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Old Feb 10, 2007 | 04:20 PM
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Default dead spots?

What are "dead spots" as far as rear end gearing goes? How does going to a higher gear ratio(numerically) or going bigger on the stall help with "dead spots?" This is a new concept for me, never heard of it.
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Old Feb 10, 2007 | 04:51 PM
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Dead spots at least to my understanding happen when the car shifts to the next gear and the rpms fall below optimim for engine torque range for a short time ,A higher numercle rear ratio keep the rpms up at a higher level lessening this effect and to a much greater level a converter can since it will keep the rpms from falling below a certain rpm threshold reguardless of gear ratio and allways hold the engine in its torque band
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Old Feb 10, 2007 | 04:59 PM
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I'm guessing by "dead spots" you mean speeds at which, when floored from a roll, the trans won't downshift to a low enough gear to jump rpms into the powerband?

The worst dead spot on the 3.23 cars is 30-45ish mph. You're going too fast to get a downshift to 1st, but slow enough that a downshift to 2nd feels weak as hell.

The worst dead spot on the 2.73 cars is 37-55ish mph Again, you're going too fast to get a downshift to 1st, but slow enough that a downshift to 2nd feels weak.

A gear change won't help as much with this as getting a higher stall TC will. The higher stall TC will "slip" the rpms up higher when going WOT than just a downshift alone at these "dead spots", putting you closer to (or into, depending on stall and vehicle speed) the powerband faster.
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Old Feb 10, 2007 | 05:50 PM
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Sounds like an awesome explanation fellas, thanks!
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Old Feb 10, 2007 | 06:25 PM
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Old Feb 10, 2007 | 09:59 PM
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With a high stall converter the car wil say in its powerband all the time regardless of the speed and gear. Changing rearend gears though will help a little with dead spots but mostly just it will move the dead spots around.
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Old Aug 27, 2007 | 07:12 PM
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Originally Posted by RPM WS6
I'm guessing by "dead spots" you mean speeds at which, when floored from a roll, the trans won't downshift to a low enough gear to jump rpms into the powerband?

The worst dead spot on the 3.23 cars is 30-45ish mph. You're going too fast to get a downshift to 1st, but slow enough that a downshift to 2nd feels weak as hell.

The worst dead spot on the 2.73 cars is 37-55ish mph Again, you're going too fast to get a downshift to 1st, but slow enough that a downshift to 2nd feels weak.

A gear change won't help as much with this as getting a higher stall TC will. The higher stall TC will "slip" the rpms up higher when going WOT than just a downshift alone at these "dead spots", putting you closer to (or into, depending on stall and vehicle speed) the powerband faster.
OK i have 2.73's, and it wont let me downshift anywhere past 28mph!? Why is tht, i always heard with 273s u can downshift atr higher speed such as 35 mph
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Old Aug 27, 2007 | 07:40 PM
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With 2.73's, the "sweet spots" are 30-35 and 70-75

I can catch first anywhere up to 35 from a roll... sounds like you need to adjust your tune.
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