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Location:
Adelaide
Registered:
May 2002
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Understanding 1/4 mile times
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Fri, 19 March 2004 07:59
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ok, have been taking my car to the track a few times now.
am trying to understand the timeslips.
i have run a few high 14's, with very different mph times, what does this mean ?! too much wheel spin ?!
14.704 @ 96.00
14.768 @ 92.80
14.715 @ 91.21
these were about a month ago, now just the other night...
14.550 @ 100.10
14.510 @ 100.18
14.694 @ 96.92
now I have heard that with the "perfect" run, a 100mph pass should be 13.9 1/4 mile times....
Brendon
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Location:
Brisbane
Registered:
October 2002
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Re: Understanding 1/4 mile times
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Fri, 19 March 2004 09:18
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hmmm the first ones were good launches with obviously less power, now it seems u have more power and less traction
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now I have heard that with the "perfect" run, a 100mph pass should be 13.9 1/4 mile times....
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perfect run?????????, a perfect run is defined by the times u get and reaction VS dial in
i.e.
u dial in at 14.00, u run a 14.000 at xxx.xxmph and u cut a .400 light, thats perfect
my brother in laws old S14 ran 13.49 at 99mph, my bosses old XW ran 13.55 at 123mph hmmmmmmmmmmmmmm,
the first set of times VS mph is fairly good, just practice the launch
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Location:
Gold Coast
Registered:
May 2002
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Re: Understanding 1/4 mile times
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Fri, 19 March 2004 10:40
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Umm unless you are bracket racing the reaction time does not effect your race agaist the other lane. It also has no bearing on your ET as well.
The ET is started as soon as you break the staging lights. Eg once the wheel passes the second beam.
Mr DOHC: As a rule of thumb if you get more wheel sping you get a higher MPH, a good 60ft time helps with ET ALOT!
If you are running 100mph yes you sould be able to crack a 13 on street tyres. Perhaps you need better tyres, a LSD or just finding the right launch rpm.
However it seems alittle strange you were running 100mph and now only low 90's, perhaps you have changed something? Perhaps it was a hotter night etc... all addes up.
Anyway, it give you something to aim for.
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Location:
sydney
Registered:
March 2003
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Re: Understanding 1/4 mile times
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Fri, 19 March 2004 12:29
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wastegate is right
when u finaaly do get good traction yr mph drops but yr time gets quicker
could also be what gear u cross the line in
my old car i used to get just b4 the finish line and have to decide whether to change into 5th gear of rev the ring out of the engine it never seemed to make much difference
i know most guys run around a 4.1 diff ratio
then about a 26 inch tall tyre
there is shitloads to much round with
but i think best thing is to be is where yr engine makes max hp as in revs and in 4th gear goin across the finish line
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Location:
Brisbane
Registered:
October 2002
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Re: Understanding 1/4 mile times
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Fri, 19 March 2004 13:03
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when u finaaly do get good traction yr mph drops but yr time gets quicker
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please explain how the mph drops, there is no reason for the mph to drop, the "gap" between them will decrese
i.e. 14.0 @ 95mph vs 13.7 @ 97mph
why would u go
14.0 @95 vs 13.7 @ 91mph
when u have a better launch u r able to get up to speed better.
oh btw, i know ALOT about drag racing
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Location:
Brisbane
Registered:
October 2002
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Re: Understanding 1/4 mile times
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Fri, 19 March 2004 13:10
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the reaction time does not affect your race agaist the other lane. It also has no bearing on your ET as well.
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u r right it doesnt, thats why auto boosted cars sit there and build up boost during qualifying/testing, they can and it wont do shit to their ET, but if they do that in a race they'll be shot.
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Mr DOHC: As a rule of thumb if you get more wheel sping you get a higher MPH
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once again, how does that work out, if u mean mph VS ET then yes, but wheelspin will not get u hi mph
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a good 60ft time helps with ET ALOT!
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how much would my 2.84 60ft kill me {fucking flatspot}
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Location:
sydney
Registered:
March 2003
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Location:
Brisbane
Registered:
May 2002
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Re: Understanding 1/4 mile times
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Sat, 20 March 2004 01:19
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| Mr DOHC wrote on Fri, 19 March 2004 23:10 |
how much would my 2.84 60ft kill me {fucking flatspot}
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That's a woeful 60ft time. I thought I was going pretty bad with a 2.7, but 2.84 is truly bad!
On street tyres you should be aiming for a low 2 second 60ft, you might even creep into the 1.9's if you're good. Something must be wrong - either you have major traction issues or your launch technique sucks. Probably both! 
Anyway remember if you can knock half a second off your 60ft time (which is more than doable) you'll be looking at a 13 second pass, or pretty close to it.
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