Filed under: Analysis / Opinion, Hardware, Software, Tips and tricks, Odds and ends, iPhone, App Store
Two auto performance meters for iPhone
What? Gas is super expensive right now, and you want it even cheaper? Wish granted: our friends at Autoblog have also dug up an app called g-tac, which will track your times and even graph them out for you. Unfortunately, g-tac won't do the cool accelerometer stuff, measuring out your lateral gs and horsepower for you, but you know the old saying: you can have things fast, good, or cheap, and you only get to pick two.
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Reader Comments (Page 1 of 1)
Vince said 6:35PM on 7-30-2008
What's with posting right on the hour/half-hour today? Every post is either right on an hour or half-hour all day.
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Michael Rose said 9:19PM on 7-30-2008
That's what we usually do, Vince -- have you noticed a different schedule?
Vince said 11:54PM on 7-30-2008
No need for the snotty tone, I've just never realized that before.
Vince said 12:04AM on 7-31-2008
No need for the snotty tone, I just never realized that before.
Vince said 4:31PM on 8-01-2008
I get voted down for asking a question and then receiving a rude, arrogant answer, while the rude, arrogant one gets voted up? What a GREAT blog!
Jeff said 6:51PM on 7-30-2008
I've been contemplating getting a g-tech for a while (since they came out, really) but haven't gotten around to it.
This little app sounds very cool, if it's even REMOTELY accurate (+ or - maybe 25hp? that's be okay)
but i find it a little suspect.
what's too bad is that this app can't sense RPMs. :\
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caleb said 7:49PM on 7-30-2008
And how the heck can it determine HP without knowing RPMs?
Ryan said 6:58PM on 7-30-2008
Can someone please explain to me how they determine horsepower from this app? Is it acceleration over time or what?
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elvio said 7:29PM on 7-30-2008
horsepower is a non-metric unit of power (wikipedia says ~746 watts). the total power is total work done divided by the time interval (P_tot=W_tot/time). total work done is a force over a distance (W=F*distance=m*a*distance). the iphone's accelerometers give the instantaneous acceleration, you give the application your vehicle's mass, and the application knows how long it took you to drive a known distance (like a quarter-mile) by integrating the acceleration to get an instantaneous velocity and multiplying that by the clock.
Roberto said 7:32PM on 7-30-2008
RPMs can be derived from the vibration frequency, picked up by the microphone and accelerometer.
HP can be derived from the mass of the car times the measured acceleration, plus the coefficient of drag times speed.
Speed can be derived by integrating the acceleration over time.
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Andre said 9:49PM on 7-30-2008
I tried it. It's not that accurate, but it appears consistent. It's off by about 25HP on my car, and at least 0.5 to 0.75 seconds on 0-60. Didn't try the 1/4 mile.
Still, a great app.
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Jonas said 12:46AM on 7-31-2008
I would like to see something like this on the Installer :)
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Jim Danner said 6:42AM on 7-31-2008
We're working hard on a "community" application, CarTrack, that does these things and more. If you'd like to give some input or be a tester, visit http://hackint0sh.org/forum/showthread.php?t=16443
It will definitely not cost $13.
mare said 1:10AM on 7-31-2008
Does it come with cheap gas?
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Miguel A said 4:21AM on 7-31-2008
HI, i´m rx8 owner.. and i use in tracks my car...
i want an app that measure the time that you spend to ride from one point to other point, get it by GPS position.
this is good for a track day, to know how do spend to run one lap.
there is some forum of iphone app developers to make the suggest for someone do that app?
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Dan S. said 9:56AM on 7-31-2008
I hope everyone realizes that these Apps are toys -- there's little hope of accurate track mapping, timing and accurate power estimation (which, relies on you knowing exactly how much your car -- with you and a variable load of gasoline in it -- weighs).
Even the G-Tech's are woefully inaccurate for anything other than "entertainment."
If you want a real, accelerometer/GPS-based performance data logger, they start at around $1000.
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Bingo said 11:47AM on 7-31-2008
Anybody have Dynolicious and can say whether metric values can be set up i.e. km/h? I'm still waiting for a response from them on this question - there is no screenshot/documentation in iTunes/their web site of what can be changed in the set up screen.
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Rockstar said 5:12PM on 7-31-2008
I have a hard time thinking this even comes close to as accurate as the g-tech.
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Richard Williams said 5:05PM on 8-07-2008
It's actually more accurate than the G-tech.
http://www.garage419.com/episode/419_20080807
It was only off by 4.6 HP versus a mustang dynamometer. I'm just curious if those of you who claim that it is off by 25 hp have actually run your car on a legitimate dynamometer recently before trying the app.
While the program may be cheap, comparing it to the G-tech in terms of cost seems pretty ridiculous. The iphone 3G unsubsidized is speculated to be in the $600-$700 for the hardware alone.
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jess said 7:24PM on 8-14-2008
Hey, I’m from MyRide.com, and we’re now using Dynolicious as part of our car reviews (the first ones to do it!). Check out how the new Smart Car stacked up performance wise at http://www.myride.com/lifestyle/iphone_road_test_2008_smart_passion_cabriolet-4138-page1.html&id=31000
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