Dynolicious

[Super Shredder]

Dynolicious for iPhone:

with stock car i ran 13.8 at 100mph w/231hp
with intake, inlet, and motor mount i ran a 13.3 at 102mph w/247hp

anyone else have a dynolicious? its been proven to be accurate within 5hp give or take of a real dyno.

best 13 dollars i've ever forced someone to spend. if they come out with a newer iphone i will be on that quick. best application i've ever seen.

[LordWorm]

"proven to be accurate within 5hp" is dubious at best. If you get the weight wrong, you're results will be out. If it doesn't take into account aerodynamic drag, your results will be out. If it doesn't factor in gear ratios and RPM, results will be out (because it will use acceleration in G forces, converted to wheel torque, thrown against gear ratio and RPM to calculate power) etc etc etc...

more likely, it makes some rough assumptions - the power results its comes out with should be taken with a grain of salt

HOWEVER

it is probably a very good tool for determining if a mod has given you any gains. Its a pretty good App otherwise ;)

[Super Shredder]

"proven to be accurate within 5hp" is dubious at best. If you get the weight wrong, you're results will be out. If it doesn't take into account aerodynamic drag, your results will be out. If it doesn't factor in gear ratios and RPM, results will be out (because it will use acceleration in G forces, converted to wheel torque, thrown against gear ratio and RPM to calculate power) etc etc etc...

more likely, it makes some rough assumptions - the power results its comes out with should be taken with a grain of salt

HOWEVER

it is probably a very good tool for determining if a mod has given you any gains. Its a pretty good App otherwise ;)

garage 419 proved it to be accurate to a real dyno, and more accurate than an msd dashhawk type of computer that plugs into your car, forgot what it was called, you can check it out on youtube, stock i went to a 1/4th mile street event and put down a 13.8 at 101mph, the reason i was so impressed is because it was so accurate to what previous run i had done and with the mods it seemed even more accurate. i used 3800 as my weight.

[MShreve]

"proven to be accurate within 5hp" is dubious at best. If you get the weight wrong, you're results will be out. If it doesn't take into account aerodynamic drag, your results will be out. If it doesn't factor in gear ratios and RPM, results will be out (because it will use acceleration in G forces, converted to wheel torque, thrown against gear ratio and RPM to calculate power) etc etc etc...

more likely, it makes some rough assumptions - the power results its comes out with should be taken with a grain of salt

HOWEVER

it is probably a very good tool for determining if a mod has given you any gains. Its a pretty good App otherwise ;)

It doesn't care (or know) about anything except the G forces. It's an accelerometer. In order to calculate HP all it needs to know is the weight of the car (1 Hp = 746 Watts or 550 foot pounds per second). As long as you get the weight close the results shouldn't be off by much at all.

[Super Shredder]

btw lordworm, is that screen name Cryptopsy related?

[MShreve]

best 13 dollars i've ever forced someone to spend.

(lol)

I kinda want one too. Not for the phone, not for the browser, not for the network, but just because of all the cool apps that are out, and the fact that apple was smart enough to include things like an accelerometer. Awesome little gadget.

[amilliems6]

wait so this is an app on the iphone?

[Blendercloud]

I have the iPhone 3G, and if I could go back... I'd probably go after the Google Android instead. Since the software is open source, the development is a lot better for apps and whatnot. Plus you don't have to screw around with iTunes.

As for the app, $13 is a lot of money for an app. Most I've ever spent was $10 and that was for software (Orb Live) to be able to stream movies and music and access my home computer all from my phone.

[LordWorm]

btw lordworm, is that screen name Cryptopsy related?
Yes, yes it is.


garage 419 proved it to be accurate to a real dyno, and more accurate than an msd dashhawk type of computer that plugs into your car, forgot what it was called, you can check it out on youtube, stock i went to a 1/4th mile street event and put down a 13.8 at 101mph, the reason i was so impressed is because it was so accurate to what previous run i had done and with the mods it seemed even more accurate. i used 3800 as my weight.
They proved how many cars? how many different configurations etc?


It doesn't care (or know) about anything except the G forces. It's an accelerometer. In order to calculate HP all it needs to know is the weight of the car (1 Hp = 746 Watts or 550 foot pounds per second). As long as you get the weight close the results shouldn't be off by much at all.

Yes yes, i know how it works... all i'm saying that in order to ACCURATELY calculate what kind of power the car is making, at what RPM (and thus to be of any real use) it needs to take into account a multitude of other factors (more so than a traditional chassis dyno, which won't care about many, if any, of the parasitics at play). G force alone won't tell you enough either - so it'll be factoring some "best guesses" about the parasitics, and so forth (it'll best guess the coefficient of drag, friction, etc etc) - if you had 2 cars with identical power, identical weight, but one was say - a bread van, and the other was a sleek sports car, one would think the sports car will read higher "Power" as it will accelerate faster (especially at high speeds) - take it back to the dyno and (all things being equal) they would register the same power.

I'm not saying its an altogether useless application - just saying, its best to take these "accelerometer dynos" with a grain of salt - it may be more accurate than others, it just means that the assumptions it makes are better. Its a fantastic little application for proving whether a mod made you more power - and it'd give a fair approximation of HOW much more power it made, but to say its accurate "within 5%", and to put any stock into the results it gives you for bragging rights or what-not is a little silly....

my 2 cents.

[Captain KRM P5]

i have the program and in my own personal experience was not terribly impressed, tried it on a few cars

[MShreve]

Yes yes, i know how it works... all i'm saying that in order to ACCURATELY calculate what kind of power the car is making, at what RPM (and thus to be of any real use) it needs to take into account a multitude of other factors (more so than a traditional chassis dyno, which won't care about many, if any, of the parasitics at play). G force alone won't tell you enough either - so it'll be factoring some "best guesses" about the parasitics, and so forth (it'll best guess the coefficient of drag, friction, etc etc) - if you had 2 cars with identical power, identical weight, but one was say - a bread van, and the other was a sleek sports car, one would think the sports car will read higher "Power" as it will accelerate faster (especially at high speeds) - take it back to the dyno and (all things being equal) they would register the same power.

I'll give you some of that. It's definitely not going to give you as much info as a true dyno. But as for the peak HP number it doesn't have to factor in wind resistance, drive train losses, etc. All it has to know is that it took X amount of time to accelerate Y amount of weight to Z amount of speed. Since it's already setup to know Z (60mph) and the user inputs Y (~3600lbs) then all it has to do is calculate the time to figure out WHP. I agree that wind resistance is a factor, but it's a real world factor that can't be eliminated UNLESS you're on a dyno.

[LordWorm]

I'll give you some of that. It's definitely not going to give you as much info as a true dyno. But as for the peak HP number it doesn't have to factor in wind resistance, drive train losses, etc. All it has to know is that it took X amount of time to accelerate Y amount of weight to Z amount of speed. Since it's already setup to know Z (60mph) and the user inputs Y (~3600lbs) then all it has to do is calculate the time to figure out WHP. I agree that wind resistance is a factor, but it's a real world factor that can't be eliminated UNLESS you're on a dyno.

It will (most likely) be assuming a coefficient of drag (0.3 or whatever the "average" is for a car) - as well as assuming a coefficient of friction (no idea what a best guess on this would be). If it doesn't know RPM, it *cannot* tell you *where* you are making power (crucial for lots of people) - there are about a dozen other variables which could be taken into account (if it were possible, i know its not possible with the iphone) that would make it far more accurate.

My point is, they cannot claim a 5% to a real dyno, because it is going to differ WILDLY between cars - hell dyno figures vary wildly between dynos... so which dyno are they matching it to?

As for the peak power - it WILL need to factor in drag - it is using acceleration to derive power - the more drag your car has, the less power is available for acceleration (more power is used up overcoming the drag) - thus the acceleration will be lower. If you have 2 cars with the same power, same weight, wildly different coefficients of drag, the car with more drag will read a lower peak power on a "dyno" that is using acceleration to achieve its result.

So, what i'm saying is - nice app. Cool gadget. Very useful for telling you if something you've changed on your car has made an impact on performance (we don't all have access to dynos we can just use whenever we want!). But its not a dyno - and the hp figure it gives should not be accepted as anywhere *near* accurate. All it really does is backup the butt dyno - and any claims on power it makes should be treated with as much respect as a butt dyno claim ;)

[MShreve]

My point is, they cannot claim a 5% to a real dyno, because it is going to differ WILDLY between cars - hell dyno figures vary wildly between dynos... so which dyno are they matching it to?

Ok, that I totally agree with.

All I'm saying is that it is a good measure of actual work done (HP) which is going to be accurate enough for most. Plus it will do 0-60's and 1/4 mile...which you can't get accurate numbers for on a dyno because of the fact that it's a controlled environment (no wind resistance).

As you point out, different dynos can vary considerably. So in reality there is no measure of WHP that can ever be considered to be EXACTLY accurate. All you ever get is comparison numbers between different runs using the same device (dyno, iPhone, DH, etc). And $13 is pretty hard to beat.

[LordWorm]

. All you ever get is comparison numbers between different runs using the same device (dyno, iPhone, DH, etc). And $13 is pretty hard to beat.

and with that I completely agree.

The application might say 150hp, then you go and do a cold air intake, and it shows 160hp...you cannot expect either reading to be a true indication of what power you are making - but it is useful in PROVING that you increased the power....it will also give a fair indication of how much you've improve the horsepower by (in this case 6.25%) - and in that, its a fantastic tool to have.

And the price is very hard to go past - sure it doesn't do all the things that other more fancy "in car dynos" do, but some of those units run up in the hundreds of dollars - forgetting the cost of the phone, $13 for a tool that proves beyond any doubt that a mod has made you go up (or heaven forbid down) in power is great to have....

as for real world dynos - it depends on how they've been configured - and there are certainly some brands which are better than others - the issue comes in with the SAE corrections etc (correcting for altitude, humidity, temperature etc) - non-corrected values on a quality well configured dyno should be considered accurate - problem is that its difficult to compare a non-corrected value....the real power in a dyno is the ability to simulate load, and thus TUNE a car - the pretty graph it prints out at the end is really just icing on the cake....

[MShreve]

You obviously know a great deal more than I do about this...I'm by no means an expert. But coming from a mild physics background the math seems pretty simple.

There are variables that need to be considered to get an accurate reading of WHP, I'm not disputing that. But assuming that:
* whoever built the app didn't screw up their math
* the assumed drag is close
* the piezoelectric sensor isn't messed up (I'm assuming that's what they use)
* the iPhone is solidly mounted to the car
then working out how many WHP is required shouldn't wildly vary from that of a well calibrated dyno. Being within +\- 5% seems pretty reasonable to me (+\- 12.35 WHP in Super Shredder's case).

Great discussion BTW. I like your style.

[MShreve]

They obviously use way more complicated math then what I have above. In fact they could probably just use the drag, vehicle weight and peak G numbers between shifts and convert it into peak WHP without factoring any time at all.

[MikeLikesMazda]

off topic, but MShreve, i do believe our avatars are very similar lol

[MShreve]

off topic, but MShreve, i do believe our avatars are very similar lol

Ha, those are pretty close. I wish mine was a little better quality.

I have no idea why I'm defending the iPhone...I don't even own one. (silly)

I guess I'm just defending these accelerometer devices in general. I don't think they should be automatically dismissed.

In my free time I fly remote control helicopters, which use 1 to 3 axis peizoelectric gyros for flight assistance, and have seen first-hand how amazingly precise and accurate they can be.

[MikeLikesMazda]

i have an ipod touch and am considering getting the app. as long as it gives me a ballpark estimate as to whether my mods give me better numbers i'll be happy

[Super Shredder]

the TV show Supercars Exposed and expert champion drifter Tanner Faust use dynolicious to test the new cars they drive on the show. I beleive the newest test was on a new BMW M5

[MShreve]

I just did some research on this...since I'm in the process of setting up my DH.
Here's what I found:

Curb weight - 3589 lbs (full fluids, no occupants)
Drag coefficient - .31
Frontal area - 24.66 sq/ft

I calculated frontal area based off of an exterior width of 70.1" and an exterior height of 56.3" minus 10%. Hopefully that's close enough. Frontal area's not that crucial until you reach higher speeds (60mph+). If anybody has a more precise frontal area calculation let me know.