victor25

I did some searching on Rennlist and found quite a bit on G-tech, but there is not much on apps.
Has anyone played with dyno apps on there Android or iPhones? I reacently purchased a Galaxy 3 cell phone and was wondering what the best android app is. I would like to find an app that uses both the GPS and accelerometer features of the phones. I found quite a few apps online like Dynolicious, adyno, dinodyno, Dynomaster, etc... Thought I'd see if anyone has played with them yet instead of my new phone being the ginnie pig.
I know there is no substitute for a good dyno run, but I cant go to the dyno every time I supercharger a car, or make updates and changes to my cars.
Also contemplated getting a G-tech, but why have another piece of electronics if my phone can do it. It would just be nice to have something on my cell that would give me a good quick baseline, then comparison runs. This way everything would always be at my finger tips

Thoughts - suggestions

KenRudd

I've used aDyno and Dynolicious, and had a difficult time getting any kind of consistancy on the readings, and certainly not enough to tell if any changes I mkae have any effect. In contrast, the aLap HD product ( from the aDyno team) is a fantastic track timing tool.

victor25

Hey Ken.. Yeah that looks pretty cool. Do you have a way to get your engine rpms into the readings?. I see it uses an OBD2 to read the rpms and other data. Have you figured out any way to pull this type of data from out cars. I wonder if John Speak or Jim Corneman could output that data from the sharktuner??? If so, then I could plot the 1/8 or 1/4 mile times, and or 0-60/100 with the g-force readings and rpm readings to make some usable data.

KenRudd

I don't have a way to get the RPM. As you said, app is looking for OBDII input, which obviously is not available. No doubt there is some way to get that data into the phone, but way beyond my skill set.

KenRudd

Sort of related:
http://electronics.stackexchange.com...or-motorcycles
http://ecuhacking.activeboard.com/t3...o-ecu-harness/
http://gridconnect.com/bluetooth-to-rs232.html
I'm assuming that motorcycles do not have OBDII ( Am I wrong?) so they face a similar challenge.

KenRudd

So, continuing that line of thought, both the Shark Tuner and Theo's tool might be able to send output though a bluetooth device like http://gridconnect.com/bluetooth-to-rs232.html formatted in a way that it "looks like" OBDII data to the App.

victor25

Thats exactly what I was thinking

KenRudd

With a later 928 with the round diagnostic port, you may be able to use a 19 Pin to 16 Pin OBD2 Car Diagnostic Adapter Connector Cable like this:
http://www.ebay.com/itm/251027209679...84.m1438.l2648

to tie directly to an off the shelf OBDII>Bluetooth adapter and maybe get a subset of the data you need. Or maybe not, but if you already have a the OBDII>Bluetooth, it would only cost $19.99 to find out.

IcemanG17

okay....the pure G force programs like Gtech and Dynolicous have their flaws....but when I noticed my street 928 seemed flat....I ran some tests again.....turned out dynolicious agreed with my butt-o-meter....the car was nearly 1 second slow 0-60.....

long story short my knock sensors and hall sensor (cam timing) were bad.....fixed it.....everything went back to normal!!!!!!

victor25

I will have to do some research on that to see what the output is. Has anyone ever tried one of those?
Here's another thought.... a tablet can run windows and so a sharktuner yes. It may also have an accelerometer and Gps, giving us everything in one pkg ??

jcorenman

Let me throw some comments in here, with the caveat that I am by no means an expert on the ODB stuff.

There are a bunch of goals here but they basically come down to a simple/cheap method for measuring engine performance. The "dyno" phone app's would be perfect, if they worked. My experience is the same, inconsistent results. The reason is that the g-sensor and GPS in a phone are pretty crude, by instrumentation standards. The GPS updates once a second, with time measured to the nearest second, and isn't differential (DGPS) as far as I know-- which means a measurement "jitter" of 30 feet or more.

The aLap manual has some comments about this, and they recommend an external bluetooth 10Hz differential GPS.

I haven't found a spec on the typical phone g-sensor (accelerometer), but there are anecdotes of 10% errors or more. In horsepower terms, that would be +/- 50 hp. It might be possible to calibrate an individual phone to reasonable accuracy, but sounds like a losing proposition. This, I think, is the basic limitation of the phone-dyno app's.

OBD-II is another can of worms. None of the 928's are OBD-II compliant, it didn't become a requirement until 1996 (coincidentally the year that Porsche stopped production for the 928 and I think some other models).

OBD-II is not a single interface, but rather a collection of different alternatives-- three or four different methods of connecting, over the years. I believe that, going forward, only the CAN bus interface is going to be supported, but the ODB-II framework does include the K & L bus used on the later 928's. That does not mean, however, that all connecting devices support it, it only means that they "may". The chance of any recent data-logger being compatible with the K/L bus is just about nil. And even then, that bus only provides diagnostic data, not real-time data.

RPM data (in the form of the tach pulse signal) is available on the 928's diagnostic connector, but (as far as I can determine) that is not part of the OBD-II spec, and not likely supported.

OK, that's a bunch of cold water on the parade, and I apologize. So what CAN be done?? Certainly, a special-purpose interface could be built as part of Sharktuner or independently, which would mimic an ODB-II/CAN bus connection that could be connected to a bluetooth interface to a phone. Or, skip the OBD-II connection and just go straight to bluetooth with simulated CAN bus data. That is certainly do-able, the problem is how to make it happen for a small market of folks that (how can I put this politely?) aren't renowned for being big spenders. And I don't mean that critically, anyone who owns these cars has lots of things competing for limited car-bucks.
If there was a market, and some way to fund the R&D (or even keep the lights on) then it could certainly be done.

But let's go back to the basic problems: Victor, even fancy instrument-grade electronics aren't going to get you the 1% measurement of engine performance (e.g. 5 hp) that tells you whether some tweak made things better or worse. That requires real physical measurement of engine torque, which is what a dyno does.

The next best thing might just be a stopwatch. Rolling start, 3000-6000 rpm or whatever range is of interest, same piece of road each time in the highest gear that you can get away with, without going to jail. It doesn't have to be flat, in fact uphill is much better. Or quarter-mile times, but the standing-start introduces more variables.

And let's keep kicking this around, maybe we'll come up with something.

Cheers, Jim

John Speake

When developing an EZ-F chip for the 84-86 Euro 16v cars I used a self contained accelerometer device from Race-Technology. It does give an reading of max power, but I didn't trust that and the surge when changing gear can fool it.

I measured 30-90mph acceleration times, which I thought could give consistancy. No standing start variances. The device measured times between the 10mph increments, these were then plotted on an Excel spreadsheet.

It's not the absolute power measurement you want, but certainly gives a good indication of changes to the car's power and torque.

AO

The problem with the iphene apps is its too easy to cheat or bump it and get false readings. There just is no substitute for a chassis dyno. That said, I do own a G-Tech Pro. Here's an old thread that was pretty fun...

https://rennlist.com/forums/928-foru...60-4-4sec.html

victor25

Hey Andrew.... yeah I looked over a few of the G-tech threads, including yours, before posting this one. I have a feeling that is prob the way I will end up going, but thought I would test the waters and get some opinions on the iPhone and Android stuff.

John... it sounds like you are using the other option of an accelerometer instead of gps locator. That would also do what I am looking for. Basically I just want to track simple before and after data to show the improvments. So John, is there some simple way we can use the sharktuner data in combination with other inputs like MPH, GPS distance traveled, or accelerometer g-force data to make some really cool output. I am sure that would make one hell of a virtual dyno!!

This is what has really sparked my interest. Granted our phones have both, but like Jim said the GPS does not refresh quickly enough for accurate distance output, but I do think the built in accelerometer would work. Or is there a unit that does accurately combine them? I really like that alap recorder HD that Ken is using. Have you guys checked that out? its pretty cool.

victor25

How about something like this hooked to one of the sharktuner inputs???? . http://adafruit.com/products/163?gcl...Fe5FMgodew8AAA It has a 3v +/- Gforce output. Basically all we have to do is give it power, run a output line to one of the sharktuner external inputs, then mount it in correctly in the car. We would then be able to plot the data in the sharktuner with everything else like RPMs, maf output and AF data