0-60 in 4.8, how accurate are those phone apps?
05-15-2019, 08:03 PM
#1
Heel & Toe
Thread Starter
0-60 in 4.8, how accurate are those phone apps?
i have a timer app called race timer for the iphone that times your 0-6- and quarter mile, i ran a 0-60 in 4.8 seconds with an automatic. is it accurate or is it off by a half a second?
1994 C4 in good condition with a auto trans.
1994 C4 in good condition with a auto trans.
Last edited by 94c4562; 05-15-2019 at 08:43 PM.
05-17-2019, 07:13 AM
#2
Melting Slicks
It's probably off. I think the phone apps just use an accelerometer sensor and they aren't the "most" accurate thing in the world. If you have 3.07 gears you might be in the low 5's? Stock engine and car otherwise I am presuming?
05-17-2019, 08:23 AM
#3
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They are off, but certainly better than the g-tech thing we used to use years ago.
05-17-2019, 10:35 AM
#4
Drifting
A 1hz (updates 1 time per second) GPS sampling rate isn't very accurate over short distances.
Using something like the Torque Pro App that is paired to OBDII (newer cars) and also compares GPS data can be slightly more accurate.
The Dragy 10hz GPS device is pretty darn accurate but ~$149.
Using something like the Torque Pro App that is paired to OBDII (newer cars) and also compares GPS data can be slightly more accurate.
The Dragy 10hz GPS device is pretty darn accurate but ~$149.
05-17-2019, 11:37 AM
#5
Drifting
You get what you pay for. a Free or cheap app... that should be enough said.
05-17-2019, 11:41 AM
#6
Burning Brakes
Most of them use an accelerometer in the phone paired with GPS. They are somewhat accurate. The 1hz sampling rate holds them back. Probably ~0.3 seconds off.
06-27-2019, 06:46 AM
#8
Heel & Toe
The Gtech device you're referring to is actually very accurate. The only thing the Gtech gets wrong is the trap speed which is typically 5-6 mph slower than what Gtech calculates. However, actual times are usually within a couple tenths. You can search other forums online and this is confirmed over and over even at the track.
06-27-2019, 07:44 AM
#9
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The Gtech device you're referring to is actually very accurate. The only thing the Gtech gets wrong is the trap speed which is typically 5-6 mph slower than what Gtech calculates. However, actual times are usually within a couple tenths. You can search other forums online and this is confirmed over and over even at the track.
What may have changed in the years since, I dont know and dont care, they fell out of fashion on this C4 forum.
Last edited by vader86; 06-27-2019 at 07:46 AM.
06-27-2019, 10:12 AM
#10
Safety Car
I have a 20 year old Gtech Pro and I love that thing. It is extremely accurate when compared to one of todays phones. The processor in the Gtech operates at 50 hz and has a 9-axial IMU sensor (accelerometer, gyro and magnetometer).
The processor in the "G-TECH is dedicated hardware with an update rate of 50Hz!"
The GTECH Pro is only accurate if the cars weight is very accurate and from then on it is as good as a dyno. There have been tests where they dyno'd the car and then used the Gtech and found the numbers very close.
The older one like mine has shift lights that can sense when I have past the peak of my torque curve and tell me to shift for maximum acceleration. It also shows me if my timing change made a difference in power or not. What else can tell you right away whether you gained 2 hp or lost 2. I used this device to help with getting my carburetor setup better. I would do a 0-60 run and then modify/adjust and the retest within minutes. I used mine in my C3 at the race track and it really helped me make the car run more consistently.
I still have and use mine and I used it on my C4 a lot. It is a valuable tuning tool that works well, the only down side is it isn't cheap. The new ones are better than mine and have different features.
My Gtech Pro is still one of my most important tuning tools and will be until I break it.
Regards,
Chris
The processor in the "G-TECH is dedicated hardware with an update rate of 50Hz!"
The GTECH Pro is only accurate if the cars weight is very accurate and from then on it is as good as a dyno. There have been tests where they dyno'd the car and then used the Gtech and found the numbers very close.
The older one like mine has shift lights that can sense when I have past the peak of my torque curve and tell me to shift for maximum acceleration. It also shows me if my timing change made a difference in power or not. What else can tell you right away whether you gained 2 hp or lost 2. I used this device to help with getting my carburetor setup better. I would do a 0-60 run and then modify/adjust and the retest within minutes. I used mine in my C3 at the race track and it really helped me make the car run more consistently.
I still have and use mine and I used it on my C4 a lot. It is a valuable tuning tool that works well, the only down side is it isn't cheap. The new ones are better than mine and have different features.
My Gtech Pro is still one of my most important tuning tools and will be until I break it.
Regards,
Chris
06-30-2019, 03:53 AM
#12
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I used the Racechrono app with a Garmin Glo 10hz GPS. It saves the captured data in the same format as Racelogic and you can download Racelogics software for free to analyze your runs. It was real accurate but you will end at about the same cost as the Dragy. I think a 5-10 hz GPS is required to get accurate result, especially for faster cars with a steep acceleration curve
Last edited by bogor; 06-30-2019 at 03:58 AM.
06-30-2019, 05:23 AM
#13
that sounds really fast for an Auto C4.
I dont trust apps on a phone to be particularly good at anything - they're a small device that does an OK job at lots and lots of things, but does very, very few things very well.
I dont trust apps on a phone to be particularly good at anything - they're a small device that does an OK job at lots and lots of things, but does very, very few things very well.
07-01-2019, 10:30 AM
#14
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St. Jude Donor '05
shift light on a cel phone?
07-04-2019, 01:49 PM
#16
Safety Car
Hey JrRifleCoach!
The GTECHs have been updated and todays units are better than mine. Mine was one of their first models and it had shift lights and it saved the data for review afterwards. The new RR model uses a 50 Hertz GPS and tells you if you have improved in your lap times on a track. It would be helpful to anybody auto crossing. My older unit does not have a GPS as part of it.
I will probably get the RR model next as my daughter wants to try auto crossing. Take look at their website and see just how modern they are. You won't be disappointed at their technology as their accuracy is still incredible compared to any kind of cell phone software.
This is the Road racing model and it is sweet. Here is a link to their site for those interested. www.gtechpro.com
Good Luck
Chris
The GTECHs have been updated and todays units are better than mine. Mine was one of their first models and it had shift lights and it saved the data for review afterwards. The new RR model uses a 50 Hertz GPS and tells you if you have improved in your lap times on a track. It would be helpful to anybody auto crossing. My older unit does not have a GPS as part of it.
I will probably get the RR model next as my daughter wants to try auto crossing. Take look at their website and see just how modern they are. You won't be disappointed at their technology as their accuracy is still incredible compared to any kind of cell phone software.
This is the Road racing model and it is sweet. Here is a link to their site for those interested. www.gtechpro.com
Good Luck
Chris