Directscan Time Slip?
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BobbyBuick
Well-Known Member
- Joined
- May 24, 2001
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for me its not i checked 10.38 pass was 13 seconds and i started the frame of 1 mph
Because Direct Scan doesn't use an acclerometer, it calculates those items along with HP and TQ, making them all horribly inacurate.
Direct Scan is great for monitoring the sensors that actually feed the ECM, but pretty much sucks at calculated items.
Direct Scan is great for monitoring the sensors that actually feed the ECM, but pretty much sucks at calculated items.
Its pretty accurate when you don't spin the tires and you have the correct tire size entered in. Look at the buffer in scope mode and check out the mph. You need to zero out the distance by typing in "0" when you are at the point where the car starts moving to zero out the distance (time and distance are displayed at the very bottom). Check out the time when the distance at the bottom reads 1320 feet and the time will be very close to actual ET. You may have to make small adjustments to the tire size to get it dead on. Other things such as 60', 1/8 time, etc will be very close too. Keep in mind that the mph that shows up at 1320 will be higher than what the timeslip shows since the mph on the timeslip is averaged over the last two timers on the track and is not the peak mph.
- Joined
- Aug 1, 2003
- Messages
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DS is very accurate if you set it up
with correct tire height , gear ratio entered into the preference menu and dont slip the tires
i can make a pass whether it be on track or on back road and even if no slip (happens at the track sometimes ) i can tell exactly what the 60' 330-1/8 -1000 and 1/4 times are and the 1/8 and 1/4 mph will be off by less than 2 mph (usually DS will show slightly higher)
i set my DS to record off tps (3.40)
for starters set tire height
26.1 for MT 255/50-16
28.2 for mt 275/60-15
slicks are nearly impossible to get true data since the grow over 100mph , but atleast you'll have data to base your next tunin move from
for hp t/q to be close it has to have a # thats close so set the vehicle weight as well, most tracks have a scale , i dont rely on those #s for anything but once set they will reflect if HP/tq is up or down, but so would your timeslip MPH.
after a pass and after youv'e saved the data go back to the data look at scope mode and move the pointer to where the car is has moved 1foot (rollout through stage beams) , now press 0 (zero)so the data will be from the true start point of the run .
fast forward to end of run and verify the distance is 1320 or so for the time on the slip , use your time slip and compare to the recorded data to fine tune tire height and (you cant change height on recorded data but you can set preferences and make another pass and see changes from that run data
once you have tire height correct and zero your runs your data will be within one or two frames (1/18-2/18sec) usually the 1ft method will be within .05 seconds if you want to get even closer to the true start of when you broke the beams , advance to 60' and compare to the time slip 60' then back up and rezero untill those two times match .
now when you make a pass and look at the data , reset the start point as mention , now exit and look at timeslip on DS
with correct tire height , gear ratio entered into the preference menu and dont slip the tires
i can make a pass whether it be on track or on back road and even if no slip (happens at the track sometimes ) i can tell exactly what the 60' 330-1/8 -1000 and 1/4 times are and the 1/8 and 1/4 mph will be off by less than 2 mph (usually DS will show slightly higher)
i set my DS to record off tps (3.40)
for starters set tire height
26.1 for MT 255/50-16
28.2 for mt 275/60-15
slicks are nearly impossible to get true data since the grow over 100mph , but atleast you'll have data to base your next tunin move from
for hp t/q to be close it has to have a # thats close so set the vehicle weight as well, most tracks have a scale , i dont rely on those #s for anything but once set they will reflect if HP/tq is up or down, but so would your timeslip MPH.
after a pass and after youv'e saved the data go back to the data look at scope mode and move the pointer to where the car is has moved 1foot (rollout through stage beams) , now press 0 (zero)so the data will be from the true start point of the run .
fast forward to end of run and verify the distance is 1320 or so for the time on the slip , use your time slip and compare to the recorded data to fine tune tire height and (you cant change height on recorded data but you can set preferences and make another pass and see changes from that run data
once you have tire height correct and zero your runs your data will be within one or two frames (1/18-2/18sec) usually the 1ft method will be within .05 seconds if you want to get even closer to the true start of when you broke the beams , advance to 60' and compare to the time slip 60' then back up and rezero untill those two times match .
now when you make a pass and look at the data , reset the start point as mention , now exit and look at timeslip on DS
With our Rally computer, which is an odometer accurate to + or - 3 or so feet per mile, we have been able to plot tire growth vs. mph and even for radial tires, its significant.
A 255/50ZR16, which you would think would not grow much is about 25.57" tall at 65 mph, 25.89" tall at 115 mph and 26.05" tall at 140 mph, vs. a published height of 26.1" tall (unmounted).
A 255/50ZR16, which you would think would not grow much is about 25.57" tall at 65 mph, 25.89" tall at 115 mph and 26.05" tall at 140 mph, vs. a published height of 26.1" tall (unmounted).
