iPhone Alternative to G-Tech...

[Nem]

I wish you could edit the plots to display more detail, perhaps this will come in an update.

Sounds like your iPhone sensors have gone out of sync or you have another car profile added or have trans losses added?

Hi. I've not added or changed anything in the setup at all.

I have it mounted on a ped3 mount fixed to my dashboard, so it's nice and secure.

I've just done a calibration on it so will try a couple of runs later and see if it's changed at all.

Nick

 

[Dangerous Dave]

LOL? Yes, because GPS is really quick and accurate.

Ah GPS based stuff, you tryed any of these actual 0-60 & 1/4 mile apps?

GPS based data would be less accurate compared to a accelemeter based system, this is due to the lag and Inacuracies in the gps signals.

If you know how much force you need to accelerate something then you can figure out its speed and hence distance traveled and time easy enough.

I always thought GPS was more accurate which is why all the mags etc use a GPS Race Logic system for timings.

The only GPS I have used was a friends system attached to a laptop and it gave a 0-60 run in 6.5 seconds exactly the same timings most mags got for my car.

I've used a G-Tech and it said 6.2 seconds which is impossible in my car without a remap or a hill.

 

[Firestar_3x]

I was refering to Bugs attempts at using a GPS based iPhone program the iPhone GPS sensor isn't very accurate, well not down to the 2cm the Vbox can do or so it states this is in optimal conditions.

The accuracy of the software in the OP is detailed in the video link and is very close to real timings on a closed loop 1/4 mile.

 

[Hawk Tuah]

GPS is accurate at calculating your speed over distance.

For measuring a 0-60 its practically useless.

 

[flat-6]

Right been out in the 5er as the sun is out and it isn't 0C for once.

The roads were all wet with a bit of salt on. Had to launch at 2500rpm otherwise crazy wheelspin ensued. I have it set at 1440kg (inc 100kg for me) which is probably about right but there is some assorted crap in the boot.

Best of three runs this:




This gave 0-60 is 8.3s and peak HP of 147hp. This seems fast given the low-grip conditions - the peak HP is also lower than I would have thought to haul 1.5t of BMW to 60 in just over 8 sec. Stock HP should be 184hp but the engine has 160k miles on it and obv is >20 years old.

Quite impressed with the software.

 

[Nem]

I've found out a lot more about this now having read some info and done some more testing.

You only need one gear to get the hp result, so if you are not worried about the 0-60 stuff there is an easier way to get ths hp.

Start off in 2nd and just go all the way to the redline and then slow down. With this method I can get pretty consistant results. Now I've added in my transmission loss I can see the first couple of runs I got at 274hp were just flukes and have been disregarded.

Nick

 

[wez130]

There's a free app i found on appstore too, not tested it yet though, it's called pocket dyno.

 

[Firestar_3x]

Cheers for the update lads, i'm going to have a run this weekend if i can find some non wet roads!