not so good track times

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Old 06-05-2011, 11:47 AM
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Default not so good track times

so i headed to the track last night looking to see some improved track times with the new 78mm Fast intake and 3.90 gear(swapped the ls6 for the Fast and went from a 3.42 to the 3.90)
instead of quicker times i pulled slower times!
previously i was getting an average 1.75-9 60ft and this time around i could only pull high 1.8s(this isnt my normal track so maybe it wasnt prepped as well as the other?)

here's some times from one of my last passes with the ls6 intake and 3.42 gears:
60ft - 1.798
1/8 mile - 7.888
mph - 89.17
and another with a not so good 60ft:
60ft - 1.900
1/8 - 8.101
mph - 87.25

here is the best from last night:
60ft - 1.888
1/8 mile - 8.216
mph - 84.59

now i know there are a lot of variables such as different track, temperature, etc. but do you think i should be losing that much mph with switching to the 3.90s or are there too many variables to even compare these track times?
any informative input is greatly appreciated
Old 06-05-2011, 11:54 AM
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did you have it retuned?
Old 06-05-2011, 12:55 PM
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yea i drove to my closest tuner and we hooked up hp tuners and set everything accordingly
im not sure about the exact DA but the track i ran with the 3.90s is 145ft above sea level and the track i ran with the 3.42s is 242ft above sea level..both should have been around the same temp but not sure on the % humidity
Old 06-06-2011, 07:46 AM
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what do yall think of this:
Yank SS converters favor taller gears over what people normally think would be ideal gearing.I'm running a ss4000 in my camaro with 26 tall tires and 3.42's.Without a doubt going over the logs,g-tech,and gps they all show that taller gears would net me quicker/faster times.With the higher engine stall speeds and torque multiplication like that of the SS series.They pull so much harder at the bottom of every gear.The vehicle doesn't require shorter gears that are often used to keep engine rpm's up throughout the run.Now there's obviously gonna be a point of diminishing return using too tall of a gear but,IMO 3.42 or 3.23's are gonna work best for you.
Keep in mind you have also dramatically lowered the stall point by making it easier for the converter to move the truck.You now have higher 60' times cause,the truck moves out before the engine&converters inertia builds to a optimal point.Think of a converter as a energy storage for the rotating mass.The higher stall speed (or point when the turbines release fluid towards the strator)the more inertia is built up.Now this is given the engine is in its powerband at the stall point.Fluid is then released and effectively gets muitiplied by the strator. Giving the engine more mechanical leverage against the vehicle/drivetrain.
Old 06-08-2011, 05:36 PM
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Actually, yes, I see that being true, which is why they recommend a higher stall with a smaller gear. The fact of the matter is, you need to find the right stall for your gear. I'll soon be putting a 3600 I'm my Vette with 2.73 gears, not the best setup, but it will do until I can change the gear to a 3.42.
Old 06-08-2011, 09:58 PM
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well it looks like ill be calling Dave at Yank tomorrow to see what he thinks..my 3.42s are up for grabs if ya have a 7.5



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