dead spots?
02-10-2007, 04:20 PM
#1
TECH Enthusiast
Thread Starter
Join Date: May 2006
Location: Metairie, LA
Posts: 631
Likes: 0
Received 0 Likes
on
0 Posts
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.
02-10-2007, 04:51 PM
#2
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
__________________
02-10-2007, 04:59 PM
#3
LS1Tech Administrator
iTrader: (3)
Join Date: Nov 2001
Location: Schiller Park, IL Member: #317
Posts: 32,046
Likes: 0
Received 1,493 Likes
on
1,075 Posts
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.
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.
02-10-2007, 09:59 PM
#6
TECH Fanatic
iTrader: (9)
Join Date: Dec 2004
Location: Schaumburg, IL
Posts: 1,693
Likes: 0
Received 0 Likes
on
0 Posts
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.
08-27-2007, 07:12 PM
#7
On The Tree
Join Date: Feb 2007
Posts: 151
Likes: 0
Received 0 Likes
on
0 Posts
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.
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.
