how does the horsepower calculation work

[Yves]

I purchases the QSTARZ gps 10hz for logging purposes.

I cannot seem to understand how it works. I'm getting positive and negative numbers and when I go the highest hp/tq value, it doesn't seem to coincide with a fast acceleration or so. (Maybe there is some delay since the peak in hp/tq comes about 4 sec late and at a lot less speed and map readings for instance)

How accurate is the reading ?

[LT401Vette]

It is normal for HP and TQ can go negative during deceleration.

The lag should be well under a second. Can you post a short data log?

[Yves]

I'm not sure, but I see the highest positive number in hp (in this case 504) in a place where I was basically at an idle and coming off a high rpm acceleration. I would normally expect this hp at the higher rpm/high kPa area. So it looks to me as if it has produced this hp at the peak in rpm/map just before. In that particular spot I see the hp basically flatline, which doesn't seem correct.

I have a testdrive before this one with even higher hp rating (close to 800 hp) and at similar rpm...

[LT401Vette]

The HP is based on the Speed, backing up and looking at the speed in that log, there does seem to be a lag happening. It isn't a constant lag though, it looks more like the speed stops keeping up at some points, then does a quick catch up causing a big power spike.

Is the GPS in a place it good enough visibility of the sky?

[Yves]

It's a C3 corvette. There is not much room below the windscreen. The gps was besides the laptop in the front seat.

Must add that it was connected to the laptop with the usb cable since it was charging.

[Yves]

Well this continues. For some reason, I seem to have an issue with TS not wanting to connect to the ecu at times when I have the gps connected with bluetooth.

[LT401Vette]

What sort of Laptop and OS are you using?

[LT401Vette]

I have a laptop here that I am reproducing the big lag to the GPS. It is not the GPS's fault as logging the same car with Shadow Dash and same QStarz 10Hz is working properly. It seems to be TS related on some laptops. I am looking at a fix.

What type of laptop are you using?

[Iuri GTS]

I have a lag about 10 secs using TS and no lag using shadow dash with the same QStarz.
I'm using a CarPC with Windows XP

[LT401Vette]

I have a lag about 10 secs using TS and no lag using shadow dash with the same QStarz.

Yep, when investigating this, I got about the same thing. All was good in SD, but from TunerStudio there was a lag.
It should be squared away now. I want to do some further testing and should have a patch beta out early next week.

[Iuri GTS]

OK. Thank you. If you need you can count on me. I tried to use the Qstarz through USB but I had the same lag.

[Yves]

I have a laptop here that I am reproducing the big lag to the GPS. It is not the GPS's fault as logging the same car with Shadow Dash and same QStarz 10Hz is working properly. It seems to be TS related on some laptops. I am looking at a fix.

What type of laptop are you using?

Sorry for late response, Dell precision 4500 with quad core laptop and windows 8 64 bit. Plenty memory, plenty speed.

I had an issue this morning with ts stalling. I sent the debug file (without Gps attached). Meantime I updated the java 64 bit version and it seems to do fine now. Haven't tried it with gps at the moment. Will do that tomorrow.

[LT401Vette]

I put out a beta that resolves this issue:
http://www.efianalytics.com/TunerStudio/beta/