I did another coast down test, as I was given different formula which does not need so long road.
However I have not yet had luck to get formula to work correctly, problem is my inputs to excel, I'm pretty sure.
Basicly there one starts at some speed, coast down to certain speed and marks up time it took, then second test at slower speed.
I did put those speed tests to spreadsheet from instructables, modified spreadsheet so that it takes only two first rows into account and that way I got results of cd = 0.3697 and Crr = 0.0187
Was there thread about coast down test values from this tool? It would be nice to compare if that is completely out of window result.
If I get that other formula to work in excel I will share spreadsheet and instructions as it would be nice to know differences between methods with bit larger sample base.
It is Bosch formula, so it should be somewhat usable I believe.
edit:
Here is the spreadsheet, it is not working too well for me, but perhaps my road was not quite level, but test with your data and post if it does work, it really should work just fine.
http://jtbo.pp.fi/images/ZX/science/cd_crr_calc.xls
Idea is to test how long it takes to slow down to 80 to 70kph test 2 is for slow speed, no aero influence so 40-30kph is ok I guess, slower the better probably. I have posted earlier link to spreadsheet that contains really lot of car models with their frontal area and cd value listed, it is at aero section of board in topic that contains cd information of vehicles, so one can try to get frontal area from there.
edit2: I learned that there was error in formula, one plus sign needed to be minus sign and it works now even for me, updated spreadsheet to reflect correction.
So my cd is 0.36-0.38, can't get much more accurate without taking more measures of measuring frontal area and better estimation of weight.
CRR is 0.012, but I need to test even lower speed to really get air resistance out of equation, testing from 20kph or so should be most accurate.