Cheap Performance Meter

[S2central.net]

Yeah but only during a run that has been started from standstill... Although there is that other datalogging mode that I haven't used - more for trackday datalogs but yes it could be used for A-B logs now that you mention it... My head hurts today !

[EspenW]

Yeah but only during a run that has been started from standstill... Although there is that other datalogging mode that I haven't used - more for trackday datalogs but yes it could be used for A-B logs now that you mention it... My head hurts today !

What is the problem of starting from a standstill? Just get going in 1st or 2nd, shift into third and run to redline (where speed limits allow..). Then sit down and analyze data from whatever time/speed bracket you wish.

[Rusty]

The data logging is awesome. Turn on the GPS and press go on the phone and then drive. do anyhting you want and then sort the data in post processing. Currently takes an age to sift the data but I'm sure I'll sort an analysis tool at some point. The S4 data was really encouraging, I'm looking forward to getting on with the S2 data I got today and also taking some new data on my test road as it's flat and I can do runs in both directions. 35 to 65 is best for the S2 as this takes into account the turbo lag in second so boost threshold is 3500rpm or <35mph. Top end is about 68 at the rev limiter so 65 is about 7krpm, plenty for the wee k24 to play with.

As for V, T and X stream, I'd be more than keen to have a god go with these when I've got this data logger sorted. Very kind of you mr. Paul to let me play with these home brews

As for converting to kph, no probs, it's all logged, I just use mph. It gives m/s, kph and mph.

I've looked at the S4 acceleration data and it's a billionty trillion times better than the data I got yesterday. Will give some power at the wheels calculations a good go and see where we get to...

Reason for the poor data yesterday was that I had between 5 and 7 satelites locked on and the unit was obstructed by the roof. Today the unit was seeing the sky through the windscreen and had 8 to 10 satelites locked on.

[Rusty]

Just done a power and torque curve from GPS data and RR measured losses (I know.. I know...) Anyway, with the acceleration data averaged over 1s to reduce noise it's pretty damned good. Power at the wheels of 255, max calculated fly of 310 at 6000, torque of 330 at 4000 ish and losses between 1.15 and 1.3. Really not far out and I've used my S2 losses data for it. Here ya go:-

[S2central.net]

What is the problem of starting from a standstill? Just get going in 1st or 2nd, shift into third and run to redline (where speed limits allow..). Then sit down and analyze data from whatever time/speed bracket you wish.

Its just logistics really... maybe in Norway its easier to find a nice deserted stretch of wide open two lane black top but where I am - thats a long drive off and I can't keep turning up to the same place in the road for performance tests before locals start calling the cops (or worse) - I know if some idiot was doing launches outside my house at 10pm every weekend I'd be pretty hacked off...

Just saying its nice to be able to use the GPS style machine for more generic / real-world comparative tests with in gear acceleration etc versus the GTech methods which require launches for most repeatability - and that its easier to get noticed that way.

[S2central.net]

@Andy - do you need some help creating a more powerful number crunching in Excel ? I'm happy to help if you wish - done a few whizzy things in Excel over the years...

[Rusty]

Yeah, that would be great. I'll keep playing for the mo and get a method that I think works. If you could then review that and make a some fancy code then that'd be great! I should learn VB for Excel really as I dabble in VBA for MS Access quite a bit at the mo.

[S2central.net]

Macros in Excel are pretty easy to build once you get your head round them - they are built on top of VB (I'm sure the fulltime IT folk will correct me if I'm wrong on that).

[Rusty]

Ah, macros I can do!

Will get the S2 data sorted by the weekend and see where I'm at with it. If I get the prepeatability of the S4 data then I'll be chuffed!

[Rusty]

Some 0-60 data I took yesterday. Need to do it on some flat road but this was the best I could do in current circumstances...

[Prophet_dlx]

really good times there. Are those for your car or the s4?

[Rusty]

Homefried S2 I like to practice. That was in damp conditions, tried it with the diff lock on and that was the faster time but was also down hill.

Need to do 4 runs, 2 in each direction on level ground. Also thinking of doing a run-down loss run for power from 2nd gear, saves calculating air resistance and losses as they're all covered but a run-down.

[S2central.net]

I gotta get you under 5s Andy - pretty darn good though... Whats your launch tactic - dumping hard from 4k - 5k - what ?

[A80Avant]

and i presume the dip in the graph is the spinning at the beggining??

[Prophet_dlx]

seems to be shifting from 1st to 2nd...IMHO