I guess this should go in performance....

I'd like to be able to afford a dyno but I can't so I've been looking at other alternatives... So far I've seen PocketDYNO, gTech Pro, and the PocketLOGGER.

I was wondering if anyone has had experience with any of these (or one I missed) and how they like it. I already have a palm pilot and I like the idea of using that rather than a laptop. I kindof like the g-force testing but I don't really need it. I'm mainly interested in seeing how any mods I make affect the performance.
-Chris

 

You forgot the free ButtDyno

Seriously, I'd recommend paying the $75 for a dyno run between mods; all the other items you listed are going to be vague at best.

 

via pocketlogger

--
Cheese

 

via pocketlogger

 

macncheese,

How did you do logging with Pocketlogger when you don't have a pulley?

 

I have a GTech/Pro Competition - a great little gadget. The power results it gives are pretty consisent as long as you do a few runs and average them. Being able to test over and over and over again is worth a lot. I have been checking the power of my car every morning on the way to work and found a steep curve between air temperature and power:
- 49 degrees: 145hp
- 51 degrees: 143hp
- 59 degrees: 139hp
- 61 degrees: 138hp
- 70 degrees: 133hp
- 75 degrees: 131hp
This is far steeper than I expected but seems to be reasonably consistent. I'd love to hear from others who have tested the effect of air temp to see if they get similar results - these seem to show 3x the effect of figures from JCW.

I also found a large difference between a just warmed engine and one that has done 15 miles. The hotter engine gets up to 10hp less.

With all these changes, I question the accuracy of telling anything from just a few dyno runs - how can you be confident you have warmed the engine exactly the same and use the same air temp. In fact, doing back to back runs on a dyno making a change in between almost insures you have different engine temps.

Based on lots of runs with the GTech, I can confidently say my Rogue intake added 7hp, the Magnaflow exhaust added another 10hp and the Borla, when I swapped exhausts, added 5hp on top of the Rogue.

I have managed to permanently mount the GTech to the base of one of the cup holders. You get the added beneift of getting lots of lights to flash when you pull a high-G corner that passes a threshhold you have set

 

>>macncheese,
>>
>>How did you do logging with Pocketlogger when you don't have a pulley?


I have a pulley!? But yeah, thats your "overdrive" pulley data that you sent me and my "stock" pulley data. Only the stock data in this graph was collected via pocketlogger...


--
Cheese

 

Hey FLKeith,

I have a GTech/Pro also.. do you recalibrate it every morning too?
I have found the re-calibration to be kind of tedious.

I mount mine using the suction cup attachment to the smooth part of the dash at the highest(flattest) point right over the glove box... how did you mount it to the cupholder??

You're right about averaging the runs. And running/accelerating on a flat road really makes a big difference in accuracy.

 

I think this thread has convinced me that my very first "performance mod" will be one of these data logging devices! It would be silly to start adding parts and never REALLY know what did what.

 

Logged with prototyped BiM-COM software:

 

>>Hey FLKeith,
>>
>>I have a GTech/Pro also.. do you recalibrate it every morning too?
>>I have found the re-calibration to be kind of tedious.
>>
>>I mount mine using the suction cup attachment to the smooth part of the dash at the highest(flattest) point right over the glove box... how did you mount it to the cupholder??
>>
>>You're right about averaging the runs. And running/accelerating on a flat road really makes a big difference in accuracy.

No - I recallibrated several times when I first got it but then left it alone.

I have mounted it in the cup holder by removing the screw at the bottom of the cup holder. I cut a piece of wood to fit in the bottom of the holder and held it in place with a longer screw. Then the permanent mounting bracket from the GTech was mouted on the wood. It is just the right size to conveniently have the unit at the top of the holder. It avoids the problems with the suction cup falling off and it always available.

 

Thanks for the info!

 

>>Logged with prototyped BiM-COM software:

Show off.

--
Cheese

 

This is what the GTech looks like when mounded in one of the cup holders:

 

Anyone with software that can log speed and rpm should give this a try:

http://www.ross-tech.com/Andys-Stuff/mini/dynoplot5.xls

In my GTI 1.8T, I got results within 2 whp of DynoJet runs.

 

I have a question about that Excel spreadsheet.

It says to do a full-throttle single-gear acceleration and then push in the clutch and let the car decelerate.

In his example, he had RPM=6800 and MPH=108 so which gear did he start out in?

If I take a guess at the tire diameter of 24 Inches, and the listed 2002 VW GTI gear ratios, I think it
might be 3rd gear.

Is that what I would do?

1) Start rolling in first gear.
2) Shift into 3Rd gear and stomp on it....

 

That's 108 km/h. I tended to do these runs in 2nd gear, but 3rd should work fine provided you like endangering your license.

It doesn't matter how you get rolling, just make sure you are in the gear you intend to use at low rpm.

 

And then what about those decel-times.

Do I just record the time from when I push in the clutch at the top-speed
to when each of the speeds in the acceleration column are reached?

 

Andy?

Do you know the answer to this?

 

http://forums.audiworld.com/vag/msgs/457.phtml