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Best RPM to shift for 1/4 mile times?

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Old 05-12-2010, 01:51 AM
  #11  
Diabolical!
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I shift at almost 6500 RPMs on 12 lbs. of boost. Yeah, I'm gonna blow it one day...
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Old 05-12-2010, 09:46 AM
  #12  
AmericanSpeed
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When I was just CAI+tune only, I had my rev limiter set to 6900 rpm, I'd shift around 6700 rpm (past the stripe at the top of 3rd gear).

With the blower setup I shift at 6500.
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Old 05-12-2010, 10:38 AM
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gman73
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I think I need to experiment with the shifting. Some people say unless you have cams, shifting at 6500 RPMS is too high as the power drops off to much. I am thinking 6200 to 6300 would be the sweet spot.
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Old 05-12-2010, 11:10 AM
  #14  
AmericanSpeed
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Power does drop, but you have to decide the lesser of the two evils: over revving and losing some power there but when you shift you are starting at a higher (better rpm), or shifting a little earlier and falling at a lower rpm in the next gear and losing power there.

Experiment, the proof is in the pudding.
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Old 05-12-2010, 01:30 PM
  #15  
Nuke
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The factory red line is 6250. Brenspeed set mine at 6800 but I dropped it down to 6500. I bounce off it from time to time if I'm not paying attention.

Experiment and see what's best for you. Max torque occurs somewhere around 5200-5400 RPM if I recall but it's SOOOOO hard to not let it keep winding up.
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Old 05-12-2010, 02:01 PM
  #16  
ski
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Crossing the finish line in 3rd gear, instead of 4th, should result in a lower e.t. as the car loses momentum whenever a shift is made. With 3.55 gears, stock tires, and a good launch one should be able to finish in 3rd by shifting in the mid-upper 6K rpm range, as discovered by American Speed(and others).
However, the rev limiter should be set at least 400 rpm higher than the shift rpm as the TB starts to close 300-400 rpm lower than the rev limit setting. Also, suggest setting the rev limit back down to a lower setting for daily driving.
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Old 05-12-2010, 02:11 PM
  #17  
avengence
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I was actually wondering the same thing. I usually end up burying the needle before shifting but didnt know if that helps at all. Guess it could.

I know this is off topic but someone was telling me that getting a better launch (lower 60') will yield a slower trap speed (MPH) but a lower ET. Is this true?

Thanks for all the info!
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Old 05-12-2010, 02:35 PM
  #18  
gman73
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Originally Posted by avengence View Post
I was actually wondering the same thing. I usually end up burying the needle before shifting but didnt know if that helps at all. Guess it could.

I know this is off topic but someone was telling me that getting a better launch (lower 60') will yield a slower trap speed (MPH) but a lower ET. Is this true?

Thanks for all the info!
That's true. At the 1/8 mile track with street tires my 60' times would be anywhere from 1.89 to 2.3. E.Ts would be 8.8 to 9.3 with a trap speed of 81-83. Now with drag radials my 60' is 1.81 to 2.0 my E.Ts 8.69 to 8.9 and my trap speed is 78 to 79 mph.
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Old 05-12-2010, 05:01 PM
  #19  
90stang5.0
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Sounds like 6300-6700 RPM is the best, but I will have to experiment a little. Thanks for the information.

AmericanSpeed - those times are impressive with stock tires.
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Old 05-12-2010, 07:22 PM
  #20  
baddog671
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I think I was shifting somewhere in the 5500rpm range, but then again, my 1/4 times weren't the best :/
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