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0-60 time
- Thread starter Nothgiel
- Start date
:driving:
thecookie125
Member
I clocked my 3.0si at 5.1 using a GPS app on the a15, that figure seems very low however so i'm not sure if I believe it.
I haven’t (don’t want to) try a full on drag start in the //M, though my old 3.0 was tested on a number of occasions in the company of other ‘road warriors’.
If you miss the boat by a few fractions of a seconds, hit the limiter, miss the sweet spot, find a tiny spot of gravel/water/oil, tyres not properly warmed up, on budgets... I think you get the point... it’ll be different every time.
I expect anyone performing these tests will first ‘lay some heated rubber’ on the tarmac before the proper run... plus have worked out if can remain in 2nd when they hit 60 & the optimum change point.
All in all... so many factors that change each time, almost impossible to replicate manufacturer times
If you miss the boat by a few fractions of a seconds, hit the limiter, miss the sweet spot, find a tiny spot of gravel/water/oil, tyres not properly warmed up, on budgets... I think you get the point... it’ll be different every time.
I expect anyone performing these tests will first ‘lay some heated rubber’ on the tarmac before the proper run... plus have worked out if can remain in 2nd when they hit 60 & the optimum change point.
All in all... so many factors that change each time, almost impossible to replicate manufacturer times
Nothgiel said:
Yes, though my old E85 had numerous exuberant launches. I bought around 40k & sold on 85k, so personally would say despite heavy use its transmission & engine was still as robust as the day I bought it. My buyer subsequently sold on here a few years later, where I know he utilised & enjoyed the loud pedal similar to me.
I really don’t think you have too much to worry about, unless you carelessly dump the clutch
As long as you're not running a 10hz gps this is not accurate. Normal gps chips have a 1sec refresh so this time can range between 4.1 and 6.1 sec.thecookie125 said:
Afaik bmw only releases an 'official' 0-62mph time (0-100kph) and that is 5,9sec for the prefl 3.0i and 5,7sec for the fl 3.0si (both manual gearbox)
Nick9one1 said:
No its not. In the first place the obd2 speed info is not accurate at all (the 1 or 2 mile speed difference are the 1 or 2 miles that take the longest to overcome!) and in the 2nd place the obd2 update speed is slow and not a constant.
In practice the only way to make a reasonable accurate speed measurement is by means of a 10hz gps and a performace app that can handle that (I think like harry's laptimer, and there also used to be a version of racechrono that could measure the gps updatespeed and therefore verify the margin of error).
Of a dedicated device like vbox, which also uses a 10hz gps (I think they now even have faster systems).
OBD2 and cellphone GPS stuff is way to slow with updatespeeds up to 1 sec (so 2sec(!) error margin). Some apps try to minimize that lag by using the accelerometer data for the start but that only solves half the problem and isnt a real solution to the problem
I've tested 10hz gps setups (I have a qstarz 10hz gps, they are very cheap) compared to things that use obd2 or cellphone gps and the differences are quite large and inconsistent (so one run the difference can be 0,3sec, the other run up to 1sec).
I used to have an old symbian telephone with an app where you could force the bluetoothconnection in a fixed serial rate so you could exclude any potential lag in that conversion too.
If torque displays 'real' speed it can only be on basis of the internal phone gps.Nick9one1 said:
As I've explained that is totally unsuitable for acceleration measurements because it releases its NMEA data with 1hz. Much too slow.
As far as obd2 speed is concerned, there is only 1 signal and that is very inaccurate. GPS speed is well within 0,1m/hr, a whole magnitude more accurate than the obd2 speed. And as I also explained, the obd2 signal is not a consistent signal, Its inconsistent, depending on how much data is sent over the canbus. ITs a serial bus typology, so update speed is dependant on how much is sent in communication between the 10 or so cpu's that talk over that bus. Unsuitable for accurate measurements, Sure you will get a value, but no accuracy within reasonable certaincy (yes 1 second or so but that's worth nothing in these times you want to measure, you need at least 4 or 5 times that accuracy to have a value that means anything).
Buy a 10hz gps, do some measurements and you will understand what I mean. If you get some measurements that are bang on while other measurements differ 0,5sec or more, that means the system is s###.
Thats why NO party that wants to do measurements that bare ANY credibility (like magazines etc) uses an obd2 based system and ALL use a 10hz GPS based system or faster (like vbox), or if they can afford it even more (professional) systems like radar.
BTW bluetooth is easily fast enough to send a 10hz NMEA datastream so if bluetooth is not fast enough for obd2, that means your connection or transfer is very very bad. To give you an example, KKL bus speed topology is about 100 times(!) as slow as bluetooth 1 (which is ~1mbit). Bluetooth 2.0 (since 2004) is ~3 times faster than that. So easily fast enough for the datatransfer. If that has any impact its because of bad hardware (fake interface chips?) or bad software.
CAN bus (the fastest of the 2 variants) is between 2 and 6 times as slow as bluetooth so that also doesnt have to be a problem when protocols are implemented correctly.
Which type of OTG OBD2 adapter are you using? ELM327 based?