the aDyno (free) and Dynomaster ($4.99) apps on my Android smartphone. In order to increase GPS accuracy, I have been using a RoyalTek RBT-2300 Bluetooth GPS puck instead of the phone's internal GPS. Yesterday I did a quarter mile run using the above setup on the aDyno app. The numbers seem pretty consistent with what I would have expected, other than having a horrible 60' time.

Has anybody here used a setup like this at the strip and compared the results with their actual timeslip? If nobody else has yet, I will if I can find time to get to MIR this year, and I will let you all know. Below is my aDyno app info. I was approximately 300 ft above sea level and the temperature outside was 81 degrees. The humidity somewhere between 80% & 90%. I ran in manual mode, nannies turned off, shifted at the beeps, and launched at about 1000rpm. I am running about 40psi on my Michelin PSS tires and did not warm them up...maybe that is the reason for the bad 60' time???

60': 2.46
330': 5.80
660': 8.55 @ 92.5 mph
1000': 10.80
1320': 12.80 @ 117.8 mph

10: 0.77
20: 1.48
30: 2.13
40: 2.79
50: 3.64
60: 4.54
70: 5.67
80: 6.85
90: 8.12
100: 9.70
110: 9.70
120: 13.3
130: 15.4

I will have to try another 1/4 mile run with the Dynomaster app. After looking back through different this run (and previous runs), it seems there is a glitch in displaying the 0-110mph time. It shows the 0-100 and 0-110 times as exactly the same, but 0-120 seems correct...huh?

DonTN

iTrader: (2)

I've wondered the same thing with my app. The best 0-60 time that I've been able to get is 5.3 though.

jadu

iTrader: (42)

The code developers should have tested their app on the drag strip. They should be happy to discuss their testing methods if you kindly ask. I personally have not used the app? Does it give your resulting hp at the crank?and is weight and altitude inputs on the app? I've personally utilitzed accelerometer mems chips and all it gives is the resulting g force on the xy and z axis. All other inputs are calculatesd in the algorithm

EDIT: it looks like their using the GPS to determine distance. Your accuracy is only as good as your GPS system. If you travel exactly 10' and your GPS says you traveled 11'6", there goes your % error

caymandive

iTrader: (2)

Doesn't look too accurate. MPH is high and ET should be lower.

Gymkata

I was thinking the same thing, but my 60' time is .6 seconds slower than your's when you got the 11.91. If you subtract the .6, it would be a 12.2 run...12.2 @ 117.8 sounds about right, especially when looking at your best of 11.91 @ 120. If you factor in the humidity and heat, those also made it a little slower than it could have been under optimal conditions. My GPS link was very solid (I think 13 satellites with a 10 (Hz?) refresh), but that still has an accuracy range of about 8 feet, so there slight variation.

I guess I just need to get some DRs and head to MIR and find out for sure.

ToothDoc

A lot of those GPS/accelerometer type things don't account for 1 foot rollout and they also measure actual speed at the 1/4 mile vs a trap speed which is typically 1-2 mph higher. I've had TWO accelerometer units and now a GPS unit. The GPS unit is more accurate than accelerometer types. You can probably take off .1 second off your 60' times and .2 second overall et. Also, you can drop the 1/4 speed by about 1-2 mph. That puts you at 12.6@115-116 mph. But your 60' is quite bad actually. Drop the weight - fuel load, spare tire. With the mods you have, you should be seriously spinning out your tires if you just mash the throttle - you probably need to smoothly mash the pedal.

caymandive

iTrader: (2)

^
Based on my journal comparing the DA and mods, that should be very close to what he should be running. 12.6@115.

Gymkata

Ok, that makes sense. With the 275mm Michelin PSS tires I can hook up much better than with the DWS tires, but I still have serious traction issues if I just stomp on it. I may try to get to MIR next weekend to see how I fare there.

Super6

iTrader: (1)

I've got the dynolicious app and think its cool, but not very accurate. I'm a pretty avid cyclist and gps all my rides using a garmin 500, I've also compared the gps measurement to some of the iphone gps devices and there are some descrepencies. I would suggest for a few hundred bucks, get a garmin watch and make a few test runs in the F. You can download the data into garmins software and get much more accurate data.

Gymkata

I have a few GPS watches, one of which is a Garmin...just have to find them. Any discrepancies vs a Garmin would have to be the problem of the performance app, not the GPS data though since I am using a very quick and accurate External GPS puck.