Hello,
Since our new crank pulleys should be coming soon ( :D ), I've been wondering about trying to quantify any performance increases. Hopefully without the use of expensive dedicated test equipment? I've heard that an iphone or ipod touch can be used as an accelerometer (with an app, I assume, and if you know the vehicle weight etc.). I also found this dedicated model, which seems to be a reasonable deal for those of us without fancy phones.

Has anyone used either of these options, or something similar? How would it compare to a real dyno or professional equipment? I know it wouldn't be AS accurate, but are we talking +/- 1% , 10%, or ??? IOW would they be close enough for a curious hobbyist, or not worth the time/money?

Thanks!
Andy

 

I have a G-tech meter wich is one of the more popular accelerometers on the market.

Is a great tool but is not really intended to measure power.


This tool is really accurate measuring acceleration, 1/4, 0-60, brake times



But when it comes to power is really hard to achive concistent numbers. You will find to you get different HP/TQ numbers on different launches with the same car on the same conditions...

That is my experience at least.


Another thing you need to concider is that the gains we will be seeing in our cars are very small so in order to measure them you need back to back dyno testing.

For example, the NST U-Drive pulley for the Yaris made extra 3 whp on Dynatek's Dyno.

The best Idea would be to get a baseline dyno and then do another one on the same dyno and similar weather conditions after all the mods.

 

That was my plan, just with one of these simple accelerometers. Maybe 3 trials before and 3 after the mod. I probably won't buy one of these, but if I can borrow a friend's ipod touch, I'll post here and let y'all know what I found (if anything).
Thanks,
Andy

 

I have Dynolicious on my iPod touch and I love it. I don't know how accurate it really is, because I haven't compared it to real equipment, but it's great. The most I've ever been able to get it up to was .93g's going around a corner (after tires/suspension) and .81g's around that same corner (stock tC).

Again, I don't know how accurate it is, but it showed improvement after mods, so I guess it's pretty good for before and after.

 

as for the iphone or itouch. you can use as gauges (air/fuel, boost ect)

 

I have Dynolicious as well and love it for what it is. It is simply a measure of gains and allows you to compare.
First off all my test were preformed at 5500 ASL (5% loss of power per every 1k feet above sea level) and are completely uncorrected (what actually is hitting the ground). I also have an auto trans.

Base Line- Average of 3 Runs- 69 HP
Changed Trans Fluid to RP Max ATF- 70 HP- (+1)
Fujita CAI- 75HP- (+5)

These numbers seem to coincide with claims made by the manufactures.

A ten dollar app from iTunes is a whole lot less than multiple Dyno runs. I don't know what everyone else thinks, but I can think of better things to spend my money on than Dyno runs. I have nothing to prove on the Dyno, just looking for a log an compare gains and my iPhone turned out to be a great tool.

 

I believe the pulley will show some power on graphs, but the main improvement is actually the responsiveness of the engine itself.