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So, went to Eastern Creek dragway last night...mixed result.

ran 10.96 @ 127mph

Had two runs....

First run the launch didnt feel clean so I got off it and braked at 3/4 track (to keep above 11.00)....ran 12.1 @ 69mph..(we get booted under 11.00 without a rollcage in Australia)

Second run launch felt good so I stayed on it....

Looking at the data in my Vbox I should have stayed on it in the first run..it was running strong at 7.0 @ 103mph half track and my 0-62mph was 3.0 sec ...second run was 3.2 sec

Looking at the video below you can see that the car actually bogged when shifting into second. Its hard to tell but 1st gear was all wheel spin (I had an aggressive 4000rpm launch map) I shifted at the rev limit but because of the wheel spin the vehicle speed was not there and she bogged...(the tacho goes as low as 3000rpm after the shift).

The bogging down probably cost me 2-3mph and a few tenths.

timeslip



 

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im going to have to do a few launches to get that down pat before a 10 sec kick out run
 

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car year? mods?
 

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Discussion Starter · #6 ·
What was your 1/4 mi time and trap speed according to vbox?
1/4 time was exactly the same as the track timing...didnt look at MPH...dont have the SD card with me right now to check it
I have found the V Box to be spot on with track timing at either the strip or circuit
 

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My mph on the vbox is 2.7 mph faster on avg in the past 20+ runs. I think the mph is slower at my track. Just wondering if others have same difference between vbox and drag mph.

1/4 time was exactly the same as the track timing...didnt look at MPH...dont have the SD card with me right now to check it
I have found the V Box to be spot on with track timing at either the strip or circuit
 

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My mph on the vbox is 2.7 mph faster on avg in the past 20+ runs. I think the mph is slower at my track. Just wondering if others have same difference between vbox and drag mph.
I literally have done dozens of runs with my vbox at the track. It is the difference in how the timing equipment calculates the average speed over the last 66' of the run. I have found that the track trap speed is about 1.3% lower (on average) than the vbox trap speed. I think the mph differential will be more dependent on how fast the car is...i.e.the higher the trap speed...the bigger the mph differential. That is why I would be curious to hear what % higher it is.

Just an FYI, Sacramento Raceway (never been there...just seen some data and some way off trap speeds) has been known to trap higher on the timeslip than on vboxes...probably because they have the timing lights too close and the system is calculating it based on the standard 66'. I asked someone who frequents Sacramento to go a constant speed (cruise control) over the last half of the track (verified on the GPS). If it came back any different (within reason) then that would be proof of the timing equipment being set up properly.

Tom
 

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My mph on the vbox is 2.7 mph faster on avg in the past 20+ runs. I think the mph is slower at my track. Just wondering if others have same difference between vbox and drag mph.
will check this at Santa Pod and report back ..... stay tuned
 
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