OBD Bluetooth Strangeness

"saabstory | fixes bikes, breaks cars" (saabstory) 12/28/2014 at 18:54 • Filed to: None

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My brother got me one of these for Christmas and when I tested it out the other day, it told me that my max horsepower was 365. That sounds amazing, but my '06 9-5 Aero was advertised as making between 256 and 275 horses. Does anyone have experience with these (and the Torque Pro app)? Is there some sort of calibration I have to do?

Übel > saabstory | fixes bikes, breaks cars 12/28/2014 at 18:59

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You probably have the wrong weight inputted. Even so, it's never going to be accurate beyond a really really rough guess.

That being said, those things are amazing for everything else. I had mine set up as a boost gauge/MPG gauge in my last car and totally loved it!

Hi there > saabstory | fixes bikes, breaks cars 12/28/2014 at 19:00

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I've had good luck with these, but I do not trust the HP calculator. I mainly use them to check/clear codes and to have a way more diverse and informative dash instrument cluster. Also, I do not use an adapter that looks like that, but instead an OBDLink MX.

Tohru > saabstory | fixes bikes, breaks cars 12/28/2014 at 19:01

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It doesn't actually know the output of your car - that's not something the computer in the car knows, so the unit can't read it. It does some math based on what you input and the accelerometer reading and gives its best guess.

If you want to know your actual HP output, go to a dyno.

Though, I've also heard you can get a rough guess at horsepower with the following math:

HP = weight/(1/4 mi. ET/5.825)^3

saabstory | fixes bikes, breaks cars > Hi there 12/28/2014 at 19:02

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Yeah, I was a little dubious of that feature because if it was truly accurate, dynamometers would be obsolete, right?

Hi there > saabstory | fixes bikes, breaks cars 12/28/2014 at 19:03

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Yup.

44444444444 > saabstory | fixes bikes, breaks cars 12/28/2014 at 19:04

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Torque says the R cars are making like 60psi of boost... I wish.

saabstory | fixes bikes, breaks cars > Übel 12/28/2014 at 19:05

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I have the most correct weight I could and everything inputted. I'm guessing it's just not very accurate for measuring power and torque, and if it were dyno places would be out of business. I've used it as an error code scanner once already and it's awesome for vacuum and stuff like that. Being a Saab, it's already got a boost gauge (and it even shows negative pressure, so I assume its previous owner messed around with the ECU a little bit).

saabstory | fixes bikes, breaks cars > 44444444444 12/28/2014 at 19:07

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Haha, it's been right for my car so far. A wish for that much boost is a deathwish.

saabstory | fixes bikes, breaks cars > Tohru 12/28/2014 at 19:08

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I thought as much. If you could accurately determine power and torque for $20 it'd be a Christmas miracle. And dyno places would be put out of business. Then again, maybe it's a conspiracy by big dyno.

44444444444 > saabstory | fixes bikes, breaks cars 12/28/2014 at 19:11

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Not to Volvo! the new 4 cylinder makes 50lbs!

http://jalopnik.com/volvos-450-hp-…

saabstory | fixes bikes, breaks cars > 44444444444 12/28/2014 at 19:37

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That's amazing! I have to imagine that's all three together, but that's still a lot of boost.

claramag, Mustaco Master > saabstory | fixes bikes, breaks cars 12/28/2014 at 20:57

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yeah no the Hp thing is pretty inaccurate. My old 6er does not make 1136 to the wheel

It's great for CFM, codes, and monitoring fuel. Also checking for pinging

DoYouEvenShift > saabstory | fixes bikes, breaks cars 12/28/2014 at 21:44

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I love those things, however I never used the HP feature. Torque Pro is amazing for reading/clearing codes and streaming live data.

AMGtech - now with more recalls! > 44444444444 12/29/2014 at 01:09

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Looks like an incredible achievement! But that article says the FUEL pumps push 50psi, not intake charge. I'm certainly not saying it isn't possible, but that is a ton of force to cram into a cylinder. The CLA45 peaks at 26.7psi and most cars are in the 10-20psi range. I would imagine this Volvo is probably in the range of 30-35psi intake charge.

44444444444 > AMGtech - now with more recalls! 12/29/2014 at 08:57

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Ah no, I figured it out... There was a typo earlier stating that the car was boosting to 50psi... It was corrected to the fuel pump is 50psi (dunno why that's important).

Yeah, I agree they're probably in the 30ish psi range

doodon2whls > saabstory | fixes bikes, breaks cars 12/29/2014 at 15:11

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The "HP Calculator" uses acceleration (delta V) and the vehicle mass to _estimate_ HP. Therefore, if you are climbing a grade at a constant speed, you are producing HP, but the app will likely say zero... Similar errors can happen while descending a grade in the opposite direction.

Like others have said - forget that that calculation exists b/c it is rubbish. The rest of the sensor data - especially the raw channel data - is very good, though...

saabstory | fixes bikes, breaks cars > doodon2whls 12/29/2014 at 15:12

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Ah, and since the acceleration comes from my phone, it's going to be really really unreliable.

doodon2whls > saabstory | fixes bikes, breaks cars 12/29/2014 at 15:17

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I think the app can use delta V from the vehicle speed OBD channel and calculate Acceleration in that way also... I can't recall if there is a toggle setting for that or not... Either way, it's just not an accurate calculation despite what the Torque Wiki says .

saabstory | fixes bikes, breaks cars > doodon2whls 12/29/2014 at 15:36

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Yeah, I never thought it would be. I think that it's calculating acceleration from my phone's accelerometer because I can shake the phone and pull 4 or 5 gs.

AMGtech - now with more recalls! > 44444444444 12/29/2014 at 17:37

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Ahh that makes sense. Don't know why they would advertise the fuel pressure. Most systems have been running 50-60psi for around 15 years now, not including the high pressure systems required for direct injection of course.