I've just bought an AC-22 performance meter and I am trying to set it up as accurately as I can.
I need to calculate my car's CdA and rolling resistance. I've tried coastdown timings but these are difficult to time accurately giving dramatically variable results.
I would have thought that the CdA would be 'known' statistic but I can't find any info anywhere. I've found that the car's Cd is 0.31, but can find nothing for CdA. My car's a 9-3 Aero, which would be similar to a Viggen aerodynamically (I guess).
Any info (or educated guesses) would be most welcome
Straight out of the box which apparently should be accurate to about 2-3% I got the following results:-
'02 9-3 Aero (stock 205BHP, 280NM) 0-60mph 7.11s and a 1/4 mile 15.78 @ 93.?? mph. (I did a 7.00s on a slight decline, and 7.58s on the way back up). I also did some shabby 8 seconders, as well as aborting one or two runs due to excessive wheel-spin an uncontrollable torque-steer
By comparison, the same AC-22 in my mates Audi S3 (225BHP, 280NM, 4WD, 6 speed) gave a best time of 7.3?s on the slight decline, so I don't think my timings are over-optimistic). He was severely hampered by having to change into 3rd to get to 60mph. The S3 should be sub 7sec.
I need to calculate my car's CdA and rolling resistance. I've tried coastdown timings but these are difficult to time accurately giving dramatically variable results.
I would have thought that the CdA would be 'known' statistic but I can't find any info anywhere. I've found that the car's Cd is 0.31, but can find nothing for CdA. My car's a 9-3 Aero, which would be similar to a Viggen aerodynamically (I guess).
Any info (or educated guesses) would be most welcome
Straight out of the box which apparently should be accurate to about 2-3% I got the following results:-
'02 9-3 Aero (stock 205BHP, 280NM) 0-60mph 7.11s and a 1/4 mile 15.78 @ 93.?? mph. (I did a 7.00s on a slight decline, and 7.58s on the way back up). I also did some shabby 8 seconders, as well as aborting one or two runs due to excessive wheel-spin an uncontrollable torque-steer
By comparison, the same AC-22 in my mates Audi S3 (225BHP, 280NM, 4WD, 6 speed) gave a best time of 7.3?s on the slight decline, so I don't think my timings are over-optimistic). He was severely hampered by having to change into 3rd to get to 60mph. The S3 should be sub 7sec.