iPhone Dynolicious vs Dragstrip

[Caduceus]

You might have seen my post last week about Wednesday night drags at Willowbank. I wasn't planning on going again for a while but the wife is away tonight so I thought "what the hell". Same setup as last week. JB3 v1.1 with all else stock. Very slightly cooler (about 25-26 deg) and noticeably less humid.

Anyway, good news is I ran a PB. Second run of the night 13.065 @ 109.28 mph. Happy, yes, but I want that 12 badly now. I can see how this becomes addictive. 60' time was 2.125.

The reason for the post is I ran my iPhone "Dynolicious" application while on the strip. On the run above, the iPhone dyno gave an ET of 13.06 @ 116.2 mph. It got the ET exactly right to the 1/100th of a second. Amazing. The trap speed is out a bit. This may be partly because at the strip, the trap speed is calculated via sensors placed 66' before the finish and on the finish itself. This means cars are moving slightly quicker across the line than the time slip indicates but it certainly isn't enough to account for 7 mph. Still, for a simple application it's remarkably accurate.

The first run I iPhone dyno'd showed 13.50 @ 109.5 vs the time slip of 13.378 @ 108.85 mph. Not quite as close on the ET but almost perfect on the trap this time.

Here is a download of the performance graph from the PB run:



There are a couple of bugs in the program still. The Y axis is labelled MPH and HP but the data plotted is actually KPH and KW. I told the application to use metric - it just didn't adjust the graph legend. The power output at the wheels seems about right (peak 224) considering I was using the published weight of the car - actual weight might be a bit more meaning I have more power than it thinks. I've had the car dyno'd at 238kW at the wheels.

I'm fairly sure the blips on the yellow power curve in second and third gear represent wheelspin and DTC functioning, since it occurs just after the clutch is released.

Cheers guys!

[xbook]

That's cool thanks for sharing !!!

Lemme ask you, where did you place your iphone for this test? I can't seem to find a good spot to wedge mine to do these tests.

-J

[Caduceus]

Here's another one. I wasn't going to upload this one since it was my worst run of the night but when I took a close look at it, there is some excellent information to be seen about why it was a sub-optimal run.



The time slip showed 13.772 @ 106.23. iPhone showed 13.81 @ 112.4. ET near perfect again but trap overestimated. Oh well.....

Now for the learning points:

1. On this run I decided to use more rpm on launch and a more aggressive clutch release since my earlier runs had hooked up fairly well. Predictable results unfortunately - see the yellow curve for loss of traction and DTC correction. This is "one quick press" DTC mode which was how I got my best times the previous week. With DSC and DTC off there is too much wheelspin so for now, I'm sticking with one press DTC mode.

2. By the time I grabbed 2nd I knew this wasn't going to be a PB. However, I missed the change into 3rd by trying to be super quick on the shift. It's the first time I've ever missed a gearshift in this car. I thought I was immune to that problem but the big dip in the yellow power curve says otherwise - compare to the graph in the previous post.

So in conclusion, the iPhone Dynolicious application appears to be an accurate performance measurement tool and an even better analysis and learning tool for acceleration testing.

Cheers!

[Caduceus]

Originally Posted by xbook

That's cool thanks for sharing !!!

Lemme ask you, where did you place your iphone for this test? I can't seem to find a good spot to wedge mine to do these tests.

-J

Assuming you have an empty passenger seat, move the thigh support forward, stand the phone vertically in the gap near the front of the seat and then push the thigh support back to wedge the phone firmly in place.

It's very secure and won't damage the phone. You can still reach the "start test" button easily.

Hope this helps.

[larryn]

That's pretty cool.

I've been working with the dev on another similar app called gMeter. It's a windows mobile app, specifically designed for the HTC Touch Pro (ATT Fuze), Touch HD, and Touch Diamond.

http://www.extreme-apps.com/scrsht.php

It has a lot of the same functionality (plus or minus), uses the accelerometer and the GPS simultaneously, and does have Excel file output support (csv), as well as on screen lap displays with accel and decell points. Pretty cool.

I want to take it with me to the strip, like you did, to see just how accurate it is...

[FJP135i]

Pretty impressive. And great times. I've a recent owner and also added this application - cant wait to try it now. Also a question, you have 238kw at the wheels - what work have you done to the car to achieve this? Awesome times!

[xbook]

Originally Posted by Caduceus

Assuming you have an empty passenger seat, move the thigh support forward, stand the phone vertically in the gap near the front of the seat and then push the thigh support back to wedge the phone firmly in place.

It's very secure and won't damage the phone. You can still reach the "start test" button easily.

Hope this helps.

Caduceus, you are BRILLIANT!! thanks so much. This puzzle has had me scratching my noggin for 3 months. I was just about to buy a darn mount for the phone. Thanks for saving me the $$, now I can put it into buying a nice 12 pack of beer instead. Which is a much better use of my funds :headbang: I will drink the 1st beer in your honor, kind sir, knight of the iphone mounting...

-Jason

[Caduceus]

Originally Posted by FJP135i

Pretty impressive. And great times. I've a recent owner and also added this application - cant wait to try it now. Also a question, you have 238kw at the wheels - what work have you done to the car to achieve this? Awesome times!

JB3 v1.1 Plug n Play.

Mail order direct from BMS in the US. Delivery in less than a week. DIY installation in less than an hour. Otherwise a "bog standard" 135. What a great car........

[Addict...Nah Im A Junkie!]

Here's a little video comparing the dynolycious, g-tech pro, and a shop dyno. Pretty interesting.

http://www.garage419.com/episode/419_20080807

How did you have your iPhone mounted?? Did you tie it down (secure it) in some manner, b/c small shifts can corrupt your data.

[Breville]

Brilliant post mate. Now I'm going to have to borrow my wifes iPhone..

[Guran]

Excellent work Caduceus. Are you able to output the Dynolicious data, rather than just a graph? Might be worth putting your car on a weighbridge to get an accurate idea of RWkW. A visit to a local scrap dealer should do the trick.

[Guran]

BTW, you're right about the terminal speed. Drag strips only quote the average speed for the final 66 feet of the run. With Dynolicious etc, you should get a higher trap speed because it should give the actual speed at the end of the quarter mile.

This is an interesting read:
http://www.edmunds.com/insideline/do...ticleId=130988

[Caduceus]

Originally Posted by Guran

Excellent work Caduceus. Are you able to output the Dynolicious data, rather than just a graph? Might be worth putting your car on a weighbridge to get an accurate idea of RWkW. A visit to a local scrap dealer should do the trick.

Unfortunatley I don't believe you can export the data other than as a JPG image of the graph. It does however give you quite a few additional readings which I didn't discuss above:

0-10 kph, 0-20 kph etc in 10 kph intervals up to 0-160 kph. My best 0-100 was 5.06 and best 0-160 (close enough to the old ton) was 10.00 flat.

It also gives 60', 330', 1/8 mile, 1000' and 1/4 mile times and speeds.

It records maximum speed, maximum acceleration (in G) and peak horsepower.

And finally, there's a skidpan application which gives lateral cornering forces and a full 360 deg G force plot but I've not played with that at all.

Sorry, I'm starting to sound like an infomercial.........

[135i_TT]

Dynolicious is very nice... crazy how much technology is put into something so small now...

Some people have been wondering if the G1 is capable of using Dynolicious Software but they responded no, even though the G1 and a few other phones have the "Accelerometer" software the phones just arent powerful enough to run the dyno software...

just thot id throw that out there..